EP3743539A1

EP3743539A1 - Evaporator for evaporating a source material, material deposition source, deposition apparatus and methods therefor

Info

Publication number: EP3743539A1
Application number: EP18701455.0A
Authority: EP
Inventors: Claire ARMSTRONG; Frank Schnappenberger; Thomas Deppisch; Jose Manuel Dieguez-Campo; Anja MAURISCHAT; Susanne Schläfer
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2020-12-02
Also published as: CN111655898A; WO2019145014A1

Abstract

An evaporator (100) for evaporating a source material (105) is described. The evaporator includes a crucible (110) having an inner volume (101) for receiving the source material (105) and a first heater (121) for heating the source material (105). The first heater (121) is provided at a top wall (111) of the crucible (110). Further, a method of evaporating a source material is described. The method includes providing a crucible (110) having an inner volume (101) for receiving the source material and evaporating the source material by heating the source material using a first heater (121) provided at a top wall (111) of the crucible (110).

Description

EVAPORATOR FOR EVAPORATING A SOURCE MATERIAL, MATERIAL DEPOSITION SOURCE, DEPOSITION APPARATUS AND

METHODS THEREFOR

TECHNICAL FIELD [0001] Embodiments of the disclosure relate to deposition apparatuses for depositing one or more layers on a substrate, particularly a flexible substrate. In particular, embodiments of the present disclosure relate to apparatuses and methods for coating a substrate with one or more layers, e.g. for thin-film solar cell production, flexible display production or thin-film battery production. More particularly, embodiments of the present disclosure relate to apparatuses and methods for coating a flexible substrate in a roll-to-roll (R2R) process. Specifically, embodiments of the present disclosure relate to evaporators employed in such deposition apparatuses for evaporating the material to be deposited on the substrate.

BACKGROUND

[0002] Processing of flexible substrates, such as plastic films or foils, is in high demand in the packaging industry, semiconductor industries and other industries. Processing may consist of coating of a flexible substrate with a material, such as a metal, a semiconductor and a dielectric material, etching and other processing actions conducted on a substrate for the respective applications. Systems performing this task generally include a coating drum, e.g. a cylindrical roller, coupled to a processing system with a roller assembly for transporting the substrate, and on which at least a portion of the substrate is coated. [0003] For example, a coating process such as a CVD process or a PVD process, particularly a sputter process, can be utilized for depositing thin layers onto flexible substrates. Roll-to-roll deposition apparatuses are to be understood in that a flexible substrate of a considerable length, such as one kilometre or more, is uncoiled from a storage spool, coated with a stack of thin layers, and recoiled again on a wind-up spool. In particular, the increasing demand for flexible touch panel elements, flexible displays, and flexible photovoltaic modules result in an increasing demand for depositing suitable layers in R2R- coaters. Accordingly, there is a continuous demand for improved thin film coating apparatuses and methods for various applications. In particular, the evaporation of the material to be deposited still poses some challenges with respect to providing the optimal evaporation conditions for various materials to be evaporated.

[0004] In view of the above, an evaporator, a deposition source, a deposition apparatus and methods therefor are provided which are improved compared to conventional evaporators, deposition sources, apparatuses and methods therefor.

SUMMARY

[0005] In light of the above, an evaporator for evaporating a source material, a material deposition source for depositing material on a substrate, a deposition apparatus for depositing material onto a substrate, a method of evaporating a source material, and a method of depositing evaporated material on a substrate according to the independent claims are provided. Further aspects, advantages, and features are apparent from the dependent claims, the description, and the accompanying drawings. [0006] According to an aspect of the present disclosure, an evaporator for evaporating a source material is provided. The evaporator includes a crucible having an inner volume for receiving the source material. Further, the evaporator includes a first heater for heating the source material. The first heater is provided at a top wall of the crucible. [0007] According to a further aspect of the present disclosure, a material deposition source for depositing material on a substrate is provided. The material deposition source includes an evaporator for evaporating a source material according to embodiments described herein. Further, the material deposition source includes a distribution assembly connected to the evaporator. The distribution assembly is configured for directing the evaporated source material to the substrate.

[0008] According to another aspect of the present disclosure, a deposition apparatus for depositing material onto a substrate is provided. The deposition apparatus includes a vacuum deposition chamber and a material deposition source having a distribution assembly connected to an evaporator according to embodiments described herein. At least the distribution assembly of the material deposition source is arranged within the vacuum deposition chamber.

[0009] According to a further aspect of the present disclosure, a method of evaporating a source material is provided. The method includes providing an evaporator comprising a crucible having an inner volume for receiving the source material. Further, the method includes evaporating the source material by heating the source material using a first heater provided at a top wall of the crucible. [0010] According to a yet further aspect of the present disclosure, a method of depositing evaporated material on a substrate is provided. The method includes conducting the method of evaporating a source material according to embodiments described herein. Further, the method includes guiding the evaporated source material from the crucible into a distribution assembly having a plurality of outlets, and directing the evaporated source material by the plurality of outlets to the substrate.

[0011] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatus include method aspects for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:

FIG. 1 shows a schematic view of an evaporator for evaporating a source material according to embodiments described herein;

FIGS. 2 and 3 show schematic views of an evaporator for evaporating a source material according to further embodiments described herein;

FIG. 4 shows a schematic view of an evaporator for evaporating a source material according to embodiments described herein, including a connection pipe for connecting the evaporator to a distribution assembly according to embodiments described herein; FIGS. 5 and 6 show schematic views of an evaporator for evaporating a source material according to further embodiments described herein;

FIG. 7 shows a schematic view of a material deposition source for depositing material on a substrate according to embodiments described herein;

FIG. 8 shows a schematic view of a deposition apparatus for depositing material onto a substrate according to embodiments described herein; FIG. 9 shows a flowchart for illustrating a method of evaporating a source material according to embodiments described herein; and

FIG. 10 shows a flowchart for illustrating a method of depositing evaporated material on a substrate according to embodiments described herein. DETAILED DESCRIPTION OF EMBODIMENTS

[0013] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations. [0014] With exemplary reference to FIG. 1, an evaporator 100 for evaporating a source material 105 according to the present disclosure is described. According to embodiments which can be combined with any other embodiments described herein, the evaporator 100 includes a crucible 110 having an inner volume 101 for receiving the source material 105. Typically, the inner volume 101 corresponds to a space confined within the top wall 111, the side walls 112 and the bottom wall of the crucible. In particular, as shown in FIG. 1, the top wall 111 is opposite the bottom wall 113. In other words, typically the top wall 111 is facing the bottom wall 113. The side walls 112 connect the bottom wall with the top wall. Accordingly, as exemplarily shown in FIG. 1, typically the source material 105 is in contact with the bottom wall 113 and at least a portion of the side walls 112, particularly the lower portions of the side walls. Further, the evaporator 100 includes a first heater 121 for heating the source material 105. As exemplarily shown in FIG. 1, the first heater 121 is provided at a top wall 111 of the crucible 110. In particular, the first heater 121 can be provided around an opening 115 providing a passage for evaporated material from the inner volume 101. For instance, the first heater 121 can be provided on an outside surface of the top wall 111 of the crucible 110. Although not explicitly shown, alternatively the first heater 121 can be provided in the top wall 111 of the crucible 110.

[0015] Accordingly, embodiments of the evaporator as described herein are improved compared to conventional evaporators. In particular, embodiments of the evaporator as described herein have the advantage that for evaporating the source material, only a portion of the source material is heated to the evaporation or sublimation temperature of the source material. More specifically, embodiments of the apparatus as described herein provide for the possibility to apply heat at the solid/gaseous interface of the source material. In the figures, the solid/gaseous interface of the source material 105 is exemplarily indicated by the dotted line from which the arrows originate. The arrows originating from said dotted line symbolize evaporated source material.

[0016] Accordingly beneficially, during operation only an upper portion of the complete amount of source material provided in the crucible is heated, which can be beneficial in order to avoid degradation of sensitive source materials. Further, providing heat substantially only to the solid/gaseous interface of the source material has the effect that less energy is needed for the evaporation of the source material. Accordingly, beneficially embodiments of the evaporator as described herein are more efficient and can be operated at lower costs compared to conventional evaporators. Moreover, heating the source material from the top can be advantageous for controlling the evaporation rate. [0017] Before various further embodiments of the present disclosure are described in more detail, some aspects with respect to some terms used herein are explained.

[0018] In the present disclosure, an“evaporator for evaporating a source material” can be understood as an evaporator configured for evaporating a source material by heating the source material employing a heater. For instance, the“source material” may be a material having an evaporation temperature of about l00°C to about 600°C. In particular, the“source material” can be an organic material, for instance for organic light emitting diode (OLED) production.

[0019] In the present disclosure, a“crucible” can be understood as a device having a reservoir for the material to be evaporated by heating the crucible. Accordingly, a“crucible” can be understood as a source material reservoir which can be heated to vaporize the source material into a gas by at least one of evaporation and sublimation of the source material. The reservoir can have an inner volume for receiving the source material to be evaporated, e.g. an organic material. For example, the inner volume of the crucible can be between 100 cm³ and 3000 cm³, particularly between 700 cm³ and 1700 cm³, more particularly 1200 cm³. Typically, the inner volume of the crucible is provided by the product of the height H, the width (W) and the length (L), as exemplarily shown in FIG. 5.

[0020] In the present disclosure, a“heater for heating the source material” can be understood as a heating unit or heating device configured to heat the source material, particularly to vaporize the source material into a gaseous source material. Upon heating the source material by the heater as described herein, the source material provided in the inner volume of the crucible is heated up to a temperature at which the source material evaporates. For instance, initially the material to be evaporated can be in the form of a powder. Source materials in powder form are typically poor thermal conductors. As a result, it typically takes a long time to fully heat through the whole volume of source material, and the system is slow to respond to any imposed changes in temperature (i.e. temperature changes for adjusting the evaporation rate). By providing an evaporator as described herein, i.e. having a first heater provided at a top wall of the crucible, the response time to temperature changes can be reduced. [0021] As exemplarily shown in FIG.l, according to some embodiments which can be combined with other embodiments described herein, the top wall 111 of the crucible 110 includes an opening 115 providing a passage for evaporated material from the inner volume 101 of the crucible. Although not explicitly shown, according to another implementation, an opening providing a passage for evaporated material from the inner volume of the crucible can be provided in a side wall 112 of the crucible 110, particularly an upper portion of the side wall of the crucible.

[0022] With exemplary reference to FIG. 2, according to some embodiments which can be combined with other embodiments described herein, the evaporator 100 further includes a second heater 122 provided at a side wall 112 of the crucible 110.

[0023] For instance, the second heater 122 can be provided on an outside surface of the side wall 112 of the crucible 110. Although not explicitly shown, alternatively the second heater 122 can be provided in the side wall 112 of the crucible 110. In particular, the second heater 122 can be provided by two separate second heaters provided at opposing side walls as exemplarily shown in FIG. 2. Although not explicitly shown, it is to be understood that the second heater can be provided by four separate second heaters each provided at one of the four sidewalls of the crucible. Fig. 5 shows an isometric schematic view of the crucible having four sidewalls connecting the bottom wall 113 with the top wall 111 of the crucible. Accordingly, one or more second heaters, particularly two or four second heaters, can be provided on respective outside surfaces of the side walls of the crucible. Alternatively, one or more second heaters, particularly two or four second heaters, can be provided in the respective side walls of the crucible. Accordingly, providing one or more second heaters as described herein can be beneficial for generating a homogeneous evaporation of the source material.

[0024] With exemplary reference to FIG. 3, according to some embodiments which can be combined with other embodiments described herein, the evaporator 100 further includes a third heater 123 provided at a bottom wall 113 of the crucible 110. For instance, the third heater 123 can be provided on an outside surface of the bottom wall 113 of the crucible 110. Although not explicitly shown, alternatively the third heater 123 can be provided in the bottom wall 113 of the crucible 110. Providing a third heater as described herein can be beneficial for improving the evaporation of the source material. For instance, it can be beneficial to preheat the source material by the third heater such that the thermal energy for the evaporation of the source material applied by the first heater can be reduced.

[0025] According to some embodiments which can be combined with other embodiments described herein, the evaporator 100 further includes a connection pipe 130, as exemplarily shown in FIG. 4. In particular, a first end 131 of the connection pipe may have a first orientation and is connected to the opening 115 of the crucible. Further, typically a second end 132 of the connection pipe 130 has a second orientation which is different from the first orientation. In other words, the connection pipe 130 can include a bending 133. For instance, the first orientation of the first end 131 of the connection pipe 130 can be vertical ± 20°, particularly vertical ± 5°. The second orientation of the second end 132 of the connection pipe 130 can be horizontal ± 20°, particularly horizontal ± 5°. In FIG. 4 the vertical direction is indicated by arrow V and the horizontal direction is indicated by arrow H.

[0026] Accordingly, it is to be understood that the connection pipe 130 is configured for guiding evaporated material from the crucible to a distribution assembly 210, as described in more detail with reference to FIG. 7. In the present disclosure, a“connection pipe” can be understood as a pipe or tube which is configured for providing fluid communication between the crucible and the distribution assembly as described herein.

[0027] According to some embodiments which can be combined with other embodiments described herein, the inner volume 101 of the crucible has a height H, a width W and a length L, the length L being larger than the height H, as exemplarily shown in FIG. 5. In particular, a ratio of the height H of the inner volume to the length of the inner volume H/L is 0.8 or less, particularly 0.7 or less, more particularly 0.6 or less. Providing a ratio of H/L < 0.8, the surface of the source material exposed to heat provided from the first heater 121 at the top wall 111 can be increased. Accordingly, the solid/gaseous interface of the source material can be increased which can be beneficial for improving the evaporation conditions.

[0028] Accordingly, the crucible may be an elongated crucible configured for providing a large top surface of source material provided in the crucible. As exemplarily described with reference to FIG. 3, the evaporator may include three separate heaters to allow for independent heating of the source material from the top, the sides and the bottom. In particular, by providing a top heater, i.e. the first heater as described herein, the top surface area of the source material can directly be heated which has the advantage that the entire volume of source material does not have to be at the same temperature for evaporation to occur. Accordingly, embodiments of the evaporator as described herein provide for a better evaporation process control, since a faster response time to imposed temperature changes can be realized. Further, it is to be noted that by using independent heaters for the top, the sides and the bottom of the crucible, the bulk of the source material can remain at a lower temperature than the top surface, which is beneficial for slowing down the rate of material degradation.

[0029] With exemplary reference to FIG. 6, according to some embodiments which can be combined with other embodiments described herein, the evaporator 100 further includes a controller 160. The controller 160 is configured for providing a first control signal Sl to the first heater 121. Further, the controller 160 can be configured for providing a second control signal S2 to the second heater 122. For instance, the second control signal S2 can be different from the first control signal S 1. In particular, the first control signal S 1 typically controls the heating of the first heater 121 and the second control signal S2 controls the heating of the second heater 122. More specifically, the first control signal Sl may trigger to heat the first heater 121 to a first temperature and the second control signal S2 may trigger to heat second heater 122 to a second temperature. Typically, the first temperature is different from the second temperature. In particular, the first temperature can be higher than the second temperature. Accordingly, by providing an evaporator having a controller as described herein, an evaporator is provided with which evaporation source material can be controlled and adjusted according to the source material used.

[0030] According to some embodiments which can be combined with other embodiments described herein, the controller 160 can be configured for providing a third control signal S3 to the third heater 123. For example, the third control signal S3 can be different from the first control signal Sl and/or the second control signal S2.

[0031] In particular, the third control signal S3 typically controls the heating of the third heater 123. More specifically, the third control signal S3 may trigger to heat the third heater 123 to a third temperature. Typically, the first temperature is different from the first temperature and/or the second temperature. For instance, the third temperature can be lower than the first temperature and/or the second temperature. Accordingly, controlling heating of the third heater 123 by a controller as described herein can be beneficial to provide for a preheating of the source material. Preheating of the source material can be beneficial for optimizing the evaporations conditions, particularly advantageous for sensitive source materials. For instance, preheating of the source material can be beneficial for reducing the thermal energy for the evaporation of the source material applied by the first heater.

[0032] With exemplary reference to FIG. 7, a material deposition source 200 for depositing material on a substrate 201 according to the present disclosure is described. According to embodiments which can be combined with any other embodiments described herein, the material deposition source 200 includes an evaporator 100 for evaporating a source material 105 according to embodiments described herein. Further, the material deposition source 200 includes a distribution assembly 210 connected to the evaporator 100. For instance, the distribution assembly 210 can be connected to the evaporator 100 via a connection pipe 130 as described herein. Typically, the distribution assembly 210 is configured for directing the evaporated source material to the substrate 201.

[0033] In the present disclosure, “material deposition source” can be understood as a device or assembly configured for providing a source of material to be deposited on a substrate. In particular, a“material deposition source” may be understood as a device or assembly having an evaporator including a crucible configured to evaporate the material to be deposited. Further, a “material deposition source” of the present disclosure typically includes a“distribution assembly” configured for guiding gaseous, evaporated source material to a substrate to be coated.

[0034] In the present disclosure, a“distribution assembly” can be understood as an assembly configured for providing evaporated material, particularly a plume of evaporated material, from the distribution assembly to the substrate. For example, the distribution assembly may include a distribution pipe which can be an elongated cube. For instance, a distribution pipe as described herein may provide a line source with a plurality of outlets 205. Typically, the plurality of outlets 205 are arranged along the length of the distribution assembly, as exemplarily shown in FIG. 7.

[0035] Accordingly, the distribution assembly can be a linear distribution showerhead, for example, having a plurality of openings (or an elongated slit) disposed therein. A showerhead as understood herein can have an enclosure, hollow space, or pipe, in which the evaporated material can be provided or guided, for example from the evaporation crucible to the substrate. According to embodiments which can be combined with any other embodiments described herein, the length of the distribution pipe may correspond at least to the width of the substrate to be coated. In particular, the length of the distribution pipe may be longer than the width of the substrate to be coated, at least by 10% or even 20%. For example, the length of the distribution pipe can be 1.3 m or above, for example 2.5 m or above. Accordingly, a uniform deposition at the edges of the substrate can be provided. According to an alternative configuration, the distribution assembly may include one or more point sources which can be arranged along a horizontal direction.

[0036] For example, the distribution assembly can be configured to provide a line source, e.g. extending essentially in a horizontal direction H as shown in FIG. 7. In the present disclosure, the term“essentially in a horizontal direction" is to be understood to allow for a deviation from the horizontal direction of 10°, particularly 5° or below.

[0037] Accordingly, as exemplarily indicated by the dotted arrows in FIG. 7, embodiments on the material deposition source 200 as described herein are configured for guiding the evaporated source material from the evaporator 100, through the distribution assembly to the substrate 201. As shown in FIG. 7, the evaporated source material exits the distribution assembly though the plurality of outlets 205 of the distribution assembly. For example, the one or more outlets of the distribution assembly, e.g. a distribution pipe, can be nozzles arranged along a longitudinal axis of the distribution assembly. For instance, the longitudinal axis of the distribution assembly can be essentially horizontal, as exemplarily shown in FIG. 7.

[0038] In the present disclosure, the term“substrate” may embrace flexible substrates such as a web or a foil. However, the present disclosure is not limited thereto, and the term“substrate” may also embrace substantially inflexible substrates, e.g., a wafer, slices of transparent crystal such as sapphire or the like, or a glass plate. The term“substantially inflexible” is understood to distinguish over“flexible”. Specifically, a substantially inflexible substrate can have a certain degree of flexibility, e.g. a glass plate having a thickness of 0.5 mm or below, wherein the flexibility of the substantially inflexible substrate is small in comparison to the flexible substrates. [0039] According to embodiments described herein, the substrate may be made of any material suitable for material deposition. For instance, the substrate may be made of a material selected from the group consisting of glass (for instance sodalime glass, borosilicate glass etc.), metal, polymer, ceramic, compound materials, carbon fiber materials or any other material or combination of materials which can be coated by a deposition process. In particular, a “flexible substrate” may be understood as a substrate that is bendable. In particular, a flexible substrate as referred to herein may be understood as a substrate suitable for being coated in an evaporation apparatus, in particular in a reactive evaporation apparatus. For example, the flexible substrate may be a foil or a web, e.g. foil or a web made of or containing plastics and polymers (such as polypropylene, PET substrates, substrates made of or containing OPP, BOPP, CPP, PE, LDPE, HDPE, OPA, PET), pre-coated paper, or biodegradable films (such as PL A).

[0040] With exemplary reference to FIG. 8, a deposition apparatus 300 for depositing material onto a substrate 201 according to the present disclosure is described. According to embodiments which can be combined with any other embodiments described herein, the deposition apparatus 300 includes a vacuum deposition chamber 310 and a material deposition source 200 according embodiments described herein. As exemplarily shown in FIG. 8, at least the distribution assembly 210 of the material deposition source 200 is arranged within the vacuum deposition chamber 310. The evaporator 100 connected to the distribution assembly 210 via the connection pipe 130 may be arranged outside the vacuum deposition chamber 310.

[0041] In the present disclosure, a“vacuum deposition chamber” is to be understood as a chamber configured for vacuum deposition. The term“vacuum”, as used herein, can be understood in the sense of a technical vacuum having a vacuum pressure of less than, for example, 10 mbar. Typically, the pressure in a vacuum chamber as described herein may be between 10 ⁵ mbar and about 10 ⁸ mbar, more typically between 10 ⁵ mbar and 10 ⁷ mbar, and even more typically between about 10 ⁶ mbar and about l0 ⁷ mbar. According to some embodiments, the pressure in the vacuum chamber may be considered to be either the partial pressure of the evaporated material within the vacuum chamber or the total pressure (which may approximately be the same when only the evaporated material is present as a component to be deposited in the vacuum chamber). In some embodiments, the total pressure in the vacuum chamber may range from about 10 ⁴ mbar to about 10 ⁷ mbar, especially in the case that a second component besides the evaporated material is present in the vacuum chamber (such as a gas or the like).

[0042] According to some embodiments which can be combined with other embodiments described herein, the deposition apparatus 300 can be a roll-to-roll deposition apparatus, as exemplarily shown in FIG. 8. Accordingly, the substrate can be a flexible substrate. Further, the deposition apparatus may have at least one roll configured for transporting the flexible substrate. In particular, the deposition apparatus 300 may include a first spool chamber 311, a vacuum deposition chamber 310 arranged downstream from the first spool chamber 311, and a second spool chamber 312 arranged downstream from vacuum deposition chamber 310. The first spool chamber 311 typically houses a storage spool 313 with a flexible substrate wound thereon, and the second spool chamber 312 typically houses a wind-up spool 314 for winding the coated flexible substrate thereon after deposition. Further, a roller assembly 315 comprising a plurality of rolls or rollers can be provided for transporting the substrate along a substrate transportation path from the storage spool 313 through the vacuum deposition chamber 310 to the wind-up spool 314.

[0043] The term“downstream from” as used herein may refer to the position of the respective chamber or of the respective component with respect to another chamber or component along the substrate transportation path. For example, during operation, the substrate is guided from the first spool chamber 311 through the vacuum deposition chamber 310 and subsequently guided to the second spool chamber 312 along the substrate transportation path via the roller assembly 315. Accordingly, the vacuum deposition chamber 310 is arranged downstream from the first spool chamber 311, and the second spool chamber 312 is arranged downstream from the vacuum deposition chamber 310.

[0044] Although not explicitly shown, it is to be understood that according to some embodiments which can be combined with other embodiments described herein, one or more further vacuum deposition chambers may be provided. For instance, one or more further vacuum deposition chambers can be provided between the first spool chamber 311 and the vacuum deposition chamber 310. Additionally or alternatively, one or more further vacuum deposition chambers can be provided between the vacuum deposition chamber 310 and the second spool chamber 312.

[0045] With exemplary reference to the flowchart shown in FIG. 9, a method 400 of evaporating a source material according to the present disclosure is described. The method 400 includes providing (block 410) an evaporator 100 including a crucible 110 having an inner volume 101 for receiving the source material. In particular, the evaporator 100 is an evaporator according to embodiments described herein. Further, the method 400 includes evaporating (block 420) the source material by heating the source material using a first heater 121 provided at a top wall 111 of the crucible 110. [0046] According to some embodiments which can be combined with other embodiments described herein, the method 400 of evaporating a source material includes heating the source material using a second heater 122 and/or a third heater 123 as described herein. In particular, the method 400 of evaporating a source material may include controlling the heating of the first heater 121 and/or the second heater 122 and/or the third heater 123 by using a controller 160, as for example described with reference to FIG. 6.

[0047] With exemplary reference to the flowchart shown in FIG. 10, a method 500 of depositing evaporated material on a substrate according to the present disclosure is described. The method 500 includes conducting (block 510) the method 400 of evaporating a source material according to embodiments described herein. Additionally, the method 500 includes guiding (block 520) the evaporated source material from the crucible into a distribution assembly having a plurality of outlets. Further, the method 500 includes directing (block 530) the evaporated source material by the plurality of outlets to the substrate.

[0048] In view of the embodiments described herein, it is to be understood that the embodiments of the evaporator, the embodiments of the deposition source, the embodiments of apparatuses and the embodiments of the methods therefor are improved with respect to the state of the art. In particular, embodiments of the present disclosure have the advantage that the evaporation of source material can be controlled and adjusted such that the evaporation of source material can be optimized according to the source material used. More specifically, embodiments of the present disclosure beneficially provide the possibility to avoid degradation of sensitive source materials because the heating of the source material can be selectively applied to the solid/gaseous interface of source material. Accordingly, beneficially embodiments of the present disclosure are more efficient and can be operated at lower costs compared to the state of the art.

[0049] While the foregoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope, and the scope is determined by the claims that follow.

Claims

1. An evaporator (100) for evaporating a source material (105), comprising:

- a crucible (110) having an inner volume (101) for receiving the source material (105); and

- a first heater (121) for heating the source material (105), the first heater

(121) being provided at a top wall (111) of the crucible (110).

2. The evaporator (100) according to claim 1, further comprising a second heater (122) provided at a side wall (112) of the crucible (110).

3. The evaporator (100) according to claim 1 or 2, further comprising a third heater (123) provided at a bottom wall (113) of the crucible (110).

4. The evaporator (100) according to any of claims 1 to 3, the top wall (111) comprising an opening (115) providing a passage for evaporated material from the inner volume (101).

5. The evaporator (100) according to claim 4, further comprising a

connection pipe (130), wherein a first end (131) of the connection pipe has a first orientation and is connected to the opening (115), and wherein a second end (132) of the connection pipe (130) has a second orientation which is different from the first orientation.

6. The evaporator (100) according to claim 5, the first orientation being

vertical ± 20°, particularly vertical ± 5°, and the second orientation being horizontal ± 20°, particularly horizontal ± 5°.

7. The evaporator (100) according to any of claims 1 to 6, the inner volume (101) having a height (H), a width (W) and a length (L), the length (L) being larger than the height (H).

8. The evaporator (100) according to claim 7, wherein a ratio of height

to length (H/L) is 0.8 or less, particularly 0.7 or less.

9. The evaporator (100) according to any of claims 2 to 8, further comprising a controller (160), the controller being configured for providing a first control signal (Sl) to the first heater (121) and for providing a second control signal (S2) to the second heater (122), the second control signal (S2) being different from the first control signal (Sl).

10. The evaporator (100) according to any of claims 3 to 8 and 9, the

controller being configured for providing a third control signal (S3) to the third heater (123), the third control signal (S3) being different from the first control signal (Sl). 11. A material deposition source (200) for depositing material on a substrate (201), comprising:

- an evaporator (100) for evaporating a source material (105) according any of claims 1 to 10; and

- a distribution assembly (210) connected to the evaporator (100), the distribution assembly (210) being configured for directing the evaporated source material to the substrate.

12. A deposition apparatus (300) for depositing material onto a substrate (201), comprising:

- a vacuum deposition chamber (310); and - a material deposition source (200) according claim 11 , wherein at least the distribution assembly (210) is arranged within the vacuum deposition chamber (310).

13. The deposition apparatus (300) according to claim 12, wherein the

deposition apparatus is a roll-to-roll deposition apparatus, and wherein the substrate is a flexible substrate, the deposition apparatus having at least one roll configured for transporting the flexible substrate.

14. A method (400) of evaporating a source material, the method comprising:

- providing an evaporator (100) comprising a crucible (110) having an inner volume (101) for receiving the source material; and

- evaporating the source material by heating the source material using a first heater (121) provided at a top wall (111) of the crucible (110).

15. A method (500) of depositing evaporated material on a substrate; the method comprising:

- conducting the method (400) of evaporating a source material according to claim 14;

- guiding the evaporated source material from the crucible into a distribution assembly having a plurality of outlets, and

- directing the evaporated source material by the plurality of outlets to the substrate.