Retaining ring for substrate polisher

Abstract

A polishing head is adapted to handle a panel substrate in order to perform a chemical mechanical polishing operation on the panel substrate. A retaining ring of the polishing head includes recesses that accommodate corners of the panel substrate. The recesses prevent inner sides of the retaining ring from contacting the corners of the panel substrate. During the chemical mechanical polishing operation, the recesses mitigate a risk of damaging the corners of the substrate through impacts from the inner sides of the retaining ring.

Description

PATENTAttorney Docket No.: 44025098W001RETAINING RING FOR SUBSTRATE POLISHERBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to systems and methods for handling substrates, particularly non-circular substrates, for a polishing operation during the manufacture of semiconductor devices.Description of the Related Art

[0002] Chemical Mechanical Polishing (CMP) is commonly used during the manufacture of semiconductor devices to planarize or polish a layer of material deposited on a substrate surface. In a typical CMP process, a substrate is retained by a polishing head which presses the substrate towards a rotating polishing pad in the presence of a polishing fluid. Generally, the polishing fluid comprises an aqueous solution of one or more chemical constituents and nanoscale abrasive particles suspended in the aqueous solution. At least a portion of the material deposited on the substrate surface is forced into contact with a polishing pad, and is removed from the substrate through a combination of chemical and mechanical activity provided by the polishing fluid and relative motion between the substrate and the polishing pad.

[0003] The substrate often shifts slightly underneath the polishing head, and periodically impacts an inside surface of a retaining ring of the polishing head. Impacts or side loads on the substrate exerted by the retaining ring can damage the edge of the substrate, and can damage the retaining ring itself. A noncircular substrate, such as a panel substrate of a generally quadrilateral shape, is especially at risk of damage by impact or side loads exerted by the retaining ring at a corner of the substrate. Furthermore, interaction between the substrate and the retaining ring during CMP processes can cause nonuniformities in the material that had been deposited near the edge of the substrate.

[0004] Thus, there is a need for improved apparatus and processes that alleviate the above problems.8631846_2 1PATENTAttorney Docket No.: 44025098W001SUMMARY

[0005] The present disclosure generally relates to systems and methods for handling substrates, particularly non-circular substrates. The systems and methods of the present disclosure are applicable for polishing operations on the substrates during the manufacture of semiconductor devices.

[0006] In one aspect, a retaining ring for use with a substrate includes a body. An aperture in the body is bounded by a plurality of inner sides of the body. The plurality of inner sides includes a first inner side, a second inner side, and a corner coupling the first inner side to the second inner side. The corner includes a recess coupled with the aperture. The recess is bounded by first, second, and third walls. The first wall is substantially straight, and is coupled to the first inner side. The second wall is substantially straight, and is substantially perpendicular to the first wall. The third wall is substantially straight, and is substantially parallel to the first wall. The third wall is coupled to the second inner side.

[0007] In another aspect, a retaining ring for use with a substrate includes a body. An aperture in the body is bounded by a plurality of inner sides of the body. The plurality of inner sides includes a first inner side, a second inner side, and a third inner side. A first corner coupling the first inner side to the second inner side includes a first recess coupled with the aperture. A second corner coupling the second inner side to the third inner side includes a second recess coupled with the aperture. A first shape of the first recess is different from a second shape of the second recess.

[0008] In another aspect, a method of handling a substrate includes determining an orientation of a substrate, and determining an orientation of a retaining ring coupled to a polishing head. The method further includes adjusting one of the orientation of the retaining ring or the orientation of the substrate to align the retaining ring with the substrate. The method further includes coupling the substrate to the polishing head.8631846_2 2PATENTAttorney Docket No.: 44025098W001BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of the scope of the disclosure, as the disclosure may admit to other equally effective embodiments.

[0010] Figure 1 schematically illustrates a polishing and cleaning system.

[0011] Figures 2A and 2B schematically illustrate exemplary polishing heads that may be used in the polishing and cleaning system of Figure 1 .

[0012] Figure 3A schematically illustrates a retaining ring that may be used with the polishing head of Figure 2A.

[0013] Figure 3B schematically illustrates a retaining ring that may be used with the polishing head of Figure 2B.

[0014] Figures 4A and 4B schematically illustrate exemplary aspects of a substrate that may be processed in the polishing and cleaning system of Figure 1.

[0015] Figures 4C and 4D schematically illustrate exemplary aspects of a substrate that may be processed in the polishing and cleaning system of Figure 1.

[0016] Figures 5 and 5A schematically illustrate exemplary details of a retaining ring.

[0017] Figures 6 and 6A schematically illustrate exemplary details of a retaining ring.

[0018] Figures 7 and 7A schematically illustrate exemplary details of a retaining ring.8631846_2 3PATENTAttorney Docket No.: 44025098W001

[0019] Figures 8A and 8B schematically illustrate a juxtaposition between a substrate and a retaining ring.

[0020] Figures 9A and 9B schematically illustrate a juxtaposition between a substrate and a retaining ring.

[0021] Figures 10A and 10B schematically illustrate a juxtaposition between a substrate and a retaining ring.

[0022] Figure 11 is a flow diagram of an exemplary method of handling a substrate.

[0023] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0024] The present disclosure concerns apparatus, systems, and methods for handling substrates, such as for a polishing operation. More particularly, the present disclosure concerns the handling of non-circular substrates, such as substrates having at least one substantially straight edge.

[0025] Figure 1 schematically illustrates a polishing and cleaning system 100. The polishing and cleaning system 100 includes a factory interface 102, at which substrates on a carrier 104 (such as a cassette or a Front Opening Unified Pod) are unloaded. As illustrated, a substrate 124 is shown after having been unloaded from the carrier 104.

[0026] The substrate 124 is non-circular, and may be referred to as a panel substrate. Although depicted as being generally quadrilateral in shape, the substrate 124 may take the form of other geometric shapes, such as shapes having three, five, six, seven, eight, or more sides. The substrate 124 is shown lying in the X-Y plane. In an example, a length 126 of the substrate 124 measures 515 mm and a width 128 of the substrate measures 510 mm.8631846_2 4PATENTAttorney Docket No.: 44025098W001

[0027] In some embodiments, the length 126 of the substrate 124 is shorter than 515 mm. In some examples, the length 126 of the substrate 124 may be 500 mm or less, such as 400 mm or less, 300 mm or less, or 200 mm or less. In some embodiments, the width 128 of the substrate 124 is shorter than 510 mm. In some examples, the width 128 of the substrate 124 may be 500 mm or less, such as 400 mm or less, 300 mm or less, or 200 mm or less.

[0028] In some embodiments, the length 126 of the substrate 124 is longer than 515 mm. In some embodiments, the width 128 of the substrate 124 is longer than 510 mm.

[0029] In some embodiments that may be combined with other embodiments, the substrate 124 is generally rectangular in shape. In some embodiments that may be combined with other embodiments, the substrate 124 is generally square in shape. In some embodiments that may be combined with other embodiments, the substrate 124 is 1 mm or less in thickness (i.e., in the Z direction), such as 0.9 mm or less, 0.8 mm or less, or 0.75 mm or less.

[0030] The polishing and cleaning system 100 includes a polishing station 106 that includes one or more polishers 108 that perform a chemical mechanical polishing (CMP) process on each substrate 124. The polishing and cleaning system 100 includes a cleaning station 116, at which each substrate 124 is cleaned and dried after undergoing the CMP process.

[0031] The substrate 124 is conveyed to the polishing station 106 by a polishing head 110. The polishing head 110 is moved over the substrate 124, and picks up the substrate 124, such as by applying a suction to the substrate 124. One or more sensors 118, such as a camera, may be used to assist the alignment of the polishing head 110 with the substrate 124 before the polishing head 110 picks up the substrate 124. The polishing head 110 carries the substrate 124 to the polishing station 106, and holds the substrate 124 during the CMP process.8631846_2 5PATENTAttorney Docket No.: 44025098W001

[0032] The polishing head 110 carries the substrate 124 from the polishing station 106 to the cleaning station 116, where the polishing head 110 releases the substrate 124 for cleaning and drying. Then the substrate 124 is conveyed back to the factory interface 102, and is loaded back onto a carrier, such as carrier 104.

[0033] In some embodiments, the polishing and cleaning system 100 includes a controller 120 that monitors and controls one or more operations of the polishing and cleaning system 100. In some embodiments, operations controlled by the controller 120 include one or more CMP operations, one or more cleaning operations, or one or more drying operations. In some embodiments, the controller 120 receives information from the sensor 118 concerning the orientation of the substrate 124 in the X-Y plane, and controls the positioning of the polishing head 110 into alignment with the substrate 124 to enable the polishing head 110 to pick up the substrate 124. In some embodiments, the controller 120 monitors and controls the transport of the substrate 124 within the polishing and cleaning system 100.

[0034] The controller 120 includes a central processing unit (CPU), a memory containing instructions, and support circuits for the CPU. The memory, or non-transitory computer readable medium, is one or more of a readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, flash drive, or any other form of digital storage, local or remote. The support circuits are coupled to the CPU for supporting the CPU. The support circuits include cache, power supplies, clock circuits, input / output circuitry and subsystems, and the like. Operations and operating parameters are stored in the memory as a software routine that is executed or invoked to configure the controller 120 into a specific purpose controller to control the operations of the polishing and cleaning system 100. The controller 120 is configured to conduct one or more of the operations described herein. The instructions stored on the memory, when executed, cause one or more of the operations described herein to be conducted.8631846_2 6PATENTAttorney Docket No.: 44025098W001

[0035] In some embodiments, the controller 120 includes, or is coupled to, a transmitter / receiver that facilitates communication with other devices, such as a base station or other controllers of other systems, such as other polishing and cleaning systems.

[0036] Figures 2A and 2B schematically illustrate exemplary polishing heads 110. In Figure 2A, the polishing head 110 is represented by polishing head 130. Polishing head 130 includes a housing 132. A support plate 136 is coupled to, and suspended from, the housing 132. In some embodiments, the support plate 136 is movable in the Z direction with respect to the housing 132. When the polishing head 130 picks up the substrate 124, the substrate 124 is suspended from the support plate 136, and extends in the X-Y plane. In some embodiments, a suction is applied to the substrate 124 via a membrane 138 on the support plate 136 in order to couple the substrate 124 to the polishing head 130.

[0037] A retaining ring 160A is coupled to the housing 132. The retaining ring 160A surrounds the substrate 124 in the X-Y plane. The retaining ring 160A is sized such that a clearance 152 exists between the substrate 124 and the retaining ring 160A in order to accommodate dimensional tolerances of the substrate 124 and of the retaining ring 160A.

[0038] Figure 3A schematically illustrates the retaining ring 160A in the X-Y plane. In the illustrated example, the retaining ring 160A includes a body 162A. An aperture 170 in the body 162A is bounded by inner sides 172, 174, 176, and 178. Inner sides 172, 174, 176, and 178 are substantially straight. In an example, at least a portion of each of inner sides 172, 174, 176, and 178 extends with a degree of curvature less than or equal to five degrees, such as less than or equal to four degrees, less than or equal to three degrees, less than or equal to two degrees, or less than or equal to one degree. In some embodiments, at least a portion of each of inner sides 172, 174, 176, and 178 extends with a degree of curvature of zero degrees.8631846_2 7PATENTAttorney Docket No.: 44025098W001

[0039] Inner side 172 is substantially perpendicular to inner side 174. In an example, an angle between inner sides 172 and 174 is from 85 to 90 degrees, such from 86 to 90 degrees, from 87 to 90 degrees, from 88 to 90 degrees, or from 89 to 90 degrees. In some embodiments, an angle between inner sides 172 and 174 is 90 degrees. Inner side 174 is substantially perpendicular to inner side 176. In the illustrated embodiment, the retaining ring 160A is configured for use with substrates 124 that are quadrilateral-shaped, such as rectangular or square-shaped.

[0040] Inner side 176 is substantially parallel to inner side 172, and is substantially perpendicular to inner side 178. In an example, an angle between inner sides 172 and 176 is less than or equal to five degrees, such as less than or equal to four degrees, less than or equal to three degrees, less than or equal to two degrees, or less than or equal to one degree. In some embodiments, an angle between inner sides 172 and 176 is zero degrees. Inner side 178 is substantially parallel to inner side 174, and is substantially perpendicular to inner side 172.

[0041] In other embodiments, the retaining ring 160A may be configured for use with substrates124 that are triangular-shaped or substrates 124 that have more than four sides. For instance, in examples in which the substrate 124 is generally hexagonal, the aperture 170 may be bounded by six sides in a similar hexagonal configuration.

[0042] In the illustrated example, the retaining ring 160A includes outer sides 182, 184, 186, and 188. Outer sides 182, 184, 186, and 188 are substantially straight, and form a generally quadrilateral shape. Outer side 182 is substantially parallel to inner side 172, outer side 184 is substantially parallel to inner side 174, outer side 186 is substantially parallel to inner side 176, and outer side 188 is substantially parallel to inner side 178. In other examples, the retaining ring 160A may include outer sides that form a different shape, such as a hexagon.8631846_2 8PATENTAttorney Docket No.: 44025098W001

[0043] In some embodiments, a thickness of the retaining ring 160A (i.e. , in the Z direction) is the same as the thickness of the substrate 124. In other embodiments, the thickness of the retaining ring 160A is greater than the thickness of the substrate 124. In other embodiments, the thickness of the retaining ring 160A is less than the thickness of the substrate 124.

[0044] The retaining ring 160A is made of a polymeric material, such as a thermoplastic, such as a polyaryletherketone (PAEK). In an example, the retaining ring 160A is made of polyetheretherketone (PEEK). Further aspects of the substrate 124 and the retaining ring 160A are described below with respect to subsequent Figures.

[0045] Returning to Figure 2A, a coupler 134 on the housing 132 connects the polishing head 130 to a robot or other mechanism that manipulates the polishing head 130. The coupler 134 communicates one or more of power, sensor signals, control signals, or fluids to or from the polishing head 130.

[0046] In a CMP operation, the polishing head 130 places the substrate 124 on a polishing pad 114 that is coupled to a platen 112. The polishing head 130 retains hold of the substrate 124 while applying a downward force to the substrate 124 in the Z direction. The polishing fluid (including abrasive particles) is applied to the polishing pad 114 while the platen 112 and polishing pad 114 rotate in the X-Y plane, and the polishing head 130 moves the substrate 124 across the polishing pad 114 while the polishing pad 114 rotates.

[0047] In Figure 2B, the polishing head 110 is represented by polishing head 140. Polishing head 140 includes a housing 142. A support plate 146 is coupled to, and suspended from, the housing 142. In some embodiments, the support plate 146 is movable in the Z direction with respect to the housing 142. When the polishing head 140 picks up the substrate 124, the substrate 124 is suspended from the support plate 146, and extends in the X-Y plane. In some embodiments, a suction is applied to the substrate 124 via a membrane 148 on the support plate 146 in order to couple the substrate 124 to the polishing head 140.8631846_2 9PATENTAttorney Docket No.: 44025098W001

[0048] A retaining ring 160B coupled to the polishing head 140 surrounds the substrate 124 in the X-Y plane. The retaining ring 160B is coupled to the support plate 146. As illustrated, in some embodiments, the retaining ring 160B is coupled to the support plate 146 via the membrane 148, such as by a suction applied to the retaining ring 160B using a membrane 148. Additionally, or alternatively, the retaining ring 160B may be coupled to the support plate 146 by fasteners, such as bolts. The retaining ring 160B is sized such that a clearance 154 exists between the substrate 124 and the retaining ring 160B in order to accommodate dimensional tolerances of the substrate 124 and of the retaining ring 160B.

[0049] In some embodiments, the retaining ring 160B functions as an adapter for use with substrates 124 that have a length 126 and a width 128 shorter than a standard dimension of a circular substrate. In an example, the polishing head 140 may be configured to handle circular substrates that are 300 mm in diameter, whereas the substrate 124 may be square-shaped with a side length of from 140 mm to 200 mm.

[0050] Figure 3B schematically illustrates the retaining ring 160B in the X-Y plane. In the illustrated example, the retaining ring 160B includes a body 162B. As described above with respect to retaining ring 160A, an aperture 170 in the body 162B is bounded by the inner sides 172, 174, 176, and 178. In the illustrated embodiment, the retaining ring 160B is configured for use with substrates 124 that are quadrilateral-shaped, such as rectangular or squareshaped. In other embodiments, the retaining ring 160B may be configured for use with substrates 124 that are triangular-shaped or substrates 124 that have more than four sides, such as described above.

[0051] As illustrated, an outward side 180 of the retaining ring 160B is circular. In some embodiments, an outer diameter of the retaining ring 160B is sized such that the retaining ring 160B is adapted to fit with polishing heads 110 that are configured to handle circular substrates. In an example, the outer diameter of the retaining ring 160B is 300 mm to fit polishing heads 110 that are configured to handle circular substrates that are 300 mm in diameter. In 8631846_2 10PATENTAttorney Docket No.: 44025098W001 other examples, the outer diameter of the retaining ring 160B is greater than 300 mm. In other examples, the outer diameter of the retaining ring 160B is less than 300 mm.

[0052] In some embodiments, a thickness of the retaining ring 160B (i.e. , in the Z direction) is the same as the thickness of the substrate 124. In other embodiments, the thickness of the retaining ring 160B is greater than the thickness of the substrate 124. In other embodiments, the thickness of the retaining ring 160B is less than the thickness of the substrate 124.

[0053] The retaining ring 160B is made of a polymeric material, such as a thermoplastic, such as a PAEK. In an example, the retaining ring 160B is made of PEEK. Further aspects of the substrate 124 and the retaining ring 160B are described below with respect to subsequent Figures.

[0054] Returning to Figure 2B, as illustrated, in some embodiments, an outer ring 150 is coupled to the housing 142. The outer ring 150 surrounds the retaining ring 160B in the X-Y plane. The outer ring 150 is sized such that a clearance 156 exists between the retaining ring 160B and the outer ring 150 in order to accommodate dimensional tolerances of the retaining ring 160B and of the outer ring 150. In some embodiments, the outer ring 150 may be omitted.

[0055] A coupler 144 on the housing 142 connects the polishing head 140 to a robot or other mechanism that manipulates the polishing head 140. The coupler 144 communicates one or more of power, sensor signals, control signals, or fluids to or from the polishing head 140.

[0056] In a CMP operation, the polishing head 140 operates in a similar way to the polishing head 130, by applying a downward force to the substrate 124 in the Z direction, and moving the substrate 124 across the polishing pad 114 while the polishing pad 114 rotates in the X-Y plane.

[0057] Figures 4A to 4D schematically illustrate aspects of the substrate 124 in further detail. In Figure 4A, the substrate 124 is represented by substrate 210. Substrate 210 is generally quadrilateral-shaped, with sides 212, 214, 216, 8631846_2 11PATENTAttorney Docket No.: 44025098W001 and 218. Sides 212, 214, 216, and 218 are substantially straight. Side 212 is substantially perpendicular to side 214. Side 214 is substantially perpendicular to side 216. Side 216 is substantially parallel to side 212, and is substantially perpendicular to side 218. Side 218 is substantially parallel to side 214, and is substantially perpendicular to side 212. Side 212 transitions to side 214 at corner 222. Side 214 transitions to side 216 at corner 224. Side 216 transitions to side 218 at corner 226. Side 218 transitions to side 212 at corner 228.

[0058] Figure 4B is an enlargement of a portion of Figure 4A at the corner 222 where side 212 transitions to side 214. The corner 222 is representative of each other corner 224, 226, and 228 of the substrate 210. The corner 222 includes a chamfer 230 that forms a transition between side 212 and side 214. The chamfer 230 is coupled to side 212 at a transition point 232. The chamfer 230 is coupled to side 214 at a transition point 236. The chamfer 230 is substantially straight, and is oriented at an obtuse angle 234 with respect to side 212, and at an obtuse angle 238 with respect to side 214. The obtuse angle 234 is equal to the obtuse angle 238. The corner 222 is symmetrical about an axis 272 in the X-Y plane that passes through a projected point of intersection 274 of side 212 and side 214, and bisects the angle 276 between side 212 and side 214.

[0059] Each corner 222, 224, 226, and 228 of the substrate 210 is configured as depicted in Figure 4B, including a chamfer 230 at the transition between each corresponding pair of adjacent sides (i.e. , (i) side 212 and side 214, (ii) side 214 and side 216, (iii) side 216 and side 218, and (iv) side 218 and side 212, respectably). The chamfer 230 at each corner 222, 224, 226, and 228 mitigates a risk of damage to the substrate 210 at the corners 222, 224, 226, and 228 during handling, and during operations, such as CMP.

[0060] In Figure 4C, the substrate 124 is represented by substrate 250. Substrate 250 is generally quadrilateral-shaped, and includes the sides 212, 214, 216, and 218, as described above with respect to substrate 210. Substrate 250 includes the three corners 224, 226, and 228, as described above with respect to substrate 210. Side 214 transitions to side 216 at corner 224. Side 8631846_2 12PATENTAttorney Docket No.: 44025098W001216 transitions to side 218 at corner 226. Side 218 transitions to side 212 at corner 228. Instead of the corner 222, substrate 250 includes a corner 252 at the transition between adjacent sides 212 and 214.

[0061] Figure 4D is an enlargement of a portion of Figure 4C at the corner 252 where side 212 transitions to side 214. The corner 252 includes a chamfer 260 that forms the transition between side 212 and side 214. The chamfer 260 is coupled to side 212 at a transition point 262. The chamfer 260 is coupled to side 214 at a transition point 266. The chamfer 260 is substantially straight, and is oriented at an obtuse angle 264 with respect to side 212, and at an obtuse angle 268 with respect to side 214.

[0062] As illustrated, in some embodiments, the obtuse angle 264 is greater than the obtuse angle 268. In other embodiments, the obtuse angle 264 is less than the obtuse angle 268. The corner 252 is asymmetrical about the axis 272 in the X-Y plane.

[0063] The chamfer 260 at the corner 252 mitigates a risk of damage to the substrate 250 at the corner 252 during handling, and during operations, such as CMP.

[0064] In some embodiments, the corner 252 functions as a reference feature of the substrate 250 by presenting a shape that is visually different to the shape of the comers 224, 226, and 228. For example, the location and rotational orientation of the substrate 250 in the X-Y plane with respect to a datum (such as a fixed point in the polishing and cleaning system 100) can be determined by identifying the shape, rotational orientation, and location of the corner 252 of the substrate 250.

[0065] In some embodiments, a sensor, such as sensor 118, such as a camera, is used to identify which corner of a substrate 124, 250 corresponds with the corner 252. The asymmetry of corner 252 (described above) compared to the symmetry of comers 224, 226, 228 (described above with reference to corner 222) facilitates the visual identification of corner 252. Additionally, the8631846_2 13PATENTAttorney Docket No.: 44025098W001 asymmetry of corner 252 facilitates the determination of the rotational orientation of the substrate 124, 250 in the X-Y plane.

[0066] Figure 5 schematically illustrates an embodiment depicting exemplary details of the retaining ring 160A. In Figure 5, the retaining ring 160A is represented by retaining ring 300. The retaining ring 300 includes the aperture 170 in the body 162A bounded by inner sides 172, 174, 176, and 178, as described above. Inner side 172 transitions to inner side 174 at corner 302. Inner side 174 transitions to inner side 176 at corner 304. Inner side 176 transitions to inner side 178 at corner 306. Inner side 178 transitions to inner side 172 at corner 308.

[0067] Figure 5A is an enlargement of a portion of Figure 5 at the corner 302 where inner side 172 transitions to inner side 174. The corner 302 is representative of each other corner 304, 306, and 308 of the retaining ring 300. The corner 302 includes a recess 310 bounded by walls 312, 314, and 316. The recess 310 is coupled with the aperture 170. The recess 310 forms a lateral extension to the aperture 170 (i.e., in the X-Y plane) in a direction towards an outer corner 190 that includes a transition between outer side 182 and outer side 184. The walls 312, 314, and 316 are substantially straight.

[0068] A transition 320 between inner side 172 and wall 312 includes a curved portion 322. The curved portion 322 has a radius 324. Wall 312 is oriented at an obtuse angle 326 with respect to inner side 172, and extends in a direction towards outer side 182.

[0069] A transition 330 between wall 312 and wall 314 includes a curved portion 332. The curved portion 332 has a radius 334. As illustrated, in some embodiments, the radius 334 is larger than the radius 324. In some embodiments, the radius 334 is less than or equal to the radius 324. In some embodiments, wall 314 is substantially perpendicular to wall 312. Wall 314 extends away from wall 312 in a direction towards outer side 184.8631846_2 14PATENTAttorney Docket No.: 44025098W001

[0070] A transition 340 between wall 314 and wall 316 includes a curved portion 342. The curved portion 342 has a radius 344. As illustrated, in some embodiments, the radius 344 is greater than the radius 324. In some embodiments, the radius 344 is less than or equal to the radius 324. As illustrated, in some embodiments, the radius 344 is equal to the radius 334. In some embodiments, the radius 344 is greater than the radius 334. In some embodiments, the radius 344 is less than the radius 334.

[0071] Wall 316 is oriented to extend between the aperture 170 and the outer side 184. In some embodiments, wall 316 is substantially perpendicular to wall 314, and is substantially parallel to wall 312. In some embodiments, wall 316 is equal in length to wall 312.

[0072] Wall 316 is oriented at an obtuse angle 356 with respect to inner side 174, and extends in a direction towards outer side 184. As illustrated, in some embodiments, the obtuse angle 356 is equal to the obtuse angle 326. In some embodiments, the obtuse angle 356 is not equal to the obtuse angle 326.

[0073] A transition 350 between wall 316 and inner side 174 includes a curved portion 352. The curved portion 352 has a radius 354. As illustrated, in some embodiments, the radius 354 is equal to the radius 324. In some embodiments, the radius 354 is greater than the radius 324. In some embodiments, the radius 354 is less than the radius 324. As illustrated, in some embodiments, the radius 354 is less than the radius 334 or the radius 344. In some embodiments, the radius 354 is greater than or equal to the radius 334 or the radius 344.

[0074] As illustrated, the corner 302 is symmetrical about an axis 192 in the X-Y plane that passes through a projected point of intersection 194 of inner side 172 and inner side 174, and bisects the angle 196 between inner side 172 and inner side 174. The shape of the recess, such as delineated by walls 312, 314, 316, results in the corner 302 being symmetrical about the axis 192 in the X-Y plane.8631846_2 15PATENTAttorney Docket No.: 44025098W001

[0075] Each corner 302, 304, 306, and 308 is configured as depicted in Figure 5A, including a recess 310 configured as shown at the transition between each corresponding pair of adjacent inner sides (i.e., (i) inner side 172 and inner side 174, (ii) inner side 174 and inner side 176, (iii) inner side 176 and inner side 178, and (iv) inner side 178 and inner side 172, respectably).

[0076] In some embodiments, the retaining ring 160B includes the exemplary details described above with respect to retaining ring 300, including the comers 302, 304, 306, and 308.

[0077] Figure 6 schematically illustrates another embodiment depicting exemplary details of the retaining ring 160A. In Figure 6, the retaining ring 160A is represented by retaining ring 400. The retaining ring 400 includes the aperture 170 in the body 162A bounded by inner sides 172, 174, 176, and 178, as described above. Inner side 172 transitions to inner side 174 at corner 402. Inner side 174 transitions to inner side 176 at corner 404. Inner side 176 transitions to inner side 178 at corner 406. Inner side 178 transitions to inner side 172 at corner 408.

[0078] Figure 6A is an enlargement of a portion of Figure 6 at the corner 402 where inner side 172 transitions to inner side 174. The corner 402 is representative of each other corner 404, 406, and 408 of the retaining ring 400. The corner 402 includes a recess 410 bounded by wall 412. The recess 410 is coupled with the aperture 170. The recess 410 forms a lateral extension to the aperture 170 (i.e., in the X-Y plane) in a direction towards the outer corner 190. A transition 420 between inner side 172 and wall 412 includes a curved portion 422. The curved portion 422 has a radius 424.

[0079] Wall 412 is curved. As illustrated, in some embodiments, wall 412 includes an arc of a circle. In some embodiments, wall 412 includes an arc that is greater than half of a circle. In some embodiments, wall 412 includes an arc that is less than or equal to half of a circle. In some embodiments, wall 412 is curved, but does not includes an arc of a circle.8631846_2 16PATENTAttorney Docket No.: 44025098W001

[0080] In embodiments in which wall 412 includes an arc of a circle, the arc of the circle has a radius 414. As illustrated, in some embodiments, the radius 414 is larger than the radius 424. In some embodiments, the radius 414 is less than or equal to the radius 424.

[0081] A transition 430 between wall 412 and inner side 174 includes a curved portion 432. The curved portion 432 has a radius 434. As illustrated, in some embodiments, the radius 434 is equal to the radius 424. In some embodiments, the radius 434 is greater than the radius 424. In some embodiments, the radius 434 is less than the radius 424. As illustrated, in some embodiments, the radius 434 is less than the radius 414. In some embodiments, the radius 434 is greater than or equal to the radius 414.

[0082] As illustrated, the shape of the recess 410, such as delineated by wall 412 including an arc of a circle, results in the corner 402 being symmetrical about the axis 192 in the X-Y plane.

[0083] Each corner 402, 404, 406, and 408 is configured as depicted in Figure 6A, including a recess 410 configured as shown at the transition between each corresponding pair of adjacent inner sides (i.e., (i) inner side 172 and inner side 174, (ii) inner side 174 and inner side 176, (iii) inner side 176 and inner side 178, and (iv) inner side 178 and inner side 172, respectably).

[0084] In some embodiments, the retaining ring 160B includes the exemplary details described above with respect to retaining ring 400, including the comers 402, 404, 406, and 408.

[0085] Figure 7 schematically illustrates another embodiment depicting exemplary details of the retaining ring 160A. In Figure 7, the retaining ring 160A is represented by retaining ring 500. The retaining ring 500 includes the aperture 170 in the body 162A bounded by inner sides 172, 174, 176, and 178, as described above. The retaining ring 500 includes the three comers 304, 306, and 308, as described above with respect to retaining ring 300. Inner side 174 transitions to inner side 176 at corner 304. Inner side 176 transitions to8631846_2 17PATENTAttorney Docket No.: 44025098W001 inner side 178 at corner 306. Inner side 178 transitions to inner side 172 at corner 308. Instead of the corner 302, retaining ring 500 includes a corner 502 at the transition between adjacent inner sides 172 and 174.

[0086] Figure 7A is an enlargement of a portion of Figure 7 at the corner 502 where inner side 172 transitions to inner side 174. The corner 502 includes a recess 510 bounded by walls 512, 514, 516, and 518. The recess 510 is coupled with the aperture 170. The recess 510 forms a lateral extension to the aperture 170 (i.e., in the X-Y plane) in a direction towards the outer corner 190. The walls 512, 514, 516, and 518 are substantially straight. A transition 520 between inner side 172 and wall 512 includes a curved portion 522. The curved portion 522 has a radius 524. Wall 512 is oriented at an obtuse angle 526 with respect to inner side 172, and extends in a direction towards outer side 182.

[0087] A transition 530 between wall 512 and wall 514 includes a curved portion 532. The curved portion 532 has a radius 534. In some embodiments, the radius 534 is larger than the radius 524. In some embodiments, the radius 534 is less than or equal to the radius 524. Wall 514 extends in a direction towards outer side 184. In some embodiments, wall 514 is substantially parallel to inner side 172.

[0088] A transition 540 between wall 514 and wall 516 includes a curved portion 542. The curved portion 542 has a radius 544. In some embodiments, the radius 544 is larger than the radius 534. In some embodiments, the radius 544 is less than or equal to the radius 534. In some embodiments, wall 516 is substantially perpendicular to wall 512. Wall 516 extends away from wall 514 in a direction towards outer side 184.

[0089] A transition 550 between wall 516 and wall 518 includes a curved portion 552. The curved portion 552 has a radius 554. As illustrated, in some embodiments, the radius 554 is greater than the radii 524, 534, and 544. In some embodiments, the radius 554 is less than or equal to one or more of the radii 524, 534, and 544. Wall 518 extends in an orientation between the8631846_2 18PATENTAttorney Docket No.: 44025098W001 aperture 170 and the outer side 184. In some embodiments, wall 518 is substantially perpendicular to wall 516, and is substantially parallel to wall 512.

[0090] Wall 518 is oriented at an obtuse angle 566 with respect to inner side 174, and extends in a direction towards outer side 184. As illustrated, in some embodiments, the obtuse angle 566 is equal to the obtuse angle 526. In some embodiments, the obtuse angle 566 is not equal to the obtuse angle 526.

[0091] A transition 560 between wall 518 and inner side 174 includes a curved portion 562. The curved portion 562 has a radius 564. As illustrated, in some embodiments, the radius 564 is equal to the radius 524. In some embodiments, the radius 564 is greater than the radius 524. In some embodiments, the radius 564 is less than the radius 524. As illustrated, in some embodiments, the radius 564 is less than the radius 554. In some embodiments, the radius 564 is greater than or equal to the radius 554.

[0092] As illustrated, the shape of the recess 510, such as delineated in part by wall 514 and curved portion 552, results in the corner 502 being asymmetrical about the axis 192 in the X-Y plane.

[0093] In some embodiments, the corner 502 functions as a reference feature of the retaining ring 500 by presenting a shape that is visually different to the shape of the comers 304, 306, and 308. For example, the location and rotational orientation of the retaining ring 500 in the X-Y plane with respect to a datum (such as a fixed point in the polishing and cleaning system 100) can be determined by identifying the shape, rotational orientation, and location of the corner 502 of the retaining ring 500.

[0094] In some embodiments, a sensor, such as sensor 118, such as a camera, is used to identify which corner of a retaining ring 160A, 500 corresponds with the corner 502. The asymmetry of corner 502 (described above) compared to the symmetry of comers 304, 306, and 308 (described above with reference to corner 302) facilitates the visual identification of corner8631846_2 19PATENTAttorney Docket No.: 44025098W001502. Additionally, the asymmetry of corner 502 facilitates the determination of the rotational orientation of the retaining ring 160A, 500 in the X-Y plane.

[0095] In some embodiments, the retaining ring 160A includes a combination of exemplary details described above with respect to retaining ring 400 and the corner 502 of retaining ring 500. In an example, the retaining ring 160A includes the comers 502, 404, 406, and 408. In such embodiments, the corner 502 may function as a reference feature by presenting a shape that is visually different to the shape of the comers 404, 406, and 408.

[0096] In some embodiments, the retaining ring 160A includes a combination of exemplary details described above with respect to retaining ring 300 and retaining ring 400. In an example, the retaining ring 160A includes one, two, or three of comers 302, 304, 306, 308, and includes one, two, or three of comers 402, 404, 406, 408. In such embodiments, the corner 502 may function as a reference feature, such as described above.

[0097] In some embodiments, the retaining ring 160A includes a combination of exemplary details described above with respect to retaining ring 300, retaining ring 400, and retaining ring 500. In an example, the retaining ring 160A includes one or two of comers 302, 304, 306, 308; and includes one or two of comers 402, 404, 406, 408; and includes corner 502. In such embodiments, the corner 502 may function as a reference feature, such as described above.

[0098] In some embodiments, the retaining ring 160B includes the exemplary details described above with respect to retaining ring 500, including the comers 502, 304, 306, and 308. In such embodiments, the corner 502 may function as a reference feature, such as described above.

[0099] In some embodiments, the retaining ring 160B includes a combination of exemplary details described above with respect to retaining ring 400 and the corner 502 of retaining ring 500. In an example, the retaining ring8631846_2 20PATENTAttorney Docket No.: 44025098W001160B includes the corners 502, 404, 406, and 408. In such embodiments, the corner 502 may function as a reference feature, such as described above.

[0100] In some embodiments, the retaining ring 160B includes a combination of exemplary details described above with respect to retaining ring 300, retaining ring 400, and retaining ring 500. In an example, the retaining ring 160B includes one or two of comers 302, 304, 306, 308; and includes one or two of comers 402, 404, 406, 408; and includes corner 502. In such embodiments, the corner 502 may function as a reference feature, such as described above.

[0101] Figures 8A and 8B schematically illustrate a juxtaposition between the substrate 124 configured as substrate 210 and the retaining ring 160A configured as retaining ring 300. Figure 8A depicts corner 308 of retaining ring 300 and corner 228 of the substrate 210. The substrate 210 is shown abutted against inner sides 172 and 178. The corner 228 is in the recess 310, but does not contact any portion of the retaining ring 300.

[0102] The chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 300. A transition point 246 between the side 212 and the chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 300. A transition point 248 between the side 218 and the chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 300. The recess 310 mitigates a risk of damage to the substrate 210 by preventing the corner 228 of the substrate 210 from being subject to impacts or side loads exerted by the retaining ring 300.

[0103] Figure 8B depicts corner 302 of retaining ring 300 and corner 222 of the substrate 210. The substrate 210 is abutted against inner sides 172 and 178, as shown in Figure 8A. Despite the clearance 152 between the side 214 of the substrate 210 and inner side 174 of the retaining ring 300, the corner 222 is in the recess 310, and does not contact any portion of the retaining ring 300.8631846_2 21PATENTAttorney Docket No.: 44025098W001

[0104] The chamfer 230 of the corner 222 is in the recess 310, but does not contact any portion of the retaining ring 300. The transition point 232 between the side 212 and the chamfer 230 of the corner 222 is in the recess 310, but does not contact any portion of the retaining ring 300. The transition point 236 between the side 214 and the chamfer 230 of the corner 222 is in the recess 310, but does not contact any portion of the retaining ring 300. The recess 310 mitigates a risk of damage to the substrate 210 by preventing the corner 222 of the substrate 210 from being subject to impacts or side loads exerted by the retaining ring 300.

[0105] The configuration shown in Figures 8A and 8B applies also to the retaining ring 160B when the retaining ring 160B includes the comers 302, 304, 306, and 308.

[0106] Figures 9A and 9B schematically illustrate a juxtaposition between the substrate 124 configured as substrate 210 and the retaining ring 160A configured as retaining ring 400. Figure 9A depicts corner 408 of retaining ring 400 and corner 228 of the substrate 210. The substrate 210 is shown abutted against inner sides 172 and 178. The corner 228 is in the recess 410, but does not contact any portion of the retaining ring 400.

[0107] The chamfer 230 of the corner 228 is in the recess 410, but does not contact any portion of the retaining ring 400. The transition point 246 between the side 212 and the chamfer 230 of the corner 228 is in the recess 410, but does not contact any portion of the retaining ring 400. The transition point 248 between the side 218 and the chamfer 230 of the corner 228 is in the recess 410, but does not contact any portion of the retaining ring 400. The recess 410 mitigates a risk of damage to the substrate 210 by preventing the corner 228 of the substrate 210 from being subject to impacts or side loads exerted by the retaining ring 400.

[0108] Figure 9B depicts corner 402 of retaining ring 400 and corner 222 of the substrate 210. The substrate 210 is abutted against inner sides 172 and 178, as shown in Figure 9A. Despite the clearance 152 between the side 2148631846_2 22PATENTAttorney Docket No.: 44025098W001 of the substrate 210 and inner side 174 of the retaining ring 300, the corner 222 is in the recess 410, and does not contact any portion of the retaining ring 400.

[0109] The chamfer 230 of the corner 222 is in the recess 410, but does not contact any portion of the retaining ring 400. The transition point 232 between the side 212 and the chamfer 230 of the corner 222 is in the recess, but does not contact any portion of the retaining ring 400. The transition point 236 between the side 218 and the chamfer 230 of the corner 222 is in the recess 410, but does not contact any portion of the retaining ring 400. The recess 410 mitigates a risk of damage to the substrate 210 by preventing the corner 222 of the substrate 210 from being subject to impacts or side loads exerted by the retaining ring 400.

[0110] The configuration shown in Figures 9A and 9B applies also to the retaining ring 160B when the retaining ring 160B includes the comers 402, 404, 406, and 408.

[0111] Figures 10A and 10B schematically illustrate a juxtaposition between the substrate 124 configured as substrate 250 and the retaining ring 160A configured as retaining ring 500. Figure 10A depicts corner 308 of retaining ring 500 and corner 228 of the substrate 250. The substrate 250 is shown abutted against inner sides 172 and 178. The corner 228 is in the recess 310, but does not contact any portion of the retaining ring 500.

[0112] The chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 500. The transition point 246 between the side 212 and the chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 500. The transition point 248 between the side 218 and the chamfer 230 of the corner 228 is in the recess 310, but does not contact any portion of the retaining ring 500. The recess 310 mitigates a risk of damage to the substrate 250 by preventing the corner 228 of the substrate 250 from being subject to impacts or side loads exerted by the retaining ring 500.8631846_2 23PATENTAttorney Docket No.: 44025098W001

[0113] Figure 10B depicts corner 502 of retaining ring 500 and corner 252 of the substrate 250. The substrate 250 is abutted against inner sides 172 and 178, as shown in Figure 10A. Despite the clearance 152 between the side 214 of the substrate 210 and inner side 174 of the retaining ring 500, the corner 252 is in the recess 510, and does not contact any portion of the retaining ring 500.

[0114] The chamfer 260 of the corner 252 is in the recess 510, but does not contact any portion of the retaining ring 500. The transition point 262 between the side 212 and the chamfer 260 of the corner 252 is in the recess 510, but does not contact any portion of the retaining ring 500. The transition point 266 between the side 214 and the chamfer 260 of the corner 252 is in the recess 510, but does not contact any portion of the retaining ring 500. The recess 510 mitigates a risk of damage to the substrate 250 by preventing the corner 252 of the substrate 250 from being subject to impacts or side loads exerted by the retaining ring 500.

[0115] The configuration shown in Figures 10A and 10B applies also to the retaining ring 160B when the retaining ring 160B includes the corner 502 and one or more of comers 304, 306, or 308.

[0116] The configuration shown in Figures 9A and 10B applies also to the retaining ring 160A when the retaining ring 160A includes the corner 502 and one or more of comers 404, 406, or 408.

[0117] The configuration shown in Figures 9A and 10B applies also to the retaining ring 160B when the retaining ring 160B includes the corner 502 and one or more of comers 404, 406, or 408.

[0118] Figure 11 is a flow diagram of an exemplary method 600 of handling a substrate. Operation 602 includes determining an orientation of a substrate. In some embodiments, the substrate is laying in an X-Y plane. In some embodiments that may be combined with other embodiments, the substrate is a panel substrate, and is configured similar to substrate 250.8631846_2 24PATENTAttorney Docket No.: 44025098W001

[0119] In some embodiments that may be combined with other embodiments, the substrate includes three comers of a similar first shape, and one corner of a second shape different to the first shape. In some embodiments that may be combined with other embodiments, one of the first shape or the second shape exhibits a symmetrical configuration in the X-Y plane, and the other of the first shape or the second shape does not exhibit a symmetrical configuration in the X-Y plane. In some examples, the symmetrical configuration includes symmetry about an axis in the X-Y plane that passes through a projected point of intersection of two adjacent sides of the substrate, and that bisects an angle between the two adjacent sides.

[0120] In some embodiments that may be combined with other embodiments, operation 602 includes using a sensor, such as sensor 118, such as a camera, to identify a portion of the substrate that matches a predetermined shape. In some embodiments that may be combined with other embodiments, the portion of the substrate is an alignment feature of the substrate. In some embodiments that may be combined with other embodiments, the alignment feature of the substrate is a shape of a corner of the substrate. In some examples, the corner is configured similar to corner 252 of substrate 250.

[0121] Operation 604 includes determining an orientation of a retaining ring coupled to a polishing head. In some embodiments that may be combined with other embodiments, the retaining ring is configured similar to retaining ring 160A or retaining ring 160B. In some embodiments that may be combined with other embodiments, the retaining ring includes a configuration similar to retaining ring 500.

[0122] In some embodiments that may be combined with other embodiments, the retaining ring includes three internal corners of a similar first shape, and one corner of a second shape different to the first shape. In some embodiments that may be combined with other embodiments, one of the first shape or the second shape exhibits a symmetrical configuration in the X-Y plane, and the other of the first shape or the second shape does not exhibit a symmetrical configuration in the X-Y plane. In some examples, the symmetrical 8631846_2 25PATENTAttorney Docket No.: 44025098W001 configuration includes symmetry about an axis in the X-Y plane that passes through a projected point of intersection of two adjacent sides of the retaining ring, and that bisects an angle between the two adjacent sides.

[0123] In some embodiments that may be combined with other embodiments, operation 604 includes using a sensor, such as sensor 118, such as a camera, to identify a portion of the retaining ring that matches a predetermined shape. In some embodiments that may be combined with other embodiments, the portion of the retaining ring is an alignment feature of the retaining ring. In some embodiments that may be combined with other embodiments, the alignment feature of the retaining ring is a shape of a recess of a corner of the retaining ring. In some examples, the corner is configured similar to corner 502 of retaining ring 500.

[0124] Operation 606 includes adjusting one of the orientation of the retaining ring or the orientation of the substrate to align the retaining ring with the substrate. In some embodiments that may be combined with other embodiments, operation 606 includes moving one of the substrate or the retaining ring laterally in the X-Y plane. In some embodiments that may be combined with other embodiments, operation 606 includes rotating one of the substrate or the retaining ring in the X-Y plane.

[0125] In some embodiments that may be combined with other embodiments, aligning the retaining ring with the substrate includes positioning an alignment feature of the retaining ring above (in the Z direction) an alignment feature of the substrate. In an example, the alignment feature of the retaining ring is positioned directly above the alignment feature of the substrate.

[0126] Operation 608 includes coupling the substrate to the polishing head. In some embodiments that may be combined with other embodiments, operation 608 includes moving at least one of the substrate or the polishing head towards the other of the substrate or the polishing head. In some embodiments that may be combined with other embodiments, operation 608 includes positioning the retaining ring around the substrate.8631846_2 26PATENTAttorney Docket No.: 44025098W001

[0127] In some embodiments that may be combined with other embodiments, operation 608 includes juxtaposing the alignment feature of the substrate with the alignment feature of the retaining ring. In some examples, juxtaposing the alignment feature of the substrate with the alignment feature of the retaining ring includes positioning the alignment feature of the substrate into the alignment feature of the retaining ring.

[0128] In some embodiments that may be combined with other embodiments, operation 608 includes applying a suction to the substrate using the polishing head. In some examples, applying a suction to the substrate using the polishing head includes applying the suction using a membrane coupled to a support plate of the polishing head.

[0129] In some embodiments that may be combined with other embodiments, method 600 includes using the polishing head to carry the substrate to a polishing station. In some embodiments that may be combined with other embodiments, method 600 includes performing a CMP operation on the substrate. In some embodiments that may be combined with other embodiments, performing the CMP operation on the substrate includes applying a downward force in the Z direction onto the substrate using the polishing head while the substrate contacts a polishing pad. In some embodiments that may be combined with other embodiments, method 600 includes using the polishing head to carry the substrate to a cleaning station. In some embodiments that may be combined with other embodiments, method 600 includes releasing the substrate from the polishing head.

[0130] Embodiments of the present disclosure provide apparatus, systems, and methods that mitigate a risk of damage to a substrate during a CMP process. The risk of damage to the substrate is mitigated by preventing impacts on one or more portions of an edge of the substrates by a retaining ring. The one or more portions of the edge of the substrate are weaker portions of the substrate, such as corners of the substrate, compared to other portions, such as central edge portions, of the substrate.8631846_2 27PATENTAttorney Docket No.: 44025098W001

[0131] Embodiments of the present disclosure provide apparatus, systems, and methods that facilitate the performing of a CMP process on a panel substrate. Embodiments of the present disclosure provide apparatus, systems, and methods that facilitate aligning a polishing head and a panel substrate, and coupling the panel substrate to the polishing head.

[0132] It is contemplated that any one or more elements or features of any one disclosed embodiment or example may be beneficially incorporated in any one or more other non-mutually exclusive embodiments or examples. While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.8631846_2 28

Claims

PATENTAttorney Docket No.: 44025098W001What is claimed is:1 . A retaining ring for use with a substrate, the retaining ring comprising: a body; an aperture in the body bounded by a plurality of inner sides of the body, the plurality of inner sides including a first inner side and a second inner side; and a corner coupling the first inner side to the second inner side, the corner including a recess coupled with the aperture, the recess bounded by first, second, and third walls; wherein: the first wall is substantially straight, and is coupled to the first inner side; the second wall is substantially straight, and is substantially perpendicular to the first wall; the third wall is substantially straight, and is substantially parallel to the first wall; and the third wall is coupled to the second inner side.

2. The retaining ring of claim 1 , wherein a shape of the recess is symmetrical about an axis in an X-Y plane, the axis passing through a projected point of intersection of the first and second inner sides, and bisecting an angle between the first and second inner sides.

3. The retaining ring of claim 1 , wherein a shape of the recess is asymmetrical about an axis in an X-Y plane, the axis passing through a projected point of intersection of the first and second inner sides, and bisecting an angle between the first and second inner sides.

4. The retaining ring of claim 1 , wherein the second wall is coupled between the first wall and the third wall.8631846_2 29PATENTAttorney Docket No.: 44025098W0015. The retaining ring of claim 4, wherein the first wall extends at an obtuse angle to the first inner side towards an outer side of the body, and a transition from the first inner side to the first wall includes a first curved portion.

6. The retaining ring of claim 5, wherein a transition from the first wall to the second wall includes a second curved portion.

7. The retaining ring of claim 6, wherein a radius of the first curved portion is less than a radius of the second curved portion.

8. The retaining ring of claim 4, further comprising a fourth wall bounding the recess, the fourth wall coupled between the first wall and the second wall.

9. The retaining ring of claim 8, wherein the fourth wall is substantially parallel to the first inner side.

10. A retaining ring for use with a substrate, the retaining ring comprising: a body; an aperture in the body bounded by a plurality of inner sides of the body, the plurality of inner sides including a first inner side, a second inner side, and a third inner side; a first corner coupling the first inner side to the second inner side, the first corner including a first recess coupled with the aperture; a second corner coupling the second inner side to the third inner side, the second corner including a second recess coupled with the aperture; wherein a first shape of the first recess is different from a second shape of the second recess.

11. The retaining ring of claim 10, wherein the first shape is symmetrical about a first axis in an X-Y plane, the first axis passing through a first projected point of intersection of the first and second inner sides, and bisecting a first angle between the first and second inner sides.8631846_2 30PATENTAttorney Docket No.: 44025098W00112. The retaining ring of claim 11 , wherein the second shape is asymmetrical about a second axis in the X-Y plane, the second axis passing through a second projected point of intersection of the second and third inner sides, and bisecting a second angle between the second and third inner sides.

13. The retaining ring of claim 10, wherein: the first recess is bounded by first, second, and third walls; the first wall is substantially straight, and is coupled to the first inner side; the second wall is substantially straight, and is coupled between the first wall and the third wall; and the third wall is substantially straight, and is coupled to the second inner side.

14. The retaining ring of claim 13, wherein the second wall is substantially perpendicular to the first wall.

15. The retaining ring of claim 13, wherein the third wall is substantially parallel to the first wall.

16. A method of handling a substrate, the method comprising: determining an orientation of a substrate; determining an orientation of a retaining ring coupled to a polishing head; adjusting one of the orientation of the retaining ring or the orientation of the substrate to align the retaining ring with the substrate; and coupling the substrate to the polishing head.

17. The method of claim 16, wherein determining an orientation of the substrate includes identifying a first portion of the substrate that matches a first predetermined shape.

18. The method of claim 17, wherein the first portion of the substrate includes a corner of the substrate.8631846_2 31PATENTAttorney Docket No.: 44025098W00119. The method of claim 17, wherein determining an orientation of the retaining ring includes identifying a second portion of the retaining ring that matches a second predetermined shape.

20. The method of claim 19, wherein the second portion of the retaining ring includes a recess of a corner of the retaining ring.8631846_2 32

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