An elastic membrane and carrier head for chemical mechanical polishing

Abstract

The application discloses an elastic film and a bearing head for chemical mechanical polishing, the elastic film comprising: a circular bottom plate part; an outer peripheral wall comprising an upright part, a pleat part and a first horizontally extending part, the upright part vertically extending upward along the periphery of the bottom plate part, the pleat part being located above the upright part, and the first horizontally extending part horizontally extending from the top of the pleat part towards the inside; and at least one inner peripheral wall concentrically arranged on the inside of the outer peripheral wall; wherein the pleat part is a flange structure with an opening facing the inside, and the projection of the pleat part towards the bottom plate part at least partially covers the upright part.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical polishing technology, and more specifically, relates to an elastic membrane and a bearing head for chemical mechanical polishing. Background Technology

[0002] 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. CMP is an ultra-precision surface processing technology that achieves global planarization.

[0003] Chemical mechanical polishing typically involves holding the wafer to the bottom of a support head, with the side of the wafer having the deposited layer abutting against the upper surface of the polishing pad. The support head rotates in the same direction as the polishing pad under the actuation of the drive assembly, applying a downward load to the wafer. Polishing fluid is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, allowing the wafer to undergo chemical mechanical polishing under the combined action of chemicals and machinery.

[0004] Existing bearing heads are equipped with multi-chamber elastic membranes, each with multiple adjustable pressure chambers to act on different annular regions of the wafer. Due to the complexity of the edge chambers of the elastic membrane, controlling the polishing load application in the wafer edge region becomes more difficult. Furthermore, the retaining ring and polishing pad at the bottom of the bearing head are consumables; during polishing, these components experience varying degrees of wear, placing higher demands on the pressure loading of the bearing head.

[0005] Therefore, it is necessary to optimize the structure of the elastic membrane, improve the applicability of the bearing head, and ensure the stability of wafer polishing. Summary of the Invention

[0006] This invention provides an elastic membrane and a support head for chemical mechanical polishing, aiming to at least solve one of the technical problems existing in the prior art.

[0007] A first aspect of the present invention provides an elastic membrane for chemical mechanical polishing, comprising:

[0008] The circular base plate;

[0009] The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion.

[0010] And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall;

[0011] The pleated portion is an inwardly folded edge structure, and its projection toward the base plate at least partially covers the upright portion.

[0012] In some embodiments, the pleated portion is a V-shaped fold with the opening facing inward.

[0013] In some embodiments, the pleated portion includes a first wall panel and a second wall panel, the first wall panel extending upward and outward from the top of the upright portion, and the second wall panel extending upward and inward from the top of the first wall panel and connected to the first horizontal extension portion.

[0014] In some embodiments, the angle between the first wall panel and the second wall panel is less than 180°.

[0015] In some embodiments, the angle between the first wall panel and the first horizontal extension is a first tilt angle, and the angle between the second wall panel and the first horizontal extension is a second tilt angle, wherein the first tilt angle is greater than or equal to the second tilt angle.

[0016] In some embodiments, the difference between the first tilt angle and the second tilt angle is 0 to 30°.

[0017] In some embodiments, the junction of the first horizontal extension and the second wall panel is located inside the upright portion.

[0018] In some embodiments, the horizontal distance between the outer edge of the joint between the first wall panel and the second wall panel and the outer side surface of the upright portion is -3mm to 2mm.

[0019] In some embodiments, the top end of the upright portion is provided with a connecting portion, the connecting portion extends upward along the inner edge of the upright portion, and the pleated portion is formed by folding the top end of the connecting portion.

[0020] In some embodiments, the thickness of the connecting portion is greater than the thickness of the pleated portion.

[0021] In some embodiments, the horizontal distance between the inner sidewall of the connecting portion and the outer sidewall of the upright portion is 2 to 8 mm.

[0022] In some embodiments, the second tilt angle is less than 10°.

[0023] In some embodiments, the second tilt angle is 3 to 5°.

[0024] In some embodiments, the first tilt angle is 2 to 5 times the second tilt angle.

[0025] In some embodiments, a groove is provided on the inner side of the junction between the base plate and the upright portion, and the thickness of the base plate gradually decreases from the inside to the outside at the edge position.

[0026] A second aspect of the present invention provides an elastic membrane for chemical mechanical polishing, comprising:

[0027] The circular base plate;

[0028] The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion.

[0029] And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall;

[0030] The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects to the first horizontal extension portion. The thickness of the first wall panel is less than the thickness of the second wall panel.

[0031] In some embodiments, the thickness of the second wall panel is less than the thickness of the first horizontal extension.

[0032] In some embodiments, the first and second wall panels form an inwardly opening V-shaped fold.

[0033] In some embodiments, the angle between the first wall panel and the second wall panel is less than 120°.

[0034] In some embodiments, the angle between the first wall panel and the first horizontal extension is a first tilt angle, and the angle between the second wall panel and the first horizontal extension is a second tilt angle, wherein the first tilt angle is greater than or equal to the second tilt angle.

[0035] In some embodiments, the junction of the first horizontal extension and the second wall panel is located inside the upright portion.

[0036] In some embodiments, the outer edge of the junction of the first wall panel and the second wall panel is flush with the outer peripheral wall of the annular groove disposed on the upright portion.

[0037] In some embodiments, the top end of the upright portion is provided with a connecting portion, the connecting portion extends upward along the inner edge of the upright portion, and the pleated portion is formed by folding the top end of the connecting portion.

[0038] In some embodiments, the thickness of the connecting portion is greater than the thickness of the first wall panel.

[0039] In some embodiments, the thickness of the connecting portion is 1.5 to 10 times the thickness of the first wall panel.

[0040] In some embodiments, the horizontal distance between the inner sidewall of the connecting portion and the outer sidewall of the upright portion is 2 to 8 mm.

[0041] A third aspect of the present invention provides an elastic membrane for chemical mechanical polishing, comprising:

[0042] The circular base plate;

[0043] The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion.

[0044] And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall;

[0045] The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects with the first horizontal extension portion. The thickness of the first horizontal extension portion is at least 10% greater than the thickness of the second wall panel.

[0046] A fourth aspect of the present invention provides an elastic membrane for chemical mechanical polishing, comprising:

[0047] The circular base plate;

[0048] The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion.

[0049] And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall;

[0050] The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects to the first horizontal extension portion. The thickness of the second wall panel is at least 10% greater than the thickness of the first wall panel.

[0051] A fifth aspect of the present invention provides a support head for chemical mechanical polishing, comprising a support disk, a retaining ring, and the elastic membrane described above, wherein the elastic membrane is disposed at the bottom of the support disk and the retaining ring is disposed on the outer periphery of the elastic membrane.

[0052] In one embodiment, the elastic membrane is disposed on the bottom of a support plate via an annular pressure plate, the bottom of the support plate being provided with concentric annular grooves, and the pleats of the elastic membrane being disposed on the lower side of the annular grooves.

[0053] The beneficial effects of this invention include:

[0054] a. The pleats on the outer peripheral wall of the elastic membrane are folded with the opening facing inward to improve the flexibility of the pleats, avoid sudden expansion of the edge of the elastic membrane under pressure, and ensure the smoothness of load application.

[0055] b. The inward-opening folded edge structure has the advantage of structural stability, effectively ensuring the controllability of the folded edge structure under pressure expansion, and avoiding the elastic membrane from abutting against the inner wall of the retaining ring and interfering with the application of polishing load;

[0056] c. The pleated part has a V-shaped folded edge structure, which helps to reduce the sensitivity of the wear retaining ring to pressure regulation and improve the pressure regulation capability of the bearing head;

[0057] d. The elastic membrane with pleats is configured so that the chamber formed by the pleats can generate good pressure response over a large range, thereby expanding the "adjustable pressure window" at the edge of the elastic membrane and effectively enhancing the pressure regulation capability of the elastic membrane;

[0058] e. The thickness of the first horizontal extension, the second wall panel, and the first wall panel gradually decreases to control the pressure response sequence of each part in the fold and improve the reliability of the flexible deformation of the fold. Attached Figure Description

[0059] The advantages of the present invention will become clearer and easier to understand through the following detailed description in conjunction with the accompanying drawings, which are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0060] Figure 1 This is a schematic diagram of a chemical mechanical polishing system provided in an embodiment of the present invention;

[0061] Figure 2 This is a schematic diagram of a support head for chemical mechanical polishing provided in an embodiment of the present invention;

[0062] Figure 3 yes Figure 2 A magnified view of a section at point A in the middle;

[0063] Figure 4 This is a schematic diagram of the pressurized expansion of the first pressure chamber of an existing elastic membrane;

[0064] Figure 5 This is a schematic diagram of the pressurized expansion of the first pressure chamber of the elastic membrane according to an embodiment of the present invention;

[0065] Figure 6 This is a partial schematic diagram of an embodiment of the present invention, showing that the pleated part is a V-shaped folded elastic membrane;

[0066] Figure 7 This is a schematic diagram of an elastic membrane provided in another embodiment of the present invention;

[0067] Figure 8 This is a schematic diagram of a support head for chemical mechanical polishing provided in another embodiment of the present invention;

[0068] Figure 9 yes Figure 8 A magnified view of a section at point B in the middle;

[0069] Figure 10 This is a partial schematic diagram of an elastic membrane provided in another embodiment of the present invention. Detailed Implementation

[0070] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0071] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0072] In this invention, "Chemical Mechanical Polishing (CMP)" is also called "Chemical Mechanical Planarization (CMP)," and the wafer (W) is also called the substrate (Substrate), with the same meaning and actual function.

[0073] The embodiments disclosed in this invention generally relate to chemical mechanical polishing (CMP) systems used in the semiconductor device manufacturing industry. During CMP, a polishing slurry composed of submicron or nano-sized abrasive particles and a chemical solution flows between a wafer and a polishing pad. The slurry is uniformly distributed under the transport and centrifugal force of the polishing pad, forming a liquid film between the wafer and the pad. The chemical components in the liquid react with the wafer, converting insoluble substances into soluble substances. These reactants are then removed from the wafer surface by the micromechanical friction of the abrasive particles and dissolved in the flowing liquid. In other words, surface material is removed during the alternating process of chemical film formation and mechanical film removal to achieve surface planarization, thereby achieving global planarization.

[0074] Figure 1 This is a schematic diagram of a chemical mechanical polishing system 1000 provided in an embodiment of the present invention. The chemical mechanical polishing system 1000 includes a support head 100, a polishing disk 300, a polishing pad 200, a trimming section 400, and a liquid supply section 500. The polishing pad 200 is disposed on the upper surface of the polishing disk 300, and the polishing pad 200 and the polishing disk 300 rotate together around the Ax axis. The horizontally movable support head 100 is disposed above the polishing pad 200, and the bottom of the support head 100 holds the wafer to be polished. The trimming section 400 oscillates around a fixed point, and the trimming head disposed thereon rotates itself and applies a downward load to trim the surface of the polishing pad 200. The liquid supply section 500 is disposed above the polishing pad 200 to distribute polishing liquid onto the surface of the polishing pad 200.

[0075] During the polishing operation, the carrier head 100 presses the surface of the wafer to be polished against the surface of the polishing pad 200. The carrier head 100 rotates and reciprocates radially along the polishing disk 300, gradually removing the surface of the wafer in contact with the polishing pad 200. Simultaneously, the polishing disk 300 rotates, and the liquid supply unit 500 sprays polishing liquid onto the surface of the polishing pad 200, supplying the polishing liquid between the wafer and the polishing pad 200. Under the chemical action of the polishing liquid, and through the relative movement of the carrier head 100 and the polishing disk 300, the wafer rubs against the polishing pad to achieve global polishing.

[0076] Figure 2 This is a schematic diagram of a carrier head 100 provided in an embodiment of the present invention. The carrier head 100 includes:

[0077] The coupling disc 12 is a disc-shaped component with a flange (not shown) connected to the drive unit on its upper part;

[0078] The carrier disk 13 is a disc-shaped component. The carrier disk 13 is disposed below the coupling disk 12 via the rolling diaphragm 21. Specifically, the second clamping ring 19 and the third clamping ring 20 clamp the outer edge and inner edge of the rolling diaphragm 21 respectively, and combine them with the carrier disk 13 and the coupling disk 12, so that the carrier disk 13 can rotate as a whole with the coupling disk 12.

[0079] The balance frame 11 includes a central shaft and flanges, and is coaxially disposed between the connecting disc 12 and the bearing disc 13. Specifically, the shaft of the balance frame 11 is slidably inserted into the central shaft hole of the connecting disc 12 and is capable of moving vertically. The flange of the balance frame 11 is connected to the central stepped hole of the bearing disc 13 by means of a washer 17, a first clamping ring 18, and bolts (not shown), so that the bearing disc 13 can rotate and / or move vertically together with the balance frame 11.

[0080] The elastic membrane 14 is clamped and attached to the lower part of the support plate 13 by the annular pressure plate 15, and can move and / or rotate together with the support plate 13;

[0081] And a retaining ring 16, which is disposed around the elastic membrane 14 and located at the lower part of the carrier plate 13.

[0082] Furthermore, the elastic diaphragm 14, the annular pressure plate 15, and the bearing plate 13 combine to form multiple pressure chambers (C1, C2, C3, C4, C5, C6, C7). The bearing head 100 is provided with multiple gas channels that can be coupled and connected to external gas paths. Figure 2 (Not shown) These gas channels pass through the coupling disk 12, the bearing disk 13, and the annular pressure disk 15 to communicate with the pressure chambers respectively, thereby adjusting the chamber pressure by introducing or extracting gas into these pressure chambers. In particular, the pressure in the pressure chamber C8 can be adjusted through a through hole in the coupling disk 12 that extends vertically parallel to the central axis of the balance frame 11, thereby achieving vertical displacement of the bearing disk 13 and the elastic diaphragm 14 relative to the coupling disk 12.

[0083] Figure 3 yes Figure 2 A partially enlarged view of the bearing head 100 corresponding to point A, wherein the elastic membrane 14 includes:

[0084] The base plate 141 is a circular disk-shaped structure for receiving the wafer to be polished;

[0085] The outer peripheral wall extends upward along the outer edge of the bottom plate 141;

[0086] And at least one inner peripheral wall 142, which is an annular structure and is concentrically disposed on the inner side of the outer peripheral wall.

[0087] Figure 3 In the illustrated embodiment, the outer peripheral wall includes:

[0088] The upright part 143 extends vertically upward along the periphery of the base plate part 141;

[0089] A pleated portion 144 is provided on the upper side of the upright portion 143;

[0090] And a first horizontal extension 145, which extends horizontally inward from the top of the pleated portion 144.

[0091] In this invention, the pleated portion 144 is an inwardly folded edge structure. Figure 3 In the middle, the pleated portion 144 includes a first wall panel 144b and a second wall panel 144c. The first wall panel 144b extends upward and outward from the top of the upright portion 143, and the second wall panel 144c extends upward and inward from the top of the first wall panel 144b and connects with the first horizontal extension portion 145 to form an inwardly opening V-shaped fold on the upper part of the outer peripheral wall of the elastic membrane 14.

[0092] Figure 3 In the illustrated embodiment, a connecting portion 144a is provided at the top of the upright portion 143, extending vertically upwards. A first wall panel 144b extends upwards and outwards from the top of the connecting portion 144a. The connecting portion 144a prevents the first wall panel 144b with the V-shaped fold from contacting the top of the upright portion 143, thus ensuring the adjustment function of the V-shaped fold.

[0093] Meanwhile, the connecting portion 144a can adjust and control the overall deformation of the wrinkled portion 144 to achieve normal wafer loading and polishing load application. Specifically, the connecting portion 144a can be used to adjust the overall height of the elastic film 14 so that the base plate portion 141 of the elastic film 14 can attract and load the wafer.

[0094] Furthermore, the connecting portion 144a is located directly above the inner ring of the elastic membrane 14, and the inner ring of the elastic membrane 14 is engaged with the inner side of the upright portion 143 to enhance the structural strength of the upright portion 143. The downward load formed by the inflation and pressurization of the first pressure chamber C1 formed by the pleated portion 144 is transmitted downward through the connecting portion 144a and the upright portion 143 to regulate the pressure acting on the wafer edge region and control the removal rate of the wafer surface material.

[0095] Figure 3 In the illustrated embodiment, the thickness of the connecting portion 144a is greater than the thickness of the first wall panel 144b and the second wall panel 144c. Providing a thicker connecting portion 144a ensures that it has appropriate strength, preventing the V-shaped fold from expanding and pressing against the top surface of the upright portion 143, ensuring the normal expansion of the pleated portion 144, and adjusting the load applied via the outer peripheral wall of the elastic membrane 14.

[0096] In some embodiments, the thickness of the connecting portion 144a is 3 to 6 times the thickness of the first wall panel 144b, and the thickness of the connecting portion 144a is 2 to 4 times the thickness of the second wall panel 144c. It is understood that the thickness of the connecting portion 144a should not be too large. If the thickness of the connecting portion 144a is too large, even approaching the thickness of the upright portion 143, the connecting portion 144a will severely affect the overall flexibility of the wrinkled portion 144, which is detrimental to the accurate control of polishing pressure.

[0097] Figure 3 In the illustrated embodiment, the connecting portion 144a extends upward along the inner edge of the upright portion 143, and the horizontal distance between the connecting portion 144a and the outer surface of the upright portion 143 is 5 mm, such that the pleated portion 144 is located on the upper side of the upright portion 143. Preferably, the horizontal distance between the inner sidewall of the connecting portion 144a and the outer surface of the upright portion 143 is 2 to 8 mm.

[0098] Figure 3 In this structure, the elastic membrane 14 also includes a connecting rib 146, which extends from the top of the upright portion 143 toward the inner side of the elastic membrane and is fixed to the annular pressure plate 15. The top of the inner peripheral wall 142 adjacent to the outer peripheral wall has a second horizontal extension portion 147 extending horizontally toward the inner side of the elastic membrane 14. The outer peripheral wall, the first horizontal extension portion 145, the inner peripheral wall 142, the second horizontal extension portion 147, and the annular pressure plate 15 form a second pressure chamber C2.

[0099] Figure 3 In the embodiment shown, the connecting portion 144a extends upward along the inner edge of the upright portion 143 to control the size of the first pressure chamber C1 formed by the pleated portion 144, the first horizontal extension portion 145, the connecting rib 146 and the annular pressure plate 15, and at the same time, it is beneficial to the pressure deformation of the first pressure chamber C1.

[0100] When the first pressure chamber C1 is pressurized, the pleated portion 144 expands outward under pressure. Since the first wall plate 144b and the second wall plate 144c form an inwardly opening V-shaped fold, this V-shaped fold can move downwards in the vertical direction; when the first pressure chamber C1 is evacuated, the V-shaped fold contracts due to the air being drawn in, and it can move upwards in the vertical direction. That is, in this invention, the movement direction of the edge portion of the elastic membrane 14 is clearly defined when the pleated portion 144, which opens inwards, is pressurized or evacuated, which helps to improve the accuracy of pressure control.

[0101] Figure 4 This is a schematic diagram of the pressure chamber C1' of the existing elastic membrane 14' after being pressurized and expanded. The existing elastic membrane 14' is equipped with a bending structure with the opening facing outwards. After the pressure chamber C1' is pressurized and expanded, it is turned outwards. Figure 4 In the diagram, dashed lines represent the state of the pressure chamber after expansion.

[0102] When the existing elastic membrane 14' is pressurized, the outward-facing bending structure deforms from the inside out; due to the large deformation amplitude of the outward-facing bending structure, its controllability is poor. Therefore, the bending structure of the existing elastic membrane 14' is very likely to come into contact with the inner wall of the retaining ring 16, causing the existing elastic membrane 14' to lose its stable state.

[0103] Figure 5 This is a schematic diagram of the first pressure chamber C1 of the elastic membrane 14 after being pressurized. Solid lines indicate that the pleated part 144 is in a static state, and dashed lines indicate that the pleated part 144 is in a pressurized expansion state.

[0104] Figure 5 In this invention, the V-shaped fold formed by the first wall plate 144b and the second wall plate 144c exhibits relatively small deformation during inflation, remaining in a controllable state. Adjusting the structural parameters of the folded portion 144 allows for controlled expansion and movement within the gap between the elastic membrane 14 (in a static state) and the retaining ring 16, preventing the outer edge of the folded portion 144 from contacting the inner wall of the retaining ring 16 and thus affecting the load application on the edge portion of the elastic membrane 14. Compared to the prior art, the elastic membrane 14 provided by this invention, equipped with an inwardly opening V-shaped fold, offers the advantage of structural stability.

[0105] Figure 4 In the existing elastic membrane 14', when pressurized or evacuated, the direction of movement of the existing elastic membrane 14' with its outward-facing bending structure is uncertain. This is because the bending structure of the existing elastic membrane 14' has a critical state, which is the state in which the bending structure folds from the inside out. Figure 4 Regarding the existing elastic membrane 14' shown, its movement state differs before and after the critical state of the bending structure, which to some extent affects the accurate application of the polishing load. Compared to existing elastic membranes, Figure 5 The elastic membrane 14 shown is configured with an inwardly folded edge structure, which can accurately control the upward or downward movement of the elastic membrane 14 and effectively improve the pressure control capability of the edge portion of the elastic membrane.

[0106] Furthermore, the existing elastic membrane 14' ( Figure 4 As shown, a large deflection torque is generated during use, especially when the bearing head switches from normal rotation to an emergency stop. This affects the service life of the elastic membrane to some extent. However, the elastic membrane 14 provided by this invention has a smaller deflection torque during use, which helps to extend the service life of the elastic membrane and control the cost of the wafer polishing process.

[0107] In addition, existing elastic membranes 14' ( Figure 4As shown, the pressure chamber C1' undergoes abrupt changes during pressurization and expansion, which to some extent affects the "adjustable pressure window" at the edge of the existing elastic membrane 14'. This abrupt change refers to the existing elastic membrane 14' passing through a critical state, where the bending structure changes from an outward-facing opening to an inward-facing opening. Specifically, if the pressure in pressure chamber C1' increases to a certain value and then continues to be pressurized, instability in the chamber pressure will occur; or, if pressure chamber C1' depressurizes to a certain value and then continues to depressurize, and the pressure value of pressure chamber C1' does not change significantly, then the depressurized pressure chamber C1' will have almost no pressure response.

[0108] and Figure 5 The elastic membrane 14 shown does not have the problem of pressure abrupt changes. Therefore, the elastic membrane 14 provided by the present invention enables the first pressure chamber C1 to generate a good pressure response over a large range, thereby expanding the "adjustable pressure window" of the edge portion of the elastic membrane 14 and effectively enhancing the pressure regulation capability of the elastic membrane 14. In other words, even a slight adjustment of the first pressure chamber C1 can regulate the removal rate of the wafer edge region, which is beneficial for achieving global planarization of the wafer.

[0109] Figure 3 In this embodiment, the first horizontal extension 145 abuts against the support plate 13, and the junction of the first horizontal extension 145 and the second wall panel 144c is located inside the upright portion 143. Preferably, the vertical projection of the junction of the first horizontal extension 145 and the second wall panel 144c coincides with the connecting portion 144a, so that the expansion of the V-shaped fold on the upper side of the upright portion 143 is controllable. In this invention, vertical projection refers to projection along the vertical direction; specifically, the vertical projection of the junction of the first horizontal extension 145 and the second wall panel 144c is the projection of the junction onto the bottom plate portion 141. In the context of this application, inside / outside refers to the centerline and / or the intermediate layer.

[0110] In one embodiment of the elastic membrane 14 provided by the present invention, the joint between the first wall panel 144b and the second wall panel 144c is located on the upper side of the upright portion 143, and the horizontal distance between the outer edge of the joint and the outer surface of the upright portion 143 is -3mm to 2mm. A negative horizontal distance means that the joint between the first wall panel 144b and the second wall panel 144c is located on the inner side of the outer surface of the upright portion 143. It should be noted that if the outer edge of the joint is flush with the outer surface of the upright portion 143, the horizontal distance between the outer edge of the joint and the outer surface of the upright portion 143 is zero; if the outer edge of the joint is located on the outer side of the outer surface of the upright portion 143, the horizontal distance between the outer edge of the joint and the outer surface of the upright portion 143 is positive.

[0111] Figure 6In the illustrated embodiment, the outer edge of the junction between the first wall panel 144b and the second wall panel 144c is located outside the outer side of the upright portion 143, and the projection of the pleated portion 144 toward the bottom plate portion 141 completely covers the upright portion 143. That is, the radial length of the V-shaped fold is greater than the radial length of the upright portion 143, so as to increase the flexibility of the pleated portion 144, reduce the sensitivity of the elastic membrane 14 to the wear of the retaining ring, and improve the pressure regulating performance of the bearing head.

[0112] Understandably, the outer edge of the junction between the first wall plate 144b and the second wall plate 144c can also be flush with the outer surface of the upright portion 143. This arrangement allows control over the load exerted by the upright portion 143 on the wafer edge, thereby regulating the material removal rate in the corresponding area.

[0113] In one embodiment of the present invention, the angle between the first wall panel 144b and the second wall panel 144c is less than 180°. That is, the pleated portion 144 has at least an inwardly opening bend in the static state, so that the pleated portion 144 can expand outward under pressure. Preferably, the angle between the first wall panel 144b and the second wall panel 144c is 15 to 120°.

[0114] Figure 3 In the illustrated embodiment, the angle between the first wall plate 144b and the second wall plate 144c is 15 to 45°. After the first pressure chamber C1 is pressurized, the V-shaped fold with the opening facing inward expands inside the retaining ring 16. At the same time, after the first pressure chamber C1 is evacuated, the V-shaped fold with the opening facing inward moves effectively in the vertical direction to adjust the load applied to the wafer edge region and precisely control the material removal rate of the wafer edge region.

[0115] Figure 6 This is an enlarged view of the layout of the elastic membrane 14 provided in an embodiment of the present invention. The angle between the first wall panel 144b and the first horizontal extension 145 is a first tilt angle α, and the angle between the second wall panel 144c and the first horizontal extension 145 is a second tilt angle β, wherein the first tilt angle α is greater than the second tilt angle β. It should be noted that the angles between the first wall panel 144b and the first horizontal extension 145, and the angles between the second wall panel 144c and the first horizontal extension 145, are acute angles to facilitate comparison of the size of the angles.

[0116] The above-described arrangement of the elastic membrane 14 causes the expanded pleats 144 to tilt slightly downwards, so as to avoid the top of the pleats 144 abutting against the bottom surface of the carrier disk 13 and interfering with the application of polishing pressure in the wafer edge region.

[0117] Preferably, the difference between the first tilt angle α and the second tilt angle β is less than or equal to 30°, so as to control the smoothness of the V-shaped fold deformation of the elastic membrane 14 under pressure.

[0118] As Figure 6 In a variant of the embodiment, the first tilt angle α can also be equal to the second tilt angle β. That is, the difference between the first tilt angle α and the second tilt angle β is 0°, and the pleated portion 144 forms a symmetrical V-shaped fold along its horizontal center line, so that the deformation of the pleated portion 144 under pressure expansion is relatively stable.

[0119] Figure 7 This is a schematic diagram of an elastic film 14 provided in another embodiment of the present invention. A groove 141a is provided on the inner side of the junction of the base plate portion 141 and the upright portion 143. The thickness of the edge of the base plate portion 141 gradually decreases from the inside to the outside to enhance the flexibility of the edge of the base plate portion 141 and adjust the polishing pressure of the wafer edge region.

[0120] Preferably, the minimum thickness at the edge of the base plate portion 141 is 60% to 80% of the thickness at other locations of the base plate portion 141 to ensure the flexibility of the edge of the base plate portion 141. In some embodiments, the minimum thickness at the edge of the base plate portion 141 is 146 to 148 mm from the center of the elastic film 14 to accurately adjust the polishing load in the wafer edge region.

[0121] Figure 7 In the illustrated embodiment, the thickness of the base plate portion 141 at the edge varies by a length of 1 to 5 mm to fully cover the area where the wafer edge polishing pressure changes abruptly, thereby improving the ability to control the wafer edge pressure.

[0122] To ensure proper transmission of the polishing load, the thickness of the connecting portion 144a is greater than the thickness of the first wall plate 144b, so that the load formed by the first pressure chamber C1 enclosed by the pleats 144, connecting ribs 146, etc., can be transmitted downwards via the connecting portion 144a and the upright portion 143. In some embodiments, the thickness of the connecting portion 144a is 1.5 to 10 times the thickness of the first wall plate 144b to ensure smooth transmission of the polishing load, so that the connecting portion 144a and the first horizontal extension 145 have greater rigidity, while the pleats 144 disposed between them can undergo orderly flexible deformation.

[0123] Figure 8 This is a schematic diagram of a bearing head provided in an embodiment of the present invention. Figure 9 yes Figure 8 A magnified view of a section at point B. (Compared to...) Figure 2 Compared to the illustrated embodiment, the second tilt angle formed between the second wall plate 144c and the first horizontal extension 145 is less than 10°, in order to control the expansion of the first pressure chamber C1 in the vertical direction, adjust the degree of downward transmission of the load formed in the first pressure chamber C1, and regulate the removal rate of the wafer edge region. Preferably, the angle between the second wall plate 144c and the first horizontal extension 145 is 3 to 5°.

[0124] In some embodiments, the angle between the second wall panel 144c and the first horizontal extension 145 may also be 0°. That is, the second wall panel 144c and the first horizontal extension 145 are located on the same horizontal plane. This structure is consistent with the groove portion 141a of the elastic membrane 14. Figure 10 (As shown) The combination ensures the flexibility of the edge portion of the elastic membrane 14 and improves the accuracy of polishing pressure loading.

[0125] Figure 10 This is a partial schematic diagram of the elastic film 14 provided in one embodiment of the present invention, wherein the first tilt angle α is 4 times the second tilt angle β. In some embodiments, the first tilt angle α is 2 to 5 times the second tilt angle β. The above-described arrangement of the elastic film 14 causes the expanded wrinkled portion 144 to tilt slightly downward, so as to avoid the top of the wrinkled portion 144 abutting against the bottom surface of the support disk 13 and interfering with the application of polishing pressure in the wafer edge region.

[0126] Meanwhile, one embodiment of the present invention also provides an elastic film 14 for chemical mechanical polishing. Figure 7 This is a partial schematic diagram of the elastic membrane 14.

[0127] In this embodiment, the pleated portion 144 of the elastic membrane 14 has the following characteristics: the thickness of the first wall plate 144b is less than the thickness of the second wall plate 144c. That is, when the first pressure chamber C1 is pressurized or depressurized, the thinner first wall plate 144b will move first than the second wall plate 144c, so as to accurately control the movement trend of the edge portion of the elastic membrane 144 and enhance the accuracy of polishing load control.

[0128] Figure 7 In this design, the thickness of the second wall plate 144c is less than the thickness of the first horizontal extension 145, so that when the first pressure chamber C1 is pressurized or depressurized, the second wall plate 144c operates before the first horizontal extension 145. That is, the thicknesses of the first horizontal extension 145, the second wall plate 144c, and the first wall plate 144b gradually decrease, thus determining the operating sequence of each component when the chamber is pressurized or depressurized. Specifically, the first wall plate 144b operates before the second wall plate 144c, and the second wall plate 144c operates before the first horizontal extension 145, so as to control the deformation of the pleated portion 144 according to a predetermined pattern, ensuring the controllability of the elastic deformation of the edge portion of the elastic membrane 14.

[0129] In one embodiment of the present invention, the thickness of the first horizontal extension 145 is at least 10% greater than the thickness of the second wall panel 144c, so as to control the flexibility of the second wall panel 144c and achieve orderly deformation of the pleated portion 144. Preferably, the thickness of the first horizontal extension 145 is 10%-60% greater than the thickness of the second wall panel 144c, so that there are some differences in the flexibility of the first horizontal extension 145 and the second wall panel 144c.

[0130] In one embodiment of the present invention, the thickness of the second wall panel 144c is at least 10% greater than the thickness of the first wall panel 144b, so as to adjust the flexibility of the pleated portion 144 and realize the orderly deformation of the pleated portion 144. Preferably, the thickness of the second wall panel 144c is 10%-30% greater than the thickness of the first wall panel 144b, so as to improve the flexibility of the first wall panel 144b, so that the first wall panel 144b, the second wall panel 144c and the first horizontal extension 145 undergo orderly expansion and contraction deformation.

[0131] Figure 7 In the embodiment shown, the first wall panel 144b and the second wall panel 144c form an inwardly opening V-shaped fold. The angle between the first wall panel 144b and the second wall panel 144c is less than 120°, so that the folded part 144 expands outward when pressurized, avoiding abrupt changes in the folded part 144 and ensuring the stability of the pressurized expansion of the first pressure chamber C1.

[0132] In some embodiments, the outer edge of the joint between the first wall panel 144b and the second wall panel 144c is flush with the outer peripheral wall of the annular groove 143a disposed on the upright portion 143, such as... Figure 7 As shown. Figure 2 The outer ring shown is disposed in the annular slot 143a. The outer ring and the inner ring are combined to ensure that the upright portion 143 is in a vertical state. The load formed in the first pressure chamber C1 can be transmitted downward through the upright portion 143, the inner ring and the outer ring forming assembly to ensure the accuracy of load application in the wafer edge region.

[0133] In some embodiments, the thickness of the second wall plate 144c is equal to the thickness of the first horizontal extension 145, the thickness of the second wall plate 144c is greater than the thickness of the first wall plate 144b, and the thickness of the connecting portion 144a is greater than the thickness of the second wall plate 144c, so as to ensure the flexibility of the edge portion of the elastic film 14, accurately control the polishing load in the wafer edge region, and improve the uniformity of wafer polishing.

[0134] Figure 8 This is a schematic diagram of a support head 100 for chemical mechanical polishing provided by the present invention. The support head 100 includes a support disk 13, a retaining ring 16, and the elastic membrane 14 mentioned above. The elastic membrane 14 is disposed at the bottom of the support disk 13, and the retaining ring 16 is disposed on the outer periphery of the elastic membrane 14.

[0135] Figure 8In this design, the elastic membrane 14 is positioned at the bottom of the support plate 13 via an annular pressure plate 15. The bottom of the support plate 13 has concentric annular grooves 13a, and the wrinkled portions 144 of the elastic membrane 14 are located below these grooves. The annular grooves 13a provide space for the expansion and deformation of the wrinkled portions 144, effectively preventing the expanded wrinkled portions 144 from contacting the bottom surface of the support plate 13 and affecting the accurate control of the polishing load. It should be noted that in... Figure 2 In the illustrated embodiment, the bottom of the support plate 13 may also be provided with an annular groove 13a to provide space for the expansion and deformation of the folded portion 144.

[0136] The elastic membrane 14 provided by this invention is configured with inwardly opening pleated portions 144 to enhance the flexibility of the edge portion of the elastic membrane and improve the pressure control capability of the wafer edge region. As the number of wafers polished by the bearing head 100 increases, the retaining ring 16 will experience varying degrees of wear, and the worn retaining ring 16 will affect the removal rate of the wafer edge region. The pleated portions 144 of the elastic membrane 14 provided by this invention have an inwardly opening folded edge structure, which effectively enhances the pressure control capability of the elastic membrane edge, so as to appropriately compensate for the wear of the retaining ring 16 and achieve accurate control of the pressure in the wafer edge region.

[0137] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0138] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An elastic membrane for chemical mechanical polishing, characterized in that, include: The circular base plate; The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the base plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally from the top of the pleated portion toward the inward side. And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall; The pleated part is an inwardly opening folded edge structure, and its projection toward the bottom plate at least partially covers the upright part; The pleated part is a V-shaped folded edge with the opening facing inward. It includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright part, and the second wall panel extends upward and inward from the top of the first wall panel and is connected to the first horizontal extension part. The top of the upright part is provided with a connecting part, which extends upward along the inner edge of the upright part, and the pleated part is formed by folding the top edge of the connecting part.

2. The elastic membrane as described in claim 1, characterized in that, The angle between the first wall panel and the second wall panel is less than 180°.

3. The elastic membrane as described in claim 1, characterized in that, The angle between the first wall panel and the first horizontal extension is the first tilt angle, and the angle between the second wall panel and the first horizontal extension is the second tilt angle. The first tilt angle is greater than or equal to the second tilt angle.

4. The elastic membrane as described in claim 3, characterized in that, The difference between the first tilt angle and the second tilt angle is 0~30°.

5. The elastic membrane as described in claim 1, characterized in that, The junction between the first horizontal extension and the second wall panel is located inside the upright portion.

6. The elastic membrane as described in claim 1, characterized in that, The horizontal distance between the outer edge of the joint between the first and second wall panels and the outer side surface of the upright part is -3mm to 2mm.

7. The elastic membrane as described in claim 1, characterized in that, The thickness of the connecting portion is greater than the thickness of the folded portion.

8. The elastic membrane as described in claim 1, characterized in that, The horizontal distance between the inner wall of the connecting part and the outer side of the upright part is 2~8mm.

9. The elastic membrane as described in claim 3, characterized in that, The second tilt angle is less than 10°.

10. The elastic membrane as described in claim 9, characterized in that, The second tilt angle is 3~5°.

11. The elastic membrane as claimed in claim 9, characterized in that, The first tilt angle is 2 to 5 times the second tilt angle.

12. The elastic membrane as claimed in claim 1, characterized in that, A groove is provided on the inner side of the junction between the base plate and the upright part, and the thickness of the base plate gradually decreases from the inside to the outside at the edge.

13. An elastic membrane for chemical mechanical polishing, characterized in that, include: The circular base plate; The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion. And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall; The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects with the first horizontal extension portion to form an inwardly opening V-shaped folded edge structure. The thickness of the first wall panel is less than the thickness of the second wall panel.

14. The elastic membrane as claimed in claim 13, characterized in that, The thickness of the second wall panel is less than the thickness of the first horizontal extension.

15. The elastic membrane as described in claim 13, characterized in that, The first and second wall panels form an inward-facing V-shaped folded edge.

16. The elastic membrane as claimed in claim 13, characterized in that, The angle between the first wall panel and the second wall panel is less than 120°.

17. The elastic membrane as claimed in claim 13, characterized in that, The angle between the first wall panel and the first horizontal extension is the first tilt angle, and the angle between the second wall panel and the first horizontal extension is the second tilt angle. The first tilt angle is greater than or equal to the second tilt angle.

18. The elastic membrane as claimed in claim 13, characterized in that, The junction between the first horizontal extension and the second wall panel is located inside the upright portion.

19. The elastic membrane as claimed in claim 13, characterized in that, The outer edge of the joint between the first wall panel and the second wall panel is flush with the outer peripheral wall of the annular groove disposed on the upright part.

20. The elastic membrane as claimed in claim 13, characterized in that, The top of the upright part is provided with a connecting part, which extends upward along the inner edge of the upright part, and the pleated part is formed by folding the top edge of the connecting part.

21. The elastic membrane as claimed in claim 20, characterized in that, The thickness of the connecting part is greater than the thickness of the first wall panel.

22. The elastic membrane as claimed in claim 21, characterized in that, The thickness of the connecting part is 1.5 to 10 times the thickness of the first wall panel.

23. The elastic membrane as claimed in claim 22, characterized in that, The horizontal distance between the inner wall of the connecting part and the outer side of the upright part is 2~8mm.

24. An elastic membrane for chemical mechanical polishing, characterized in that, include: The circular base plate; The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion. And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall; The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects with the first horizontal extension portion to form an inwardly opening V-shaped folded edge structure. The thickness of the first horizontal extension portion is at least 10% greater than the thickness of the second wall panel.

25. An elastic membrane for chemical mechanical polishing, characterized in that, include: The circular base plate; The outer peripheral wall includes an upright portion, a pleated portion and a first horizontal extension portion. The upright portion extends vertically upward along the periphery of the bottom plate portion. The pleated portion is located above the upright portion. The first horizontal extension portion extends horizontally inward from the top of the pleated portion. And at least one inner peripheral wall, which is concentrically disposed on the inner side of the outer peripheral wall; The pleated portion includes a first wall panel and a second wall panel. The first wall panel extends upward and outward from the top of the upright portion, and the second wall panel extends upward and inward from the top of the first wall panel and connects with the first horizontal extension portion to form an inwardly opening V-shaped folded edge structure. The thickness of the second wall panel is at least 10% greater than the thickness of the first wall panel.

26. A support head for chemical mechanical polishing, characterized in that, It includes a support plate, a retaining ring, and an elastic membrane as described in any one of claims 1 to 25, wherein the elastic membrane is disposed at the bottom of the support plate and the retaining ring is disposed on the outer periphery of the elastic membrane.

27. The bearing head as described in claim 26, characterized in that, The elastic membrane is disposed on the bottom of the support plate via an annular pressure plate. The bottom of the support plate is provided with concentric annular grooves, and the pleats of the elastic membrane are disposed on the lower side of the annular grooves.

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