US20200094375A1

US20200094375A1 - Multiple zone pad conditioning disk

Info

Publication number: US20200094375A1
Application number: US16/582,452
Authority: US
Inventors: Stan D. Tsai; Luke S. Tsai
Original assignee: Cana Diamond Technology LLC
Current assignee: Cana Diamond Technology LLC
Priority date: 2018-09-26
Filing date: 2019-09-25
Publication date: 2020-03-26
Also published as: CN110948392A; KR20200035367A; TW202015861A

Abstract

A pad conditioning disk configured to condition a polishing pad of a chemical mechanical polishing tool including a plurality of zones comprising cutting elements that selectively engage the polishing pad based on a positioning of the plurality of zones, is provided. An associated chemical mechanical polishing (CMP) tool and method for conditioning a polishing pad during a chemical mechanical polishing process is also provided.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Application No. 62/737,078, filed Sep. 26, 2018, and entitled “Pad Conditioning Disk with Multiple Zones.”

FIELD OF TECHNOLOGY

The following relates to embodiments of a pad conditioning disk, and more specifically to embodiments of a multiple zone pad condition disk for use with a chemical mechanical polishing tool.

BACKGROUND

Chemical Mechanical Polishing or Planarization (CMP) is a polishing process for silicon wafers and other substrates that utilizes a slurry, with its chemistry and abrasives, on a polishing pad, with a combination of chemical and mechanical effects for removal of excess materials over the top and for achieving desired thickness with smooth and flat surfaces of the silicon wafer and other substrates. The polishing pads require optimal surface porosity for successful CMP and tend to lose surface porosity as a result of surface degradation over time. Polishing pad conditioning disks are a critical element of the CMP technology used to create, maintain and recreate the optimal surface porosity of the polishing pad.

SUMMARY

An aspect relates to a pad conditioning disk configured to condition a polishing pad of a chemical mechanical polishing tool, comprising: a plurality of zones comprising cutting elements that selectively engage the polishing pad based on a positioning of the plurality of zones.
In an exemplary embodiment, the plurality of zones are moveable with respect to each other,
In an exemplary embodiment, the plurality of zones are moveable with respect to each other so that cutting elements of a first zone of the plurality of zones contact the polishing pad during a chemical mechanical polishing process while cutting elements of a second zone of the plurality of zones do not contact the polishing pad,
In an exemplary embodiment, a first zone of the plurality of zones comprise grit diamonds of a certain shape, size, distribution and density, and a second zone of the plurality of zones comprises chemical vapor deposition (CVD) diamond film coated on a textured surface.
In an exemplary embodiment, the cutting elements of each zone are diamonds or diamond-like films of a same shape, size, distribution, density, and configuration, or the cutting elements of each zone are diamonds of a different shape, size, distribution, density, and configuration.
In an exemplary embodiment, a connection means operably connects the plurality of zones and facilitates independent movement between the plurality of zones.
In an exemplary embodiment, in a first position of the pad conditioning disk, a first zone is recessed, and the cutting elements of a second zone contact the polishing pad, and, in a second position, the first zone protrudes from the second zone in a direction toward the polishing pad and the cutting elements of the first zone contact the polishing pad.
In an exemplary embodiment, the pad conditioning disk is connected to a pad conditioner arm of the chemical mechanical polishing tool by a moveable connector, and an actuator facilitates independent movement between the first zone and at least another zone.
In an exemplary embodiment, a first zone is connected to a pad conditioner arm of the chemical mechanical polishing tool by a first moveable connector and a second zone is connected to the pad conditioner arm by a second moveable connector. At least one of the first moveable connector is actuated along a Z-axis to facilitate vertical independent movement of the first zone with respect to the second zone, and the second moveable connector is actuated along a Z-axis to facilitate vertical independent movement of the second zone with respect to the first zone.
In an exemplary embodiment, the plurality of zones are at least one of: circles, rings, radial pies, spiral ribs, rectangular or triangular cutouts, and dies.
Another aspect relates to a chemical mechanical polishing tool, comprising: a polishing pad disposed on a platen, the polishing pad configured to polish a substrate, a polishing fluid delivery arm, the polishing fluid delivery arm configured to deliver a polishing fluid during a pad conditioning process, and a conditioner assembly, the conditioner assembly including: a pad conditioner arm connected to a machine base of the chemical mechanical polishing tool, and a pad conditioning disk connected to the pad conditioner arm, the pad conditioning disk having at least two zones that are activated with respect to each other for selectively engaging the polishing pad.
In an exemplary embodiment, the at least two zones each include cutting elements that are a same shape, size, distribution, density, and configuration or a different shape, size, distribution, density, and configuration.
In an exemplary embodiment, the chemical mechanical polishing tool comprises elements to activate and deactivate zone switches
In an exemplary embodiment, the pad conditioner arm contains two or more independent mechanisms to connected to corresponding zones of the pad conditioning assembly.
Another aspect relates to a method for conditioning a polishing pad during a chemical mechanical polishing process, the method comprising: selectively activating a selected zone of a pad condition disk having a plurality of zones, each of the plurality of zones having cutting elements for conditioning the polishing pad, wherein a selection of the zone to use for conditioning the polishing pad depends on a plurality of factors, and applying a downforce to the pad conditioning disk that brings the cutting elements of the selected zone in contact with the polishing pad but not the cutting elements of the other zones.
In an exemplary embodiment, the plurality of factors include a polishing recipe, a polishing event, a usage time of the chemical mechanical polishing tool, an interval of a number of wafers polished by the chemical mechanical polishing tool, a defined schedule, an optimal surface porosity of the polishing pad, and a feedback from a dynamic feedback system.
In an exemplary embodiment, the factor is a feedback from a dynamic feedback system, the feedback including a performance of a wafer, a friction between the wafer and the polishing pad, and a roughness measurement of the polishing pad.
In an exemplary embodiment, the factor for the selection of the zone to use for conditioning the polishing pad is a type of conditioning, the type of conditioning being either an in-situ conditioning period or an ex-situ conditioning period, further wherein, during the ex-situ conditioning period, cutting elements of the selected zone are engaged with the polishing pad, while cutting elements of an other zone are disengaged from the polishing pad, and during the in-situ conditioning period, cutting elements of the selected zone are disengaged from the polishing pad, while the cutting elements of the other zone are engaged.
In an exemplary embodiment, the factor for the selection of the zone to use for conditioning the polishing pad is whether the chemical mechanical polishing process is in a break-in stage or a wafer processing stage, further wherein, during pad the break-in stage, cutting elements of the selected zone are engaged with the polishing pad, while cutting elements of an other zone are disengaged from the polishing pad, and during the wafer processing stage, cutting elements of the selected zone are disengaged from the polishing pad, while the cutting elements of the other zone are engaged with polishing pad.
In an exemplary embodiment, the factor for the selection of the zone to use for conditioning the polishing pad is a type of conditioning, the type of conditioning being either in-situ condition or ex-situ conditioning.
In an exemplary embodiment, the selectively activating a different zone of the pad conditioning disk based on a change to one or more of the plurality factors. The selectively activating the different zone includes actuated a moveable connector of a pad conditioner arm to adjust a position of the selected zone with respect to the different zone.
The foregoing and other features of construction and operation will be more readily understood and fully appreciated from the following detailed disclosure, taken in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the embodiments will be described in detail, %ith reference to the following figures, wherein like designations denote like members, wherein:

FIG. 1A depicts a schematic, top view of a CMP system, in accordance with embodiments of the present invention;

FIG. 1B depicts a cross-sectional view of the CMP system of FIG. 1A, in accordance with embodiments of the present invention;

FIG. 2 depicts a schematic view of the pad condition disk having multiple zones that selectively engage a polishing pad in a first position, in accordance with embodiments of the present invention;

FIG. 3 depicts a schematic view of the pad condition disk having multiple zones that selectively engage the polishing pad in a second position, in accordance with embodiments of the present invention;

FIG. 4 depicts a schematic view of the pad condition disk having multiple zones that have different types of cutting elements, in accordance with embodiments of the present invention;

FIG. 5 depicts a schematic view of the pad condition disk having multiple zones that have different types of cutting elements in a changed position from FIG. 4, in accordance with embodiments of the present invention;

FIG. 6 depicts a perspective view of a first position of a pad conditioning disk having concentric zones, in accordance with embodiments of the present invention;

FIG. 7 depicts a bottom view of the pad conditioning disk of FIG. 6, in accordance with embodiments of the present invention;

FIG. 8 is a side view of the pad conditioning disk of FIG. 6, in accordance with embodiments of the present invention;

FIG. 9 depicts a cross-sectional view along line A-A of FIG. 7, in accordance with embodiments of the present invention;

FIG. 10 depicts a perspective view of a second position of the pad conditioning disk of FIG. 6, in accordance with embodiments of the present invention;

FIG. 11 depicts a bottom view of the pad conditioning disk of FIG. 10, in accordance with embodiments of the present invention;

FIG. 12 is a side view of the pad conditioning disk of FIG. 10, in accordance with embodiments of the present invention;

FIG. 13 depicts a cross-sectional view along line A-A of FIG. 11, in accordance with embodiments of the present invention;

FIG. 14 depicts a schematic view of the pad condition disk operably connected to a pad conditioner arm, in a first position, in accordance with embodiments of the present invention;

FIG. 15 depicts a top of FIG. 14, in accordance with embodiments of the present invention;

FIG. 16 depicts a schematic view of the pad condition disk operably connected to the pad conditioner arm, in a second position, in accordance with embodiments of the present invention;

FIG. 17 depicts a schematic view of a pad condition disk operably connected to a pad conditioner arm, in a first position, in accordance with embodiments of the present invention;

FIG. 18 depicts a top of FIG. 17, in accordance with embodiments of the present invention;

FIG. 19 depicts a schematic view of the pad condition disk operably connected to the pad conditioner arm, in a second position, in accordance with embodiments of the present invention;

FIG. 20 depicts a first configuration of a pad conditioning disk, in accordance with embodiments of the present invention;

FIG. 21 depicts a second configuration of a pad conditioning disk, in accordance with embodiments of the present invention;

FIG. 22 depicts a third configuration of a pad conditioning disk, in accordance with embodiments of the present invention;

FIG. 23 depicts a fourth configuration of a pad conditioning disk, in accordance with embodiments of the present invention; and

FIG. 24 depicts a CMP tool that utilizes the pad conditioning disk according to embodiments of the present invention.

DETAILED DESCRIPTION

A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure.
As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
In brief overview, a pad conditioning disk is a component of a CMP tool that is used to create, maintain, and restore an optimal surface porosity of a polishing pad used in the CMP process. Pad conditioning disks are required to perform multiple tasks on the polishing pad surface, including creating a polishing surface with open pores and uniform contact areas, effectively removing polish byproducts from the surface of the polishing pad, regenerating a fresh surface after polish, maintaining a consistent polishing pad surface over a lifespan of the polishing pad, and avoiding creation of large pad debris. To accomplish these tasks, cutting elements, such as diamond teeth, of the pad condition disk cut through a surface of the polishing pads. The diamonds selected for use as pad conditioning teeth play a critical role in defining a performance of a pad, which in turn defines a performance of wafer polishing, such as a removal rate, uniformity, dishing, erosion, defectivity, performance stability, etc. Diamonds are selected depending on the application and are based on a size of the diamonds, an orientation of the diamonds, and a cutting angle of the diamonds, such as a crystal shape of the diamond (e.g. sharp vs. blocky). Further considerations include a leveling of the diamond tips for uniform exposure of diamonds to the polishing pads, diamond density, and other configuration parameters.
Moreover, cutting edges of the diamond teeth of the pad condition disk wear over time, which prompts a replacement of the pad condition disk; polishing pads are typically replaced along with the pad conditioning disk even though the polishing pad is not completely out of its usage life. In addition to the expense of a new polishing pad and a new pad conditioning disk, there are significant costs associated with CMP tool unavailability and the cost to bring the CMP tool back into production with the new components.
Conventional pad conditioning disks include a single zone of diamond teeth that moves up and down as a single unit. For instance, all of the diamonds of a single pad condition disk are bonded to a single substrate, acting as a single unit in terms of an interaction with the polishing pad. Not all diamonds are effectively engaged with the polishing pad. Those in a relatively protruded position are engaged and are worn over time of usage. Meanwhile, those diamonds in a relatively recessed position are not effectively engaged with the pad surface and will not be worn over time. However, since all diamonds are bonded into a single piece, at the time the cutting edges of those protruded diamonds are worn, the entire piece needs to be replaced.
Furthermore, conventional pad conditioning disks are largely limited to a same type of diamond due to the single zone design. In many cases, CMP has multiple functional requirements for a pad conditioning process. For example, one may need to create a surface texture effectively and then to maintain it. Different types of diamond may be preferred for creating a surface texture versus for maintaining a surface. In such case, conventional pad conditioning disks, limited to have only one type of diamond, have to use a compromised type of diamond to cover both functional requirements. As a result, CMP performance suffers.
Thus, it is desirable that a pad conditioning disk generates and maintains the optimum surface porosity of the polishing pad for as long as possible. The pad conditioning disk according to embodiments of the present invention includes a plurality of zones that are individually activated so that some diamond teeth are preserved while other diamond teeth are used to condition the polishing pad. And unlike conventional disks, the preserved diamonds can be activated at a later stage in the lifespan of the pad conditioning disk to maintain a consistent cutting performance throughout the lifespan of the pad conditioning disk. In this way, an aging of the diamonds, and therefore the diamond disk can be controlled and/or programmed to extend a lifespan of the pad condition disk and consequently the polishing pad.
Moreover, the plurality of zones can include different types of diamonds in a single pad conditioning disk for added versatility and effective pad surface engineering. For example, a certain type of sharp diamond can be used for the purpose of generating a desired surface texture and a certain type of mild diamond can be used for maintaining the surface texture once created. Switching between diamond types of a single pad conditioning disk is achieved by relative movement between the zones of the pad conditioning disk. Accordingly, the pad conditioning disk according to embodiments of the present invention has multiple zones of diamonds within the same pad conditioning disk to provide dynamic control of polishing pad surface engineering, deliver improved CMP process performance (e.g. less defects with improved dishing/erosion), and extend the lifespan of the pad conditioning disk and other components of the CMP tool.
Referring now to the drawings, FIGS. 1A and 1B depict a schematic, top view and cross-sectional view, respectively, of a CMP system 10, in accordance with embodiments of the present invention. The CMP system 10 is used for CMP processes. The CMP system 10 includes a polishing fluid delivery arm 11 that is configured to deliver a polishing fluid 12 during a polishing process. The polishing fluid 12 may comprise an abrasive-containing polishing slurry or may comprise an abrasive-free liquid, which may be reactive. A polishing pad 13 is positioned on a platen 14 and is configured to polish a substrate (e.g. silicon wafer). The platen 14 is utilized to rotate the polishing pad 13 during processing such that the polishing pad 13 planarizes or polishes a surface of the substrate disposed on the polishing pad 13. The polishing pad 13 is a consumable product having a polishing surface and may be secured to the platen 14. The substrate is retained by a polishing head 15 that rotatably contacts the substrate during processing. The polishing head 15 optionally includes a retaining ring that prevents the substrate from moving out from under the polishing head 15 during polishing. The CMP system 10 further includes a conditioner assembly that includes a pad condition disk 100 operably connected to a pad conditioner arm 17 via shaft 16; the pad conditioner arm 17 is connected to a machine base of a chemical mechanical polishing tool. The shaft 16 is disposed through a machine base of the CMP tool 10. The pad conditioner arm 16 may rotate about an axis normal to the machine base. In an exemplary embodiment, the rotation is facilitated by bearings between the machine base 130 and the pad conditioner arm such that the pad conditioner arm 16 rotates the pad conditioning disk 100. The disk 100 may further spin at a certain rotational speed. A downward force is applied to urge the pad conditioning disk 100 against the polishing pad 13.
The pad conditioning disk 100 includes a plurality of zones that are include cutting elements that selectively engage the polishing pad 113 based on a positioning of the zones. The zones can be independently and/or individually activated with respect to each other for selectively engaging the polishing pad 13. For example, diamonds on the pad conditioning disk 100 are grouped into two or more zones. FIG. 2 depicts a schematic view of the pad condition disk 100 having multiple zones that selectively engage a polishing pad 13 in a first position, in accordance with embodiments of the present invention. In the illustrated embodiment, the pad conditioning disk 100 includes a first zone 1 with cutting elements 3 and a separate second zone 2 with cutting elements 4. Here, the cutting elements 3, 4 are the same for both the first zone 1 and the second zone 2. The cutting elements 3, 4 are intended to cut through the polishing pad 13 to restore and/or maintain a desired/optimal surface porosity of the polishing pad 13, as described supra. Cutting elements 3, 4 are in most cases diamonds but could be other cutting elements, such as SiC, SiO2, ceramic materials, diamond-like films, and the like. Furthermore, cutting elements may also include or may be replaced with brushes and other contact mechanisms that can be applied to help clean and maintain a pad surface. In the first position shown in FIG. 2, the cutting elements 3 associated with the first zone 1 engages the polishing pad 13 while the cutting elements 4 associated with the second zone 2 does not engage the polishing pad 13. Thus, the cutting elements 4 are preserved because the cutting elements 4 are not mechanically engaging with the surface of the polishing pad 13.
FIG. 3 depicts a schematic view of the pad condition disk 100 having multiple zones that selectively engage the polishing pad 13 in a second position, in accordance with embodiments of the present invention. In the second position shown in FIG. 3, a position of the first zone 1 and the second zone 2 has changed and the cutting elements 4 associated with the second zone 2 are now engaged with the polishing pad 13 while the cutting elements 3 associated with the first zone 1 are now not engaged with the polishing pad 13. Thus, the cutting elements 3 are preserved at least temporarily because the cutting elements 3 are now not mechanically engaging with the surface of the polishing pad 13. FIG. 3 also depicts a scenario where the cutting edges of the cutting elements 3 are no longer effective to maintain a desired cutting performance and so the second zone 2 is activated to bring the cutting elements 4 into active engagement with the polishing pad 13 while the first zone 1 moves away from the polishing pad 13 so that the cutting elements 3 no longer engages the polishing pad 13.
Accordingly, exemplary embodiments of the pad conditioning disk 100 include a plurality of zones 1, 2 each comprising cutting elements 3, 4 that selectively engage the polishing pad 13 based on a positioning of the plurality of zones 1, 2. When the first zone 1 is positioned closer to the polishing pad 13 than the second zone 2, the cutting elements 3 engage the polishing pad 13, as shown in FIG. 2. When the second zone 2 is positioned closer to the polishing pad 13 than the first zone 1, the cutting elements 4 engage the polishing pad 13. The change in positioning between the zones 1, 2 is achievable because each zones 1, 2 is individually moveable with respect to each other.
Each zone can be activated in a variety of ways to facilitate movement of the zones. In an exemplary embodiment, the zones are activated by pushing down one or more zones along a Z axis while pulling up on other zones. Deactivated zone(s) are lifted up from the polishing pad if necessary to avoid engagement with the polishing pad at a time when other zones are actively conditioning the polishing pad. Additionally, different zones can be applied with different downward forces as necessary. Various mechanisms can be used to activate individual zones. Activation mechanisms can be electric, mechanical, or electromechanical. For instance, zones can be actuated electrically via a motor, a battery, a shape memory actuator, such as nitinol, a solenoid, magnets, one or more servo motors, one or more stepper motors, electroactive polymers, a piezoelectric, switches, and the like. Zones can be actuated mechanically via springs, pneumatic components, screws, hydraulic components, pulleys, gears, light, ball and detents, and the like. A combination of electrical mechanisms and mechanical mechanisms may also be used. Furthermore, the pad conditioning disk having multiple zones can be a stand-alone unit with its own activation/deactivation mechanism or controller, or alternatively, the pad conditioning disk can be connected to the CMP system 10 where activation/deactivation is delivered by the CMP system 10.
Referring again to FIGS. 2-3, a connection means 5 operably connects the plurality of zones 1, 2 and facilitates movement between the plurality of zones 1, 2. The connection means 5 is a knob, axle, hinge, pivot joint, rod, wheel, shaft, cylinder, or similar turning device that allows certain zones to be activated and other zones deactivated. At a given time, the connection means 5 is turned in a first direction which activates certain zones while keeping other zones in a queue. For example, when the connection means 5 is turned in the first direction, the first zone 1 is activated (e.g. lowered) bringing the cutting elements 3 into engagement with the polishing pad 13 to cut into the pad for active conditioning, simultaneously deactivating (e.g. lifting) the second zone 2 to remove the cutting elements 4 from the polishing pad 13. Conversely, when the connection means 5 is turned in a second direction opposite the first direction, the second zone 2 is activated (e.g. lowered) bringing the cutting elements 4 into engagement with the polishing pad 13 to cut into the pad for active conditioning, while simultaneously deactivating (e.g. lifting) the first zone 1 to remove the cutting elements 3 from the polishing pad 13.
According to further embodiments, the pad conditioning disk 100 optionally includes a plurality of zones that have different types of cutting elements for added versatility. FIG. 4 depicts a schematic view of the pad condition disk 100 having multiple zones that have different types of cutting elements 3′, 4′, in accordance with embodiments of the present invention. In the illustrated embodiment, the pad conditioning disk 100 includes the first zone 1 with cutting elements 3′ and a separate second zone 2 with cutting elements 4′. Here, the cutting elements 3′, 4′ are not the same for both the first zone 1 and the second zone 2. The cutting elements 3′ may be a different size than the cutting elements 4′ and/or may have a different orientation and/or cutting angle than the cutting elements 4′. By way of example, the cutting elements 3′ mounted to the first zone 1 are blocky diamonds and the cutting elements 4′ mounted to the second zone 2 are sharp diamonds. In the first position shown in FIG. 4, sharp diamonds are engaged with the polishing pad 13 while the blocky diamonds are not engaged with the polishing pad 13. Thus, the blocky diamonds are preserved or intentionally not used during a specific application,
FIG. 5 depicts a schematic view of the pad condition disk having multiple zones that have different types of cutting elements in a changed position from FIG. 4, in accordance with embodiments of the present invention. In the second position shown in FIG. 5, a position of the first zone 1 and the second zone 2 has changed and the blocky diamonds are now engaged with the polishing pad 13 while the sharp diamonds are now not engaged with the polishing pad 13. Thus, the sharp diamonds are preserved or intentionally not used during a specific application because the requirements of the CMP process have changed.
The pad conditioning disk 100 with multiple zones and multiple different types of cutting elements allows for a certain desired effect. This hybrid use of different types of cutting elements on the same pad conditioning disk 100 provides a potential to combine the benefits of different types of cutting elements otherwise unachievable. By way of example, sharp diamonds can be mounted to a one zone for aggressive zone activation and blocky diamonds can be mounted to another zone for mild zone activation. During ex-situ conditioning, at a time period when the wafer is not on the polishing pad, the aggressive zone is activated to take advantage of the sharp diamond teeth that create deeper cuts and refresh the polishing pad effectively; large pad debris generated by the aggressive zone activation is then flushed out of the pad surface without touching the wafer. During in-situ conditioning when wafers are being polished at the same time, the mild zone is activated to take advantage of the blocky diamond teeth that provide gentle cuts, which helps maintain an even and consistent surface. The mild zone activation also helps get better dishing/erosion performance while avoiding the potential to scratch the wafer as a result of large pad debris.
Various combinations of cutting element types can be used with the various zones. For example, a first zone may use conventional diamond grit while a second uses chemical vapor deposition (CVD) diamonds. More than two different types of cutting elements can be used in a single pad conditioning disk. In a pad condition disk having four different zones, four different types of cutting elements can be used. Alternatively, if a pad conditioning disk having four zones, two different types of cutting elements can be used; two zones can have the same type of cutting element and the remaining two zones can have the same type of cutting elements.
Turning now to an exemplary embodiment of a pad conditioning disk according to embodiments of the present invention. FIG. 6 depicts a perspective view of a first position of a pad conditioning disk 200 having concentric zones, in accordance with embodiments of the present invention. FIG. 7 depicts a bottom view of the pad conditioning disk 200 of FIG. 6, in accordance with embodiments of the present invention. FIG. 8 is a side view of the pad conditioning disk 200 of FIG. 6, in accordance with embodiments of the present invention. FIG. 9 depicts a cross-sectional view along line A-A of FIG. 7, in accordance with embodiments of the present invention. As shown in FIGS. 6-9, the pad conditioning disk 200 includes an outer zone 201 and an inner zone 202. The inner zone 202 is recessed at least slightly with respect to the outer zone 201; the inner zone 202 resides within the empty area encircled by an inner diameter edge surface of the outer zone 201. In this first position, the cutting elements of the outer zone 201 engage the polishing pad and the cutting elements of the inner zone 202 do not engage the polishing pad.
FIG. 10 depicts a perspective view of a second position of the pad conditioning disk 200 of FIG. 6, in accordance with embodiments of the present invention. FIG. 11 depicts a bottom view of the pad conditioning disk 200 of FIG. 10, in accordance with embodiments of the present invention. FIG. 12 is a side view of the pad conditioning disk 200 of FIG. 10, in accordance with embodiments of the present invention. FIG. 13 depicts a cross-sectional view along line A-A of FIG. 11, in accordance with embodiments of the present invention. As shown in FIGS. 10-13, the inner zone 202 is now closer to the polishing pad such that, in this second position, the cutting elements of the inner zone 202 engage the polishing pad and the cutting elements of the outer zone 201 do not engage the polishing pad.
A connection means 205 facilitates the movement of the outer zone 201 with respect to the inner zone 202, or vice versa. The connection means 205 is a threaded connection between the outer zone 201 and the inner zone 202. In an exemplary embodiment, the outer zone 201 includes female threads circumferentially disposed along an inner surface of the outer zone 201, and the inner zone 202 includes corresponding male threads that cooperate with the female threads of the outer zone 201. In another embodiment, the outer zone 201 may include the male threads and the inner zone 202 may include the female threads. Threading action of one or both of the zones 201, 202 in either a clockwise or counter-clockwise direction achieves relative movement of the zones 201, 202. Thus, if the inner zone 202 is activated (e.g. the cutting elements of the inner zone 202 are desired at a given time), the inner zone is either drawn forward towards the polishing pad or the outer zone 201 is drawn away, or a combination of both forward and rearward movement. The relative movement between the outer zone 201 and the inner zone 202 as a result of the connection means 205 is best shown by FIGS. 9 and 13. In alternative embodiments, the connection means 205 is formed by a single spiral groove in either the outer zone 201 or the inner zone 202 in a similar place as the threads and a lip/tongue-'projection that fits within the groove and travels circumferentially around the groove to achieve relative vertical movement between the outer zone 201 and the inner zone 202.
Continuing with the pad conditioning disk 200, FIGS. 14-16 depict an exemplary embodiment of activating one of the plurality of zones 201, 202 to change a position of the zone 201 with respect to zone 202. FIG. 14 depicts a schematic view of the pad condition disk 200 operably connected to a pad conditioner arm 16, in a first position, in accordance with embodiments of the present invention. The cutting elements of outer zone 201 are connected to a substrate 210 by fastener 207. The substrate 210 is connected to the pad conditioner arm 16 by a movable connector 19, as shown in FIG. 15. The movable connector 19 is a shaft fixedly connected to the substrate and/or outer zone 201 and movably connected to the pad conditioner arm 16. The position of the connectors 19 a, as shown in FIG. 15 is merely for illustration and could be positioned at different locations, for example at the center of the disk, and the connection may be done using other mechanical configurations. In the first position depicted by FIG. 14, the inner zone 202 is recessed between the outer zone 201 ring such that the cutting elements of inner zone 202 would not engage the polishing pad, while the cutting elements of outer zone 201 would engage the polishing pad. FIG. 16 depicts a schematic view of the pad condition disk 200 operably connected to the pad conditioner arm 16, in a second position, in accordance with embodiments of the present invention. In the second position depicted by FIG. 16, a relative position between the outer zone 201 and the inner zone 202 has changed; the inner zone 202 protrudes out from the outer zone 201. In this position, the cutting elements of the inner zone 202 would now be in engagement with the polishing pad while the cutting elements of the outer zone 201 would no longer be in engagement with the polishing pad. The movement of the zones 201, 202 relative to each other is effectuated by a threaded connection therebetween, as described supra with respect to connection means 205. A motor rotates the moveable connector 19 which in turn rotates the substrate 110 and consequently the outer zone 201 fastened to the substrate 210. The rotation of the outer zone 201 causes the inner zone 202 to move up or down depending on the direction of the rotation due to the threaded connection.
FIGS. 17-19 depict another exemplary embodiment of activating one of the plurality of zones 201, 202 to change the position of the zone 201 with respect to zone 202. FIG. 17 depicts a schematic view of the pad condition disk 200 operably connected to a pad conditioner arm 16, in a first position, in accordance with embodiments of the present invention. The cutting elements of the outer zone 201 are connected to a substrate 210 by fasteners 207 and the cutting elements of the inner zone 202 are connected to a separate substrate 211 by fasteners 208. The substrates 210, 211 are connected to the pad conditioner arm 16 by separate connectors 19 a and 19 b, respectively. The movable connectors 19 a, 19 b are a shaft fixedly connected to the respective substrate and movably connected to the pad conditioner arm 16, as shown in FIG. 18. The position of the connectors 19 a, 19 b as shown in FIG. 18 are merely for illustration and could be positioned at different locations, and the connection may be done using other mechanical configurations. In the first position depicted by FIG. 17, the inner zone 202 is recessed between the outer zone 201 ring such that the cutting elements of inner zone 202 would not engage the polishing pad, while the cutting elements of outer zone 201 would engage the polishing pad. FIG. 19 depicts a schematic view of the pad condition disk 200 operably connected to the pad conditioner arm 16, in a second position, in accordance with embodiments of the present invention. In the second position depicted by FIG. 19, a relative position between the outer zone 201 and the inner zone 202 has changed; the inner zone 202 protrudes out from the outer zone 201. In this position, the cutting elements of the inner zone 202 would now be in engagement with the polishing pad while the cutting elements of the outer zone 201 would no longer be in engagement with the polishing pad. The movement of the zones 201, 202 relative to each other is effectuated by actuation of one or both of the movable connectors 19 a, 19 b along a Z axis. An actuator, such as motor, pneumatic actuator, hydraulic actuator, mechanical actuator, and the like, actuates one or both of the moveable connectors 19 a, 19 b along a Z axis to change the position of the zones 201, 202. By way of example, the movable connector 19 a is actuated in an upward direction to raise the outer zone 201 a distance while the movable connector 19 b is actuated in a downward direction to lower the inner zone 202. In other examples, only the movable connector 19 a is actuated or only the movable connector 19 b is actuated to activate the zones 201, 202 to a desired positioning or configuration.
The various zones of the pad conditioning disk according to embodiments of the present invention may be designed in various geometric shapes and configurations. For instance, the zones may be concentric rings, radial pies, spiral ribs, and dies, which comprise a circular pad condition disk. FIGS. 20-23 depict just a few possible configurations of the multiple zones. FIG. 20 depicts pad conditioning disk 300, in accordance with embodiments of the present invention. Pad conditioning disk 300 includes two separate zones 301, 302 that are concentrically arranged as an outer zone 301 and an inner zone 302. FIG. 21 depicts pad conditioning disk 400, in accordance with embodiments of the present invention. Pad conditioning disk 400 includes three zones 401, 402, 403. Zone 401 and 403 are arranged as radial pie sections along an outer ring of the pad conditioning disk 400. Zone 402 is arranged as a center portion within the outer ring of the pad conditioning disk 400. FIG. 22 depicts pad conditioning disk 500, in accordance with embodiments of the present invention. Pad conditioning disk 500 includes sixteen total zones arranged circumferentially around the pad conditioning disk 500. The sixteen total zones are comprised of four different types of cutting elements labeled as 501, 502, 503,and 504. While sixteen total zones are shown, any number of zones may be used in a similar configuration. 23 depicts pad conditioning disk 600, in accordance with embodiments of the present invention. Pad conditioning disk 600 includes thirty-two total zones arranged in rows and columns across the pad conditioning disk 600. The thirty-two zones are comprised of five different types of cutting elements labeled as 601, 602, 603, 604, and 605. While thirty-two total zones are shown, any number of zones may be used in a similar configuration. Further, O-rings and/or other insulation devices are optionally disposed in between the zones to avoid chemical/slurry/byproduct accumulation.
With continued reference to the drawings, FIG. 24 depicts a CMP tool 1000 that utilizes the pad conditioning disk according to embodiments of the present invention. The CMP tool 1000 comprises a polisher having a machine base 130, a polishing fluid delivery arm 190, a polishing pad 104 disposed on a platen 102, a polishing head 106, a conditioner assembly 122, and a controller 152. The machine base 130 supports the platen 102, the polishing fluid delivery arm 190 and the conditioner assembly 122. The platen 102 supports polishing head 106. The polishing head 106 may be rotated by a motor 120, thereby rotating the substrate 118 against the polishing pad 104 about a central axis D of the polishing head 106. A sensor 148 may be utilized to obtain a metric of force required to rotate the substrate 118 against the polishing pad 104.
The platen 102 is utilized to rotate the polishing pad 104 during processing such that the polishing pad 104 planarizes (or “polishes”) the surface of the substrate 118 disposed on the pad 104. The polishing pad 104 is a consumable product having a polishing surface and may be secured to the platen 102. The platen 102 and the polishing pad 104 is rotated by a motor 112 coupled to the platen 102 by a shaft 114. The motor 112 is utilized to move the polishing pad 104 relative to the substrate 118 retained in the polishing head 106. In the illustrated embodiment, the motor 112 rotates the platen 102 in the X-Z plane about a central axis A normal to the platen 102. A sensor 150 may be utilized to obtain a metric indicative of the force required to rotate the platen 102 and polishing pad 104 relative to the substrate 118 and/or conditioner assembly 122
The polishing fluid delivery arm 190 provides a polishing fluid to the surface of the polishing pad 104 during polishing. The conditioner assembly 122 generally includes a conditioning head 108, a shaft 126, and an arm 128. The shaft 126 and arm 128 support the conditioning head 108 above the platen 102. The conditioning head 108 retains the conditioning disk according to embodiments of the present invention which is selectively placed in engagement with the polishing pad 104 to condition the surface of the polishing pad 104. The shaft 126 is disposed through the machine base 130 of the CMP tool 1000. The shaft 126 may rotate about an axis B normal to the machine base 130, the rotation facilitated by bearings 132 between the machine base 130 and the shaft 126, such that the arm 128 rotates the conditioning head 108. In one embodiment, a sweep actuator 144 coupled to the shaft 126 may rotate the shaft 126 to urge the arm 128 to sweep the conditioning head 108 across the polishing pad 104. The conditioning head 108 rotates the conditioning disk about an axis C disposed normally through the conditioning disk. In one embodiment, a motor 134 is utilized to rotate the conditioning disk relative to the polishing pad 104. In one embodiment, the motor 134 is disposed in a housing 136 at a distal end of the arm 128.
A down force actuator 140 is utilized to urge the conditioning disk against the polishing pad 104. The down force actuator 140 is configured to selectably set the force applied by the conditioning disk 124 on the polishing pad 104. In one embodiment, the down force actuator 140 may be disposed between the arm 8 and the shaft 126, or in other suitable locations. A down force sensor 142 is utilized to detect a metric indicative of the down force of the conditioning disk applied against the polishing pad 104. In one embodiment, the down force sensor 142 may be positioned in-line of the down force actuator 140, or may be placed in other suitable locations.
In general, a controller 152 is used to control one or more components and processes performed in the CMP tool 1000. The controller 152 may be coupled at various points to the CMP tool 1000 in order to transmit and receive signals from various components. For instance, the controller may be connected to a dynamic pad conditioning disk feedback system The dynamic feedback system collects a reading of pad roughness and transmitted by a central processing unit 154 to a server for calculating whether additional conditioning of the polishing pad is required. Adjustments can be made by the controller 152 based on the calculations received from the server. The dynamic feedback system may also capture high resolution optical images of the polishing pad surface to analyze pad roughness by the server. The dynamic feedback system can also be used to measure torque and friction or other components of the CMP tool 1000. Further, the feedback system can be used for adjustment of downforce and/or adjustment of a proportion in using aggressive zone to mild zone use for pad conditioning.
The controller 152 is generally designed to facilitate the control and automation of the CMP tool 1000 and typically includes a central processing unit (CPU) 154, memory 156, and support circuits (or I/O) 158. The CPU 154 may be one of any form of computer processors that are used in industrial settings for controlling various system functions, substrate movement, chamber processes, process timing and support hardware sensors, robots, motors, timing devices, etc.), and monitor the processes (e.g., chemical concentrations, processing variables, chamber process time, 110 signals, etc.). The memory 156 is connected to the CPU 154, and may be one or more of a readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data can be coded and stored within the memory for instructing the CPU 154. The support circuits 158 are also connected to the CPU 154 for supporting the processor in a conventional manner. The support circuits 158 may include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like. A program, or computer instructions, readable by the controller 152 determines which tasks are performable on a substrate. Preferably, the program is software readable by the controller 152 that includes code to perform tasks relating to monitoring, execution and control of the movement, support, and/or positioning of a substrate in the polisher 100. In one embodiment, the controller 152 is used to control robotic devices to control the strategic movement, scheduling and running of the polisher 100 to make the processes repeatable, resolve queue timing issues and prevent over- or under-processing of the substrates.
Furthermore, the pad conditioning disk according to embodiments of the present invention is used to condition a polishing pad of a CMP tool. For instance, a method for conditioning a polishing pad of a chemical mechanical polishing tool includes selectively activating a selected zone of a pad condition disk having a plurality of zones. Each of the plurality of zones have cutting elements for conditioning the polishing pad. The selection of the zone to use for conditioning the polishing pad depends on a plurality of factors. The plurality of factors include a polishing recipe, a polishing event, a usage time of the chemical mechanical polishing tool, an interval of a number of wafers polished by the chemical mechanical polishing tool, an optimal surface porosity of the polishing pad, and the like.
By way of example, an initial zone is selected for conditioning the pad and is activated accordingly so that the cutting elements of the initial zone will be used for conditioning the polishing pad. The initial zone was selected based on the fact that the CMP process is currently being performed ex-situ, when the wafer is not being polished on the pad simultaneously, and the cutting elements of the initial zone are optimal for ex-situ conditioning. A downward force (e.g. downforce) is applied to the pad conditioning disk that brings the cutting elements of the initially selected zone in engagement with the polishing pad but not the cutting elements of the other zones. If the CMP process is changed to in-situ conditioning, when the wafer is being polished on the pad simultaneously, a new, different zone is selectively activated based on the change from ex-situ condition to in-situ conditioning. The combination of ex-situ and in-situ creates a desirable pad surface texture, minimizes the pad conditioning by-product, and avoids excessive pad wear.
By way of another example, an initial zone is selected for conditioning the pad and is activated accordingly so that the cutting elements of the initial zone will be used for conditioning the polishing pad. The initial zone was selected to condition the conditioning pad for “x” number of wafers polished by the CMP tool. A downward force (e.g. downforce) is applied to the pad conditioning disk that brings the cutting elements of the initially selected zone into engagement with the polishing pad but not the cutting elements of the other zones so the cutting elements are preserved. After “x” number of wafers are polished by the CMP tool, a new, different zone is selectively activated to condition the polishing pad for another “x” number of wafers. In this case, both zones have the same type of cutting elements. In this way, the cutting elements wear at different rates and the pad conditioning disk does not need to be changed to utilize new cutting elements for optimal performance,
In further examples, during a pad break-in period where the polishing pad is new, used, or not being actively used for a period of time, one zone of the cutting elements is activated with a certain type of diamonds engaging with the pad surface to create a desirable surface texture/porosity, and the other zones are disengaged. During a processing period when the polishing pad is being actively used for wafer polishing, a different zone is activated with a certain different type of diamonds, with the first zone of diamonds disengaged, to create a different type of pad surface texture/porosity (e.g. smooth and consistent), with different size (e.g. finer) of cutting byproducts. During a polishing process, in particular during ex-situ conditioning, when the wafer is not being polished on the pad simultaneously, one zone of the diamonds is activated with a certain type of the diamonds engaging with the pad surface to create a desirable surface texture/porosity, with certain size of cutting byproduct, and the other zones are dis-engaged. During a polishing process, in particular during in-situ conditioning, when the wafer is being polished on the pad simultaneously, a different zone is activated with a certain different type of diamonds, with the first zone of diamonds disengaged, to create a different type of pad surface texture/porosity (e.g. smooth and consistent), with different size (e.g. finer) of cutting byproducts. The combination of which creates a desirable performance and to avoid excessive pad wear.
Further, the method can also be applied during a CMP process, where during a first portion of polish of polishing process, a first zone of the diamonds is activated with a certain type of the diamonds engaging with the pad surface to create a desirable surface texture/porosity, and the other zones are dis-engaged. During a second portion of a polish, a second zone of the diamonds is activated with a certain different type of diamonds, with the first zone of diamonds dis-engaged, to create a different type of pad surface texture/porosity.
Moreover, different applications can be used to share the same platen. For instance, if a first application is being used, a first zone of the diamonds is activated with a certain type of the diamonds engaging with the pad surface to create a desirable surface texture/porosity, and the other zones are disengaged. If a second application is being used, a second zone of the diamonds is activated with a certain type of the diamonds engaging with the pad surface to create desirable surface texture/porosity, and the other zones are dis-engaged. If a third application is being used, a third zone of the diamonds is activated with a certain type of the diamonds engaging with the pad surface to create a desirable surface texture/porosity, and the other zones are disengaged, and so on with additional applications.
While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, as required by the following claims. The claims provide the scope of the coverage of the invention and should not be limited to the specific examples provided herein.

Claims

What is claimed is:

1. A pad conditioning disk configured to condition a polishing pad of a chemical mechanical polishing tool, comprising:

a plurality of zones comprising cutting elements that selectively engage the polishing pad based on a positioning of the plurality of zones.

2. The pad condition disk of claim 1, wherein the plurality of zones are moveable with respect to each other.

3. The pad condition disk of claim 1, wherein the plurality of zones are moveable with respect to each other so that cutting elements of a first zone of the plurality of zones engage the polishing pad during a chemical mechanical polishing process while cutting elements of a second zone of the plurality of zones do not engage the polishing pad.

4. The pad conditioning disk of claim 1, wherein the cutting elements are diamonds or diamond-like films of a same or a different shape, size, distribution, density, and/or configuration.

5. The pad conditioning disk of claim 1, wherein at least one cutting element is a brush.

6. The pad conditioning disk of claim 1, wherein a first zone of the plurality of zones comprise grit diamonds of a certain shape, size, distribution and density, and a second zone of the plurality of zones comprises chemical vapor deposition (CVD) diamond film coated on a textured surface.

7. The pad conditioning disk of claim 1, wherein the pad conditioning disk is connected to a pad conditioner arm of the chemical mechanical polishing tool by a moveable connector, and an actuator facilitates movement between the first zone and at least another zone.

8. The pad conditioning disk of claim 1, wherein a first zone is connected to a pad conditioner arm of the chemical mechanical polishing tool by a first moveable connector and a second zone is connected to the pad conditioner arm by a second moveable connector, further wherein at least one of:

the first moveable connector is actuated along a Z-axis to facilitate vertical independent movement of the first zone with respect to the second zone; and

the second moveable connector is actuated along a Z-axis to facilitate vertical independent movement of the second zone with respect to the first zone.

9. The pad conditioning disk of claim 1, wherein the plurality of zones are at least one of: circles, rings, radial pies, spiral ribs, rectangular or triangular cutouts, and dies.

10. A chemical mechanical polishing tool, comprising:

a polishing pad disposed on a platen, the polishing pad configured to polish a substrate;

a polishing fluid delivery arm, the polishing fluid delivery arm configured to deliver a polishing fluid during a pad conditioning process; and

a conditioner assembly, the conditioner assembly including:

a pad conditioner arm connected to a machine base of the chemical mechanical polishing tool, and

a pad conditioning disk connected to the pad conditioner arm, the pad conditioning disk having at least two zones that are activated with respect to each other for selectively engaging the polishing pad.

11. The chemical mechanical polishing tool of claim 10, wherein the chemical mechanical polishing tool comprises elements and mechanisms to activate and deactivate zone switches

12. A method for conditioning a polishing pad during a chemical mechanical polishing process, the method comprising:

selectively activating a selected zone of a pad conditioning disk having a plurality of zones, the plurality of zones having cutting elements for conditioning the polishing pad, wherein a selection of the zone to use for conditioning the polishing pad depends on a factor of a plurality of factors; and

applying a downforce to the pad conditioning disk that brings the cutting elements of the selected zone in engagement with the polishing pad but not the cutting elements of the other zones.

13. The method of claim 12, wherein the plurality of factors include a polishing recipe, a polishing event, a usage time of the chemical mechanical polishing tool, an interval of a number of wafers polished by the chemical mechanical polishing tool, a defined schedule, or feedback from a dynamic feedback system.

14. The method of claim 12, wherein the factor is a feedback from a dynamic feedback system, the feedback including a performance of a wafer, a friction between the wafer and the polishing pad, a roughness measurement of the polishing pad, and/or a porosity measurement of the polishing pad.

15. The method of claim 12, further comprising:

selectively activating a different zone of the pad conditioning disk based on a change to one or more of the plurality factors.

16. The method of claim 15, wherein the selectively activating the different zone includes actuating a moveable connector of a pad conditioner arm to adjust a position of the selected zone with respect to the different zone.

17. The method of claim 12, wherein the cutting elements of each zone are diamonds or diamond-like films of a same or a different shape, size, distribution, density, and configuration.

18. The method of claim 12, wherein the factor for the selection of the zone to use for conditioning the polishing pad is a type of conditioning, the type of conditioning being either an in-situ conditioning period or an ex-situ conditioning period, further wherein, during the ex-situ conditioning period, cutting elements of the selected zone are engaged with the polishing pad, while cutting elements of an other zone are disengaged from the polishing pad, and during the in-situ conditioning period, cutting elements of the selected zone are disengaged from the polishing pad, while the cutting elements of the other zone are engaged.

19. The method of claim 12, wherein the factor for the selection of the zone to use for conditioning the polishing pad is whether the chemical mechanical polishing process is in a break-in stage or a wafer processing stage, further wherein, during pad the break-in stage, cutting elements of the selected zone are engaged with the polishing pad, while cutting elements of an other zone are disengaged from the polishing pad, and during the wafer processing stage, cutting elements of the selected zone are disengaged from the polishing pad, while the cutting elements of the other zone are engaged with polishing pad.