WO2025068174A1

WO2025068174A1 - Arrangement and method for probing a wafer

Info

Publication number: WO2025068174A1
Application number: PCT/EP2024/076772
Authority: WO
Inventors: Steve Mitchell; Armin CZECH; Fabian GERALD
Original assignee: Ams Osram AG
Current assignee: Ams Osram AG
Priority date: 2023-09-26
Filing date: 2024-09-24
Publication date: 2025-04-03
Anticipated expiration: 2026-03-26

Abstract

An arrangement is provided, comprising a wafer chuck and a light source. The wafer chuck comprises a plate with a mounting surface for mounting a wafer, the plate is arranged in the beam path of the light source and the plate is translucent. Further, a method for probing a wafer with an arrangement is provided.

Description

ARRANGEMENT AND METHOD FOR PROBING A WAFER

The present disclosure relates to an arrangement and to a method for probing a wafer.

It is an object to provide an arrangement for efficiently probing a wafer. A further object is to provide a method for efficiently probing a wafer with an arrangement.

According to at least one aspect of the arrangement, the arrangement comprises a wafer chuck. The wafer chuck can comprise or consist of a plate.

According to at least one aspect of the arrangement, the arrangement comprises a light source. The light source can be configured to emit electromagnetic radiation, e.g. light. A wavelength of the emitted electromagnetic radiation can be in the ultraviolet (UV) range, the visible range or the infrared (IR) range of the electromagnetic spectrum, for example. The light source can be any light source suitable to emit electromagnetic wavelength of a desired wavelength range. For example, the light source can be configured to emit the electromagnetic radiation homogeneously or at least approximately homogeneously. For example, the light source comprises a semiconductor device, e.g. a LED, a light guide, e.g. a light foil, or a halogen lamp.

The light source can be configured for multi-spectral illumination of a wafer attached to the wafer chuck. This can mean that the light source can emit light with multiple wavelengths at the same time or consecutively. According to at least one aspect of the arrangement , the wafer chuck comprises a plate . The plate can comprise a mounting surface for mounting a wafer .

The plate can comprise a main extension plane . For example , a thickness of the plate can correspond to an extension of the plane along a vertical direction . Here and in the following, a vertical direction is understood to mean a direction which is directed perpendicular to the main extension plane of the plate . A lateral direction is understood to mean a direction which is parallel to the main extension plane of the plate . The vertical direction and the lateral direction are orthogonal to each other . The extension of the plate in the vertical direction can be small in comparison with an extension of the plate in the lateral direction .

The plate can be mechanically bearing . This can mean, that the plate comprises a suf ficient thickness . The plate can comprise a three dimensional shape . For example , the plate can be cylindrical or cuboid . The thickness of the plate can depend on a material of the plate . For example , the thickness of the plate can be at least 1 mm, for example at least 2 mm, at least 5mm or at least 10 mm, for example . The thickness of the plate can be at most 200 mm, at most 100 mm, at most 20 mm or at most 10 mm, for example . A diameter of the plate can be within a range from 50 mm to 500 mm, inclusive , for example between 100 mm and 450 mm, between 150 mm and 350 mm or between 280 mm and 250 mm . Additionally or alternatively, the diameter of the plate can be at least 50 mm, at least 100 mm, at least 200 mm, at least 300 mm or at least 500 mm . For example , the mounting surface of the plate is configured to enable an attachment of a wafer, in particular of exactly one wafer . Alternatively, the mounting surface can be configured for the attachment of two or more wafers .

The plate or, in particular, the mounting surface of the plate can be roughened . For example , the plate comprises a grit number within a range from 120 grit to 600 grit . The roughening of the plate can facilitate the ease of removing the wafer or the wafer on the foil from the mounting surface . However, it is also possible that the mounting surface of the plate is smooth .

The plate can comprise a notch . For example , the notch is rectangular-shaped or square-shaped in top view . The notch can be arranged at an outer portion of the plate . For example , the notch is arranged completely around the plate . In this case , the notch can be confined by the plate on two sides . Alternatively, the plate can comprise a plurality of individual notches . In this case , a number of notches can correspond to a number of clamps . For example , each notch is then confined by the plate on four sides .

For instance , the plate can be transparent , at least in parts opaque acting as di f ferent levels of di f fusor, include structures or etching to manipulate a light ray direction and/or contain filters to block speci fic wavelengths .

According to at least one aspect of the arrangement , the plate is arranged in the beam path of the light source . For example , electromagnetic radiation emitted by the light source is emitted in a direction towards the plate or is directed towards the plate . According to at least one aspect of the arrangement , the plate is translucent . It is also possible , that the plate is transparent . In particular, the plate can be translucent or transparent for wavelengths of a large range of the electromagnetic spectrum . Alternatively, the plate can be translucent or transparent only for speci fic wavelengths . For example , the plate is translucent or transparent for electromagnetic radiation emitted by a light source . In particular, the plate can be translucent or transparent for electromagnetic radiation which is to impinge , for example during a wafer test , on the wafer or on the optoelectronic device comprised by the wafer . That the plate is translucent and/or transparent can mean that at least 50% , for example at least 70% , at least 80% , at least 90% , at least 95% or at least 99% of said electromagnetic radiation impinging on the plate are transmitted through the plate , for example .

The plate can comprise glass or consist of glass . Additionally or alternatively, the plate can comprise or consist of sapphire and/or quartz glass ( SiCy ) . However, it is possible , that the plate comprises any material comprising a suf ficiently high transmittance of electromagnetic radiation of the desired wavelength range . For example , the material of the plate can comprise a suf ficiently low thermal expansion, such that a si ze of the plate is at least approximately constant for di f ferent temperatures of the plate which are relevant during use of the plate . For example , the plate can comprise or consists of a ceramic material and/or a plastic . It is possible , that the plate can withstand a force from probe needles such that there is no or only a minimal deflection of the plate . For example , a deflection of the plate during contacting with the probe needles is at most 10 pm .

According to at least one aspect , the wafer chuck comprises a further plate . The further plate can comprise similar or the same features as the plate . However, for example , one of the plates can have a thickness smaller than the other plate . This can mean, that the thinner plate is not the mechanically bearing part of the wafer chuck .

The further plate can be arranged spaced apart from the plate . This can mean that , for example , a gap is formed between the plate and the further plate . A vertical extension of the gap can be defined by a distance between the plate and the further plate .

As the further plate may not be the mechanically bearing part of the wafer chuck, it is possible to form the further plate thinner . Thus , for example , the further plate can be the thinner plate . For example , the thickness of the further plate can be at most 10 mm, for example at most 5 mm or at most 1 mm . Due to the further plate being formed thinner than the plate , a si ze , in particular an extension of the wafer chuck along the vertical direction can be decreased, for example . Thus , for example , a compact wafer chuck can be obtained .

According to at least one aspect , the further plate is arranged on a side of the plate opposite the mounting surface . This can mean, that the mounting surface can be an outer surface of the wafer chuck . The further plate can be arranged spaced apart from the plate . An orientation of the further plate can be the same as an orientation of the plate . In other words , a main extension plane of the further plate can be parallel to the main extension plane of the plate .

According to at least one aspect , a gap is arranged between the plate and the further plate . The gap can comprise a height corresponding to the extension along the vertical direction, for example in a stacking direction along which the plate follows the further plate or vice versa . For example , the height of the gap can be at least 100 pm, for example at least 1 mm or for example at least 2mm, at least in places . It is possible , that the height of the gap is between 1 mm and 50 mm, for example between 2 mm and 7 mm . It is also possible that the height of the gap is at most 10 cm, for example at most 20 mm, at most 10 mm or at most 5 mm .

For example , the height of the gap can be chosen such that a suitable flow rate of a medium flowing through the gap can be obtained . The gap can extend over a complete area or at least approximately over the complete area of the plate between the plate and the further plate .

According to at least one aspect , the plate and the further plate are translucent . Thus , electromagnetic radiation, for example light , can ef ficiently be transmitted through the wafer chuck .

According to at least one aspect , the wafer chuck comprises a plate and a further plate , wherein the plate comprises a mounting surface for attaching a wafer, the further plate is arranged on a side of the plate opposite the mounting surface , a gap is arranged between the plate and the further plate , and the plate and the further plate are translucent . An idea of this aspect is to provide a wafer chuck that can be tempered. In other words, a temperature of the wafer chuck can be adjusted. This can, for example, enable measurements with an attached wafer at different temperatures. With the wafer chuck, it is possible to perform temperature-controlled wafer probe tests of optoelectronic devices, in particular of optoelectronic devices which can be contacted on a backside and illuminated from a front side of the wafer. For example, this applies for optoelectronic devices comprising a through- silicon via (TSV) . Using the wafer chuck, it is possible to test wafers upside down.

In general, upside down is understood to mean that an active side of the optoelectronic devices of the wafer is attached to a carrier, e.g. the wafer chuck. Usually, it is then possible to contact the optoelectronic devices from the side of the wafer facing away from the carrier, e.g. the wafer chuck .

A medium for tempering the wafer chuck can be arranged in the gap. For example, the medium is directly applied to the gap. The medium can be translucent or transparent. The medium can comprise a gas and/or a liquid. Thus, due to the gap, the wafer chuck can be easily tempered. In particular, the wafer chuck can be free of electric heaters, Peltier elements, ducts and pipes, e.g. metal pipes or glass pipes for carrying nitrogen, for example. In other words, the wafer chuck can be free of any deflecting or absorbing elements. Thus, a transmission of light through the wafer chuck can be improved. Further, a homogeneity or uniformity of the electromagnetic radiation passing through the wafer chuck can be improved. For example, the wafer attached to the wafer chuck can be homogeneously illuminated through the wafer chuck . For example , the electromagnetic radiation is homogeneous or at least approximately homogeneous over the complete area of the wafer or at least over a complete active region of the wafer .

According to at least one aspect , the plate comprises glass and/or sapphire . Additionally, the further plate can comprise glass and/or sapphire . For instance the plate and/or the further plate can comprise SiCy . Glass or sapphire can comprise a suitable transparency . Further, glass or sapphire can comprise a suf ficiently low thermal expansion . Additionally, a di f fusor, in particular an optical di f fusor, can ef ficiently be formed of glass and/or sapphire by roughening or coating, e . g . chemical coating . It is possible that the plate and the further plate are formed of di f ferent materials .

According to at least one aspect , the wafer chuck comprises an inlet and an outlet . The inlet and the outlet can be in direct contact with the gap . The gap can be sealed except for locations of the inlet and the outlet . This can mean that a medium can enter or be released from the gap only through the inlet and/or the outlet . The inlet and the outlet can be cutouts in a sealing which seals the gap between the plate and the further plate . The inlet can be configured to inj ect a medium into the gap . The outlet can be configured to release the medium from the gap .

A cross section of the inlet and/or the outlet can comprise a rectangular shape , a circular shape or the shape of a prism, for example . The inlet and/or the outlet can comprise a height along the vertical direction . The height of the inlet and/or of the outlet can correspond to the height of the gap, for example. Alternatively, a height of the inlet or of the outlet can be smaller than the height of the gap.

A width of the inlet or of the outlet can be smaller or equal to a half of a perimeter of the gap. This can mean that it is possible, that the gap is completely surrounded by the inlet and the outlet. For example, the inlet and the outlet form a flow channel surrounding the gap. Alternatively, the inlet and the outlet can be connected with a flow channel. In this case, the medium can be spread prior to flowing through the gap. A width of the flow channel in a direction parallel to a main extension direction of the plate can be between 1 mm and 5 mm, for example between 2 mm and 3 mm, inclusive. The gap can comprise the shape of a circle, in top view. In this case, the width of the inlet and/or the width of the outlet can correspond to a length of a circular sector of the gap. For example, a center point angle of the circular sector is at most 160°, for example at most 120°, at most 90°, at most 45°, at most 5° or at most 1°.

It is possible, that the inlet comprises a lamella or a plurality of lamellas configured to direct, laminarize and/or swirl the medium, in particular a stream of the medium flowing from the inlet to the outlet via the gap.

The inlet and/or the outlet can be coupled to an external component. The external component can comprise a chiller, a heater and/or an air drying system. For example, the external component can be configured to set and/or to adjust a flow rate of the medium.

The sealing can comprise a sealing ring, for example. The sealing ring can surround the plate along the lateral direction . It is possible , that the sealing ring completely surrounds the plate along the lateral direction . The sealing ring can be in contact with the plate , for example directly adj acent to the plate . Additionally or alternatively, the sealing ring can surround the further plate at least partially or completely in the lateral direction . The sealing ring can be in contact , for example in direct contact , with the further plate .

It is also possible , that the sealing or the sealing ring is arranged between the plate and the further plate . For example , the sealing or the sealing ring can be in direct contact with the plate and the further plate . The sealing or the sealing ring can be arranged at an outer portion of the wafer chuck . For example , the sealing is arranged along a circle arc of the wafer chuck . An extension of the gap can be defined by the sealing . In particular, the gap can be located between the plate and the further plate within the sealing ring . A lateral extension of the gap can be equal to or smaller than the lateral extension of the plate and/or the further plate .

For instance , the sealing or the sealing ring can be impermeable for the medium and/or the ambient medium . For example , the sealing ring can comprise or consist of glass , sapphire and/or plastics . However, the sealing or the sealing ring can be formed of any material suitable to seal the gap between the plate and the further plate .

Due to the sealing ring, the inlet and the outlet , the medium, for example a gas or a liquid, can be easily and precisely guided through the gap . According to at least one aspect, the inlet, the outlet and the gap are configured to be flowed through by a medium. The medium can be translucent. For example, the medium can be transparent. That the medium is translucent and/or transparent can mean that at least 50%, for example at least 70%, at least 80%, at least 90%, at least 95% or at least 99% of electromagnetic radiation impinging on the medium is transmitted through the medium. In particular, the medium can be translucent or transparent for electromagnetic radiation emitted by a light source. It is also possible, that the medium is only translucent or transparent for a selected wavelength range.

For example, the medium comprises a gas or a fluid. The medium can comprise or consist of air, in particular of dry air .

According to at least one aspect, the wafer chuck comprises a further inlet and a further outlet. The further inlet can be arranged spaced apart from the inlet. The further outlet can be arranged spaced apart from the outlet. The inlet and the further inlet can be arranged on a same side of the gap. The outlet and the further outlet can be arranged on the side of the gap opposing the inlet and the further inlet. For example, the inlet, the further inlet, the outlet and the further outlet are adjacent to different circular sectors.

According to at least one aspect, the wafer chuck comprises a first elongated part. The inlet can be arranged at the first elongated part. The first elongated part can be configured to spread the medium. This can also mean that the wafer chuck comprises an oval shape, in top view. A top view can be understood to mean a view from the vertical direction. That the wafer chuck comprises an oval shape means , for example , that the plate , the further plate and/or the gap comprise an oval shape , in top view .

That the wafer chuck comprises an oval shape can for instance mean that the lateral extension of the wafer chuck can deviate from an imaginary circular shape on at least one side . For example , the lateral extension of the wafer chuck can deviate from an imaginary circular shape on two opposing sides , referred to as the first elongated part and second elongated part of the wafer chuck . For example , the inlet can be arranged at the first elongated part . The outlet can then be arranged at the second elongated part of the wafer chuck . It is also possible , that the inlet and the further inlet or a plurality of inlets are arranged at the first elongated part of the wafer chuck . A plurality of outlets , e . g . the outlet and the further outlet , can be arranged at the second elongated part of the wafer chuck .

The first elongated part and the second elongated part or the wafer chuck can form or can comprise a flow channel for spreading the medium prior to flowing through the gap .

In case the gap comprises a structure , due to the first elongated part of the wafer chuck, the medium flowing into the gap via the inlet can spread inside the gap prior to flowing through the structure . Thus , the flow of the medium can be ef ficiently laminari zed, for example .

According to at least one aspect , the mounting surface comprises a groove . The groove can be ring-shaped, in top view . Then, a diameter of the ring can be smaller than a diameter of a wafer attached to the wafer chuck . A depth of the groove in the vertical direction can be at least 10 pm, for example at least 500 pm or for example at least 1 mm .

Via the ring-shaped groove , the wafer can ef ficiently be attached to the wafer chuck .

According to at least one aspect , a structure is arranged in the gap . The structure can comprise a separation wall . The structure can be arranged in an outer portion of the gap . The structure can be configured to direct a medium through the gap . For example , the structure can be arranged along an imaginary circle .

In general , the structure can comprise any means for shaping, e . g . directing, laminari zing and/or swirling the flow of the medium through the gap .

For example , the structure can comprise at least one separation wall , for example at least two separation walls or a plurality of separation walls .

It is possible , that the separation wall or more than one separation wall are assigned to one inlet .

The separation wall/ s can be arranged in an outer portion of the gap . The outer portion of the gap can refer to a portion of the gap which does not overlap with the wafer, in particular with an active region of the wafer, in the arrangement comprising the wafer chuck, for example .

For example , the separation wall can comprise or can be a lamella . The separation wall can extend completely through the gap along the vertical direction. Alternatively, the separation wall can only partially extend through the gap along the vertical direction. In other words, the separation wall can be in direct contact with the plate and/or the further plate. The separation wall can comprise a main extension plane. The main extension plane of the separation wall can be perpendicular to the main extension plane of the plate .

For example, the structure can comprise a comb structure comprising a plurality of separation walls. The main extension planes of the separation walls can be parallel to each other. For example, the separation walls can be arranged equally or at least approximately equally spaced, e.g. along a direction perpendicular to the main extension planes of the separation walls.

As the structure is arranged in the outer portion of the gap it does not have detrimental disruptive light reflections or shadowing effects on the transmissive electromagnetic radiation. It is possible to efficiently generate a laminar air flow using a separation wall connecting the plate and the further plate, for example.

According to at least one aspect, the further plate comprises a diffusor. For example, the diffusor is an optical diffusor, which is configured to diffuse electromagnetic radiation, e.g. light, impinging on the diffusor or being transmitted through the diffusor. That the further plate comprises a diffusor can also mean, that the further plate is roughened and/or coated. The further plate can be roughened by sandblasting or etching, for example. Additionally or alternatively, the further plate can comprise the di f fusor by being coated with a material , for example .

The wafer chuck can be configured to scatter light impinging on the wafer chuck on a side of the wafer chuck facing away from the mounting surface . With the di f fusor, light can at least approximately homogeneously impinge on a wafer applied to the mounting surface of the wafer chuck . As the wafer chuck can already comprise the di f fusor, it might not be necessary to apply di f fusors to a light source or the arrangement comprising the wafer chuck .

According to at least one aspect , the further plate comprises an optical filter . The optical filter can be an optical filter plate . For instance , the optical filter can be or can comprise an infrared filter, a color filter, a polari zation filter and/or a gradient filter . For example , the optical filter is configured to correct or improve a homogeneity of the light source .

According to at least one aspect of the arrangement , the arrangement comprises a wafer chuck and a light source , wherein the wafer chuck comprises a plate with a mounting surface for mounting a wafer, the plate is arranged in the beam path of the light source , and the plate is translucent .

The wafer chuck can be the wafer chuck described herein . This means all features disclosed for the wafer chuck are also disclosed for the arrangement and vice-versa .

The arrangement can be or can comprise a wafer handling prober . With the arrangement , it is possible to illuminate electronic, electrical and/or optoelectronic devices on a wafer, in particular on an optical side of the wafer, with photodiodes arranged on one side of the plate , while the wafer comprising the electronic, electrical and/or optoelectronic devices is arranged on the other side of the plate . Due to the translucent plate it is possible to provide an optical stimulus to the devices of the wafer from the topside of the wafer chuck . This is , for example , not possible for a wafer handling prober with a plate comprising or consisting of a metal .

A surrounding of the arrangement , e . g . a light chuck, can be light blocking and/or a light barrier . This can mean that the surrounding of the light chuck is not a light guide and/or not transparent . The light source can be an internal light source , e . g . internal to the arrangement or the wafer handling prober . In particular, the light source can be internal to the surrounding of the light chuck . This can ensure that no external light is transmitted to the device under test . Additionally or alternatively, this can prevent external wavelengths from polluting the light source . For example , it is also possible , to achieve a darker environment for dark measurements . For instance , also spectral contamination to the devices under test can be avoided .

For example , the wafer comprises a single silicon wafer or two or more wafers bonded to each other, for example to combine di f ferent technologies in one integrated circuit or die or device . The wafer could be partially or completely sawn for a singulated die . Alternatively, the wafer can be unsawn for a solid wafer probe . Bonding di f ferent wafers to each other such as photodiodes and electronic circuits allows for an increased functional density and photodiode sensor density . The optoelectronic device , electronic device or electrical device to be probed during wafer probing can be referred to as device under test ( short : DUT ) . A logic, a control , an interface and/or an electrical contact can be arranged on the opposing side of the integrated circuit . It is also possible , that the wafer consists of multiple silicon wafers and/or integrated circuits .

The arrangement can be configured or adapted to replace a mechanical metal wafer handling prober or a part of a mechanical metal wafer handling prober . Advantageously, the arrangement can comprise an outer shape , for example of a housing, with a mechanically equivalent height . In this way, the arrangement can be combined with common prober chuck bases . Advantageously, the arrangement can be combined with existing prober equipment .

According to at least one aspect of the arrangement , the plate comprises glass or sapphire . It is also possible , that the plate consists of glass or sapphire . Glass or sapphire can comprise a suitable transparency .

According to at least one aspect , the arrangement further comprises a base plate . The arrangement can also comprise a support structure . The light source can be arranged on the base plate . The support structure can be arranged laterally to the light source . The plate can be arranged on the support structure .

The base plate can be configured or adapted to be attachable to a prober chuck base , for example to a common prober chuck base . For example , during wafer probing, the base plate can be attached to the prober chuck base . In particular, a side of the base plate facing away from the plate can be attached on the prober chuck base . The base plate can comprise a "U- shape" in sectional view . For example , a vertical extension of edge portions of the base plate can be larger than a vertical extension of the base plate in the region of the light source . In other words , the base plate can at least partially laterally surround the light source .

The support structure is arranged on the base plate , for example . In particular, the support structure can be arranged on the edge portions of the base plate .

The support structure can comprise a shaft configured as a guiding shaft , in particular a linear shaft . The shaft can protrude from the support structure , for instance from the plate support pillar of the support structure . For example , the base plate comprises a suitably si zed hole for receiving a part of the linear shaft . In other words , the shaft of the support structure can be guided into a hole in the base plate . The shaft can also be configured for guidance of a planarising screw of the support structure . The shaft can extend transversely or perpendicular or at least approximately perpendicular to a main extension plane of the base plate or to the main extension plane of the plate .

The support structure can comprise a planarising screw and a plate support pillar . Additionally, the support structure can comprise a spring washer . The spring washer can surround the planarising screw, for example . This can mean that the planarising screw can be guided through the spring washer .

The spring washer can be configured or adapted to simpli fy an adj ustment of a vertical position of the plate support pillar . Additionally or alternatively, the spring washer can be configured or adapted to maintain the vertical position of the plate support pillar. For example, while the plate support pillar is fastened using the planarising screw, the spring washer can prevent a sliding or gliding of the plate support pillar towards the base plate along the vertical direction .

The planarising screw can be partially inserted into the shaft of the base plate. For example, the planarising screw is configured to adjust a vertical position of the plate support pillar. The plate can be arranged on the plate support pillar. For example, the planarising screw can be configured or adapted to align the plate, e.g. by tilting. The support structure can comprise multiple planarising screws. For example, the planarising screws are arranged equally spaced apart from adjacent planarising screws. Prior to wafer probing, e.g. prior to attaching a wafer on the mounting surface of the plate, the plate can be aligned using the planarising screws.

For example, the base plate and the support structure can form or can be part of a housing or of a container for the light source, an optical stack and/or the plate. For instance, the housing or the container can be referred to as the surrounding of the arrangement. This can mean that the base plate and/or the support structure are not transparent but light blocking and/or form a light barrier.

According to at least one aspect, the arrangement further comprises a plate clamp. The plate clamp can be configured to attach the plate to the support structure. The arrangement can comprise a plate clamp screw. The plate clamp and the plate clamp screw can be configured or adapted to attach the plate to the plate support pillar . For instance , prior to wafer probing or during wafer probing, the plate can be attached to the plate support pillar using the plate clamp and the plate clamp screw .

The plate clamp can be configured to extend into the notch of the plate . The plate clamp screw can be screwed to attach the plate on the plate support pillar .

For example , the arrangement comprises six plate clamps or at least six clamps .

According to at least one aspect , the mounting surface comprises a groove . The groove can be connected with a suction hose . For example , the groove can be ring-shaped or at least approximately ring-shaped, in top view . Then, a diameter of the ring can be smaller than a diameter of a wafer attached to the wafer chuck . A depth of the groove in the vertical direction can be at least 10 pm, for example at least 500 pm or for example at least 1 mm . It is also possible , that the mounting surface comprises more than one groove , in particular more than one ring-shaped or at least approximately ring-shaped groove .

According to at least one aspect of the arrangement , the arrangement comprises a sensor . The sensor can be configured or adapted to monitor a light level of the light source . This means , during wafer probing, the sensor can monitor the light level . In this way, the sensor can be a monitoring sensor . The sensor can be arranged at an edge portion of the plate on the side of the plate facing the light source . For example , the sensor is arranged on the plate support pillar . The sensor can be arranged between the plate support pillar and the plate .

Advantageously, with the sensor the light level can be monitored during operation of the arrangement , e . g . during wafer probing . Thus , a failure or defect of the arrangement , for example of the light source , can be detected . The sensor can also be configured to monitor the light level during calibration of the arrangement .

According to at least one aspect of the arrangement , the arrangement comprises an optical stack . The optical stack can be arranged between the light source and the plate . The optical stack can be arranged spaced apart from the light source . This can lead to a gap, e . g . an air gap, being formed between the optical stack and the light source along the vertical direction . The gap can improve the light distribution . For example , the electromagnetic radiation emitted by the light source can spread throughout the gap . Thus , the emitted electromagnetic radiation can be more homogeneous when impinging on the optical stack .

The optical stack can be configured for influencing the electromagnetic radiation emitted by the light source . In particular, during operation, the optical stack can influence the electromagnetic radiation, after being coupled out of the light source . Hereby, influencing can mean that the optical stack is configured to form, di f fract , deflect or filter electromagnetic radiation impinging on the optical stack or passing through the optical stack . For instance , during operation, the optical stack forms, diffracts, deflects or filters electromagnetic radiation, e.g. light, impinging on the optical stack or passing through the optical stack.

The optical stack can comprise at least one layer. For example, each layer can have a different optical functionality. Alternatively, it is also possible the at least two layers have the same optical functionality. The optical stack can comprise or consist of at least one of the following: a diffusor, a lens, a lens plate, a prism sheet or other optics and/or optical components. For example, the at least one layer of the optical stack is a diffusor, a lens, a lens plate, a prism sheet or any other optical component configured to influence electromagnetic radiation.

For example, the optical stack is or comprises a polymer white lambertian diffusor. The polymer white lambertian diffusor can comprise a thickness of 0.1 mm. For example, a transmissivity of the diffusor, e.g. the polymer white lambertian diffusor, is, for instance for the electromagnetic radiation emitted by the light source, for example, at least 40%, for example at least 50%, for example exactly 50%, at least 70% or at least 90%.

Additionally or alternatively, the optical stack can be or can comprise a ground glass diffusor and/or a broadband hybrid diffusor. The diffusor can comprise a roughness. The roughness can be determined in terms of a grit number. For example, the grit number of the diffusor is 120 grit.

However, the grit number of the diffusor is not limited to 120 grit. Instead, the roughness of the diffusor can be any roughness suitable for influencing, in particular for diffusing, electromagnetic radiation. For example, the diffusor can be or can comprise a glass diffusor sheet, a film diffusor sheet, a paper diffusor sheet and/or any other diffusor.

The layer or the layers of the optical stack can be contained within a rigid stacking system. The rigid stacking system can comprise a height. The height of the rigid stacking system can be the extension of the optical stack along the vertical direction, e.g. along the stacking direction. In particular, the height of the rigid stacking system can be variable. The rigid stacking system can extend along the vertical direction up to the plate.

With the optical stack, the electromagnetic radiation emitted by the light source can be shaped, for example uniformly distributed, prior to impinging on the plate or on the wafer. In this way, the wafer can be homogeneously or uniformly or at least approximately homogenously or uniformly irradiated.

According to at least one aspect of the arrangement, a sealing layer completely surrounds the light source, the optical stack and/or the plate along a lateral direction.

An advantage of this aspect is that due to the sealing layer, no external light can enter the arrangement, for example. Thus, the electromagnetic radiation impinging on the wafer or on the device under test originates from the light source.

According to at least one aspect of the arrangement, the light source comprises a light guide plate. The light guide plate can comprise a transparent panel, for example a clear plastic panel. A thickness, e.g. an extension of the light guide plate in a direction perpendicular to the main extension plane of the light guide plate can be within a range of 500 pm to 10 mm, for example between 2 mm and 5 mm, inclusive .

For example , the light guide plate has a cylindrical shape . The shape of the light guide plate can be defined by a shape of the plate , the base plate , the support structure and/or the wafer . An extension of the light guide plate , for example a diameter of the light guide plate can be equal to a diameter of a wafer or to a diameter of the active region of the wafer . Alternatively, the diameter of the light guide plate can be larger than the diameter of the wafer or at least larger than the diameter of the active region of the wafer .

The light guide plate can be connected with and/or receive light or electromagnetic radiation from an external light source . That the light source is external can mean that the light source is arranged outside of the arrangement . For example , the light guide plate is connected with the external light source via a port or via multiple ports . In this case , the arrangement can comprise the port or the multiple ports . The external light source can be configured or adapted to emit electromagnetic radiation . In particular, during operation, the external light source can emit electromagnetic radiation . The external light source can be , can house or can comprise at least one of the following light sources : a halogen lamp, a fluorescent lamp, a mercury lamp, a halogen- , fluorescent- or mercury- vapour lamp, an incandescent , a LED, a discharge lamp and/or a monochromator . The external light source can be coupled to the light guide plate . For example , the external light source is coupled to the light guide plate via a light guide , e . g . a liquid light guide , and/or by an optical fiber . It is also possible , that the external light source is coupled to the light guide plate via multiple light guides or multiple optical fibers . In other words , during operation of the external light source , electromagnetic radiation generated and/or emitted by the external light source can be transported to the light guide plate by at least one light guide and/or by at least one optical fiber . For example , each light guide or optical fiber is connected to one port of the arrangement .

A light distributor can be arranged between the port/ s and the light guide plate . The light distributor can be a circular light guide , circulating around the perimeter of the light guide plate . The light distributor can be configured to receive the electromagnetic radiation from the port/ s and to spread the electromagnetic radiation prior to entering the light guide plate . In this way, the light guide plate can be homogeneously illuminated and can homogeneously irradiate the electromagnetic radiation . Therefore , it is possible to homogeneously illuminate a wafer being arranged on the mounting surface of the plate .

Alternatively, the light guide plate can receive electromagnetic radiation from an internal light source . The internal light source can comprise a LED string, for example . The internal light source can be arranged between the support structure and the light guide plate . For example , the internal light source can completely surround the light guide plate . The light guide plate can be configured to change the direction of the light emitted or generated by the light source . For instance , the light guide plate is configured to receive light on a side surface of the light guide plate . The side surface of the light guide plate can extend transversely, perpendicularly or at least approximately perpendicularly to the main extension plane of the light guide plate . The light guide plate can be configured to irradiate light in a direction perpendicular to the main extension plane of the light guide plate .

For instance , the light guide plate can be transparent , at least in parts opaque acting as di f ferent levels of di f fusor, include structures or etching to manipulate a light ray direction and/or contain filters to block speci fic wavelengths .

The light guide plate can be structured . This can mean, that the light guide plate comprises cut-outs or an array of cutouts . For example , the cut-outs can be arranged on an outer side of the light guide plate . For instance , the cut-outs are formed at the side of the light guide plate facing away from the plate , e . g . facing the base plate . The side of the light guide plate facing the base plate can be referred to as underside of the light guide plate . For example , the light guide plate comprises micro-dots being formed in its underside . The structure can comprise multiple micro-dots or multiple cut-outs . For example , the structure consists of an array of micro-dots being regularly arranged at the underside of the light guide plate . The micro-dots can be formed by etching . For example , a shape of one cut-out or one micro-dot can resemble the shape of a triangle in sectional view . This can mean that the cut-out or the micro-dot comprise the shape of a pyramid . In this case , an extension of the cut-out or the micro-dot can increase along a direction towards the base plate . The extension of the cut-out can be between 500 pm and 1 mm, for example between 700 pm and 800 pm, inclusive . A distance between adj acent cut-outs can be between 500 pm and 5 mm, for example between 700 pm and 1200 pm, inclusive .

Due to the structure , e . g . the cut-outs or micro-dots , it is possible to ef ficiently couple the electromagnetic radiation out of the light guide plate . For example , the electromagnetic radiation is reflected of f the structure of the light guide plate . The reflection of the micro-dots can go to the plate . This can mean that the electromagnetic radiation coupled into the light guide plate can at least partially be irradiation towards the plate of the arrangement . The electromagnetic radiation coupled into the light guide plate can also partially be irradiated towards the base plate of the arrangement . In other words , a part of the electromagnetic radiation can leave the light guide plate at the bottom of the light guide plate . Any light or electromagnetic radiation leaving via the bottom of the light guide plate can reflect from a reflective film towards the plate to minimi ze light loss .

The reflective film, for example a white reflective sheet , can be arranged on the base plate of the arrangement . In particular, the reflective film can be applied to the side of the base plate facing the light guide plate . In other words , the reflective film can be arranged between the light guide plate and the base plate . The reflective film can be configured to reflect impinging electromagnetic radiation, for example electromagnetic radiation being coupled out of the light guide plate in a direction towards the base plate , in a direction towards the plate .

Due to the reflective film being arranged on the side of the light guide plate facing away from the plate , the optical path of the electromagnetic radiation after being coupled out of the light guide plate until impinging on the plate is increased, for example . This enables a better spreading of the electromagnetic radiation prior, such that the plate or a wafer attached to the plate can be uni formly or at least approximately uni formly illuminated .

Such a configuration, comprising a transparent panel with micro-dots etched on the underside of the transparent panel and wherein a reflective sheet is arranged below the underside of the transparent panel can produce a uni form or homogeneous irradiation of a wafer arranged on the mounting surface of the plate or at least of a device under test ( short : DUT ) arranged in the active region of the wafer .

According to at least one aspect of the arrangement , the light source comprises a plurality of light-emitting elements . The light-emitting elements can be separately controllable .

The light source can comprise a carrier, for instance a printed circuit board ( short : PCB ) . The carrier can be populated by light-emitting elements . This can mean that light-emitting elements , in particular a plurality of lightemitting elements are arranged on the carrier . Each light-emitting element can be configured to emit electromagnetic radiation, e . g . light , with any wavelength . For example , the light-emitting element is configured to emit red light , green light , blue light , near-infrared light or infrared light . A wavelength of the electromagnetic radiation emitted by the light-emitting element can be 850 nm or 940 nm, for example . It is also possible , that the light-emitting element emits white light , for example warm-white light . A color temperature of the light emitted by the light-emitting element can be within the range from 1000 K to 9000 K, inclusive , for example within the range from 1500 K to 10000 K, inclusive , or in particular within the range from 2500 K to 3500 K . For example , the color temperature can be 2700 K or 3300 K .

For example , the light-emitting elements are arranged on the PCB such as to produce a uni form irradiance or at least approximately uni form irradiance . For this , a density of the light-emitting elements on the carrier increases towards the edge of the carrier, for example .

Alternatively or additionally, light-emitting elements arranged at the edge or close to the edge of the carrier can protrude the light-emitting elements arranged closer to the middle of the carrier along the vertical direction . In particular, the light-emitting elements arranged at the edge of the carrier can protrude the light-emitting elements arranged closer to the middle of the carrier in a direction towards the plate . In other words , the light-emitting elements arranged at the edge of the carrier can be arranged closer to the plate . Due to these arrangements , an illuminance drop at the edge of the light source and/or at the edge of the plate and/or at the edge of the wafer chuck can be reduced or prevented .

Additionally or alternatively, the wafer chuck can be larger than the wafer . In this case , preferably, the lateral extension of the light source is larger than the lateral extension of the wafer . For example , in case the light source is larger than the wafer, a decreased illuminance of the light source at the edge of the light source can be ignored .

For example , the light-emitting element can be or can comprise a light-emitting diode ( short : LED) . It is also possible , that the light-emitting element is or comprises a micro-LED .

As a broad definition, a micro-LED could be seen as any light emitting diode ( LED) - generally not a laser - with a particularly small si ze . As a rule - and this is a very important criterion in addition to si ze - a growth substrate can be removed from micro-LEDs , so that typical heights of such micro-LEDs are in the range of 1 . 5 pm to 10 pm, for example .

In principle , a micro-LED does not necessarily have to have a rectangular radiation emission surface . Generally, for example , an LED could have a radiation emission surface in which, in plan view of the layers of the layer stack, any lateral extent of the radiation emission surface is less than or equal to 100 pm or less than or equal to 70 pm .

For example , in the case of rectangular micro-LEDs , an edge length - especially in plan view of the layers of the layer stack - smaller than or equal to 70 qm or smaller than or equal to 50 qm is often cited as a criterion . Mostly, such micro-LEDs are provided on wafers with - for the qLED nondestructive^ - detachable holding structures .

At present , micro-LEDs are mainly used in displays . The micro-LEDs form pixels or subpixels and emit light of a defined color . Small pixel si ze and a high density with close distances make micro-LEDs suitable , among others , for small monolithic displays for AR applications , especially data glasses . In addition, other applications are being developed, in particular regarding the use in data communication or pixelated lighting applications . Di f ferent ways of spelling micro-LED, e . g . qLED, q-LED, uLED, u-LED or micro light emitting diode can be found in the relevant literature .

According to at least one aspect , the light source comprises a detector . In particular, the light source can comprise an optical detector . The detector can be or can comprise a spectrometer . The detector can be arranged on the carrier, on the light guide plate and/or on the light distributor . The detector can be configured or adapted to detect and/or measure a spectrum of the electromagnetic radiation emitted by the light source . This can mean that the detector detects and/or measures the spectrum of the electromagnetic radiation emitted by the light source during operation of the light source and/or the arrangement . During testing of the wafer, wavelengths of the light source measured by the spectrometer can be used during in test calculations . It is also possible , that the light source comprises multiple detectors . For example , the detectors are arranged on the carrier, the light guide plate and/or the light distributor spaced apart from each other . According to at least one aspect, the arrangement comprises a wafer. An area of the wafer can be smaller than an area of the wafer chuck. The wafer can comprise a carrier. Additionally, the wafer can comprise at least one optoelectronic device. The optoelectronic device can comprise or consist of an optical device, e.g. a photodetector. For instance, the optoelectronic device comprises a through- connection, for example a TSV ( through-silicon via) or is a TSV-device. For example, the wafer comprises a plurality of optoelectronic devices. The wafer can comprise an active region and an outer region. The optoelectronic devices are arranged in the active region of the wafer. The outer region of the wafer can also be referred to as off-zone of the wafer and is free of optoelectronic devices or comprises defective optoelectronic devices, for example.

The wafer can comprise an active side. The wafer can be arranged on the mounting surface of the plate of the wafer chuck. The active side of the wafer can face the wafer chuck. The active side of the wafer can also be referred to as optical side of the wafer. A contact side of the wafer can be the side of the wafer opposing the optical side. The wafer can comprises optoelectronic devices or optical devices, e.g. the devices to be tested. The devices to be tested can be referred to as devices under test (DUT) .

The wafer can comprise the off-zone on the optical side. For example, the off-zone laterally surrounds the region of the optical side in which the devices to be tested are arranged. The off-zone can be an outer portion of the wafer. For example, the off-zone of the wafer can be the part of the optical side of the wafer that is free of optoelectronic or optical devices or comprises only defective optoelectronic devices or optical devices , for example .

According to at least one aspect , a foil is arranged between the wafer and the wafer chuck . For instance , the foil is arranged between the wafer and the plate . The foil can be configured for removing the wafer from the plate , e . g . subsequently to conducting a wafer test . The foil can also be configured to protect the active side of the optoelectronic devices of the wafer from external influences or from being scratched or destructed . It is possible , that the foil protrudes the wafer along the lateral direction . For example , the foil protrudes the wafer along all lateral directions .

The foil can comprise a base film, an adhesive film and/or a release film, for example . This can mean, for instance , that the foil can comprise at least one layer or film . In particular, the foil can consist of multiple films . The films can be stacked along a stacking direction . For example , the stacking direction extends perpendicular to a main extension direction of the foil .

For example , the foil is arranged directly between the wafer and/or the wafer chuck . In other words , the foil can be in direct contact with the wafer and/or the wafer chuck .

Prior to arranging the wafer on the wafer chuck, the foil can be attached to the wafer . For example , the wafer can be bonded to the foil . The wafer can then be adhered to the wafer chuck via the foil . Thus , the foil can be configured or adapted to attach and/or detach the wafer from the wafer chuck . Additionally, the foil can be configured or adapted to protect the optical side of the wafer, in particular the devices under test , e . g . the optoelectronic devices arranged on the optical side of the wafer . That the optoelectronic devices are arranged on the optical side of the wafer can also mean that the optoelectronic devices are forming the optical side of the wafer . For example , during probing of the wafer on the wafer chuck, the optical side of the wafer is protected by the foil .

For example , the foil extends over the complete surface of the wafer . The foil can be laterally flush with the wafer . Alternatively, it is possible that the foil laterally protrudes the wafer . For example , the foil is arranged within a frame . When the foil is applied to the wafer, preferably, the frame does not overlap with the wafer, in particular along the vertical direction .

According to at least one aspect of the arrangement , the foil protrudes the wafer along the lateral directions . The foil can overlap with the groove . For example , the foil is attached to the mounting surface of the plate of the wafer chuck via suctioning of the groove .

According to at least one aspect of the arrangement , the light source is arranged on the side of the wafer chuck facing away from the wafer .

According to at least one aspect of the arrangement , the arrangement comprises a wafer chuck, a light source and a wafer, wherein the wafer is arranged on the mounting surface of the plate and the light source is arranged on the side of the wafer chuck facing away from the wafer . The optoelectronic devices can be arranged on the side of the wafer facing the mounting surface of the plate . With this arrangement, it can be possible to perform tests, e.g. optical tests of optoelectronic devices, in particular of optical TSV-devices on wafer-level, for example. This can also be referred to as wafer probing. Wafer probing can be understood to mean testing optoelectronic devices on waferlevel, which can refer to a configuration prior to a separation or singulation of the optoelectronic devices of the wafer, e.g. prior to cutting or breaking the wafer.

According to at least one aspect, the arrangement comprises a diffusor. The diffusor can be configured to diffuse electromagnetic radiation, for example light, passing through the diffusor. The diffusor can be arranged between the light source and the wafer chuck. For example, the diffusor can be arranged between the light source and the further plate of the wafer chuck. Advantageously, the diffusor can be exchanged or replaced easily separately of the wafer chuck and/or the light source.

According to at least one aspect of the arrangement, the arrangement comprises an optical filter. The optical filter can be arranged between the light source and the wafer chuck. The optical filter can be or can comprise an infrared filter, a color filter, a polarization filter and/or a gradient filter, for example. The optical filter can be configured to correct or improve a homogeneity of the light source, in particular of the electromagnetic radiation emitted by the light source.

According to at least one aspect of the arrangement, the wafer comprises an active region and an outer region. An optoelectronic device can be arranged in the active region. A groove can be arranged between the outer region of the wafer and the wafer chuck . A pressure in the groove can be lower than an ambient pressure . The wafer can be attached to the wafer chuck via the groove . For example , an interface between the wafer and the wafer chuck can be free of an adhesive . The outer region can be referred to as the of f- zone of the wafer .

With the groove , the wafer can be easily and non- destructively attached to the wafer chuck and/or detached from the wafer chuck . As the groove is only arranged in the outer region of the wafer, the electromagnetic radiation passing through the wafer chuck and impinging on the active region of the wafer is not deflected by the groove .

According to at least one aspect of the arrangement , a structure comprising separation walls is arranged in the gap . The structure may not overlap with the wafer along a vertical direction . Alternatively, it is possible , that the structure overlaps only with the outer region of the wafer .

An advantage of this aspect is that electromagnetic radiation passing through the wafer chuck is not influenced, e . g . absorbed or di f fracted, by the structure prior to impinging on the wafer .

According to at least one aspect of the arrangement , the wafer is contacted by probe needles on the side of the wafer facing away from the wafer chuck . The side of the wafer facing away from the wafer chuck can be the contact side of the wafer . For example , the wafer is contacted by probe needles on the contact side . With the probe needles , the devices under test can be contacted, for example electrically contacted, during probing .

Furthermore , a method for probing a wafer is provided . The method for probing a wafer can preferably be performed with the arrangement described herein . This means all features disclosed for the arrangement are also disclosed for the method for probing a wafer and vice-versa .

According to at least one aspect of the method for probing a wafer, the wafer is attached to the wafer chuck . The wafer can be attached to the mounting surface of the wafer chuck . For example , attaching the wafer to the wafer chuck can comprise placing and/or positioning the wafer on the mounting surface of the plate . For example , the wafer is positioned such that it overlaps with the groove . For example , the groove is completely covered by the wafer .

Additionally or alternatively, attaching the wafer to the wafer chuck can comprise bonding the wafer to a foil and positioning the foil on the mounting surface such that the groove is completely covered by the foil .

Attaching the wafer to the wafer chuck can further comprise suctioning of the groove .

That the groove is suctioned can mean that after suctioning of the groove a pressure in the groove is lower than an ambient pressure . For example , the wafer is arranged on the mounting surface of the plate , while the pressure in the groove corresponds to the ambient pressure . After arranging the wafer on the mounting surface , the pressure in the groove can be decreased by suctioning . For example , the groove can be suctioned with a suction hose .

According to at least one aspect of the method for probing a wafer, the wafer is illuminated with the light source .

According to at least one aspect of the method for probing a wafer, devices under test of the wafer are probed . This can mean that the devices under test are tested with regard to their functionality .

According to at least one aspect , the method for probing a wafer comprises :

- attaching the wafer to the wafer chuck,

- illuminating the wafer with the light source , and

- probing optoelectronic devices of the wafer .

According to at least one aspect , the method comprises releasing the wafer from the wafer chuck by inj ecting a gas into the groove . For example , the gas can be air . That the gas is inj ected into the groove can mean for instance that the pressure in the groove is enhanced . For example , the pressure in the groove is adj usted to the ambient pressure or is adj usted to be higher than the ambient pressure .

Therefore , the wafer may not be suctioned to the plate anymore and can be easily removed from the plate . For example , the wafer is released from the wafer chuck or the plate after wafer probing .

According to at least one aspect of the method for probing a wafer, the method comprises calibrating the arrangement prior to attaching the wafer . The calibration can comprise the creation of an illuminance map by moving an optical sensor over the wafer chuck . Additionally, the calibration can comprise programming the arrangement for achieving required irradiances .

For the calibration, a probe board can comprise the optical sensor, e . g . a photodiode , for example . The photodiode can be NIST traceable . Additionally or alternatively, the probe board can comprise a spectrometer . In other words , the optical sensor can be a spectrometer or comprise a spectrometer . The photodiode or the spectrometer can be arranged at a speci fic and known position, for example at a predetermined position on the probe board . In other words , the photodiode or the spectrometer are arranged on the probe board with a known shi ft from the center of the probe board . For example , the photodiode or the spectrometer is arranged on the side of the probe board facing the plate .

The probe board can be moved over the plate with a predetermined step si ze . For example , thereby, an illuminance map of the plate , in particular of the mounting surface of the plate can be generated and/or created . The illuminance map can then be a measure for the homogeneity of the plate , in particular of the electromagnetic radiation being transmitted through the plate .

Correction coef ficients , accounting for deviations in the homogeneity of the illuminance can be entered and/or stored in a file . The correction coef ficients can be connected to the x- and y- coordinates of the measurement position . The correction coef ficients can be used to correct the response of the device under test when tested or probed . The calibration of the arrangement can comprise a programming of the arrangement for different irradiances, e.g. for different predetermined and/or required irradiances. For example, the arrangement can be programmed in discrete steps and/or adjusted until the photodiode or the spectrometer returns the desired, predetermined and/or correct response. For example, the response of the photodiode or the spectrometer is correct in case it detects or measures the desired, predetermined and/or required irradiance.

The arrangement can also comprise internal sensors, e.g. at least one sensor and/or at least one detector. Also the internal sensors can provide a measure for the calibration of the arrangement, for example by recording the calibrated light level.

The arrangement, in particular the light source can be driven or operated with an adjustable drive current. The drive current for the calibrated arrangement or the calibrated light source can be stored in a calibration file.

According to at least one aspect of the method for probing a wafer, a standardized wafer is tested. In particular, the standardized wafer is tested after the calibration of the arrangement and/or prior to probing a wafer. The standardized wafer can be referred to as golden wafer, for example. For example, the standardized wafer is tested in predetermined positions. The standardized wafer can be tested prior to each wafer probing. In other words, prior to attaching a wafer to be probed, the standardized wafer is tested.

Due to the standardized wafer the calibration of the arrangement can be tested and/or checked easily and fast. Thus , it is not necessary to calibrate the arrangement prior to each wafer probing . Instead, it might be necessary to calibrate or re-calibrate the arrangement or the light source only when a deviation is measured during testing the standardi zed wafer .

According to at least one aspect of the method for probing a wafer, during the probing, the light level is monitored . For monitoring the light level , the arrangement can comprise the sensor . The sensor can be arranged at an edge portion of the plate on the side of the plate facing the light source . For example , the sensor is arranged on the plate support pillar . The sensor can be configured or adapted to measure the light level .

I f the sensor measures or detects a deviation from the desired light level , this can be a measure for a failure or fluctuations of the light source or of the arrangement . In this case , the arrangement or the light source can be readj usted to the value recorded during calibration for the calibrated arrangement .

Additionally or alternatively, during wafer probing, deviations from the value recorded during calibration for the calibrated arrangement can be used to correct or to compensate the shi ft , for instance for small deviations . Alternatively, for detected detrimental deviations the wafer probing can be stopped . It is possible , that the arrangement can provide , return or output possible faults , i f stopped .

Furthermore , a method for operating an arrangement is provided . The method for operating an arrangement can preferably be performed to operate the arrangement described herein. This means all features disclosed for the arrangement are also disclosed for the method for operating an arrangement and vice-versa.

According to at least one aspect of the method for operating an arrangement, the method comprises illuminating the wafer with the light source. Prior to illuminating the wafer with the light source, the wafer can be attached to the wafer chuck. For example, the wafer is applied to the mounting surface of the plate. In particular, the wafer can be applied to the mounting surface of the plate such that the wafer, e.g. the outer region of the wafer, overlaps with the groove. Alternatively, the wafer can be attached to a foil. In this case, the foil or only the foil can overlap with the groove.

According to at least one aspect of the method for operating an arrangement, the method comprises tempering the wafer with the wafer chuck. The wafer can be tempered during operation of the light source. For example, the wafer is tempered during wafer probing. For example, the wafer can be tempered to a temperature within a range from - 80°C to + 200°C, for example within a range from -40°C to + 130°C, inclusive or within a range from 0°C to 65°C, inclusive. It is possible, that the wafer is first cooled to a desired temperature and subsequently heated to another desired temperature or vice versa. Thus, the optoelectronic devices of the wafer, in particular the performance of the optoelectronic device can be easily and efficiently tested at various temperatures.

According to at least one aspect, the method for operating an arrangement comprises illuminating the wafer with the light source and tempering the wafer with the wafer chuck. For example, the method can be efficiently performed for conducting a three temperature test on optoelectronic devices or optical devices , e . g . optical sensors comprising a through silicon via ( TSV) .

According to at least one aspect of the method for operating an arrangement , the tempering of the wafer comprises applying a flow of a tempered medium from an inlet to an outlet through the gap between the plate and the further plate . For example , the flow of the tempered medium can be laminar or turbulent , in particular in a region overlapping with the wafer . The flow can comprise a constant or at least approximately constant flow rate .

That the medium is tempered can for instance mean that the medium was heated or cooled to a predetermined temperature . For example , the medium is heated or cooled by an external heater, cooler or chiller . In other words , a temperature of the medium can be adj usted to a desired temperature .

The tempered medium can be applied to the gap between the plate and the further plate of the wafer chuck via the inlet . The medium can then exchange its temperature with the plate and/or the further plate of the wafer chuck . For instance , the plate can subsequently provide a temperature di f ference to the wafer for adj usting the temperature of the wafer, e . g . for tempering the wafer .

According to at least one aspect of the method for operating an arrangement , the medium comprises a gas or a liquid . It is also possible , that the medium consists of a gas or of a liquid . A gas can be ef ficiently tempered to a desired temperature within a large temperature range by consuming only a small amount of energy . In other words , a gas can be tempered energy ef ficient . For example , the medium comprises or consists of air .

For example , i f the medium consists of a liquid, a better temperature homogeneity might be achieved over the gap .

Further advantages and advantageous designs and further developments of the arrangement and the method for probing a wafer will become apparent from the following embodiments , which are described below in association with the figures .

Figure 1 shows a schematic view of an arrangement according to an embodiment .

Figure 2 shows a schematic top view of an arrangement according to an embodiment .

Figure 3 shows a schematic side view of an arrangement with a light source comprising a light guide plate according to an embodiment .

Figure 4 shows a schematic side view of an arrangement with a light source comprising a plurality of light-emitting elements according to an embodiment .

Figure 5 shows a top view of a light source according to an embodiment . For example , the light source shown here is the light source shown in Figure 4 . Figures 6 , 7 and 8 show schematic views of a support structure according to an embodiment .

Figure 9 shows a schematic view of a plate with a groove according to an embodiment .

Figure 10 shows a schematic top view of an arrangement according to an embodiment .

Figure 11 shows a schematic sectional view of an arrangement according to an embodiment .

Figures 12 and 13 show schematic top views of an arrangement according to an embodiment .

Identical , similar or equivalent elements are marked with the same reference signs in the figures . The figures and the proportions of the elements represented in the figures among each other are not to be considered as true to scale . Rather, individual elements may be oversi zed for better representability and/or comprehensibility . Identical or ef fectively identical components and parts might be described only with respect to the figures where they occur first .

Their description is not necessarily repeated in successive figures .

Figure 1 shows a schematic view of an arrangement 1 according to an embodiment . The arrangement 1 comprises a prober chuck base 29 . For example , the base plate 26 of the arrangement 1 is arranged on the prober chuck base 29 . The arrangement 1 further comprises a wafer chuck 2 comprising plate 6 with a mounting surface 8 . The mounting surface 8 can comprise a groove 16 . Above the mounting surface 8 , a wafer 3 can be arranged .

The wafer 3 can be attached to the wafer chuck 2 via suctioning of the groove 16 . This can mean that after suctioning of the groove 16 a pressure in the groove 16 is lower than an ambient pressure . For example , the groove 16 can connected to and suctioned with a suction hose .

The wafer chuck 2 and/or the plate 6 can comprise a main extension plane . A vertical direction can extend perpendicular or at least approximately perpendicular to the main extension plane of the wafer chuck 2 . A lateral direction or lateral directions extend in parallel or at least approximately in parallel to the main extension plane of the wafer chuck 2 .

For example , the wafer 3 is in direct contact with the mounting surface 8 of the plate 6 . The wafer 3 comprises a contact side 37 and an active side 38 . The active side 38 faces the mounting surface 8 . The contact side 37 is arranged on the side of the wafer 3 opposing the contact side 37 .

Alternatively, shown here , the wafer 3 can be attached to a foil 35 . The foil 35 can be fixed in a frame 36 and/or can be surrounded by the frame 36 . For example , the foil 35 is completely surrounded by the frame 36 . The frame 36 and the wafer 3 may not overlap along the vertical direction . This can mean that a circumference of the frame 36 is larger than a circumference of the wafer 3 .

The foil 35 can be arranged between the wafer 3 and the wafer chuck 2 . In particular, the foil 35 can be arranged between the wafer 3 and the mounting surface 8 of the plate 6 of the wafer chuck 2. The foil 35 can be in direct contact with the mounting surface 8 and/or the wafer 3, e.g. with the active side 38 of the wafer 3. The foil 35 can protrude the wafer 3 along the lateral directions, for example along all lateral directions .

The foil 35 can overlap with the groove 16 of the mounting surface 8. The foil 35 can be attached to the mounting surface 8 of the plate 6 of the wafer chuck 2 via suctioning of the groove 16.

A probe board 24 can be arranged on the wafer 3, e.g. along the vertical direction. For example, the probe board 24 is arranged on the contact side 37 of the wafer 3. The probe board 24 can comprise probe needles 31. The probe needles 31 can be in direct contact with the contact side 37 of the wafer 3. For example, the probe needles 31 are configured to contact, in particular electrically contact, the contact side 37 and/or optoelectronic devices, for example devices under test of the wafer 3. With the probe needles 31, the devices under test can be contacted during probing.

The arrangement 1, for example a light source 4 of the arrangement 1, can be powered via a power cable 39. However, also other components of the arrangement 1 may be powered using the power cable 39.

In a method for probing a wafer 3 with an arrangement 1, the wafer 3 is attached to the wafer chuck 2. Further, the wafer 3 is illuminated with the light source 4. It is also possible to probe devices under test of the wafer 3. After probing the devices under test of the wafer 3, the wafer 3 can be removed from the arrangement 1. For example, the wafer 3 is removed using the foil. Alternatively, the wafer 3 can be released or removed from the wafer chuck 2 by injecting a gas into the groove 16.

Prior to attaching or arranging the wafer 3, the arrangement 1 can be calibrated. For example, the calibration of the arrangement 1 comprises the creation of an illuminance map by moving an optical sensor 30 relative to the wafer chuck 2. For example, the wafer chuck 2 moves under the probe board 24. In this case, the optical sensor 30 and/or the probe board 24 might not move.

For the calibration, the probe board 24 can comprise the optical sensor 30, e.g. a photodiode or a spectrometer, for example. The optical sensor 30 can be NIST traceable. With the data obtained by the optical sensor 30 the wafer chuck 2 can be programmed for achieving required irradiances of the light source 4, for example.

Figure 2 shows a schematic top view of an arrangement 1 according to an embodiment. The arrangement 1 comprises the wafer 3, the plate 6 comprising the mounting surface 8 and the light source 4. The light source 4 can be or can comprise a light guide plate 32. For example, shown here, the light source 4 is connected with and/or receives light or electromagnetic radiation from an external light source 40.

The light source 4, e.g. the light guide plate 32, is connected with the external light source 40 via a port 43. For example, the light source 4 can be connected with the external light source 40 via multiple ports 43, 44, namely the port 43 and a further port 44. For example, as shown in Figure 2, the arrangement 1 can comprise the port 43 and seven further ports 44. However, not shown, it is possible that the arrangement 1 comprises less than eight ports 43, 44 or more than eight ports 43, 44. The number of ports 43, 44 can be chosen as required. For example, the ports 43, 44 are arranged equally spaced from each other and surround the light source 4, e.g. the light guide plate 32. This can mean that a port 43, 44 is arranged every 45° of the circumference of the light guide plate 32 or of a sealing layer 50.

The external light source can be connected with the ports 43, 44 via a light guide 41 and a further light guide 42. The light guide 41 and/or the further light guide 42 can be or can comprise an optical fiber or a liquid light guide. For example, the light guide 41 and/or the further light guide 42 is/are configured or adapted to transport a portion of the electromagnetic radiation emitted by the external light source 40 to the light source 4. A number of light guides 41, 42 can correspond to a number of ports 43, 44. For example, each light guide 41, 42 is linked to one port 43, 44.

A light distributor 45 can be arranged between the ports 43, 44 and the light source 4, e.g. the light guide plate 32. The light distributor 45 can be a circular light guide, circulating around the perimeter of the light guide plate 32. The light distributor 45 can be configured to receive the electromagnetic radiation from the port/s 43, 44 and to spread the electromagnetic radiation prior to entering the light guide plate 32.

The mounting surface 8 comprises the groove 16. The groove 16 can be connected to a suction hose 49. For example, the groove 16 is connected with the suction hose 49 via a groove connector exit 47 and/or a suction hose connector 48 . The mounting surface 8 can be smooth . Alternatively, the mounting surface 8 can be roughened to improve the adhesion of the wafer 3 or the foil 35 on the mounting surface 8 .

The wafer chuck 2 , the plate 6 and/or the mounting surface 8 of the plate 6 of the wafer chuck 2 can be larger than the wafer 3 . For example , the center of the wafer 3 and the center of the plate 6 can overlap .

Figure 3 shows a schematic side view of an arrangement 1 with a light source 4 comprising a light guide plate 32 according to an embodiment . The arrangement 1 comprises a wafer chuck 2 and a light source 4 . The wafer chuck 2 can comprise or consist of the plate 6 with the mounting surface 8 . The mounting surface 8 is configured for mounting a wafer 3 . The plate 6 is arranged in the beam path of the light source 4 . The wafer 3 comprises the contact side 37 and the active side 38 . The wafer 3 can be attached on the mounting surface 8 such that the active side 38 faces the mounting surface 8 .

The plate 6 can be translucent or transparent . For example , the plate 6 can comprise or consist of glass or sapphire . In sectional view, the plate 6 can be , can comprise or can resemble a first cylinder with a first diameter arranged on a second cylinder with a second diameter . Thereby, the first diameter can be smaller than the second diameter . Thus , a notch can be formed . The first diameter can correspond to a diameter of the mounting surface 8 . The plate 6 can be formed or can consist of one piece .

The exposed surface of the second cylinder of the wafer chuck

2 or the plate 6 can be configured or adapted for attaching the wafer chuck 2 or the plate 6 to a support structure 52 , e . g . with a plate clamp 56 and a plate clamp screw 57 .

The support structure 52 is arranged on the base plate 26 . The support structure 52 can be arranged laterally to the light source 4 . For example , the support structure 52 is arranged on an edge portion of the base plate 26 . The support structure 52 comprises a planarising screw 53 and a plate support pillar 54 . Additionally, shown here , the support structure 52 comprises a spring washer 55 . The planarising screw 53 of the support structure 52 can go through the spring washer 55 . The linear shaft 65 can provide a vertical stability to the support structure 52 . For example , the spring washer 55 is in direct contact with the base plate 26 . The plate support pillar 54 is arranged on the side of the spring washer 55 facing away from the base plate 26 . For example , the plate support pillar 54 is directly arranged on the spring washer 55 and the two linear shafts 65 . The planarising screw 53 can extend through the plate support pillar 54 and/or the spring washer 55 . The planarising screw 53 can extend into the base plate 26 . This can mean that the planarising screw 53 is screwed into the base plate 26 .

The plate 6 can comprise an opening 66 for accessing the planarising screw 53 . In top view, the opening 66 overlaps with the planarising screw 53 . Through the opening 66 , the planarising screw 53 and, thus , a position of the plate support pillar 54 , in particular a vertical position of the plate support pillar 54 can be adj usted from a side of the plate 6 or the wafer chuck 2 facing away from the base plate 26 . The plate 6 can be arranged on the side of the support structure 52 facing away from the base plate 26 . The plate 6 can be in direct contact with the support structure 52 , for instance in direct contact with the plate support pillar 54 . Alternatively, a sensor 58 can be arranged between the plate support pillar 54 and the wafer chuck 2 or the plate 6 of the wafer chuck 2 .

The sensor 58 can be configured or adapted to monitor a light level of the light source 4 or of the light guide plate 32 . This means , during wafer probing, the sensor 58 can monitor the light level . The sensor 58 can be a monitoring sensor .

The sensor 58 can be arranged at an edge portion of the plate 6 on the side of the plate 6 facing the light source 4 .

The support structure 52 can further comprise a retaining bracket 64 for arranging an optical stack 59 , e . g . an optical stack retaining bracket 64 . The retaining bracket 64 can comprise a top support bracket and a lower support bracket . The top support bracket can be arranged between the optical stack 59 and the wafer chuck 2 using a sliding mechanism . The lower support bracket can be arranged between the optical stack 59 and the light source 4 via a sliding mechanism . The top support bracket and the lower support bracket can be in direct contact with the optical stack 59 . The retaining bracket 64 can be arranged between the wafer chuck 2 and the light source 4 . The retaining bracket 64 can be configured or adapted to arrange the optical stack 59 in the gap between the wafer chuck 2 and the light source 4 . Preferably, a distance between the optical stack 59 and the wafer chuck 2 or the plate 6 of the wafer chuck 2 is smaller than a distance between the optical stack 59 and the light source 4 . The optical stack 59 is arranged between the wafer 3 and the light source 4 , for example between the wafer chuck 2 and the light source 4 . The optical stack 59 can be configured for influencing the electromagnetic radiation 25 emitted by the light source 4 . The optical stack 59 can comprise or consist of at least one of the following : a di f fusor, a lens , a lens plate , a prism sheet or other optics and/or optical components .

A diameter of the optical stack 59 can be smaller than a diameter of the wafer chuck 2 , in particular than the second diameter of the second cylinder of the plate 6 .

It is possible , that the support structure 52 is not arranged along the complete perimeter of the arrangement 1 . Instead, the support structure 52 can be arranged at multiple distinct positions distributed along the perimeter of the arrangement 1 .

The wafer chuck 2 , e . g . the plate 6 , is attached to the support structure 52 via the plate clamp 56 . The plate clamp 56 is screwed to the plate support pillar 54 using the plate clamp screw 57 . Thereby, the plate clamp screw 57 can be screwed into the plate support pillar 54 . The plate clamp screw 57 can be screwed into the plate support pillar 54 on the side of the planarising screw 53 facing away from the optical stack 59 or the gap formed between the wafer chuck 2 and the light source 4 .

The light source 4 can be arranged on the base plate 26 . A reflective film 61 can be arranged between the light source 4 , e . g . the light guide plate 32 , and the base plate 26 . For example , the reflective film 61 is directly applied to the base plate 26 . The reflective film 61 can be configured to reflect impinging electromagnetic radiation 25 , for example electromagnetic radiation 25 being coupled out of the light guide plate 32 in a direction towards the base plate 26 , in a direction towards the wafer chuck 2 and/or towards the plate 6 .

The light guide plate 32 can be structured . This can mean, that the light guide plate 32 comprises a cut-out 60 or an array of cut-outs 60 . For example , the cut-outs 60 are arranged on an outer side of the light guide plate 32 . For instance , the cut-outs 60 are formed at the side of the light guide plate 32 facing away from the wafer chuck 2 , e . g . facing the base plate 26 or facing the reflective film 61 . For example , the cut-outs 60 are or comprise micro-dots . The micro-dots can be formed by etching . As shown here , a shape of one cut-out 60 or one micro-dot can resemble the shape of a triangle in sectional view .

The sealing layer 50 can completely surround the light source 4 , the optical stack 59 and/or the plate 6 along a lateral direction . For example , the sealing layer 50 is arranged on a side of the support structure 52 facing away from the optical stack 59 . The sealing layer 50 can be arranged on the side of the base plate 26 facing away from the light source 4 . Additionally or alternatively, the sealing layer 50 can be arranged on the side of the plate clamp 56 facing away from the wafer chuck 2 or the plate 6 of the wafer chuck 2 .

Figure 4 shows a schematic side view of an arrangement with a light source comprising a plurality of light-emitting elements according to an embodiment . The embodiment shown in Figure 4 di f fers from the embodiment shown in Figure 3 in the type of the light source 4 . For example , the light source 4 shown in Figure 4 is the light source 4 shown in Figure 5 .

The light source 4 of the embodiment shown in Figure 4 can be referred to as internal light source . The light source 4 comprises a plurality of light-emitting elements 33 , 34 . The light-emitting elements 33 , 34 can be separately controllable .

The light source 4 comprises a carrier, for instance a PCB . The carrier can be populated by light-emitting elements 33 , 34 . Each light-emitting element 33 , 34 can be configured to emit electromagnetic radiation 25 , e . g . light . The light source 4 can be attached to the base plate 26 via a fastening unit 62 .

The light-emitting elements 33 , 34 can be arranged on the wafer such as to produce a uni form irradiance or at least approximately uni form irradiance . A density of the lightemitting elements 33 , 34 on the carrier can increase towards the edge of the carrier, for example . This can mean that a distance between the light-emitting elements 33 is larger than a distance between the light-emitting elements 34 arranged at the edge of the carrier .

Alternatively or additionally, light-emitting elements 34 arranged at the edge or close to the edge of the carrier can protrude the light-emitting elements 33 arranged closer to the middle of the carrier along the vertical direction . In particular, the light-emitting elements 34 arranged at the edge of the carrier can protrude the light-emitting elements 33 arranged closer to the middle of the carrier in a direction towards the wafer chuck 2 . In other words , the light-emitting elements 34 arranged at the edge of the carrier can be arranged closer to the wafer chuck 2 or to the plate 6 .

The light source 4 can comprise a detector 63 , for example an optical detector 63 . It is also possible , that the light source 4 comprises multiple detectors 63 . The detector 63 can be or can comprise a spectrometer . The detector 63 can be arranged on the carrier of the light source 4 . The detector 63 can be configured or adapted to detect and/or measure a spectrum of the electromagnetic radiation 25 emitted by the light source 4 . The detector 63 can be arranged at any position on the carrier of the light source 4 . For example , the detector 63 is in direct contact with the carrier .

Figure 5 shows a top view of a light source according to an example . For example , the light source shown here is the light source shown in Figure 4 . The light source 4 comprises the light-emitting elements 33 arranged on the carrier and the light-emitting elements 34 arranged at an edge of the carrier . The light source 4 also comprises the detector 63 .

For example , shown here , the light-emitting elements 34 at the edge are larger than the remaining light-emitting elements 33 . The light-emitting elements 34 are arranged along a circle at an outer portion, e . g . at an edge , of the light source 4 . For example , the light-emitting elements 34 can emit red light , green light or blue light (RGB ) . It is possible , that the light-emitting elements 34 are alternatingly arranged in dependence on their color . For example , every third light-emitting element 34 is configured to emit red light . However, in general , the light-emitting elements 34 can be configured to emit or can emit light with any wavelength, e.g. in the range from 100 nm to 1400 nm, inclusive. The light-emitting elements 34 at the edge can emit white light with a color temperature between 1500 K and 10000 K, inclusive. Alternatively, the light-emitting elements 34 can emit NIR light or UV light.

Figures 6, 7 and 8 show schematic views of a support structure 52 and a plate clamp 56 according to an example.

For instance, Figures 6, 7, and 8 show a detailed view of the support structure 52 and the plate clamp 56 shown in Figures 3 and 4. The support structure 52 comprises the spring washer 55, the plate support pillar 54 and the planarising screw 53. The wafer chuck 2 or the plate 6 of the wafer chuck 2 can be attached to the plate support pillar 54 via the plate clamp 56 and the plate clamp screw 57. The planarising screw 53 and the plate claim screw 57 can be parallel to each other. In top view, Figure 8, the plate clamp 56 is "U-shaped". The plate clamp 56 does not overlap with the opening 66 in the wafer chuck 2, e.g. in the plate 6. The plate clamp 56 overlaps with the plate 6 in the region of the notch.

Figure 9 shows a schematic view of a plate 6 with a groove 16 according to an embodiment. The mounting surface 8 of the plate 6 comprises the groove 16. The groove 16 is connected to a suction hose 49. For example, the groove 16 is connected with the suction hose 49 via a groove connector exit 47 and/or a suction hose connector 48. It is also possible that the plate 6 comprises more than one groove 16, e.g. three grooves. In this case, for example, the grooves are concentric. The grooves 16 can be arranged spaced apart from each other. Figure 10 shows a schematic top view of an arrangement 1 according to an embodiment . The arrangement 1 comprises a wafer chuck 2 and a wafer 3 . The wafer 3 is attached to a mounting surface 8 of the wafer chuck 2 , for example to the mounting surface 8 of a plate 6 of the wafer chuck 2 . A diameter D3 of the wafer 3 can be smaller than a diameter D2 of the wafer chuck 2 or of the plate 6 . For example , the diameter D3 of the wafer 3 can be at least 1 cm, for example at least 2 cm, at least 3 cm or at least 5 cm smaller than the diameter of the wafer chuck 2 or of the plate 6 . It is possible , that the center of the wafer 3 at least approximately overlaps with the center of the wafer chuck 2 . This can mean that the wafer chuck 2 protrudes the wafer 3 along a lateral direction, for instance along all lateral directions .

The wafer 3 can comprise an active region and an outer region . An optoelectronic device of the wafer 3 can be arranged in the active region . For example , the active region is the part of the wafer 3 to be tested during a wafer probe test . The outer region of the wafer 3 can also be referred to as of f- zone of the wafer 3 .

Figure 11 shows a schematic sectional view of an arrangement 1 according to an embodiment . The arrangement 1 comprises the wafer chuck 2 , the wafer 3 and a light source 4 . The wafer chuck 2 shown here comprises a plate 6 , and a further plate 7 . The plate 6 comprises the mounting surface 8 for attaching the wafer 3 . The further plate 7 is arranged on a side of the plate 6 opposite the mounting surface 8 . The wafer chuck 2 can further comprise a gap 9 . The gap 9 can be arranged between the plate 6 and the further plate 7 . The plate 6 can be translucent or transparent . The further plate 7 can be translucent or transparent. For example, the plate 6 and/or the further plate 7 can comprise glass or sapphire.

For example, the wafer 3 comprises an optoelectronic device, for example at least one optoelectronic device. In particular, the wafer 3 can comprise a plurality of optoelectronic devices, e.g. optical sensors or photodetectors. The wafer 3 can be arranged on the mounting surface 8 of the plate 6. For example, the wafer 3 can be directly arranged on the mounting surface 8. Alternatively, not shown, a foil can be arranged between the wafer 3 and the wafer chuck 2. Then, for example, the wafer is applied to the foil and the foil is attached to the mounting surface 8 of the plate 6. The foil can comprise a frame.

The light source 4 is arranged on the side of the wafer chuck 2 facing away from the wafer 3. The light source 4 can be configured to emit electromagnetic radiation 25. In particular, the light source 4 can emit electromagnetic radiation 25 during operation.

The arrangement 1 shown here further comprises a diffusor 5. The diffusor 5 is arranged between the light source 4 and the wafer chuck 2. The diffusor 5 can be configured to scatter light, in particular the electromagnetic radiation emitted by the light source 4. This can mean that electromagnetic radiation 25 is distributed homogeneously prior to impinging on the wafer chuck 2. It is also possible, not shown, that the further plate 7 comprises a diffusor. This can also mean that the further plate 7 is or comprises the diffusor 5.

Additionally or alternatively, not shown, an optical filter can be arranged between the light source 4 and the wafer chuck 2, e.g. between the further plate 7 and the light source 4 or between the plate 6 and the light source 4. For instance, the optical filter can be or can comprise an infrared filter, a color filter, a polarization filter and/or a gradient filter. For example, the optical filter is configured to correct or improve a homogeneity of the light source 4. The optical filter can be arranged between the light source 4 and the diffusor 5, for example.

It is also possible that multiple optical filters are arranged between the light source 4 and the wafer chuck 2. The multiple optical filters can comprise the same features and/or functions. Alternatively, the multiple optical filters can be different from each other. For example, the optical filters can be configured to filter electromagnetic radiation with different wavelengths. It is also possible that at least two optical filters are of a different type. For example, one filter can be a color filter and one filter can be a polarization filter. The optical filters can be arranged in parallel. The optical filters can form or be part of a filter stack .

Additionally or alternatively, the further plate 7 and/or the diffusor 5 can comprise the optical filter.

The arrangement 1 can comprise a base plate 26. The components of the arrangement 1 can be arranged on the base plate 26. For example, along the vertical direction, the base plate 26, the light source 4, the diffusor 5 and/or one or multiple optical filters, the wafer chuck 2 and the wafer 3 are consecutively arranged. The arrangement 1 can comprise a probe board 24. The probe board 24 can comprise probe needles. The probe needles can be configured to contact the wafer 3, in particular the optoelectronic device/s of the wafer 3. For example, the probe board 24 can contact the wafer 3 on the side of the wafer facing away from the wafer chuck 2.

The arrangement 1, in particular the wafer chuck 2, can comprise a sealing 14. The sealing 14 can be or can comprise a sealing ring 14, for example. The sealing ring 14 can surround the gap 9 along a lateral direction. It is possible, that the sealing ring 14 surrounds the plate 6 along the lateral direction. The sealing ring 14 can be in contact with the plate, for example in direct contact with the plate 6. It is also possible that the sealing ring 14 surrounds the further plate 7 at least partially or completely in the lateral direction. The sealing ring 14 can be in contact, for example in direct contact, with the further plate 7.

The sealing ring 14 can be impermeable for the medium 15 and/or an ambient medium.

For example, the plate 6, the further plate 7, the gap 9 and the sealing 14 form an independent component, which can be arranged in the arrangement 1. The plate 6 and the further plate 7 can be attached to the sealing 14, e.g. the sealing ring 14. This can mean that a distance between the plate 6 and the further plate 7, forming the gap 9, is maintained by the sealing 14.

During operation of the arrangement, in particular during performing a method for operating an arrangement, the wafer 3 can be illuminated with the light source 4. In other words, during operation, electromagnetic radiation 25 emitted by the light source 4 can impinge on the wafer 3 . Additionally, the wafer 3 can be tempered with the wafer chuck 2 during operation of the arrangement 1 . The tempering of the wafer 3 can comprise the application of a flow of a tempered medium 15 from an inlet 10 to an outlet 12 through the gap 9 between the plate 6 and the further plate 7 . The medium 15 can comprise or consist of a gas or a liquid .

Figure 12 shows a schematic top view of an arrangement 1 according to an embodiment . Analogously to the arrangement 1 shown in Figure 9 , the arrangement 1 comprises the wafer chuck 2 and the wafer 3 . The wafer 3 is attached to the mounting surface 8 of the wafer chuck 2 . The wafer 3 can comprise the active region and the outer region, e . g . the of f- zone of the wafer 3 .

The mounting surface 8 comprises a groove 16 . The groove 16 can be ring-shaped, in top view . The groove 16 can comprise a connection to a suction hose . For example , not shown, the groove 16 can be disrupted such that the groove 16 is only imaginary ring-shaped . In this case , one end of the groove 16 can be connected to the suction hose .

The groove 16 can be arranged between the outer region of the wafer 3 and the wafer chuck 2 . Alternatively, not shown, the wafer 3 can be attached to a foil . This can mean that the foil is arranged between the wafer 3 and the wafer chuck 2 . In this case , it is possible that the foil or only the foil overlaps with the groove 16 . A pressure in the groove 16 can be lower than an ambient pressure . In this way, the wafer 3 or the foil can be sucked to the wafer chuck 2 . Thus , the wafer 3 can be attached to the wafer chuck 2 via the groove

16 .

The wafer chuck 2 can comprise an inlet 10 . The wafer chuck 2 can further comprise an outlet 12 . The inlet 10 can be configured to inj ect the medium 15 into the gap 9 . The outlet 12 can be configured to release the medium 15 from the gap 9 . The inlet 10 and the outlet 12 can be in direct contact with the gap 9 . This can mean that the medium 15 is directly inj ected into the gap 9 by the inlet 10 or directly released from the gap 9 by the outlet 12 . The gap 9 can be sealed except for locations of the inlet 10 and the outlet 12 . For example , the gap 9 is sealed by the sealing 14 , e . g . the sealing ring 14 .

Thus , the inlet 10 , the outlet 12 and the gap 9 can be configured to be flowed through by a medium 15 . The medium 15 is translucent or transparent , for example .

The wafer chuck 2 can comprise a further inlet 11 and a further outlet 13 . Then, the further inlet 11 is arranged spaced apart from the inlet 10 . Additionally, the further outlet 13 can be arranged spaced apart from the outlet 12 . The inlet 10 can the further inlet 11 can be arranged on a same side of the gap 9 . The outlet 12 and the further outlet 13 can be arranged on the side of the gap 9 opposing the inlet 10 and the further inlet 11 .

As shown here , a lateral extension of the wafer chuck 2 can deviate from an imaginary circular shape on two opposing sides . The parts of the wafer chuck 2 protruding the imaginary circular shape can be referred to as first elongated part 27 and second elongated part 28 of the wafer chuck 2.

The first elongated part 27 and the second elongated part 28 can comprise any shape suitable to spread the medium prior to flowing through the gap. The first elongated part 27 and the second elongated part 28 can be symmetrically arranged. This can mean that the wafer chuck 2 comprises a mirror axis.

For example, the inlet 10 can be arranged at the first elongated part 27. The outlet 12 can be arranged at the second elongated part 28 of the wafer chuck 2. The arrangement 1 can comprise the inlet 10 and at least the further inlet 11. For example, shown here, the arrangement 1 comprises 5 inlets 10, 11. The arrangement 1 can comprise the outlet 12 and at least the further outlet 13. For example, shown here, the arrangement 1 comprises 5 outlets 12, 13. The inlets 10, 11 are arranged on opposing sides of the gap 9. Alternatively, it is also possible that the number of inlets 10 differs from the number of outlets 12. For example, the wafer chuck 2 comprises more inlets 10 than outlets 12 or vice versa. The elongated parts 27, 28 can be configured to spread the medium 15, for example prior to reaching a structure 17 or after leaving the structure 17.

The structure 17 can be arranged in the gap 9. In particular, the structure 17 can be arranged in an outer portion of the gap 9. For example, the structure 17 can be arranged along an imaginary circle. The wafer 3 may not overlap the structure 17 along the vertical direction. Alternatively, the wafer 3 can overlap with the structure 17 along the vertical direction. In this case, preferably only the outer region or the off-zone of the wafer 3 overlap with the structure 17. Alternatively, not shown, the structure 17 can be arranged in the first elongated part 27 and/or in the second elongated part 28 . Alternatively, it is also possible that the structure 17 is arranged in the inlet 10 and/or the outlet 12 .

The structure 17 can be configured to direct the medium 15 through the gap 9 . For this , the structure 17 can comprise any means for shaping, e . g . directing, laminari zing and/or swirling the flow of the medium 15 through the gap 9 .

The structure 17 can comprise a separation wall 18 , in particular a plurality of separation walls 18 . For example the separation walls 18 are arranged in parallel . This can enable a laminar flow of the medium 15 through the gap 9 .

For transporting the medium 15 through the gap 9 , an overpressure can be applied on the side of the inlet 10 , for example in the inlet 10 . On the opposing side , for example in the outlet 12 an underpressure can be applied . Alternatively, the pressure in the outlet 12 corresponds to the ambient pressure . Thereby, the ambient pressure means the pressure of the surrounding medium of the wafer chuck 2 or the arrangement 1 . Overpressure can mean any pressure larger than the ambient pressure , whereas underpressure can refer to any pressure lower than the ambient pressure .

For example , the medium 15 is flown, blown and/or directed through the gap 9 with a predetermined flow rate . I f the flow rate is too low, a temperature gradient might be formed along the gap 9 , for example along a main extension plane of the gap 9 during use of the wafer chuck 2 or during operation of the arrangement 1 . For example , a region of the gap 9 being arranged close to the inlet 10 might experience a larger adj ustment to the initial temperature of the medium 15 , i f the medium 15 inj ected through the inlet 10 is tempered, than regions of the gap 9 arranged further away from the inlet 10 .

Figure 13 shows a schematic top view of an arrangement 1 with a wafer chuck 2 according to an embodiment . For example , the embodiment of the wafer chuck 2 shown here corresponds to the wafer chuck 2 comprised by the arrangement 1 shown in Figure 11 . The medium flow 15 can be laminar or at least approximately laminar through the gap 9 .

The invention described herein is not limited by the description given with reference to the embodiments . Rather, the invention encompasses any novel feature and any combination of features , including in particular any combination of features in the claims , even i f this feature or this combination is not itsel f explicitly indicated in the claims or embodiments .

This patent application claims priority from German patent application 10 2023 126 104 . 5 , the disclosure content of which is hereby incorporated by reference .

References

1 Arrangement

2 Wafer chuck

3 Wafer

4 Light source

5 Di f fusor

6 Plate

7 Further plate

8 Mounting surface

9 Gap

10 Inlet

11 Further inlet

12 Outlet

13 Further outlet

14 Sealing ring

15 Medium

16 Groove

17 Structure

18 Separation wall

19 Further separation wall

20 Outer portion

21 Inner region of wafer

22 Outer region of wafer

23 Optoelectronic device

24 Probe board

25 electromagnetic radiation

26 base plate

27 first elongated part

28 second elongated part

29 prober chuck base

30 photodiode or spectrometer

31 probe needles

32 light guide plate

33 light-emitting element

34 light-emitting element at edge

35 foil 36 frame

37 contact side

38 active side

39 power cable

40 external light source

41 light guide

42 further light guide

43 port

44 further port

45 light distributor

47 groove connector exit

48 suctioning hose connector

49 suctioning hose

50 sealing layer

51 light output

52 support structure

53 planarising screw

54 plate support pillar

55 spring washer

56 plate clamp

57 plate clamp screw

58 sensor

59 optical stack

60 cut-out

61 reflective film

62 fastening unit of light source 4

63 detector

64 optical stack retaining bracket

65 shaft

66 opening

D2 diameter wafer chuck

D3 diameter wafer

Claims

1. An arrangement (1) , comprising

- a wafer chuck (2) , and

- a light source (4) , wherein

- the wafer chuck (2) comprises a plate (6) with a mounting surface (8) for mounting a wafer (3) ,

- the plate (6) is arranged in the beam path of the light source ( 4 ) , and

- the plate (6) is translucent.

2. The arrangement (1) according to the previous claim, wherein the plate (6) comprises glass or sapphire.

3. The arrangement (1) according to one of the previous claims, the arrangement (1) further comprising a base plate (26) and a support structure (52) , wherein:

- the light source (4) is arranged on the base plate (26) ,

- the support structure (52) is arranged laterally to the light source (4) , and

- the plate (6) is arranged on the support structure (52) .

4. The arrangement (1) according to the previous claim, wherein the arrangement (1) further comprises a plate clamp (56) , wherein the plate clamp (56) is configured to attach the plate (6) to the support structure (52) .

5. The arrangement (1) according to one of the previous claims, wherein the mounting surface (8) comprises a groove (16) , wherein the groove (16) is connected with a suction hose (49) .

6. The arrangement (1) according to one of the previous claims, further comprising a sensor (58) , wherein the sensor (58) is configured to monitor a light level of the light source (4) , and the sensor (58) is arranged at an edge portion of the plate (6) on the side of the plate (6) facing the light source (4) .

7. The arrangement (1) according to one of the previous claims, further comprising an optical stack (59) , wherein

- the optical stack (59) is arranged between the light source (4) and the plate (6) , and

- the optical stack (59) is configured for influencing the electromagnetic radiation (25) emitted by the light source (4) .

8. The arrangement (1) according to one of the previous claims, wherein a sealing layer (50) completely surrounds the light source (4) , the optical stack (59) and/or the plate (6) along a lateral direction.

9. The arrangement (1) according to one of the previous claims, wherein the light source (4) comprises a light guide plate (32) , and the light guide plate (32) comprises cut-outs or micro-dots.

10. The arrangement (1) according to one of the claims 1 to

8, wherein the light source (4) comprises a plurality of light-emitting elements (33, 34) , wherein the light-emitting elements (33, 34) are separately controllable.

11. The arrangement (1) according to one of the previous claims, comprising a wafer (3) , wherein

- the wafer (3) comprises an active side (38) , - the wafer (3) is arranged on the mounting surface (8) of the plate (6) of the wafer chuck (2) , and

- the active side (38) of the wafer (3) faces the wafer chuck

(2) .

12. The arrangement (1) according to one of the previous claims, wherein a foil (35) is arranged between the wafer (3) and the wafer chuck (2) .

13. The arrangement (1) according to the previous claim, wherein the foil (35) protrudes the wafer (3) along the lateral directions, the foil (35) overlaps with the groove (16) , and the foil (35) is attached to the mounting surface (8) of the plate (6) of the wafer chuck (2) via suctioning of the groove (1 ) .

14. The arrangement (1) according to one of the claims 11 to

12, wherein the wafer (3) is contacted by probe needles (31) on the side of the wafer (3) facing away from the wafer chuck (2) .

15. A method for probing a wafer (3) with an arrangement (1) according to one of the previous claims, the method comprising :

- attaching the wafer (3) to the wafer chuck (2) ,

- illuminating the wafer (3) with the light source (4) , and

- probing devices under test of the wafer (3) .

16. A method for probing a wafer (3) according to the previous claim, wherein the arrangement (1) is an arrangement

(1) according to claim 5 or 13, and wherein the method comprises releasing the wafer (3) from the wafer chuck (2) by injecting a gas into the groove (16) . 17. A method for probing a wafer (3) according to one of the claims 15 to 16, wherein the method further comprises:

- calibrating the arrangement (1) prior to attaching the wafer (3) , wherein the calibration comprises:

- creating an illuminance map by moving an optical sensor

(30) over the wafer chuck (2) , and

- programming the arrangement (1) for achieving required irradiances .

18. A method for probing a wafer (3) according to one of the claims 15 to 17 with an arrangement (1) according to claim 6, wherein during the probing, the light level is monitored.