Elastic film and bearing head for chemical mechanical polishing

Abstract

The invention discloses an elastic film for chemical mechanical polishing and a bearing head, and belongs to the technical field of wafer manufacturing. The elastic film comprises: a disc-shaped bottom plate; the vertical rib extends upwards from the edge of the bottom plate; the spacing ribs are arranged on the inner sides of the vertical ribs and extend upwards from the bottom plate so as to form a plurality of sub pressure chambers through separation; the spacing rib comprises a wrinkle part and a connecting part, the wrinkle part extends up and down from the bottom plate to form an S-shaped structure, and the connecting part is arranged above the wrinkle part; the connecting part extends upwards from the wrinkle part and then horizontally extends to form a horizontal connecting section, and the horizontal connecting section is located on the other side of the wrinkle part; when the sub-pressure chambers expand or stretch out and draw back, the wrinkle parts are located on the upper side of the bottom plate.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more particularly to an elastic film and a support head 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 are usually straight ribs, which divide the chamber into multiple sub-chambers. 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. Summary of the Invention

[0007] In view of this, embodiments of this application provide an elastic membrane and a bearing head for chemical mechanical polishing, to at least partially solve the above-mentioned problems.

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

[0009] A disc-shaped base plate;

[0010] Vertical ribs extend upward from the edge of the base plate;

[0011] Spacer ribs are placed inside the vertical ribs and extend upward from the bottom plate to separate and form multiple sub-pressure chambers;

[0012] The spacer includes a pleated portion and a connecting portion. The pleated portion extends vertically from the bottom plate to form an S-shaped structure. The connecting portion is located above the pleated portion. The connecting portion extends upward from the pleated portion and then horizontally to form a horizontal connecting section. The horizontal connecting section is located on the other side of the pleated portion.

[0013] When the sub-pressure chamber expands or contracts, the folded portion is located on the upper side of the base plate.

[0014] In some embodiments, the pleated portion includes a plurality of vertical segments arranged in a horizontal direction, with adjacent vertical segments connected by an arc segment.

[0015] In some embodiments, the height of the fold is 5-10 mm.

[0016] In some embodiments, a vertical gap is provided between the arc segment on the lower side of the pleated portion and the inner side of the base plate, and the vertical gap is smaller than the height of the pleated portion.

[0017] In some embodiments, the horizontal distance between adjacent vertical segments is 2-4 times the thickness of the vertical segment.

[0018] In some embodiments, the pleated portion includes a plurality of inclined segments arranged inclined outwards, and adjacent inclined segments are connected by an arc segment to form a whole.

[0019] In some embodiments, the angle between the inclined section and the base plate is 30-60°.

[0020] In some embodiments, the Shore hardness of the folds is 35-75A.

[0021] According to a second aspect of the embodiments of this application, a support head for chemical mechanical polishing is provided, comprising:

[0022] Base;

[0023] A retaining ring is located below the base;

[0024] An air film assembly, located below the base and inside the retaining ring, is used to load the wafer to be polished;

[0025] The air-film assembly includes:

[0026] The elastic membrane described above;

[0027] 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.

[0028] An external pressure plate is concentrically positioned above the elastic membrane and has multiple fixing grooves on it;

[0029] 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;

[0030] The folded portion of the spacer rib is confined between adjacent inner pressure rings, and the folded portion slides vertically when the elastic membrane expands and contracts.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] In some embodiments, the bottom of the outer pressure plate is provided with annular ribs, and the number of ribs is multiple and concentrically arranged, with a gap between the bottom surface of the ribs and the pleats.

[0036] 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.

[0037] 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.

[0038] In some embodiments, the inner pressure ring and its adjacent stiffener are located in the same sub-pressure chamber, and the stiffener is provided with vent holes to inflate or vent towards the sub-pressure chamber, thereby adjusting the pressure of the sub-pressure chamber.

[0039] 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.

[0040] In some embodiments, the inner pressure ring is provided with three upright plates, and the multiple inner pressure rings form three upright plate assemblies; after the multiple inner pressure rings are fixed by passing connecting rods through the mounting holes of the upright plates in advance, the outer pressure plate is installed from top to bottom; when installing the outer pressure plate, the upper connecting rods are removed in sequence, and at least two connecting rods are fixed to the mounting holes of the upright plates.

[0041] In some embodiments, the top surface of the inner pressure ring is further provided with a threaded hole, and 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 as a whole.

[0042] The beneficial effects of this invention include:

[0043] a. The provided elastic membrane is equipped with spacer ribs, which include pleats that extend vertically from the base plate to form an S-shaped structure, which helps to improve the deformation capacity of the spacer ribs;

[0044] b. When a load is applied to the wafer to be polished, the sub-pressure chamber of the elastic membrane expands or contracts, and the folds are located on the upper side of the base plate to prevent the folds from abutting against the inner side of the base plate, thereby controlling the deformation range of the folds and preventing them from affecting the accuracy of the polishing load application.

[0045] c. The Shore hardness of the pleats is 35-75A to ensure that the pleats of the spacer have 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.

[0046] d. The height of the folded part is the sum of the vertical height of the vertical section and the vertical arc sections located at both ends of the vertical section. The height H of the folded part is 6-8mm, which gives the folded part of the spacer a certain deformation capacity.

[0047] e. The pleated section includes multiple inclined segments arranged outwards at an angle, with adjacent inclined segments connected by arc segments to form a whole; the angle between the inclined segments and the base plate is 30-60° to adjust the elastic deformation capacity of the pleated section.

[0048] f. 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.

[0049] g. When assembling the air-supported membrane assembly, use connecting rods to pass through the mounting holes of the vertical plate to fix multiple inner pressure rings before installing 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;

[0050] h. 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.

[0051] i. 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

[0052] 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.

[0053] Figure 1 This is a schematic diagram of an elastic membrane for chemical mechanical polishing provided in an embodiment of the present invention;

[0054] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0055] Figure 3 yes Figure 1 A magnified view of a section at point B in the middle;

[0056] Figure 4 This is a schematic diagram of a bearing head provided in an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of an air-supported membrane assembly provided in an embodiment of the present invention;

[0058] Figure 6 yes Figure 5 Longitudinal sectional view of the air-supported membrane module;

[0059] Figure 7 This is a schematic diagram of an external pressure plate provided in an embodiment of the present invention;

[0060] Figure 8 This is a schematic diagram of an inner pressure ring provided in an embodiment of the present invention;

[0061] Figure 9 This is a schematic diagram of the bottom surface of the external pressure plate provided in an embodiment of the present invention facing upwards;

[0062] Figure 10 yes Figure 6 A magnified view of a section at point D;

[0063] Figure 11 This is a schematic diagram of a plurality of inner pressure rings and a connecting rod being fixedly connected according to an embodiment of the present invention;

[0064] Figure 12 This is a schematic diagram of a polishing system provided in an embodiment of the present invention. Detailed Implementation

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Figure 1This is a schematic diagram of an elastic membrane 1 for chemical mechanical polishing according to an embodiment of the present invention. The elastic membrane 1 includes:

[0070] 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.

[0071] Vertical stiffener 12 extends upward from the edge of the base plate 11;

[0072] 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.

[0073] In this invention, the elastic membrane 1 further includes oblique ribs 14, such as... Figure 1 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.

[0074] Figure 1 In the embodiment shown, the elastic membrane 1 is divided into C1, C2, C3, C4, C5, C6, C7, C8, and C9 sub-pressure chambers to regulate the polishing load of the corresponding areas of the wafer in a zoned manner, thereby adjusting the material removal rate of each area on the wafer surface.

[0075] Figure 2 yes Figure 1 The enlarged view at point A shows that the spacer 13 includes a pleated portion 131 and a connecting portion 132. The pleated portion 131 extends vertically from the bottom plate 11 to form an S-shaped structure, and the connecting portion 132 is located above the pleated portion 131. The S-shaped structure helps to improve the deformation capacity of the spacer 13.

[0076] Furthermore, the connecting portion 132 extends upward from the pleated portion 131 to form a connecting segment 1321, such as... Figure 2 As shown, the horizontal extension forms a horizontal connecting segment 1322, which is located on the other side of the pleated portion 131, so that the fixed end of the spacer 13 (the end of the horizontal connecting segment 1322) is far away from its intersection with the base plate 11, so as to weaken or control the influence of the fixed end of the spacer 13 on the deformation of the spacer 13, so that the deformation amplitude of the spacer 13 during the loading process of the elastic membrane 1 is controllable.

[0077] Furthermore, when a load is applied to the wafer to be polished, the sub-pressure chamber of the elastic membrane 1 expands or contracts, and the pleated portion 131 is located on the upper side of the base plate 11 to prevent the pleated portion 131 from abutting against the inner side of the base plate 11, thereby controlling the deformation range of the pleated portion 131 and preventing it from affecting the accuracy of the polishing load application.

[0078] In this invention, the pleated portion 131 includes multiple vertical segments 1311 arranged horizontally, with adjacent vertical segments 1311 connected by arc segments 1312 to form an S-shaped structure. It is understood that the pleated portion 131 may have more than four vertical segments 1311, which meander horizontally in an S-shape to ensure the deformability of the pleated portion 131.

[0079] In some embodiments, the height H of the pleats 131 is 5-10 mm, such as... Figure 2 As shown, the height of the folded portion 131 is the sum of the vertical heights of the vertical segment 1311 and the arc segments 1312 located at both ends of the vertical segment 1311. Preferably, the height H of the folded portion 131 is 6-8 mm, so that the folded portion 131 of the spacer 13 has a certain deformation capacity.

[0080] Figure 2 In the illustrated embodiment, a vertical gap G is provided between the arc segment 1312 on the lower side of the pleated portion 131 and the inner surface of the base plate 11, wherein the vertical gap G is less than the height of the pleated portion 131. Preferably, the height of the vertical gap G is 2-5 mm to prevent the bottom of the pleated portion 131 from interfering with the inner surface of the base plate 11 during the loading process of the elastic membrane 1, thereby ensuring the application of loads to each sub-pressure chamber, especially the load application to the spacer rib 13 and its surrounding area.

[0081] In this invention, the horizontal distance between adjacent vertical segments 1311 is 2-4 times the thickness of the vertical segment 1311; the horizontally arranged vertical segments 1311 can also give the pleated part 131 a certain strength, which is beneficial to limiting the deformation capacity of the pleated part 131 in the horizontal direction.

[0082] Figure 3 yes Figure 1 The enlarged view at point B shows that in this embodiment, the pleated portion 131 includes multiple inclined segments 1313 arranged outwards at an angle, and adjacent inclined segments 1313 are connected as one unit by an arc segment 1312.

[0083] In some embodiments, the angle θ between the inclined segment 1313 and the base plate 11 is 30-60°, such as Figure 3 As shown, this is to adjust the elastic deformation capability of the pleated portion 131. Preferably, the angle θ between the inclined section 1313 and the base plate 11 is 45°.

[0084] In this invention, the Shore hardness of the pleated portion 131 is 35-75A to ensure that the pleated portion 131 of 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.

[0085] Figure 4 This is a schematic diagram of a carrier head 100 provided in an embodiment of the present invention, which is used for chemical mechanical polishing of wafers.

[0086] The carrier head 100 includes:

[0087] The base 10 is a disc-shaped structure and serves as the main body of the bearing head 100, primarily used to support all components.

[0088] The retaining ring 20 is located below the base 10 and is used to limit the position of the wafer to be polished, preventing the wafer from sliding out of the inside of the support head 100 under the action of centrifugal force.

[0089] 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.

[0090] 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.

[0091] Figure 4 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 (not shown) loaded in the air film assembly 30 to rotate, so as to achieve wafer polishing above the polishing pad.

[0092] Figure 5 This is a schematic diagram of an air-film assembly 30 provided in an embodiment of the present invention. Figure 6 yes Figure 5 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, with multiple inner pressure rings 32 ( Figure 6 (As shown) The outer pressure plate 33 is concentrically disposed inside the elastic membrane 1 and concentrically disposed above the elastic membrane 1.

[0093] The number of inner pressure rings 32 is multiple, and they are concentrically arranged inside the elastic membrane 1, such as... Figure 6 As shown, multiple vertical plates 31 are arranged on the upper side of the inner pressure ring 32, with adjacent vertical plates 31 arranged radially. That is, the multiple vertical plates 31 are arranged along the radial direction of the inner pressure ring 32.

[0094] Furthermore, the external pressure plate 33 is equipped with multiple fixing slots 331, such as... Figure 7 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 6 As shown, the elastic membrane 1, the inner pressure ring 32, and the outer pressure plate 33 are concentrically fixed as one unit.

[0095] In this invention, the pleated portion 131 of the spacer 13 is defined between adjacent inner pressure rings 32, such as... Figure 6 As shown, when the elastic membrane 1 expands and contracts, the wrinkled portion 131 slides vertically. This configuration ensures that when the elastic membrane 1 expands and contracts under applied load, the wrinkled portion 131 slides vertically between adjacent inner pressure rings 32, preventing the wrinkled portion 131 from tilting to either side. This avoids large fluctuations in chamber pressure on both sides of the wrinkled portion 131, which could affect the material removal rate of the wafer surface. In other words, the inner pressure rings 32 on both sides of the wrinkled portion 131 limit the horizontal freedom of the vertical segment 1311 of the wrinkled portion 131. The vertical segment 1311 can only move horizontally within the range of elastic deformation. This helps to limit the deformation amplitude of the wrinkled portion 131, thereby controlling the influence of the spacer rib 13 on the polishing load of adjacent sub-pressure chambers and improving the uniformity of wafer polishing.

[0096] Figure 7 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.

[0097] In this invention, 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, such as... Figure 5 As shown, this is to ensure the reliability of the overall fixation of the air film assembly 30.

[0098] Figure 8 This is a schematic diagram of an inner pressure ring 32 provided in an embodiment of the present invention, on which three arc-shaped plate-like upright plates 31 are disposed, and the upright plates 31 are evenly distributed along the circumferential direction of the inner pressure ring 32.

[0099] 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.

[0100] 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 8 As 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 1322 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 6 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.

[0101] 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.

[0102] Figure 9 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.

[0103] Furthermore, the bottom of the outer pressure plate 33 is also equipped with an outer pressure plate sealing groove 333, such as Figure 9 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.

[0104] Figure 6 In the embodiment shown, the outer pressure plate 33 is disposed above the elastic membrane 1, and a gap is provided between the bottom surface of the rib plate 332 and the pleated portion 131 of the spacer rib 13, such as... Figure 10 As shown, the excessive deformation of the wrinkled portion 131 affects the application of the polishing load.

[0105] In this invention, the inner pressure ring 32 and its adjacent stiffening plate 332 are located in the same sub-pressure chamber, wherein the stiffening plate 332 is provided with a vent hole 3321, such as... Figure 6 and Figure 7As shown, the pressure in the sub-pressure chamber is adjusted by inflating or deflating the chamber. Specifically, the vent 3321 is a through hole that extends along the thickness direction of the outer pressure plate 33. In some embodiments, the central axis of the vent 3321 corresponds to the apex of the arc segment 1312 of the pleated portion 131 to improve the response speed of the elastic membrane 1 to the sub-pressure chamber and increase the efficiency of the polishing load.

[0106] Furthermore, the top surface of the outer pressure plate 33 is provided with a third sealing groove 334, such as... Figure 6 and 7 As shown, the end of the upright rib 12 is provided with an upright rib connecting section 121 extending horizontally inward. Figure 1 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 4 As shown.

[0107] Figure 11 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.

[0108] In this invention, three upright plates 31 are disposed on the inner pressure ring 32, and multiple inner pressure rings 32 form three upright plate assemblies, such as... Figure 11 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.

[0109] 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.

[0110] Furthermore, the top surface of the inner pressure ring 32 is also provided with a threaded hole 323, and the connecting screw 36 passes through the disc mounting hole 335 of the outer pressure plate 33. Figure 7 (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 1322 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.

[0111] 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 5 The installation steps of the air-supported membrane assembly 30 are shown below:

[0112] 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.

[0113] 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 5 In the embodiment shown, three connecting rods 34 need to be installed;

[0114] 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 1322 of the spacer 13 is set in the first sealing groove 321;

[0115] 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.

[0116] 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 different assembly heights of the three connecting rods 34 and the inner pressure rings 32 allow for progressive assembly without disrupting the concentricity between adjacent inner pressure rings 32.

[0117] The following is combined Figure 8 The inner pressure ring 32 is shown. The installation steps of the outer pressure plate 33 in step four are briefly described. Figure 8 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.

[0118] 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.

[0119] 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;

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] In addition, the present invention also provides a polishing system 1000, the schematic diagram of which is shown below. Figure 12 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 4 The carrier head 100 is shown.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] Figure 12 In the illustrated embodiment, the carrier head 100 is configured with Figure 5 The air film assembly 30 shown has a spacer rib 13 of the elastic membrane 1 with a pleated portion 131. The pleated portion 131 is defined between adjacent inner pressure rings 32. When the elastic membrane 1 expands and contracts, the pleated portion 131 slides vertically, effectively preventing the spacer rib 13 from deforming too much during loading and affecting the accuracy of load application to the spacer rib 13 and its adjacent chambers.

[0129] Meanwhile, in this invention, multiple inner pressure rings 32 are fixed by connecting rods 34, thereby ensuring the concentricity of the inner pressure rings 32. This is beneficial for the concentric installation of the elastic membrane 1, improving the consistency of the assembly of the elastic membrane 1, and thus enhancing the stability of the bearing head 100 in use.

[0130] 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.

[0131] 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. An elastic membrane for chemical mechanical polishing, characterized in that, include: A disc-shaped base plate; Vertical ribs extend upward from the edge of the base plate; Spacer ribs are placed inside the vertical ribs and extend upward from the bottom plate to separate and form multiple sub-pressure chambers; The spacer includes a pleated portion and a connecting portion. The pleated portion extends vertically from the bottom plate to form an S-shaped structure. The connecting portion is located above the pleated portion. The connecting portion extends upward from the pleated portion and then horizontally to form a horizontal connecting section. The horizontal connecting section is located on the other side of the pleated portion. When the sub-pressure chamber expands or contracts, the folded portion is located on the upper side of the base plate.

2. The elastic membrane according to claim 1, characterized in that, The folded portion includes multiple vertical segments arranged in a horizontal direction, with adjacent vertical segments connected by arc segments to form a whole.

3. The elastic membrane according to claim 2, characterized in that, The height of the folded portion is 5-10mm.

4. The elastic membrane according to claim 3, characterized in that, A vertical gap is provided between the arc segment on the lower side of the pleated part and the inner side of the base plate, and the vertical gap is smaller than the height of the pleated part.

5. The elastic membrane according to claim 2, characterized in that, The horizontal distance between adjacent vertical segments is 2-4 times the thickness of the vertical segment.

6. The elastic membrane according to claim 1, characterized in that, The folded portion includes multiple inclined segments arranged outwards at an angle, with adjacent inclined segments connected by arc segments to form a single unit.

7. The elastic membrane according to claim 6, characterized in that, The angle between the inclined section and the base plate is 30-60°.

8. The elastic membrane according to claim 6, characterized in that, The Shore hardness of the folded portion is 35-75A.

9. A support head for chemical mechanical polishing, characterized in that, 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: The elastic membrane according to any one of claims 1 to 8; 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; The folded portion of the spacer rib is confined between adjacent inner pressure rings, and the folded portion slides vertically when the elastic membrane expands and contracts.

10. The bearing head according to claim 9, characterized in that, 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.

11. The bearing head according to claim 9, characterized in that, The upright plate is an arc-shaped plate structure, which is evenly distributed along the circumference of the inner pressure ring in multiple ways.

12. The bearing head according to claim 11, characterized in that, 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.

13. The bearing head according to claim 12, characterized in that, 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.

14. The bearing head according to claim 9, characterized in that, The bottom of the outer pressure plate is provided with annular ribs, and there are multiple ribs arranged concentrically, with a gap between the bottom surface of the ribs and the pleated part.

15. The bearing head according to claim 9, characterized in that, 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.

16. The bearing head according to claim 15, characterized in that, 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.

17. The bearing head according to claim 15, characterized in that, The inner pressure ring and its adjacent stiffener are located in the same sub-pressure chamber. The stiffener is provided with vent holes to allow air to be filled or vented toward the sub-pressure chamber, thereby adjusting the pressure of the sub-pressure chamber.

18. The bearing head according to claim 9, characterized in that, 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.

19. The bearing head according to claim 13, characterized in that, The inner pressure ring is equipped with three upright plates, and the multiple inner pressure rings form three upright plate assemblies; after the multiple inner pressure rings are fixed by passing connecting rods through the mounting holes of the upright plates in advance, the outer pressure plate is installed from top to bottom; when installing the outer pressure plate, the upper connecting rods are removed in sequence, and at least two connecting rods are fixed to the mounting holes of the upright plates.

20. The bearing head according to claim 13, characterized in that, The top surface of the inner pressure ring is also provided with a threaded hole, and the connecting screw is connected to the threaded hole through the disc through hole of the outer pressure plate to fix the elastic membrane, the inner pressure ring and the outer pressure plate into one piece.

Images