A carrier head for chemical mechanical polishing and a polishing system

Abstract

This utility model discloses a support head and polishing system for chemical mechanical polishing. The support head includes: a base; a retaining ring disposed below the base; and a gas film assembly disposed below the base and inside the retaining ring for loading the wafer to be polished. The gas film assembly includes: an elastic membrane comprising a disc-shaped base plate, upright ribs, and multiple spacer ribs, wherein the upright ribs extend upward from the edge of the base plate, and the spacer ribs extend upward from the base plate and are located inside the upright ribs; multiple inner pressure rings concentrically disposed inside the elastic membrane, with upright plates disposed on the upper side of the inner pressure rings and adjacent upright plates arranged radially; and an outer pressure plate concentrically disposed above the elastic membrane, with multiple fixing grooves disposed thereon. The upright plates pass through the fixing grooves, and connecting rods pass through the mounting holes of the upright plates to concentrically fix the elastic membrane, inner pressure rings, and outer pressure plate into a single unit. When the elastic membrane expands and contracts, the spacer ribs slide vertically in the gaps between adjacent inner pressure rings.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more particularly to a carrier head and polishing system for chemical mechanical polishing. Background Technology

[0002] The integrated circuit industry is the core of the information technology industry, playing a crucial role in promoting the digital and intelligent transformation and upgrading of the manufacturing industry. Chips are the carriers of integrated circuits, and chip manufacturing involves processes such as integrated circuit design, wafer fabrication, wafer processing, electrical measurement, dicing, packaging, and testing. Among these, chemical mechanical polishing (CMP) is one of the five core processes in wafer fabrication.

[0003] Chemical mechanical polishing (CMP) is an ultra-precision surface finishing technique that achieves global planarization. In CMP, the wafer is typically held in place by the bottom surface of a support head, with the side of the wafer containing the deposited layer resting against the upper surface of a polishing pad. The support head rotates in the same direction as the polishing pad under the actuation of a drive assembly, applying a downward load to the wafer. Polishing slurry is supplied to the upper surface of the polishing pad and distributed between the wafer and the pad, allowing the wafer to undergo CMP polishing through a combination of chemical and mechanical processes.

[0004] The carrier head is a core component of a CMP system. Its elastic diaphragm is used to load the wafer to be polished and apply load to it. The elastic diaphragm typically employs multi-zone pressure control to regulate the pressure in each chamber, thereby achieving global planarization of the wafer. Existing carrier heads suffer from at least the following problems:

[0005] (1) The ribs of the elastic membrane divide the chamber into multiple sub-chambers, which are relatively free and almost unrestrained; however, during the polishing process, the pressure fluctuations in the chambers on both sides of the ribs are large, which will affect the accuracy of the load applied to the corresponding area of ​​the ribs.

[0006] (2) As a consumable, the elastic membrane needs to be replaced regularly. When replacing the elastic membrane, the bearing head needs to be completely removed from the polishing unit. The bearing head weighs about 20kg, which will affect the efficiency of equipment maintenance. Utility Model Content

[0007] In view of this, embodiments of this application provide a carrier head and polishing system for chemical mechanical polishing, so as to at least partially solve the above-mentioned problems.

[0008] According to a first aspect of the embodiments of this application, a support head for chemical mechanical polishing is provided, comprising:

[0009] Base;

[0010] A retaining ring is located below the base;

[0011] An air film assembly, located below the base and inside the retaining ring, is used to load the wafer to be polished;

[0012] The air-film assembly includes:

[0013] An elastic membrane includes a disc-shaped base plate, upright ribs, and a plurality of spacer ribs, the upright ribs extending upward from the edge of the base plate, and the spacer ribs extending upward from the base plate and located inside the upright ribs.

[0014] Multiple inner pressure rings are concentrically arranged inside the elastic membrane, and a vertical plate is arranged on the upper side of each inner pressure ring, with adjacent vertical plates arranged radially.

[0015] An external pressure plate is concentrically positioned above the elastic membrane and has multiple fixing grooves on it;

[0016] The upright plate passes through the fixing groove, and the connecting rod passes through the mounting hole of the upright plate to concentrically fix the elastic membrane, inner pressure ring and outer pressure plate into one piece;

[0017] When the elastic membrane expands and contracts, the spacer rib slides vertically in the gap between adjacent inner pressure rings.

[0018] In some embodiments, the spacer ribs are straight ribs, which are horizontally defined by adjacent inner pressure rings.

[0019] In some embodiments, the Shore hardness of the spacer is 35-75A.

[0020] In some embodiments, the outer pressure plate is a disc-shaped structure with fixing grooves distributed radially on it; the fixing grooves are evenly distributed along the circumference of the outer pressure plate, and their shape and size match the shape and size of the upright plate.

[0021] In some embodiments, the upright plate is an arc-shaped plate structure, which is evenly distributed along the circumference of the inner pressure ring in a plurality of ways.

[0022] In some embodiments, the heights of the multiple upright plates on the inner pressure ring are different, and the vertical positions of the mounting holes corresponding to the upright plates are different.

[0023] In some embodiments, a plurality of inner pressure rings are arranged concentrically, and the upright plates of adjacent inner pressure rings are arranged radially such that the mounting holes on them are in the same vertical position to facilitate the installation of the connecting rod.

[0024] In some embodiments, the top surface of the inner pressure ring is provided with a first sealing groove and a second sealing groove, which are respectively located on both sides of the upright plate; the first sealing groove is disposed near the inner side and is used to place the end of the horizontal connecting section; the second sealing groove is used to place an annular sealing ring.

[0025] In some embodiments, the bottom of the external pressure plate is further provided with an external pressure plate sealing groove, which is located between the upright plate and the fixing groove, and the setting position of the external pressure plate sealing groove matches the setting position of the second sealing groove, for the purpose of assisting in fixing the annular sealing ring.

[0026] In some embodiments, the top surface of the outer pressure plate is provided with a third sealing groove, and the end of the upright rib is provided with an upright rib connecting section extending horizontally inward. The end of the upright rib connecting section is engaged with the third sealing groove and is pressed and fixed by the lower end surface of the base.

[0027] In some embodiments, the air-film assembly is detachably connected to the underside of the base.

[0028] According to a second aspect of the embodiments of this application, a polishing system is provided, which includes a polishing disc, a liquid supply device, a trimming device, and the aforementioned bearing head. The bearing head presses a wafer to be polished against a polishing pad above the polishing disc. The liquid supply device supplies polishing liquid between the polishing pad and the wafer. The trimming device is used to trim the surface of the polishing pad.

[0029] The beneficial effects of this utility model include:

[0030] a. A bearing head for chemical mechanical polishing is provided, wherein an elastic membrane is configured with multiple spacer ribs to separate and form multiple sub-pressure chambers; when the elastic membrane is subjected to load and expands and deforms, the spacer ribs slide vertically between adjacent inner pressure rings to prevent the spacer ribs from deflecting to either side, thereby avoiding large fluctuations in chamber pressure on both sides of the spacer ribs that would affect the material removal rate of the wafer surface.

[0031] b. One side of the spacer rib tightly covers the side of the inner pressure ring, the end of the horizontal connecting section abuts against the first sealing groove, and a gap is provided between the other side of the spacer rib and the adjacent inner pressure ring so that the spacer rib can slide freely in the gap between the adjacent inner pressure rings, thereby realizing the inflation or deflation of each sub-pressure chamber to adjust the polishing load applied to the wafer by the elastic membrane.

[0032] c. The Shore hardness of the spacer is 35-75A to ensure that the spacer has good strength. This limits the deformation capacity of the spacer to a certain extent and prevents the spacer from being excessively deformed and affecting the load application of adjacent sub-pressure chambers.

[0033] d. Multiple inner pressure rings are concentrically arranged, and the vertical plates of adjacent inner pressure rings are arranged radially. The vertical height of the mounting holes corresponding to the radially arranged vertical plates is the same, so that the connecting rod can pass through the mounting holes to fix the adjacent inner pressure rings concentrically as one unit. This is beneficial to improve the concentricity of the elastic membrane assembly.

[0034] e. When assembling the air-supported membrane assembly, first use connecting rods to pass through the mounting holes of the vertical plate to fix multiple inner pressure rings, and then install the outer pressure plate from top to bottom; when installing the outer pressure plate, remove the upper connecting rods in sequence, and fix at least two connecting rods to the mounting holes of the vertical plate to ensure the concentricity between adjacent inner pressure rings;

[0035] f. The top surface of the inner pressure ring is also provided with a threaded hole. The connecting screw is connected to the threaded hole through the plate mounting hole of the outer pressure plate to fix the elastic membrane, the inner pressure ring and the outer pressure plate into one piece.

[0036] g. The air-supported membrane assembly is detachably connected to the base by bolts. When the elastic membrane needs to be replaced, the air-supported membrane assembly can be removed from the base separately without disassembling the entire support head, which improves the convenience of operation. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0038] Figure 1 This is a schematic diagram of a support head 100 for chemical mechanical polishing provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of an air-film assembly provided in an embodiment of the present invention;

[0040] Figure 3 yes Figure 2 Longitudinal sectional view of the air-supported membrane module;

[0041] Figure 4 This is a schematic diagram of the elastic membrane 1 provided in an embodiment of the present invention;

[0042] Figure 5 yes Figure 3 A magnified view of a section at point A in the middle;

[0043] Figure 6 This is a schematic diagram of an external pressure plate provided in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the inner pressure ring 32 provided in one embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of the outer pressure plate 33 with its bottom surface facing upwards, provided in one embodiment of the present invention;

[0046] Figure 9This is a schematic diagram showing the fixed connection between multiple inner pressure rings 32 and connecting rod 34 according to an embodiment of the present invention;

[0047] Figure 10 This is a simulation analysis diagram of the wafer surface stress after loading of the sub-pressure chamber according to an embodiment of the present invention;

[0048] Figure 11 This is a schematic diagram of a polishing system provided in an embodiment of the present invention. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0050] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0051] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0052] In this invention, "Chemical Mechanical Polishing (CMP)" is also called "Chemical Mechanical Planarization (CMP)," and a wafer (W) is also called a substrate (Substrate), with the same meaning and practical function.

[0053] Figure 1This is a schematic diagram of a support head 100 for chemical mechanical polishing according to an embodiment of the present invention. The support head 100 includes:

[0054] The base 10 is a disc-shaped structure, which is the main body of the bearing head 100 and is mainly used to support all the components.

[0055] A retaining ring 20 is positioned below the base 10 to define the position of the wafer to be polished and prevent it from sliding out of the support head 100 under centrifugal force.

[0056] The air film assembly 30 is disposed below the base 10 and inside the retaining ring 20, and is used to load the wafer to be polished.

[0057] The bearing head 100 also includes a coupling disk 40, which is a disk-shaped structure. The coupling disk 40 is connected to the base 10 through an annular membrane 50. A through hole is provided in the middle of the coupling disk 40. A vertically extending shaft is provided in the middle of the base 10. The shaft can be slidably inserted into the through hole of the base 10 and can move vertically in the through hole.

[0058] Figure 1 In the middle, a connecting flange is also provided above the coupling disk 40, which is connected to the drive shaft to drive the bearing head 100 to rotate around its axis, thereby driving the wafer loaded in the air film assembly 30 to rotate, so as to achieve wafer polishing above the polishing pad.

[0059] Figure 2 This is a schematic diagram of an air-film assembly 30 provided in one embodiment of the present invention. Figure 3 yes Figure 2 A longitudinal sectional view of the air-supported membrane assembly 30. The air-supported membrane assembly 30 includes an elastic membrane 1, inner pressure rings 32 and outer pressure plates 33. Multiple inner pressure rings 32 are concentrically arranged inside the elastic membrane 1, and the outer pressure plates 33 are concentrically arranged above the elastic membrane 1.

[0060] Figure 4 This is a schematic diagram of an elastic membrane 1 provided in an embodiment of the present invention. The elastic membrane 1 includes:

[0061] The base plate 11 is a disk-shaped structure used to hold the wafer to be polished; that is, the wafer is attached to the bottom surface of the base plate 11.

[0062] Vertical stiffener 12 extends upward from the edge of the base plate 11;

[0063] Spacer ribs 13 are disposed inside the upright ribs 12 and extend upward from the base plate 11. Multiple spacer ribs 13 divide the elastic membrane 1 to form multiple sub-pressure chambers (C). It should be noted that the sub-pressure chambers of the elastic membrane 1 correspond to the areas (Zone, Z) that act on the wafer surface. Sometimes, the sub-pressure chambers of the elastic membrane 1 are also represented by Z.

[0064] In this invention, the elastic membrane 1 further includes oblique ribs 14, such as... Figure 4 As shown, it extends inward at an angle from the base plate 11 at the junction with the vertical rib 12. The diagonal rib 14 and multiple spacer ribs 13 divide the elastic membrane 1 into multiple sub-pressure chambers.

[0065] Figure 5 yes Figure 3 The enlarged view at point A shows that in this embodiment, the spacer rib 13 is a straight rib, which is defined by the inner pressure rings 32 on both sides. That is, the inner pressure rings 32 limit the large-scale deformation of the derating rib 13 in the horizontal direction. It can only be horizontally slightly displaced within the elastic deformation range, thereby effectively controlling the influence of the spacer rib 13 on the polishing load of the adjacent chamber, ensuring the accuracy of load application, and thus improving the uniformity of wafer polishing.

[0066] When the elastic membrane 1 expands and contracts, the spacer 13 slides vertically in the gap between adjacent inner pressure rings 32. With this configuration, when the elastic membrane 1 expands and contracts under applied load, the spacer 13 slides vertically between adjacent inner pressure rings 32 to prevent the spacer 13 from tilting to either side, thereby avoiding large fluctuations in the chamber pressure on both sides of the spacer 13 that would affect the material removal rate of the wafer surface.

[0067] In some embodiments, the elastic membrane 1 further includes inclined spacer ribs 13, which are distributed near the edge of the elastic membrane 1, such as... Figure 4 As shown, the spacer 13 is provided with a pleated part, which extends from the bottom plate 11 to form an S-shaped structure; the setting of the S-shaped structure is beneficial to improving the deformation capacity of the spacer 13.

[0068] The pleated portion includes multiple inclined segments arranged outwards at an angle, with adjacent inclined segments connected by arc segments to form a single unit. Furthermore, the angle θ between the inclined segment and the base plate 11 is 30-60° to adjust the elastic deformation capability of the pleated portion. Preferably, the angle θ between the inclined segment and the base plate 11 is 45°.

[0069] In this invention, the Shore hardness of the spacer 13 is 35-75A to ensure that the spacer 13 has good strength. This limits the deformation capacity of the spacer 13 to a certain extent and prevents the spacer 13 from being excessively deformed and affecting the load application of the adjacent sub-pressure chambers.

[0070] In some embodiments, the spacer 13 is disposed close to the inner pressure ring 32. During loading, the spacer 13 has minimal impact on adjacent sub-pressure chambers. This helps to reduce the impact of differences in the manufacturing materials of the spacer 13 on the load application performance of the elastic membrane 1, thereby improving the consistency of the bearing head 100 in use.

[0071] Figure 3 In the illustrated embodiment, there are multiple inner pressure rings 32, which are concentrically arranged inside the elastic membrane 1. Multiple vertical plates 31 are disposed on the upper side of the inner pressure rings 32, and adjacent vertical plates 31 are arranged radially. That is, the multiple vertical plates 31 are arranged along the radial direction of the inner pressure rings 32.

[0072] Furthermore, the external pressure plate 33 is equipped with multiple fixing slots 331, such as... Figure 5 As shown; the upright plate 31 passes through the fixing groove 331, and the connecting rod 34 passes through the mounting hole 311 of the upright plate 31, as shown. Figure 3 As shown, the elastic membrane 1, the inner pressure ring 32, and the outer pressure plate 33 are concentrically fixed as one unit.

[0073] Figure 6 In the illustrated embodiment, the outer pressure plate 33 has a disc-shaped structure with fixing grooves 331 distributed radially on it. Specifically, there are multiple fixing grooves 331, and these multiple fixing grooves 331 are arranged along the radial direction of the outer pressure plate 33 to form a fixing groove group. The multiple fixing groove groups are evenly distributed along the circumference of the outer pressure plate 33, and the shape and size of the fixing grooves 331 match the shape and size of the upright plate 31 so that the upright plate 31 disposed on the inner pressure ring 32 can pass through the fixing grooves 331, so that the mounting hole 311 of the upright plate 31 is located above the outer pressure plate 33.

[0074] In this utility model, the upright plate 31 is an arc-shaped plate structure, and correspondingly, the fixing groove 331 is an arc-shaped groove. The upright plates 31 are multiple and evenly distributed along the circumference of the inner pressure ring 32. Figure 2 As shown, this is to ensure the reliability of the overall fixation of the air film assembly 30.

[0075] Figure 7 This is a schematic diagram of an inner pressure ring 32 provided in an embodiment of the present invention. It has three arc-shaped plate-like upright plates 31 disposed thereon, and the upright plates 31 are evenly distributed along the circumferential direction of the inner pressure ring 32.

[0076] Furthermore, the multiple upright plates 31 provided on the inner pressure ring 32 have different heights, and the vertical positions of the mounting holes 311 corresponding to the upright plates 31 are different, so as to facilitate the group installation of the connecting rods 34.

[0077] In this invention, the top surface of the inner pressure ring 32 is provided with a first sealing groove 321 and a second sealing groove 322, such as... Figure 7As shown, they are located on both sides of the upright plate 31. The first sealing groove 321 is located near the inner side of the inner pressure ring 32 and is used to place the end of the horizontal connecting section 131 of the spacer rib 13; while the second sealing groove 322 is located on the other side of the upright plate 31 and is used to place the annular sealing ring 35, as shown... Figure 3 As shown. It should be noted that "inner side" here refers to the side closest to the central axis of the inner pressure ring 32.

[0078] Specifically, one side of the spacer 13 tightly covers the side of the inner pressure ring 32, and the end of the horizontal connecting section 131 abuts against the first sealing groove 321, as shown. Figure 5 As shown, a gap is provided between the other side of the spacer 13 and the adjacent inner pressure ring 32, so that the spacer 13 can slide freely in the gap between the adjacent inner pressure ring 32, thereby realizing the inflation or deflation of each sub-pressure chamber to adjust the polishing load applied to the wafer by the elastic membrane 1.

[0079] In some embodiments, the width of the gap between the other side of the spacer 13 and the adjacent inner pressure ring 32 is 5%-20% of the thickness of the spacer 13, so that the spacer 13 deforms only in the horizontal direction within the elastic deformation range, preventing the spacer 13 from being excessively deformed during polishing loading and affecting the accuracy of load application.

[0080] In some embodiments, a plurality of inner pressure rings 32 are concentrically arranged, and the upright plates 31 of adjacent inner pressure rings 32 are arranged radially. The mounting holes 311 corresponding to the radially arranged upright plates 31 have the same vertical height, that is, the mounting holes 311 of the radially arranged upright plates 31 are at the same vertical position to facilitate the installation of the connecting rod 34. The connecting rod 34 passes through the mounting holes 311 of the radially arranged upright plates 31 to fix the inner pressure rings 32, the elastic membrane 1, and the outer pressure plate 33 into one unit.

[0081] Figure 8 This is a schematic diagram of the outer pressure plate 33 with its bottom surface facing upwards, according to an embodiment of the present invention. In this embodiment, the bottom of the outer pressure plate 33 is provided with annular ribs 332, and there are multiple ribs 332 arranged concentrically.

[0082] Furthermore, the bottom of the outer pressure plate 33 is also equipped with an outer pressure plate sealing groove 333, such as Figure 7 As shown, it is located between the vertical plates 31, and the setting position of the outer pressure plate sealing groove 333 matches the setting position of the second sealing groove 322, which is used to assist in fixing the annular sealing ring 35 to ensure a reliable seal between the outer pressure plate 33 and the inner pressure ring 32.

[0083] Furthermore, the top surface of the outer pressure plate 33 is provided with a third sealing groove 334, such as... Figure 3 and Figure 6As shown, the end of the upright rib 12 is provided with an upright rib connecting section 121 extending horizontally inward. Figure 4 As shown), the end of the upright rib connecting section 121 is fastened to the third sealing groove 334 and is pressed and fixed by the lower end face of the base 10, as shown. Figure 1 As shown.

[0084] Figure 9 This is a schematic diagram of a plurality of inner pressure rings 32 and connecting rods 34 fixedly connected according to an embodiment of the present invention. In this embodiment, there are three connecting rods 34, which are arranged radially and evenly distributed around the circumference; that is, the included angle between adjacent connecting rods 34 is 120°, and an approximately triangular structure is formed between adjacent connecting rods 34 to improve the reliability of the concentric fixation of the inner pressure rings 32.

[0085] In this invention, three upright plates 31 are arranged on the inner pressure ring 32, and multiple inner pressure rings 32 form three upright plate assemblies, such as... Figure 9 As shown; when assembling the air film assembly 30, the operator first uses connecting rods 34 to pass through the mounting holes 311 of the upright plate 31 to fix multiple inner pressure rings 32, and then installs the outer pressure plate 33 from top to bottom; when installing the outer pressure plate 33, the upper connecting rods 34 are removed in sequence, and during the installation of the outer pressure plate 33, at least two connecting rods 34 are fixed in the mounting holes 311 of the upright plate 31 to ensure the concentricity between adjacent inner pressure rings 32.

[0086] Understandably, the multiple inner pressure rings 32 are fixed by the connecting rods 34, thereby ensuring the concentricity of the inner pressure rings 32. This is beneficial for the concentric installation of the elastic diaphragm 1, improving the consistency of the assembly of the elastic diaphragm 1, and thus enhancing the stability of the bearing head 100 in use.

[0087] Furthermore, the top surface of the inner pressure ring 32 is also provided with a threaded hole 323 for connecting screws 36. Figure 2 (Shown) Through the disc mounting hole 335 of the external pressure plate 33 Figure 6 (As shown) It is connected to the threaded hole 323 to fix the elastic diaphragm 1, the inner pressure ring 32 and the outer pressure plate 33 into one unit. That is, the horizontal connecting section 131 of the elastic diaphragm 1 abuts between the inner pressure ring 32 and the outer pressure plate 33 to ensure the sealing of the sub-pressure chamber.

[0088] To ensure the concentric installation of the elastic diaphragm 1, the concentricity between adjacent inner pressure rings 32 must be guaranteed. The following is a brief description. Figure 2 The installation steps of the air-supported membrane assembly 30 are shown below:

[0089] Step 1: Place multiple inner pressure rings 32 concentrically so that the mounting holes 311 on the upright plate 31 are on the same straight line, and install the annular sealing ring 35 in the second sealing groove 322 on the inner pressure ring 32.

[0090] Step 2: Pass all the connecting rods 34 through the mounting holes 311 of the upright plate 31 to fix the multiple inner pressure rings 32 into one piece; Figure 8 In the embodiment shown, three connecting rods 34 need to be installed;

[0091] Step 3: Install the elastic membrane 1 on the inner pressure ring 32 from bottom to top, so that the end of the horizontal connecting section 131 of the spacer 13 is set in the first sealing groove 321;

[0092] Step 4: Install the outer pressure plate 33 from top to bottom, and remove the upper connecting rods 34 in sequence so that the fixing groove 331 of the outer pressure plate 33 is fitted onto the upright plate 31 of the inner pressure ring 32; during the installation of the outer pressure plate 33, at least two connecting rods 34 are fixed to the mounting holes 311 of the upright plate 31.

[0093] In this invention, since the three connecting rods 34 are not concentric, the relative positions of the multiple inner pressure rings 32 can be determined by just two connecting rods 34. The three connecting rods 34 have different assembly heights with the inner pressure rings 32, allowing for progressive assembly without disrupting the concentricity between adjacent inner pressure rings 32.

[0094] The following is combined Figure 7 The inner pressure ring 32 is shown. The installation steps of the outer pressure plate 33 in step four are briefly described. Figure 7 In the middle, the mounting hole 311 includes a first mounting hole 311a, a second mounting hole 311b and a third mounting hole 311c, and their corresponding vertical heights decrease sequentially.

[0095] First, remove the connecting rod 34 installed in the first mounting hole 311a, and fit the fixing groove 331 of the outer pressure plate 33 onto the vertical plate 31 corresponding to the first mounting hole 311a. At this time, the other two connecting rods 34 are fixed in the corresponding mounting holes 311.

[0096] Next, when the outer pressure plate 33 moves downward until the first mounting hole 311a is above the outer pressure plate 33, the connecting rod 34 is installed in the first mounting hole 311a;

[0097] Next, remove the connecting rod 34 installed in the second mounting hole 311b and continue to move the outer pressure plate 33 down; when the outer pressure plate 33 moves down to the point where the second mounting hole 311b is above the outer pressure plate 33, install the connecting rod 34 in the second mounting hole 311b.

[0098] Next, remove the connecting rod 34 installed in the third mounting hole 311c and continue to move the outer pressure plate 33 down; when the outer pressure plate 33 moves down to the point where the third mounting hole 311c is above the outer pressure plate 33, install the connecting rod 34 in the third mounting hole 311c.

[0099] In this invention, the inner pressure ring 32 is equipped with upright plates 31 of different heights. The vertical height difference between the mounting holes 311 of adjacent upright plates 31 is greater than the thickness of the outer pressure plate 33, so as to facilitate the disassembly of the connecting rod 34 during the installation of the outer pressure plate 33. Specifically, the vertical distance between the lower edge of the mounting hole 311 of the higher upright plate 31 and the upper edge of the mounting hole 311 of the adjacent lower upright plate 31 is greater than the thickness of the outer pressure plate 33.

[0100] It should be noted that the air-film assembly 30 is detachably connected to the base 10 by bolts. When it is necessary to replace the elastic membrane 1, the air-film assembly 30 can be removed from the base 10 separately without disassembling the entire bearing head 100, which improves the convenience of operation.

[0101] Figure 10 This is a simulation analysis diagram of the wafer surface stress after loading of the sub-pressure chamber according to an embodiment of the present invention, wherein P C1 >P C2 The solid line represents the stress curve of the corresponding solution in this application, while the dashed line represents the stress curve of the prior art. It should be noted that the existing partition ribs are not constrained in the left and right directions, and during polishing loading, the existing partition ribs are prone to deformation in the horizontal direction.

[0102] Figure 10 In the prior art, the stress exhibits a large fluctuation near the spacer rib, which is detrimental to the uniform application of polishing load. Compared with the prior art, the spacer rib 313 in this application has a smaller overall deformation amplitude, resulting in a relatively stable stress curve acting on the wafer surface, especially on both sides of the spacer rib 313. This is beneficial for controlling the application of polishing load and ensuring accurate application of polishing load in the area corresponding to the spacer rib 313. It should be noted that... Figure 9 The sign of the stress on the wafer surface indicates the direction of the stress; if the stress on the wafer surface is negative, it indicates that the wafer surface is subjected to compressive stress; if the stress on the wafer surface is positive, it indicates that the wafer is subjected to tensile stress.

[0103] In addition, this utility model also provides a polishing system 1000, the schematic diagram of which is shown below. Figure 11 As shown, the polishing system 1000 includes a polishing disc 200, a polishing pad 300, a dressing device 400, a liquid supply device 500, and... Figure 1 The carrier head 100 is shown.

[0104] The polishing pad 300 is disposed on the upper surface of the polishing disk 200 and rotates together with it along the axis Ax; the horizontally movable bearing head 100 is disposed above the polishing pad 300, and its lower surface receives the wafer to be polished; the dressing device 400 includes a dressing arm and a dressing head, which is disposed on one side of the polishing disk 200, and the dressing arm drives the rotating dressing head to swing to dress the surface of the polishing pad 300; the liquid supply device 500 is disposed on the upper side of the polishing pad 300 to distribute the polishing liquid on the surface of the polishing pad 300.

[0105] During the polishing operation, the bearing head 100 presses the surface of the wafer to be polished against the surface of the polishing pad 300. The bearing head 100 rotates and reciprocates radially along the polishing disk 200, gradually removing the surface of the wafer in contact with the polishing pad 300. Simultaneously, the polishing disk 200 rotates, and the liquid supply device 500 sprays polishing liquid onto the surface of the polishing pad 300. Under the chemical action of the polishing liquid, the relative movement between the bearing head 100 and the polishing disk 200 causes the wafer to rub against the polishing pad 300, thus achieving polishing.

[0106] During chemical mechanical polishing, the dressing device 400 is used to dress and activate the surface morphology of the polishing pad 300. Using the dressing device 400, impurity particles remaining on the surface of the polishing pad, such as abrasive particles in the polishing slurry and waste material detached from the wafer surface, can be removed. It can also smooth out the surface deformation of the polishing pad 300 caused by abrasion, ensuring the consistency of the surface morphology of the polishing pad 300 during polishing, thereby maintaining a stable polishing removal rate.

[0107] In this embodiment, the bearing head 100 is configured with Figure 3 The air film assembly 30 shown has a spacer rib 13 of the elastic membrane 1 which is straight and is constrained by the inner pressure ring 32 in the horizontal direction. When the elastic membrane 1 is loaded, the spacer rib 13 slides vertically in the gap between adjacent inner pressure rings 32 to prevent the spacer rib 13 from deflecting to either side, thereby avoiding large fluctuations in the chamber pressure on both sides of the spacer rib 13 that would affect the material removal rate of the wafer surface.

[0108] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0109] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A carrier head for chemical mechanical polishing, characterized by, include: Base; A retaining ring is located below the base; An air film assembly, located below the base and inside the retaining ring, is used to load the wafer to be polished; The air-film assembly includes: An elastic membrane includes a disc-shaped base plate, upright ribs, and a plurality of spacer ribs, the upright ribs extending upward from the edge of the base plate, and the spacer ribs extending upward from the base plate and located inside the upright ribs. Multiple inner pressure rings are concentrically arranged inside the elastic membrane, and a vertical plate is arranged on the upper side of each inner pressure ring, with adjacent vertical plates arranged radially. An external pressure plate is concentrically positioned above the elastic membrane and has multiple fixing grooves on it; The upright plate passes through the fixing groove, and the connecting rod passes through the mounting hole of the upright plate to concentrically fix the elastic membrane, inner pressure ring and outer pressure plate into one piece; When the elastic membrane expands and contracts, the spacer rib slides vertically in the gap between adjacent inner pressure rings.

2. The load head of claim 1 wherein, The spacer bars are straight bars, which are horizontally defined by adjacent inner pressure rings.

3. The load head of claim 1 wherein, The Shore hardness of the spacer is 35-75A.

4. The load head of claim 1 wherein, The outer pressure plate has a disc-shaped structure with fixing grooves distributed radially on it; the fixing grooves are evenly distributed along the circumference of the outer pressure plate, and their shape and size match the shape and size of the upright plate.

5. The load head of claim 4 wherein, The upright plate is an arc-shaped plate structure, which is evenly distributed along the circumference of the inner pressure ring in multiple ways.

6. The load head of claim 5 wherein, The multiple vertical plates on the inner pressure ring have different heights, and the vertical positions of the mounting holes corresponding to the vertical plates are different.

7. The load head of claim 6 wherein, Multiple inner pressure rings are arranged concentrically, and the vertical plates of adjacent inner pressure rings are arranged radially so that the mounting holes on them are in the same vertical position to facilitate the installation of the connecting rod.

8. The load head of claim 1 wherein, The top surface of the inner pressure ring is provided with a first sealing groove and a second sealing groove, which are located on both sides of the vertical plate respectively; the first sealing groove is located near the inner side and is used to place the end of the horizontal connecting section; the second sealing groove is used to place the annular sealing ring.

9. The load head of claim 8 wherein, The bottom of the external pressure plate is also equipped with an external pressure plate sealing groove, which is located between the vertical plate and the fixing groove. Furthermore, the setting position of the external pressure plate sealing groove matches the setting position of the second sealing groove, which is used to assist in fixing the annular sealing ring.

10. The load head of claim 9 wherein, The top surface of the outer pressure plate is provided with a third sealing groove, and the end of the upright rib is provided with an upright rib connecting section extending horizontally inward. The end of the upright rib connecting section is fastened to the third sealing groove and is pressed and fixed by the lower end surface of the base.

11. The load head of claim 1 wherein, The air-supported membrane assembly is detachably connected to the lower part of the base.

12. A polishing system characterized by, The device includes a polishing pad, a liquid supply device, a trimming device, and a bearing head as described in any one of claims 1 to 11. The bearing head presses the wafer to be polished against a polishing pad above the polishing pad. The liquid supply device supplies polishing liquid between the polishing pad and the wafer. The trimming device is used to trim the surface of the polishing pad.

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