MEMBRANE DESIGN FOR RECTANGULAR SUBSTRATE POLISHING BY CHEMICAL MECHANICAL POLISHING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims the benefit of US provisional application number 63/718,218, filed Nov. 8, 2024, which is incorporated herein by reference in its entirety.

BACKGROUND

Field

[0002]Embodiments herein are generally directed to systems and apparatus for semiconductor manufacturing and, more particularly, to systems and apparatus for chemical mechanical polishing of a rectangular semiconductor substrate.

Description of the Related Art

[0003]Chemical mechanical polishing (CMP) is commonly used in the manufacturing of high-density integrated circuits to planarize or polish a layer of material deposited on a substrate. In a typical CMP process, a substrate is retained in a carrier head that presses the backside of the substrate towards a rotating polishing pad in the presence of a polishing fluid. Material is removed across the material layer surface of the substrate in contact with the polishing pad through a combination of chemical and mechanical activity which is provided by the polishing fluid and a relative motion of the substrate and the polishing pad. Typically, after one or more CMP processes are complete a polished substrate is further processed in one or more post-CMP substrate processing operations. For example, the polished substrate may be further processed using one or a combination of cleaning, inspection, and measurement operations. Once the post-CMP operations are complete, a substrate can be sent out of a CMP processing area to the next device manufacturing process, such as a lithography, etch, or deposition process.

[0004]The CMP polishing system can include a polishing head to hold the substrate and apply pressure to the substrate against the polishing pad during polishing. The polishing head generally includes a retaining ring disposed around the edges of the substrate to assist in holding the substrate in the polishing head. The polishing head also generally includes a flexible membrane positioned against the back side of the substrate during polishing. The pressure applied to the flexible membrane during polishing can be adjusted to change the pressure that is applied to the substrate against the polishing pad during polishing. However, when polishing a rectangular substrate, significant change will be required to accommodate the substrate geometry. Besides with the rectangular format, different zone configuration will be required to accommodate contact pressure characteristics with the rectangular substrate.

[0005]Accordingly, there is a need for improved systems and methods for polishing a rectangular substrate.

SUMMARY

[0006]In one aspect, a carrier head assembly for a chemical mechanical polishing system is provided. The carrier head assembly includes a base assembly and a rectangular membrane extending below and coupled to the base assembly. The rectangular membrane defines pressurizable chambers including a first pressurizable chamber and a second pressurizable chamber arranged, at least in part, in a chamber stack in which the first pressurizable chamber is stacked on the second pressurizable chamber. The first and second pressurizable chambers are pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber.

[0007]In another aspect, a chemical mechanical polishing (CMP) system is provided. The CMP system includes a polishing pad assembly, a rotatable arm, and a carrier head assembly coupled to the rotatable arm and configured to hold a rectangular substrate against the polishing pad assembly. The carrier head assembly includes a base assembly and a rectangular membrane extending below and coupled to the base assembly. The rectangular membrane defines pressurizable chambers including a first pressurizable chamber and a second pressurizable chamber arranged, at least in part, in a chamber stack in which the first pressurizable chamber is stacked on the second pressurizable chamber. The first and second pressurizable chambers are pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber.

[0008]In yet another aspect, a membrane for a chemical mechanical polishing system is provided. The membrane includes a chamber stack forming a first pressurizable chamber and a second pressurizable chamber upon which the first pressurizable chamber is stacked. The first and second pressurizable chambers are pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber.

BRIEF 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 of the present disclosure and are therefore not to be considered limiting of its scope, and the present disclosure may admit to other equally effective embodiments.

[0010]FIG. 1 is a schematic, side cross-sectional view of a polishing system, according to one or more embodiments.

[0011]FIG. 2A is a schematic, cross-sectional view of a carrier head assembly of the polishing system of FIG. 1, according to one or more embodiments.

[0012]FIG. 2B is a bottom view of a carrier head assembly of FIG. 2A, according to one or more embodiments.

[0013]FIG. 3A is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments.

[0014]FIG. 3B is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments.

[0015]FIG. 3C is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments.

[0016]FIG. 3D is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments.

[0017]FIG. 3E is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments.

[0018]FIG. 4A is a schematic side view of a chamber stack for a rectangular membrane, according to one or more embodiments.

[0019]FIG. 4B is a schematic side view of a chamber stack for a rectangular membrane, according to one or more embodiments.

[0020]FIG. 4C is a schematic side view of a chamber stack for a rectangular membrane, according to one or more embodiments.

[0021]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

[0022]Embodiments herein are generally directed to systems and apparatus for semiconductor manufacturing and, more particularly, to systems and apparatus for chemical mechanical polishing of a rectangular semiconductor substrate.

[0023]FIG. 1 is a schematic, side cross-sectional view of a polishing system 100, according to one or more embodiments. The polishing system 100 includes a carrier head assembly 101, a polishing pad assembly 150, a rotatable arm 103, a vacuum source 160, a gas source 170, and a controller 185. The rotatable arm 103 is configured to move the carrier head assembly 101 to position a substrate 50 over the polishing pad assembly 150 before polishing of the substrate 50 is started. The carrier head assembly 101 is further configured to retain and rotate the substrate 50 against a polishing pad 60 of the polishing pad assembly 150 during polishing of the substrate 50. The polishing pad assembly 150 can additionally rotate the polishing pad 60 to aid in the polishing of the substrate 50.

[0024]The carrier head assembly 101 includes a carrier head 110. The vacuum source 160 can be fluidly coupled to the carrier head 110 of the carrier head assembly 101, so that vacuum pressure can be applied to retain the substrate 50 in the carrier head 110. The gas source 170 can also be fluidly coupled to the carrier head 110, so that a gas supply pressure (e.g., a pressure greater than atmospheric pressure) can be applied via a membrane assembly 120, to a back side 51 of the substrate 50 in the carrier head 110 to press the opposing interface surface 52 of the substrate 50 against the polishing pad 60 when polishing of the substrate 50 is performed.

[0025]The controller 185 can be used to adjust when vacuum pressure from the vacuum source 160 is applied to the carrier head 110 and when gas supply pressure from the gas source 170 is applied to the carrier head 110. For example, before polishing of the substrate 50, vacuum pressure from the vacuum source 160 can be applied to the carrier head 110 without any gas supply pressure from the gas source 170, so that the substrate 50 is retained in the carrier head 110 and the substrate 50 can be moved into a polishing position by movement of the carrier head 110 by the rotatable arm 103 and vertical movement of the carrier head 110. During polishing of the substrate 50, vacuum pressure from the vacuum source 160 and gas pressure from the gas source 170 can be applied simultaneously to the carrier head 110, so that an appropriate amount of pressure can be applied to the back side 51 of the substrate 50 during polishing. After polishing of the substrate 50 and moving the substrate 50 to a transfer position, gas supply pressure from the gas source 170 can be applied to the carrier head 110 without any vacuum pressure from the vacuum source 160, so that the substrate 50 can be released from the carrier head 110.

[0026]The polishing pad assembly 150 includes a platen 151, a motor 152, and a shaft 153 coupling the motor 152 and the platen 151. The motor 152 is configured to rotate the shaft 153 and the platen 151 coupled to the shaft 153 about a vertical axis 156 extending through the center of the shaft 153 and the platen 151 during polishing of the substrate 50. The polishing pad 60 is positioned on the platen 151. The polishing pad 60 rotates with the platen 151 during polishing of the substrate 50.

[0027]The carrier head assembly 101 includes a shaft 108, the carrier head 110, a rotary union 107, and a plurality of motors 102, 104, 106. The shaft 108 couples the carrier head 110 to the rotary union 107. The rotary union 107 allows fluid connections from the vacuum source 160 and the gas source 170 to the carrier head 110 to be maintained as the shaft 108 and carrier head 110 are rotated during polishing of the substrate 50. The rotatable arm 103 can be rotated to position the carrier head 110 in different positions. For example, the rotatable arm 103 can move the carrier head 110 from a first position, in which the carrier head 110 is positioned over the polishing pad assembly 150 enabling the substrate 50 to be polished, to a second position over another support (not shown) where substrates can be exchanged by the carrier head 110.

[0028]The motors of the carrier head assembly 101 include a horizontal motor 102, a vertical motor 104, and a rotational motor 106. The horizontal motor 102 is configured to move the carrier head assembly 101 horizontally relative to a location on the rotatable arm 103, such as an end of the rotatable arm 103. The vertical motor 104 is configured to move the carrier head 110 vertically relative to the polishing pad assembly 150, for example to lower the substrate 50 in the carrier head 110 onto the polishing pad 60 to begin polishing or to raise the substrate 50 in the carrier head 110 away from the polishing pad 60 when polishing of the substrate 50 is completed. In some embodiments, the horizontal motor 102 and the vertical motor 104 can each be linear actuators.

[0029]The rotational motor 106 is configured to rotate the shaft 108 and the carrier head 110 that is coupled to the shaft 108, so that the substrate 50 retained in the carrier head 110 can be rotated against the polishing pad 60 during polishing of the substrate 50. The rotational motor 106 can be configured to rotate the shaft 108 and the carrier head 110 about a rotational axis 109 extending vertically through the centers of the carrier head 110 and the shaft 108.

[0030]The carrier head 110 includes a housing 111 and the membrane assembly 120. The housing 111 includes a top 112 and one or more sidewalls 113 connected to the top 112 of the housing 111. The housing 111 is disposed around an interior volume 115 of the carrier head 110.

[0031]The membrane assembly 120 extends across the interior volume 115 of the housing 111 from the one or more sidewalls 113 of the housing 111. The membrane assembly 120 can include vacuum apertures (not shown) that extend through the membrane assembly 120 to allow for vacuum to pull the substrate 50 toward the membrane assembly 120, when desired. The membrane assembly 120 includes a bottom surface 125 that contacts the back side 51 of the substrate 50. Further, the membrane assembly 120 can include a rectangular membrane 118. The rectangular membrane 118 can include a plurality of pressurizable chambers, which can be individually pressurized, or rather, pressurized independently of one another. The membrane assembly 120 can also include a retaining ring that supports and holds the rectangular membrane 118 in place.

[0032]The polishing system 100 further includes a vacuum conduit 131 and a gas source conduit 132. The vacuum conduit 131 is configured to fluidly couple one or more of the vacuum apertures in the carrier head 110 to vacuum pressure from the vacuum source 160. The gas source conduit 132 is configured to fluidly couple one or more of the pressurizable chambers within the rectangular membrane 118 in the carrier head 110 to gas supply pressure from the gas source 170. Although only one vacuum conduit 131 is shown in FIG. 1, it will be appreciated that the polishing system 100 can include a plurality of vacuum conduits. Similarly, although only one gas source conduit 132 is shown in FIG. 1, it will be appreciated that the polishing system 100 can include a plurality of gas source conduits, e.g., each fluidly coupled with one or more of the pressurizable chambers. In some embodiments, the rectangular membrane 118 can include internal channels and/or plenums connecting the pressurizable chambers to the gas source conduits 132. These internal channels and/or plenums can be kept fluidly separate from internal channels and/or plenums associated with the vacuum apertures.

[0033]The polishing system 100 can further include a plurality of valves to control the application of vacuum pressure from the vacuum source 160 and gas supply pressure from the gas source 170 to the carrier head 110. The plurality of valves includes a plurality of shut-off valves V1, V2 that are configured to open and close. The first valve V1 is configured to open to apply vacuum pressure from the vacuum source 160 to the vacuum conduit 131 and the vacuum apertures in the carrier head 110. The second valve V2 is configured to open to apply gas supply pressure from the gas source 170 to the gas source conduit 132 and the pressurizable chambers in the carrier head 110.

[0034]The plurality of valves further include a first control valve CV1 and a second control valve CV2. The control valves CV1, CV2 are configured to adjust the size of the flow path through the control valves CV1, CV2, so that the control valves CV1, CV2 can precisely control the flow through the control valve CV1, CV2 or pressure in the corresponding conduits 131, 132. The first control valve CV1 is configured to control the flow through the vacuum conduit 131 and/or pressure of the vacuum conduit 131. The second control valve CV2 is configured to control the flow through the gas source conduit 132 and/or pressure of the gas source conduit 132.

[0035]The polishing system 100 can further include a first sensor S1 and a second sensor S2. In some embodiments, the sensors S1, S2 are each a flowmeter or a pressure sensor. The first sensor S1 can be positioned downstream of the first control valve CV1 on the vacuum conduit 131. The second sensor S2 can be positioned downstream of the second control valve CV2 on the gas source conduit 132. The sensors S1, S2 can each be connected to the controller 185. The controller 185 can use measurements from the first sensor S1 to control the position of the first control valve CV1 to control the flow through the vacuum conduit 131 or pressure in the vacuum conduit 131. The controller 185 can use measurements from the second sensor S2 to control the position of the second control valve CV2 to control the flow through the gas source conduit 132 or pressure in the gas source conduit 132.

[0036]The polishing system 100 also includes the controller 185 for controlling processes performed by the polishing system 100. The controller 185 can be any type of controller used in an industrial setting, such as a programmable logic controller (PLC). The controller 185 includes a processor 187, a memory 186, and input/output (I/O) circuits 188. The controller 185 can further include one or more of the following components (not shown), such as one or more power supplies, clocks, communication components (e.g., network interface card), and user interfaces typically found in controllers for semiconductor equipment.

[0037]The memory 186 can include non-transitory memory. The non-transitory memory can be used to store the programs and settings described below. The memory 186 can include one or more readily available types of memory, such as read only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM).

[0038]The processor 187 is configured to execute various programs stored in the memory 186, such as programs that can be executed to polish the substrate 50 with the polishing system 100. During execution of these programs, the controller 185 can communicate to I/O devices through the I/O circuits 188. For example, during execution of these programs and communication through the I/O circuits 188, the controller 185 can control outputs, such as the position of valves V1, V2, CV1, CV2 to apply vacuum pressure and/or gas supply pressure to the vacuum apertures or pressurized gas to the pressurizable chambers in the carrier head 110. The memory 186 can further include various operational settings used to control the polishing system 100. For example, the settings can include durations for how long the different valves remain open or closed during the polishing processes. In some example aspects, the valves can be controlled by the controller 185 to adjust the pressure differential between pressurizable chambers arranged in a stacked configuration, or rather, in a chamber stack. Adjusting the pressure differential can adjust the applied force that the rectangular membrane 118 places on the substrate 50 via a loaded side wall, which in turn can adjust the contact pressure between the substrate 50 and the polishing pad 60.

[0039]FIG. 2A illustrates a schematic, cross-sectional view of the carrier head assembly 101, according to certain embodiments. FIG. 2B illustrates a schematic, bottom view of the carrier head assembly 101, according to one or more embodiments. As shown in FIG. 2A, a carrier head 200 includes a base assembly 204 (which may be connected directly or indirectly to a rotatable drive shaft 274), a retaining ring 210, and a flexible rectangular membrane 208. The flexible rectangular membrane 208 extends below and is connected to the base assembly 204 to provide multiple pressurizable chambers, including an inner chamber 206a, middle chambers 206b, and outer chambers 206c. Passages 212a, 212b and 212c are formed through the base assembly 204 to fluidly couple the chambers 206a, 206b, 206c, respectively, to pressure regulators in the polishing apparatus to apply pressure to the chambers 206a, 206b, 206c individually.

[0040]As shown in FIG. 2B, the outer chambers 206c are located in the corners of the rectangular membrane 208. The outer chambers 206c create zones of a desired pressure on the corners of a rectangular substrate being polished. As a rectangular substrate is being processed, the corners of the rectangular substrate undergo a stress distribution, e.g., from the rotational force applied to the rectangular substrate by the polishing pad and the carrier head, that is not seen in round substrates. As such, the outer chambers 206c allow for pressure tuning at the corners of the rectangular membrane 208 that compensate for the stress at the corners of the rectangular substrate. The inner chamber 206a is configured to apply the necessary force to the rectangular substrate for polishing. The middle chambers 206b provided an additional tuning knob for the pressure profile applied to the rectangular substrate.

[0041]Although unillustrated, the carrier head can include other elements, such as a housing that is securable to the drive shaft and from which the base assembly 204 is movably suspended, a gimbal mechanism (which may be considered part of the base assembly) that permits the base assembly 204 to pivot, a loading chamber between the base assembly 204 and the housing, one or more support structures inside the chambers 206a, 206b, 206c, or one or more internal membranes that contact the inner surface of the rectangular membrane 208 to apply supplemental pressure to the substrate.

[0042]The flexible rectangular membrane 208 is formed of a flexible and elastic fluid-impermeable material, such as neoprene, chloroprene, ethylene propylene rubber or silicone. For example, the flexible rectangular membrane 208 can be formed of either compression molded silicone or liquid injection molded silicone.

[0043]The rectangular membrane 208 is hydrophobic, durable, and chemically inert vis-à-vis the polishing process. The rectangular membrane 208 can include a central portion 220 with an outer surface that provides a mounting surface 222 for a substrate, a perimeter portion 224 that extends away from the polishing surface for connection to the base assembly 204, and one or more inner flaps 228a, 228b that extend from the inner surface of the central portion 220 and are connected to the base assembly 204 to divide the volume between the rectangular membrane 208 and the base assembly 204 into the independently pressurizable chambers 206a, 206b, 206c. The ends of the flaps 228a, 228b may be secured to the base assembly 204 by a clamp ring 214 (which may be considered part of the base assembly 204). The end of the perimeter portion 224 may also be secured to the base assembly 204 by a clamp which also may be considered part of the base assembly 204, or the end of the perimeter portion may be clamped between the retaining ring and the base. Although FIG. 2A illustrates two flaps 228a, 228b, the carrier head could have just one flap, or three or more flaps. The central portion 220 of the rectangular membrane 208 can include a flexible lip portion.

[0044]In one or more further embodiments of the present disclosure, a rectangular membrane for a polishing system can include pressurizable chambers arranged, at least in part, in a chamber stack in which one pressurizable chamber is stacked on another pressurizable chamber. The upper and lower pressurizable chambers can be pressurizable to different pressures to create a pressure differential that effectively generates a downward force through a side wall forming, at least in part, the lower pressurizable chamber. The downward force can propagate from the loaded side wall to a substrate arranged below the lower pressurizable chamber, which ultimately presses the substrate against a polishing pad. This “loading through the wall” technique can be advantageous in that the pressure differential between the chambers can be controlled to tune the force applied by the membrane at a corner, edge, or other location of the substrate, which can ultimately improve the contact pressure of the substrate and the polishing pad at such locations. Further, by loading through the wall, the load path can be through the wall rather than the back of the membrane, which can offer a focused, high resolution force at a desired location. Focused, high resolution forces can thus be applied to corners, edges, or other locations of the substrate where unsatisfactory contact pressure can develop, rather than spreading by area via the back of the membrane. Example membranes having pressurizable chambers arranged in a chamber stack are provided below.

[0045]FIG. 3A is a top plan view of a rectangular membrane 300A for a polishing system, according to one or more embodiments. The rectangular membrane 118 of FIG. 1 can be configured in a same or similar manner as the rectangular membrane 300A of FIG. 3A, for example. The rectangular membrane 300A can extend below and can be coupled to a base assembly of a carrier head assembly, for example.

[0046]As depicted in FIG. 3A, the rectangular membrane 300A has a rectangular shape, which can match or be substantially complementary in shape to a substrate arranged below the rectangular membrane 300A. The rectangular membrane 300A has a first side 301, a second side 302, a third side 303, and a fourth side 304. The first side 301 and the second side 302 connect at a first corner 311. The second side 302 and the third side 303 connect at a second corner 312. The third side 303 and the fourth side 304 connect at a third corner 313. Finally, the fourth side 304 and the first side 301 connect at a fourth corner 314. The first, second, third, and fourth sides 301, 302, 303, 304 collectively define a perimeter 305 of the rectangular membrane 300A. The rectangular membrane 300A has a center C1, and a radial direction R1 extends outward from the center C1 of the rectangular membrane 300A.

[0047]The rectangular membrane 300A defines pressurizable chambers, including a first pressurizable chamber 321, a second pressurizable chamber 322, a third pressurizable chamber 323, a fourth pressurizable chamber 324, a fifth pressurizable chamber 325, and a sixth pressurizable chamber 326. The pressurizable chambers 321-326 can each be pressurized individually to different pressures (or one or more of the chambers can be pressurized to a same pressure). In some examples, first pressurizable chamber 321 is pressurized to a first pressure, the second pressurizable chamber 322 is pressurized to a second pressure, the third pressurizable chamber 323 is pressurized to a third pressure, the fourth pressurizable chamber 324 is pressurized to a fourth pressure, the fifth pressurizable chamber 325 is pressurized to a fifth pressure, and the sixth pressurizable chamber 326 is pressurized to a sixth pressure, wherein the first pressure is greater than the second pressure, the second pressure is greater than the third pressure, the third pressure is greater than the fourth pressure, the fourth pressure is greater than the fifth pressure, and the fifth pressure is greater than the sixth pressure. Stated differently, the pressure within the pressurizable chambers 321-326 can successively decrease from the first pressurizable chamber 321 to the sixth pressurizable chamber 326. Other pressurized schemes are contemplated.

[0048]In the depicted embodiment of FIG. 3A, the fourth, fifth, and sixth pressurizable chambers 324, 325, 326 are arranged as concentric circles with respect to the center C1. The third pressurizable chamber 323 is arranged between the fourth pressurizable chamber 324 and the second pressurizable chamber 322. The second pressurizable chamber 322 is shaped to have a rectangular annulus, and extends to each side of the rectangular membrane 300A. The first pressurizable chamber 321 is shaped to have a rectangular annulus as well, and extends to each side of the rectangular membrane 300A.

[0049]In at least some examples, the first pressurizable chamber 321 and the second pressurizable chamber 322 are arranged, at least in part, in a chamber stack 330 in which the first pressurizable chamber 321 is stacked on the second pressurizable chamber 322. That is, the first and second pressurizable chambers 321, 322 are arranged in a stacked configuration. In the depicted embodiment of FIG. 3A, the first pressurizable chamber 321 is stacked on the second pressurizable chamber 322 along the perimeter 305 of the rectangular membrane 300A. The area between the dashed line and the perimeter 305 represents the area of the chamber stack 330. As will be explained in more detail below, the first and second pressurizable chambers 321, 322 can be pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber 322.

[0050]FIG. 4A depicts the chamber stack 330 of FIG. 3A. As shown in FIG. 4A, the first pressurizable chamber 321 can be pressurizable to a first pressure P1 and the second pressurizable chamber 322 can be pressurizable to a second pressure P2, with the first pressure P1 being greater than the second pressure P2. Due to the pressure differential between the first pressure P1 and the second pressure P2, a side wall 400 that forms, at least in part, the second pressurizable chamber 322 becomes “loaded”. Stated differently, a downward force F1 is generated through the side wall 400, which is vertically-oriented and is coupled with a horizontally-oriented base wall 402. The horizontally-oriented base wall 402 can contact the substrate 50 arranged below the rectangular membrane 300A. The downward force F1 can propagate from the side wall 400 downward to the substrate 50, and in this example, through or near the outer edge 53 of the substrate 50 as illustrated in FIG. 4A. Accordingly, the loaded side wall 400 and resulting downward force F1 can facilitate contact pressure between the interface surface 52 of the substrate 50 and the polishing pad 60 near or at the outer edge 53 of the substrate 50, which can ultimately lead to more uniform polishing of the substrate 50. Loading through the side wall 400 can cause the rectangular membrane 300A to provide a focused, high resolution force application to the substrate 50 near or at its outer edge 53, and as depicted in FIG. 3A, this focused force can be applied substantially along the perimeter 305 of the rectangular membrane 300A, as the chamber stack 330 is arranged substantially along the perimeter 305 of the rectangular membrane 300A. In FIG. 3A, the chamber stack 330 is arranged along an entirety of the perimeter 305. As used herein, “substantially along the perimeter” means at least seventy-five percent (75%) of the perimeter 305.

[0051]In at least some examples, the chamber stack 330 can have other configurations than the one depicted in FIG. 4A. For instance, FIGS. 4B and 4C depict schematic side views of example chamber stacks 330 that can be incorporated into the rectangular membrane 300A of FIG. 3A.

[0052]For the illustrated embodiment of FIG. 4B, the chamber stack 330 is arranged in a flap configuration in which the first pressurizable chamber 321 extends further outward than the second pressurizable chamber 322 along the radial direction R1, which extends outward from the center C1 (FIG. 3A) of the rectangular membrane 300A (FIG. 3A). In the flap configuration, at least a portion of the first pressurizable chamber 321 is arranged inward of the second pressurizable chamber 322 along the radial direction R1 and at least a portion of the first pressurizable chamber 321 is arranged outward of the second pressurizable chamber 322 along the radial direction R1. In contrast, in FIG. 4A, the first pressurizable chamber is formed, at least in part, by a side wall 406 that is stacked directly above the side wall 400 forming, at least in part, the second pressurizable chamber 322. Advantageously, with the flap configuration, force control through the side wall 400 can be achieved and full pressure contact for the zone below can be accomplished.

[0053]For the illustrated embodiment of FIG. 4C, the chamber stack 330 is arranged in a tube configuration in which the first pressurizable chamber 321 is centered on the second pressurizable chamber 322 along the radial direction R1. Stated another way, the first pressurizable chamber is formed, at least in part, by a base wall 408, an outer side wall 410, and an inner side wall 412, with the base wall 408 extending between and connecting the outer side wall 410 and the inner side wall 412. In some examples, the side wall 400 is aligned with a midpoint of a span of the base wall 408, with the span of the base wall 408 extending along the radial direction R1. Moreover, similar to the flap configuration of FIG. 4B, in FIG. 4C, the first pressurizable chamber 321 extends further outward than the second pressurizable chamber 322 along the radial direction R1. Further, in the tube configuration, at least a portion of the first pressurizable chamber 321 is arranged inward of the second pressurizable chamber 322 along the radial direction R1 and at least a portion of the first pressurizable chamber 321 is arranged outward of the second pressurizable chamber 322 along the radial direction R1. The tube configuration can, among other benefits, advantageously allow for more rapid tuning of the pressure differential between the first and second pressurizable chambers 321, 322 and thus enhanced regulation of the applied downward force F1 on the substrate 50 through the loaded side wall 400. Accordingly, with the tube configuration, force control through the side wall 400 can be achieved and full pressure contact for the zone below can be accomplished.

[0054]FIG. 3B is a top plan view of a rectangular membrane 300B for a polishing system, according to one or more embodiments. The rectangular membrane 118 of FIG. 1 can be configured in a same or similar manner as the rectangular membrane 300B of FIG. 3B, for example. The rectangular membrane 300B can extend below and can be coupled to a base assembly of a carrier head assembly, for example. The rectangular membrane 300B of FIG. 3B is configured in same manner as the rectangular membrane 300A of FIG. 3A, except as provided below.

[0055]In the illustrated embodiment of FIG. 3B, the pressurizable chambers are arranged concentrically. More particularly, at least some of the pressurizable chambers are formed as concentrically arranged circles and at least some of the pressurizable chambers are formed as concentrically arranged rectangles. In the illustrated embodiment of FIG. 3D, the fifth and sixth pressurizable chambers 325, 326 are arranged as concentric circles with respect to the center C1. The sixth pressurizable chamber 326 is the innermost chamber and includes the center C1. The fifth pressurizable chamber 325 is the next innermost chamber and surrounds, and is arranged concentrically with, the sixth pressurizable chamber 326. The fourth pressurizable chamber 324 is arranged between the fifth pressurizable chamber 325 and the third pressurizable chamber 323. The third pressurizable chamber 323 is shaped to have a rectangular annulus and surrounds the fourth pressurizable chamber 324. The second pressurizable chamber 322 is shaped to have a rectangular annulus and surrounds the third pressurizable chamber 323. The second and third pressurizable chambers 322, 323 are arranged as concentric rectangles. The second pressurizable chamber 322 extends to each side of the rectangular membrane 300B. At the corners 311, 312, 313, 314, however, the rectangular membrane 300B includes chamber stacks 330.

[0056]Specifically, the rectangular membrane 300B includes a plurality of chamber stacks 330 each arranged at respective ones of the corners 311, 312, 313, 314. Each of the chamber stacks 330 can be arranged as shown in FIGS. 4A, 4B, or 4C, or some combination thereof. In this manner, each of the chamber stacks 330 can be arranged such that, for a given one of the chamber stacks 330, the first pressurizable chamber 321 is stacked on the second pressurizable chamber 322, with the first and second pressurizable chambers 321, 322 being pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber 322. Accordingly, a focused, high resolution force can be generated at the corners 311, 312, 313, 314 of the rectangular membrane 300E, and such forces can be applied to the corners of a substrate arranged below, and in contact with, the rectangular membrane 300E. In this way, enhanced contact pressure between the corners of the substrate and a polishing pad can be achieved.

[0057]In FIG. 3B, the chamber stacks 330 each form an L-shape at their respective corners 311, 312, 313, 314 as viewed along a vertical direction (the Z-direction in this example). In at least some examples, the L-shaped chamber stacks 330 each have a first arm 332 and a second arm 334, with the second arm 334 being arranged perpendicular to the first arm 332, so as to form an L-shape.

[0058]In such examples, the first arm 332 can extend along a first direction (the X-direction in this example) so that an end boundary line of the first arm 332 is closer to an adjacent corner than is an outer corner of the adjacent inner pressurizable chamber along the first direction. For the chamber stack 330 at the first corner 311, the first arm 332 extends along the first direction (the X-direction in this example) so that an end boundary line 336 of the first arm 332 is closer to an adjacent corner (the second corner 312 in this example) than is an outer corner 333 of the adjacent inner pressurizable chamber (the third pressurizable chamber 323 in this example) along the first direction. Further, in such examples, the second arm 334 can extend along a second direction (the Y-direction in this example) so that an end boundary line of the second arm 334 is closer to an adjacent corner than is the outer corner of the adjacent inner pressurizable chamber along the second direction, wherein the first direction is perpendicular to the second direction. For the chamber stack 330 at the first corner 311, the second arm 334 extends along a second direction (the Y-direction in this example) so that an end boundary line 338 of the second arm 334 is closer to an adjacent corner (the fourth corner 314 in this example) than is the outer corner 333 of the adjacent inner pressurizable chamber (the third pressurizable chamber 323 in this example) along the second direction. The L-shaped chamber stacks 330 can advantageously be controlled independently of the other straight edges of the rectangular membrane 300B, and consequently, the force applied by the rectangular membrane 300B at the corners 311, 312, 313, 314 can be tuned and controlled for enhanced polishing.

[0059]FIG. 3C is a top plan view of a rectangular membrane 300C for a polishing system, according to one or more embodiments. The rectangular membrane 118 of FIG. 1 can be configured in a same or similar manner as the rectangular membrane 300C of FIG. 3C, for example. The rectangular membrane 300C can extend below and can be coupled to a base assembly of a carrier head assembly, for example. The rectangular membrane 300C of FIG. 3C is configured in same manner as the rectangular membrane 300B of FIG. 3B, except as provided below.

[0060]In the depicted embodiment of FIG. 3C, the chamber stacks 330 arranged at their respective corners 311, 312, 313, 314 each have an angled configuration as viewed along a vertical direction (the Z-direction in this example). Stated differently, the chamber stacks 330 arranged at their respective corners 311, 312, 313, 314 can each have a concave quadrilateral configuration as viewed along the vertical direction. Each of the chamber stacks 330 can be arranged as shown in FIGS. 4A, 4B, or 4C, or some combination thereof.

[0061]In at least some examples, the angled chamber stacks 330 each have end boundary lines that are angled with respect to both a first direction and a second direction, which is perpendicular to the first direction. For instance, as shown in FIG. 3C, the end boundary line 336 of the first arm 332 is angled with respect to a first direction (the X-direction in this example) as well as a second direction (the Y-direction in this example). The end boundary line 336 can be angled with respect to the first direction X between twenty degrees and sixty degrees (20°to 60°), including the end points, for example. Similarly, the end boundary line 338 of the second arm 334 is angled with respect to the first direction (the X-direction in this example) as well as the second direction (the Y-direction in this example). The end boundary line 338 can be angled with respect to the second direction Y between twenty degrees and sixty degrees (20°to 60°), including the end points, for example. The angled chamber stacks 330 can advantageously be controlled independently of the other straight edges of the rectangular membrane 300C, and consequently, the force applied by the rectangular membrane 300C at the corners 311, 312, 313, 314 can be tuned and controlled for enhanced polishing. The angled configuration can also provide corner stability to the rectangular membrane 300C.

[0062]FIG. 3D is a top plan view of a rectangular membrane 300D for a polishing system, according to one or more embodiments. The rectangular membrane 118 of FIG. 1 can be configured in a same or similar manner as the rectangular membrane 300D of FIG. 3D, for example. The rectangular membrane 300D can extend below and can be coupled to a base assembly of a carrier head assembly, for example. The rectangular membrane 300D of FIG. 3D is configured in same manner as the rectangular membrane 300B of FIG. 3B, except as provided below.

[0063]For the depicted embodiment of FIG. 3D, the rectangular membrane 300D includes a plurality of chamber stacks 330 arranged at respective ones of the corners 311, 312, 313, 314, with such chamber stacks 330 being L-shaped, much like the chamber stacks 330 of the rectangular membrane 300B of FIG. 3B. However, in the example of FIG. 3D, the pressurizable chambers are arranged concentrically as rectangles, or stated differently, as concentrically arranged rectangles. The fifth pressurizable chamber 325 is the innermost chamber and includes the center C1. The fourth pressurizable chamber 324 is the next innermost chamber and surrounds the fifth pressurizable chamber 325. The third pressurizable chamber 323 is the next innermost chamber and surrounds the fourth pressurizable chamber 324. The second pressurizable chamber 322 is the next innermost chamber and surrounds the third pressurizable chamber 323. Finally, the first pressurizable chamber 321 is the outermost chamber and surrounds the second pressurizable chamber 322.

[0064]As noted above, the rectangular membrane 300D includes chamber stacks 330 at the corners 311, 312, 313, 314. Each of the chamber stacks 330 can be arranged as shown in FIGS. 4A, 4B, or 4C, or some combination thereof. In this manner, each of the chamber stacks 330 can be arranged such that the first pressurizable chamber 321 is stacked on the second pressurizable chamber 322, with the first and second pressurizable chambers 321, 322 being pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber 322. Accordingly, a focused, high resolution force can be generated at the corners 311, 312, 313, 314 of the rectangular membrane 300E, and such forces can be applied to the corners of a substrate arranged below, and in contact with, the rectangular membrane 300E. In this way, enhanced contact pressure between the corners of the substrate and a polishing pad can be achieved. The rectangular concentricity can facilitate uniformity control of the pressure applied to a substrate in contact with the rectangular membrane 300D, among other benefits. The concentric rectangles of the rectangular membrane 300D can advantageously match the substrate format and input area geometry. Moreover, tuning a certain distance from the edge of the rectangular membrane 300D can be accomplished in an intuitive manner.

[0065]FIG. 3E is a top plan view of a rectangular membrane for a polishing system, according to one or more embodiments. The rectangular membrane 118 of FIG. 1 can be configured in a same or similar manner as the rectangular membrane 300E of FIG. 3E, for example. The rectangular membrane 300E can extend below and can be coupled to a base assembly of a carrier head assembly, for example. The rectangular membrane 300E of FIG. 3E is configured in same manner as the rectangular membrane 300D of FIG. 3D, except as provided below.

[0066]For the depicted embodiment of FIG. 3E, the rectangular membrane 300E includes a plurality of chamber stacks 330 arranged at respective ones of the corners 311, 312, 313, 314. The chamber stacks 330 are each arranged such that, for a given one of the chamber stacks 330, the first pressurizable chamber 321 is stacked on the second pressurizable chamber 322. For each one of the chamber stacks 330, the first and second pressurizable chambers 321, 322 are pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second pressurizable chamber 322. Accordingly, a focused, high resolution force can be applied at the corners 311, 312, 313, 314 of the rectangular membrane 300E. Each of the chamber stacks 330 can be arranged as shown in FIGS. 4A, 4B, or 4C, or some combination thereof.

[0067]In one or more further embodiments, a rectangular membrane can include a plurality of chamber stacks along its perimeter between its corners, or rather, along the sides of the rectangular membrane between the chamber stacks at the corners. For instance, for the illustrated embodiment of FIG. 3E, the rectangular membrane 300E has edge chamber stacks 340 disposed along its sides 301, 302, 303, 304 between the corners 311, 312, 313, 314. The edge chamber stacks 340 are arranged along the perimeter 305 between respective pairs of the chamber stacks 330, including one edge chamber stack 340 arranged between the chamber stacks 330 located respectively at the first and second corners 311, 312, another edge chamber stack 340 arranged between the chamber stacks 330 located respectively at the second and third corners 312, 313, a further edge chamber stack 340 arranged between the chamber stacks 330 located respectively at the third and fourth corners 313, 314, and another edge chamber stack 340 arranged between the chamber stacks 330 located respectively at the fourth and first corners 314, 311.

[0068]Each edge chamber stack 340 can include a first edge pressurizable chamber 351 and a second edge pressurizable chamber 352 arranged in a stacked configuration in which the first edge pressurizable chamber 351 is stacked on the second edge pressurizable chamber 352. The first and second edge pressurizable chambers 351, 352 are pressurizable to different pressures to create a pressure differential that provides a downward force through a side wall forming, at least in part, the second edge pressurizable chamber 352. Each of the edge chamber stacks 340 can be arranged in a same or similar manner as shown in FIGS. 4A, 4B, or 4C, or some combination thereof.

[0069]In at least some examples, the first and second edge pressurizable chambers 351, 352 of the edge chamber stacks 340 can be pressurizable individually and independently of the first and second pressurizable chambers of the plurality of chamber stacks 330. In this way, the “load through wall” force that the rectangular membrane 300E applies to a substrate can be controlled and tuned for the corners 311, 312, 313, 314 as well as along the perimeter 305 between the corners 311, 312, 313, 314 of the rectangular membrane 300E.

[0070]When introducing elements of the present disclosure or exemplary aspects or embodiments thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements.

[0071]The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0072]The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, the objects A and C may still be considered coupled to one another—even if objects A and C do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly in physical contact with the second object.

[0073]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.