Bearing head for wafer processing and chemical mechanical polishing equipment

Abstract

The embodiment of the invention provides a bearing head for wafer processing and chemical mechanical polishing equipment. The bearing head comprises a main body part and a bearing part, the first elastic film is connected with the surface, facing the wafer, of the main body part, a central cavity and a plurality of annular cavities are defined between the first elastic film and the main body part, and the central cavity and the annular cavities are communicated with the first ventilation pipeline, so that the first elastic film can adsorb and loosen the wafer; a plurality of air holes are formed in the surface, facing the wafer, of at least one of the annular cavities; the second elastic film is located in the annular cavity with the multiple air holes, and the second elastic film can expand and contract to block and open the air holes; when the second elastic film expands, the second elastic film does not make contact with the inner wall of the annular cavity. According to the bearing head and device for wafer processing and the wafer polishing method provided by the embodiment of the invention, the deformation of the first elastic film caused by the contact between the second elastic film and the first elastic film due to the inflation expansion of the second elastic film can be avoided.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wafer polishing technology, and in particular to a carrier head and chemical mechanical polishing equipment for wafer processing. Background Art

[0002] In the semiconductor manufacturing process, wafer polishing is one of the process steps. Most of the current carrier heads have problems such as unstable adsorption and complex operation, which affect the polishing efficiency and quality. The carrier head can adjust the pressure of the elastic membrane to achieve a series of actions of taking and placing the wafer. However, when the wafer is thin or used in a high pressure (HDF) process, the failure rate of wafer placement increases significantly. For example, in the polishing process of the third-generation semiconductor SiC wafer, due to the high elastic modulus, high specific stiffness, and stable chemical properties of the SiC substrate, high pressure (7psi) and long-term polishing (15 to 30 minutes) are required. This causes the elastic membrane and the wafer to "stick" and the conventional placement setting cannot smoothly put down the wafer. Summary of the invention

[0003] In view of this, the embodiments of the present application provide a carrier head and a chemical mechanical polishing device for wafer processing, which can prevent the second elastic membrane from inflating and contacting the first elastic membrane, causing the first elastic membrane to deform.

[0004] According to a first aspect of the present application, a carrier head for wafer processing is provided, comprising: a main body, which has a first ventilation duct and a second ventilation duct inside; a first elastic membrane, which is connected to the surface of the main body facing the wafer, and defines a central cavity and a plurality of annular cavities between the main body and the main body, the central cavity and the plurality of annular cavities are both connected to the first ventilation duct, so that the first elastic membrane can adsorb and loosen the wafer, and at least one of the plurality of annular cavities is provided with a plurality of air holes on the surface facing the wafer; a second elastic membrane, which is located in the annular cavity having the plurality of air holes, the second elastic membrane can be connected to the second ventilation duct, so that the second elastic membrane expands and contracts to block and open the air holes; when the second elastic membrane expands, the second elastic membrane has no contact with the inner wall of the annular cavity, and the width of the bottom wall of the cross section of the second elastic membrane is smaller than the width of the bottom wall of the cross section of the annular cavity, and the width of the top wall of the cross section of the second elastic membrane is smaller than the width of its bottom wall.

[0005] Optionally, the first elastic membrane includes an outer peripheral longitudinal wall, a first elastic bottom wall, multiple inner peripheral longitudinal walls and a first top wall, the first top wall is connected to the lower surface of the main body, the first elastic bottom wall is connected to the lower surface of the main body via the outer peripheral longitudinal wall, and an internal chamber is formed, the multiple inner peripheral longitudinal walls are concentrically arranged to the inner side of the outer peripheral longitudinal wall, and the diameters of the multiple inner peripheral longitudinal walls are different, so as to divide the internal chamber into the circular central cavity located in the middle and multiple annular cavities concentric with the central cavity.

[0006] Optionally, the second elastic membrane includes a second elastic bottom wall, a corrugated side wall and a second top wall, the second top wall is connected to the lower surface of the main body, the second top wall and the second elastic bottom wall are connected via the corrugated side wall to form an inflation chamber, and the inflation chamber is connected to the second ventilation duct.

[0007] Optionally, the cross-section of the second elastic membrane is trapezoidal, and when the second elastic membrane expands, the width of the second top wall is half of the width of the first top wall, and the width of the second elastic bottom wall is two-thirds of the width of the first elastic bottom wall.

[0008] Optionally, the side wall of the second elastic film is a corrugated side wall having corrugations.

[0009] Optionally, the second elastic membrane and the first elastic membrane satisfy the following relationship: Wherein, t1 is the thickness of the side wall of the second elastic membrane, and t2 is the thickness of the inner circumferential longitudinal wall.

[0010] Optionally, the second elastic membrane and the first elastic membrane satisfy the following relationship: b>5t1; wherein t1 is the thickness of the side wall of the second elastic membrane; t2 is the thickness of the inner longitudinal wall; and b is the width of a single wrinkle of the wrinkle side wall.

[0011] Optionally, the hardness of the second elastic film is smaller than that of the first elastic film, and the hardness of the second elastic film ranges from 37HA to 42HA.

[0012] Optionally, the outer surface of the second elastic film is covered with an anti-sticking layer, the anti-sticking layer is a silicone rubber layer, the thickness of the anti-sticking layer is between 0.3 mm and 0.5 mm, the anti-sticking layer has a texture, and the surface roughness of the anti-sticking layer is 1.0.

[0013] According to a second aspect of the present application, a chemical mechanical polishing device is provided, comprising a carrier head, wherein the carrier head is the carrier head described in the first aspect.

[0014] According to the carrier head provided by the embodiment of the present application, the first elastic bottom wall of the annular cavity provided with the second elastic membrane is provided with air holes, and the air holes can be blocked and opened by the expansion and contraction of the second elastic membrane, thereby enabling the wafer to be pressed on the polishing pad or adsorbed. Gas can also be blown out through the air holes to make the wafer detach from the carrier head. And when the second elastic membrane expands, the second elastic membrane has no contact with the inner wall of the annular cavity, the width of the bottom wall of the cross section of the second elastic membrane is less than the width of the bottom wall of the cross section of the annular cavity, and the width of the top wall of the cross section of the second elastic membrane is less than the width of its bottom wall. That is, the cross-sectional shape of the second elastic membrane can be a trapezoidal structure, and the width of its bottom wall is less than the width of the bottom wall of the first elastic membrane, further avoiding the second elastic membrane from contacting the side wall of the first elastic membrane when expanding, and avoiding the pressure transmitted to the first elastic membrane due to the contact between the second elastic membrane and the first elastic membrane, thereby causing uneven pressure transmission of the first elastic membrane, resulting in unstable pressure transmitted to the wafer by the first elastic membrane, resulting in low efficiency during wafer polishing operation or causing wafer damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0016] Figure 1 A structural side view of a carrier head according to the first aspect of the present application;

[0017] Figure 2 A schematic diagram of pressure transmission shown in an embodiment of the present application;

[0018] Figure 3 is a cross-sectional view of an embodiment of the carrier head along line AA according to the first aspect of the present application;

[0019] Figure 4 for Figure 3 A partial enlarged view of point B in the middle;

[0020] Figure 5 is a cross-sectional view of another embodiment of the carrier head along line AA according to the first aspect of the present application;

[0021] Figure 6 for Figure 5 A partial enlarged view of point C in the middle;

[0022] Figure 7 is a schematic diagram of a chemical mechanical polishing device according to the second aspect of the present application;

[0023] Description of reference numerals:

[0024] Chemical mechanical polishing equipment 1000;

[0025] Carrying head 100;

[0026] Main body 10;

[0027] first elastic membrane 20; outer peripheral longitudinal wall 201; first elastic bottom wall 202; inner peripheral longitudinal wall 203; first top wall 204;

[0028] Internal chamber 30; central cavity 301; annular cavity 302; air hole 3021;

[0029] Second elastic film 40; second elastic bottom wall 401; pleated side wall 402; second top wall 403; anti-sticking layer 404;

[0030] A gas-filled chamber 50;

[0031] Polishing pad 200; polishing plate 300; dresser 400; liquid supply unit 500;

[0032] Wafer W; axis Ax. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0034] As mentioned above, wafer polishing is one of the process steps in the semiconductor manufacturing process. Most of the current carrier heads 100 have problems such as unstable adsorption and complex operation, which affect the polishing efficiency and quality. The carrier head 100 can adjust the pressure of the elastic membrane to achieve a series of actions of taking and placing the wafer W. However, when the wafer W is thin or is used in a high pressure (HDF) process, the failure rate of taking and placing the wafer W increases significantly. For example, in the polishing process of the third-generation semiconductor SiC wafer, due to the high elastic modulus, high specific stiffness, and stable chemical properties of the SiC substrate, it is necessary to use high pressure (7psi) and long-term polishing (15 to 30min), which leads to a "sticking" phenomenon between the elastic membrane and the wafer W, and the conventional pick-and-place setting cannot smoothly put down the wafer W.

[0035] Therefore, the carrier head 100 needs to be able to stably adsorb the wafer W and also needs to be able to safely detach the wafer W from the carrier head 100 after the wafer W has completed the polishing operation, to prevent the wafer W from being difficult to detach due to excessive pressure from the carrier head 100 on the wafer W, or to prevent the wafer W from being damaged during detachment.

[0036] Therefore, the present application proposes a carrier head 100 and a chemical mechanical polishing device 1000 for wafer processing. Figure 1-Figure 7 The carrier head 100 for wafer processing according to an embodiment of the present application is described in detail.

[0037] According to a first aspect of the present invention, a carrier head 100 for wafer processing is provided. Figure 1 FIG. 1 shows the overall external structure of the carrier head 100. Figure 3 As shown, the carrier head 100 includes a main body 100, a first elastic membrane 20 and a second elastic membrane 40. The main body 100 may be a circular structure, and its bottom surface is circular so that the wafer W can be easily adsorbed.

[0038] like Figure 3 As shown, the main body 10 has a first ventilation pipeline (not shown in the figure) and a second ventilation pipeline (not shown in the figure) inside, and the first ventilation pipeline can provide positive pressure or negative pressure gas to the cavity formed between the first elastic membrane 20 and the main body 10. The second ventilation pipeline can provide positive pressure or negative pressure gas to the cavity formed between the second elastic membrane 40 and the main body 10.

[0039] like Figure 3 As shown, the first elastic membrane 20 is connected to the surface of the main body 10 facing the wafer W, and can define a central cavity 301 and a plurality of annular cavities 302 between the main body 100. The central cavity 301 and the plurality of annular cavities 302 are both connected to the first ventilation pipeline, so that gas can be transported into the central cavity 301 and the annular cavity 302 through the first ventilation pipeline to form a positive pressure or a negative pressure inside the cavity. It can be understood that when a positive pressure is formed by transporting gas inside the cavity, the first elastic membrane 20 expands and can press the wafer W against the polishing pad 200. When a negative pressure is formed inside the cavity, the first elastic membrane 20 contracts and can adsorb the wafer W.

[0040] In other words, the first ventilation pipeline can form positive pressure or negative pressure inside the central cavity 301 and the annular cavity 302 to achieve adsorption or release of the wafer W. For example, when positive pressure gas is introduced, the first elastic membrane 20 can be filled with gas so that the wafer W can be pressed onto the polishing pad 200 during the polishing process of the wafer W, thereby preventing the wafer W from sliding and ensuring uniform polishing of the wafer W. When negative pressure gas is connected, the bottom surface of the first elastic membrane 20 can shrink, thereby adsorbing the wafer W and achieving the transportation of the wafer W.

[0041] In some embodiments of the present invention, the central cavity 301 is a cavity corresponding to the middle area of ​​the main body 10 among the multiple cavities formed between the first elastic membrane 20 and the main body 10. The annular cavity 302 is a plurality of annular cavities surrounding the central cavity 301, and the plurality of annular cavities 302 are all concentric with the central cavity 301. That is, the annular cavity 302 surrounds the outer periphery of the central cavity 301.

[0042] In some embodiments of the present invention, Figure 3 As shown, at least one of the multiple annular cavities 302 is provided with multiple air holes 3021 on the surface facing the wafer W. When the wafer W needs to be released, air can be blown through the air holes 3021 to release the wafer W from the carrier head 100. This avoids the problem of difficulty in releasing the carrier head 100 from the wafer W due to long-term polishing operations, and avoids the inability to smoothly put down the wafer W. In addition, by providing multiple air holes 3021 on the annular cavity 3021 and blowing air at the same time, the wafer W can be more stable when released, and the wafer W can be prevented from being damaged due to uneven force.

[0043] like Figure 3 As shown, the carrier head 100 further has a second elastic membrane 40, which is located in the annular cavity 302 having a plurality of air holes 3021. The second elastic membrane 40 can be connected to the second ventilation pipeline, so that the second elastic membrane 40 expands and contracts to block and open the air holes 3021. That is, when gas is passed into the second elastic membrane 40 to form a positive pressure, the second elastic membrane 40 expands, and its bottom surface abuts against the bottom surface of the first elastic membrane 20, so that the air holes 3021 can be blocked by the second elastic membrane 40.

[0044] It can be seen that when the wafer W is polished, both the first elastic film 20 and the second elastic film 40 expand, and the second elastic film 40 can block the pores when expanding, so as to prevent the gas in the internal space of the first elastic film 20 from being filled, and prevent the gas in the first elastic film 20 from leaking from the pores 3021, so as to ensure that the first elastic film 20 can stably press the wafer W. It can also prevent the liquid (such as water or polishing liquid) generated during the polishing process of the wafer W and the debris or particles generated during the polishing process from entering the annular cavity 302 through the pores 3021, and then corroding the metal structure inside the carrier head 100.

[0045] When the second elastic membrane 40 expands, the second elastic membrane 40 has no contact with the inner wall of the annular cavity 302, and Figure 3As shown in , the width of the bottom wall of the cross section of the second elastic membrane 40 is smaller than the width of the bottom wall of the cross section of the annular cavity, and the width of the top wall of the cross section of the second elastic membrane 40 is smaller than the width of its bottom wall. That is, the cross section of the second elastic membrane 40 may be a trapezoidal structure, and the width of its bottom wall is smaller than the width of the bottom wall of the first elastic membrane 20, which further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when expanding, thereby avoiding the side wall of the first elastic membrane 20 from being bent due to the pressure applied to the side wall of the first elastic membrane 20 by the second elastic membrane 40 after contacting the first elastic membrane 20, thereby affecting the pressure control when adsorbing the wafer W.

[0046] Therefore, when the second elastic film 40 expands and blocks the air hole 3021, the second elastic film 40 avoids contacting the inner wall of the first elastic film 20, thereby preventing the pressure from being transmitted to the first elastic film 40 due to the contact between the second elastic film 20 and the first elastic film 40, causing uneven pressure transmission of the first elastic film 20, resulting in unstable pressure transmitted from the first elastic film 20 to the wafer W, resulting in low efficiency during the polishing operation of the wafer W or causing damage to the wafer W. Figure 2 , shows a schematic diagram of pressure transmission. When the second elastic membrane 40 expands and contacts the side wall of the first elastic membrane 20, the pressure transmitted from the side wall of the first elastic membrane 20 to the wafer will fluctuate as shown in the figure. Figure 2 The horizontal axis is the radius value, and the vertical axis is the pressure value.

[0047] The second elastic film 40 of the present application avoids contact with the inner wall of the first elastic film 20 , which can improve the pressure control accuracy for adsorption of the wafer W.

[0048] In the embodiment of the present invention, the bottom wall width of the cross section of the first elastic membrane 20 is represented by D3, the bottom wall width of the cross section of the second elastic membrane 40 is represented by D2, and the top wall width of the cross section of the second elastic membrane 40 is represented by D1. And D1<D2<D3. D1, D2 and D3 are all in Figure 4 It is indicated in the figure and is not marked in other figures.

[0049] According to the carrier head 100 provided in the embodiment of the present application, the first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with an air hole 3021, and the air hole 3021 can be blocked and opened by the expansion and contraction of the second elastic membrane 40, thereby being able to press the wafer W onto the polishing pad 200 or adsorb the wafer W. Gas can also be blown out through the air hole 3021 to make the wafer W detach from the carrier head 100. When the second elastic membrane 40 expands, the second elastic membrane 40 has no contact with the inner wall of the annular cavity 302, the width of the bottom wall of the cross section of the second elastic membrane 40 is smaller than the width of the bottom wall of the cross section of the annular cavity 302, and the width of the top wall of the cross section of the second elastic membrane 40 is smaller than the width of its bottom wall. That is, the cross-sectional shape of the second elastic membrane 40 can be a trapezoidal structure, and the width of its bottom wall is smaller than the width of the bottom wall of the first elastic membrane 20, which further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when expanding, and can avoid the pressure being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40, thereby causing uneven pressure transmission of the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, resulting in low efficiency during the polishing operation of the wafer W or causing damage to the wafer W.

[0050] In some embodiments of the present invention, Figure 3 As shown, the first elastic membrane 20 includes an outer peripheral longitudinal wall 201, a first elastic bottom wall 202, a plurality of inner peripheral longitudinal walls 203 and a first top wall 204. The first top wall 204 is connected to the lower surface of the main body 10. The first elastic bottom wall 202 is connected to the lower surface of the main body 10 through the outer peripheral longitudinal wall 201 to form an internal chamber 30. The plurality of inner peripheral longitudinal walls 203 are all concentrically arranged to the inner side of the outer peripheral longitudinal wall 201, and the diameters of the plurality of inner peripheral longitudinal walls 203 are different, so as to divide the internal chamber 30 into a central cavity 301 and a plurality of annular cavities 302. The width between two adjacent inner peripheral longitudinal walls 203 is as shown in FIG. Figure 4 As shown in D3.

[0051] Specifically, an internal chamber 30 is formed between the lower surface of the main body 10 and the first elastic membrane 20. The first elastic membrane 20 is connected to the lower surface of the main body 10 through the first top wall 204. The outer peripheral wall of the first elastic membrane 20 is an outer peripheral longitudinal wall 201, forming an external longitudinal wall structure. There are multiple inner peripheral longitudinal walls 203 in the internal chamber 30. Since the diameters of the multiple inner peripheral longitudinal walls 203 are different, the inner peripheral longitudinal walls 203 divide the internal chamber 30 into a central cavity 301 and multiple annular cavities.

[0052] like Figure 4As shown, in some embodiments of the present invention, the second elastic membrane 40 includes a second elastic bottom wall 401, a corrugated side wall 402 and a second top wall 403, the second top wall 403 is connected to the lower surface of the main body 10, the second top wall 403 and the second elastic bottom wall 401 are connected through the corrugated side wall 402 to form an inflation chamber 50, and the inflation chamber 50 is connected to the second ventilation duct.

[0053] like Figure 4-Figure 6 As shown, in some embodiments of the present invention, the second elastic membrane 40 includes a second elastic bottom wall 401, a corrugated side wall 402 and a second top wall 403, the second top wall 403 is connected to the lower surface of the main body 10, the second top wall 403 and the second elastic bottom wall 401 are connected through the corrugated side wall 402 to form an inflation chamber 50, and the inflation chamber 50 is connected to the second ventilation duct.

[0054] Specifically, the folded side wall 402 of the second elastic membrane 40 can be expanded when inflated, and the second elastic bottom wall 401 expands downward and blocks the air holes 3021 on the first elastic bottom wall 202, so that the first elastic bottom wall 202 can be guaranteed to expand and press the wafer W onto the polishing pad 200 when positive pressure gas is input. When the wafer W needs to be detached from the first elastic membrane 20 after polishing, the second elastic membrane 40 can also be contracted through the folded side wall 402 to open the air holes 3021 that were originally blocked by the second elastic membrane 40, so that gas is blown out from the air holes 3021, and the wafer W is blown off from the first elastic membrane 20, so that the wafer W is smoothly detached from the carrier head 100.

[0055] In addition, the design of the corrugated side wall 402 of the second elastic membrane 40 can prevent the corrugated side wall 402 of the second elastic membrane 40 from touching or abutting against the inner circumferential longitudinal wall 203 or the outer circumferential longitudinal wall 201 of the first elastic membrane 20 after the second elastic membrane 40 is inflated. This causes the inner circumferential longitudinal wall 203 and the outer circumferential longitudinal wall 201 to bend, thereby causing the first elastic bottom wall 202 of the first elastic membrane 20 to be unable to stably press the wafer W onto the polishing pad 200 due to the bending of the inner circumferential longitudinal wall 203 or the outer circumferential longitudinal wall 201, resulting in uneven polishing of the wafer W.

[0056] In some embodiments of the present invention, Figure 4 and Figure 6 As shown, the cross section of the second elastic membrane 40 is a trapezoid. When the second elastic membrane 40 expands, the width of the second top wall 403 is half of the width of the first top wall 204 , and the width of the second elastic bottom wall 401 is two-thirds of the width of the first elastic bottom wall 202 .

[0057] Specifically, the cross-sectional structure of the second elastic membrane 40 is a trapezoid, so that when the second elastic membrane 40 is inflated, the air hole 3021 can be blocked, and the second elastic membrane 40 can be prevented from contacting the inner wall of the first elastic membrane 20 after expansion, resulting in unstable pressure of the outer circumferential longitudinal wall 201 and the inner circumferential longitudinal wall 203 of the first elastic membrane 20, causing changes in the pressure transmission to the wafer W, reducing the polishing effect of the wafer W or damaging the wafer W.

[0058] Among them, Figure 3-Figure 6 As shown, the width of the second top wall 403 is half of the width of the first top wall 204, and the width of the second elastic bottom wall 401 is two-thirds of the width of the first elastic bottom wall 202. It can be understood that the width of the second elastic membrane 40 is smaller than the width of the first elastic bottom wall 202 and the width of the first top wall 204.

[0059] In some embodiments of the present invention, Figure 5 and Figure 6 As shown, the side wall of the second elastic membrane 40 is a corrugated side wall 402. By setting the side wall of the second elastic membrane 40 as the corrugated side wall 402, the second elastic membrane 40 can be further prevented from contacting the side wall of the first elastic membrane 20 after expansion.

[0060] In some embodiments of the present invention, the second elastic membrane 40 and the first elastic membrane 20 satisfy the following relationship:

[0061]

[0062] Here, t1 is the thickness of the side wall of the second elastic membrane 40 , and t2 is the thickness of the inner circumferential longitudinal wall 203 .

[0063] Specifically, Figure 4 As shown, the side wall of the second elastic membrane 40, i.e., the wall surface represented by the waist of the trapezoid of the cross section of the second elastic membrane 40, has a thickness of t1. The thickness of the inner circumferential longitudinal wall 203 is t2. Therefore, it can be known that the side wall thickness of the second elastic membrane 40 is thinner than the inner circumferential longitudinal wall 203 of the first elastic membrane 20. Therefore, its elasticity is higher than that of the inner circumferential longitudinal wall 203. It can better elastically deform, which can not only block the pores 3021, but also prevent its expansion from causing pressure on the first elastic membrane 20.

[0064] In some embodiments of the present invention, Figure 4 and Figure 6 As shown, the second elastic membrane 40 and the first elastic membrane 20 satisfy the following relationship:

[0065] b>5t1;

[0066] Wherein, t1 is the thickness of the side wall of the second elastic membrane 40;

[0067] t2 is the thickness of the inner circumferential longitudinal wall 203;

[0068] b is the width of a single pleat of the pleat sidewall 402 .

[0069] Specifically, Figure 4 As shown, the side wall of the second elastic membrane 40, i.e., the wall surface represented by the waist of the trapezoid of the cross section of the second elastic membrane 40, has a thickness of t1. The thickness of the inner circumferential longitudinal wall 203 is t2. Therefore, it can be known that the side wall thickness of the second elastic membrane 40 is thinner than the inner circumferential longitudinal wall 203 of the first elastic membrane 20. Therefore, its elasticity is higher than that of the inner circumferential longitudinal wall 203. It can better elastically deform, which can not only block the pores 3021, but also prevent its expansion from causing pressure on the first elastic membrane 20.

[0070] In addition, the side wall of the second elastic membrane 40 may also be Figure 6 As shown in FIG. 4 , the side wall has folds. The number of folds and the width of the folds of the fold side wall 402 of the second elastic membrane 40 can be determined by satisfying the above formula: b>5t1, which ensures that the second elastic membrane 40 blocks the air hole 3021 when it expands, and also prevents the pleated side wall 402 from touching or abutting against the inner peripheral longitudinal wall 203 after expansion. Figure 6 As shown, the width of the folds of the fold side wall 402 is as shown in FIG. Figure 6 As shown in H in FIG. After the second elastic film 40 is pressurized and expanded, it can completely cover the chamber, and the pressure can be evenly applied to the air film bottom plate without affecting the side wall of the elastic film.

[0071] In some embodiments of the present invention, the hardness of the second elastic film 40 is smaller than that of the first elastic film 20 , and the hardness of the second elastic film 40 ranges from 37HA to 42HA.

[0072] Specifically, the elasticity of the second elastic membrane 40 is smaller than the hardness of the first elastic membrane 20, that is, the second elastic membrane 40 has greater elasticity. The hardness of the second elastic membrane 40 ranges from 37HA to 42HA. Therefore, when the gas is filled, the second elastic membrane 40 can be softer and more elastic, thereby preventing the second elastic membrane 40 from being pressed against the first elastic bottom wall 202 after being inflated, causing the second elastic bottom wall 202 to be subjected to a large pressure and undergo a pressure change, resulting in a reduction in the polishing effect on the wafer W, or a fluctuation in the polishing rate of the wafer W. That is, the second elastic membrane 40 has better elasticity and can reduce the pressure effect on the first elastic membrane 20.

[0073] In some embodiments of the present invention, Figure 3-Figure 6As shown, the outer surface of the second elastic film 40 is covered with an anti-sticking layer 404, which is a silicone rubber layer. The thickness of the anti-sticking layer 404 is between 0.3 mm and 0.5 mm. The anti-sticking layer 404 has a texture, and the surface roughness of the anti-sticking layer 404 is 1.0.

[0074] Specifically, the surface roughness of the anti-adhesive layer 404 is 1.0, and the smaller the value, the smoother it is. Therefore, even if the second elastic film 40 expands and contacts the inner wall of the first elastic film 20, the high smoothness will avoid pressure on the first elastic film 20.

[0075] In some embodiments of the present invention, Figure 3-Figure 6 As shown, the anti-adhesive layer 404 covers the outer surface of the side wall of the second elastic film 40 and the pleated side wall 402 , thereby preventing the side wall of the second elastic film 40 or the pleated side wall 402 from adhering to the inner wall of the side wall of the first elastic film 20 .

[0076] In some embodiments of the present invention, Figure 3-Figure 6 As shown, the anti-adhesive layer 404 can cover the outer surface of the side wall of the second elastic film 40 and the folded side wall 402, and at the same time, the anti-adhesive layer 404 can also cover the outer surface of the second elastic bottom wall 401. When the carrier head 100 adsorbs the wafer W for polishing, the long-term adsorption with a large pressure may cause the second elastic bottom wall 401 and the first elastic bottom wall 202 to adhere to each other due to long-term close contact when the second elastic bottom wall 401 and the first elastic bottom wall 202 need to be separated. Therefore, the anti-adhesive layer 404 is coated on the outer surface of the second elastic bottom wall 401, which is equivalent to adding a layer of anti-adhesive structure between the second elastic bottom wall 401 and the first elastic bottom wall 202, so that the second elastic bottom wall 401 and the first elastic bottom wall 202 can be prevented from adhering to each other due to long-term close contact, and the stable separation between the second elastic film 40 and the first elastic film 20 is ensured.

[0077] Among them, Figure 3-Figure 6 The thickness of the anti-sticking layer 404 shown in the figure is for the purpose of understanding the structure and does not represent its actual size.

[0078] In some embodiments of the present invention, the anti-sticking layer 404 may be a thin film with a light texture, so as to further avoid adhesion between the first elastic film 40 and the first elastic film 20 .

[0079] The following first introduces Figure 7 As shown, a chemical mechanical polishing device 1000 according to the second aspect of the present application.

[0080] In some embodiments of the present invention, the chemical mechanical polishing device 1000 may include a carrier head 100. The carrier head 100 may be the carrier head 100 of the first embodiment described above. In addition, the chemical mechanical polishing device 1000 may further include a polishing pad 200, a polishing disk 300, a dresser 400, and a liquid supply unit 500. The polishing pad 200 is disposed on the upper surface of the polishing disk 300 and rotates along the axis Ax together with the polishing disk 300. The axis Ax is as shown in FIG. Figure 7 As shown in . The carrier head 100 can move horizontally and is located above the polishing pad 200. The lower surface of the carrier head 100 can absorb the wafer W to be polished. The dresser 400 includes a dresser arm and a dresser head, which is arranged on one side of the polishing plate 300. The dresser arm drives the rotating dresser head to swing to dress the surface of the polishing pad 200. The liquid supply part 500 is arranged above the polishing pad 200 to spread the polishing liquid on the surface of the polishing pad 200.

[0081] According to the chemical mechanical polishing device 1000 of the second aspect of the present application, since it has the carrier head 100 of the first aspect, it has the same beneficial effects as the carrier head 100 of the first aspect. The first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with an air hole 3021, and the air hole 3021 can be blocked and opened by the expansion and contraction of the second elastic membrane 40, thereby enabling the wafer W to be pressed on the polishing pad 200 or adsorbed. Gas can also be blown out through the air hole 3021 to make the wafer W detach from the carrier head 100. And when the second elastic membrane 40 expands, the second elastic membrane 40 has no contact with the inner wall of the annular cavity 302, the width of the bottom wall of the cross section of the second elastic membrane 40 is smaller than the width of the bottom wall of the cross section of the annular cavity 302, and the width of the top wall of the cross section of the second elastic membrane 40 is smaller than the width of its bottom wall. That is, the cross-sectional shape of the second elastic membrane 40 can be a trapezoidal structure, and the width of its bottom wall is smaller than the width of the bottom wall of the first elastic membrane 20, which further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when expanding, and can avoid the pressure being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40, thereby causing uneven pressure transmission of the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, resulting in low efficiency during the polishing operation of the wafer W or causing damage to the wafer W.

[0082] According to a third aspect of the present invention, a wafer polishing method is provided, which is applicable to controlling the carrier head 100 of the first aspect, and includes:

[0083] Step S1: The second ventilation pipe of the carrier head 100 inflates the second elastic membrane 40 so that the second elastic membrane 40 expands to block the air hole 3021, and the second elastic membrane 40 does not contact the inner peripheral longitudinal wall 203 when expanding;

[0084] Specifically, in this step, the second elastic membrane 40 is inflated through the second ventilation pipeline, so that the second elastic membrane 40 can expand and block the air hole 3021, so that the annular cavity 302 can form a sealed cavity. In addition, when the second elastic membrane 40 expands, the second elastic membrane 40 does not contact the inner circumferential longitudinal wall 203, so that the second elastic membrane 40 can avoid exerting pressure on the first elastic membrane 20, so that the inner circumferential longitudinal wall 203 of the first elastic membrane 20 undergoes pressure changes.

[0085] Step S2: The carrier head 100 moves to a wafer W picking position, and the first elastic bottom wall 202 of the first elastic film 20 is bonded to the wafer W;

[0086] Specifically, in this step, the carrier head 100 moves to the wafer W grabbing position, and the first elastic film 20 contacts the wafer. At this time, the air holes 3021 of the first elastic film 20 are blocked by the second elastic film 40, so that the first elastic film 20 can be completely attached to the wafer.

[0087] Step S3: The first ventilation pipeline forms a negative pressure in the internal chamber 30 so that the middle portion of the first elastic bottom wall 202 is separated from the wafer W and the wafer W is adsorbed;

[0088] Specifically, in this step, the first ventilation line forms a negative pressure in the internal chamber 30 of the first elastic membrane 20 , and the middle portion of the first elastic bottom wall 202 of the first elastic membrane 20 is separated from the wafer, thereby adsorbing the wafer W.

[0089] Step S4: the carrier head 100 drives the wafer W to move to the polishing plate 300, and lowers the height of the carrier head 100 to make the wafer W fit with the polishing pad 200;

[0090] Specifically, the carrier head 100 drives the wafer W to move synchronously to the polishing plate 300 , and the carrier head 100 lowers its height to make the wafer W fit with the polishing pad 200 , so as to facilitate the subsequent wafer W polishing operation.

[0091] Step S5: the first ventilation pipeline forms a positive pressure on the internal chamber 30, so that the first elastic bottom wall 202 contacts the surface of the wafer W and presses the wafer W onto the polishing pad 200, and at the same time the second ventilation pipeline inflates the second elastic membrane 40 to block the air hole 3021, and the polishing pad 200 performs a polishing operation on the surface of the wafer W;

[0092] Specifically, in this step, positive pressure gas is rushed into the internal chamber 30, the first elastic membrane 20 expands, and the first elastic bottom wall 202 completely adheres to the surface of the wafer W, and presses the wafer W to the polishing pad 200. The second elastic membrane 40 is inflated and expands to block the air hole 3021, so that the wafer W can be stably pressed on the polishing pad 200, thereby stabilizing the position of the wafer W and polishing the surface of the wafer W evenly.

[0093] Step S6: After polishing is completed, the first ventilation pipeline forms a negative pressure in the internal chamber 30, so that the middle part of the first elastic bottom wall 202 is separated from the wafer W, and the wafer W is adsorbed and moved to the wafer W placement position;

[0094] Specifically, in this step, after polishing is completed, negative pressure is formed in the internal chamber 30, so that the middle part of the first elastic bottom wall 202 is separated from the wafer W, and the wafer W is adsorbed again, and the movement of the polishing head drives the wafer W to move to the wafer placement position.

[0095] Step S7 : the second ventilation pipeline stops inflating to shrink the second elastic membrane 40 and open the air holes 3021 , and the first ventilation pipeline blows out the gas through the air holes 3021 to separate the wafer W from the first elastic bottom wall 202 of the first elastic membrane 20 .

[0096] Specifically, in this step, the second elastic film 40 contracts and opens the air holes 3021, so that the gas can be blown out from the air holes 3021. Therefore, the gas can be blown out from the air holes 3021 to smoothly separate the wafer W from the carrier head 100. This can achieve rapid grasping and placement of the wafer W, and can also prevent the wafer W from being damaged during the removal process.

[0097] According to the wafer polishing method of the third aspect of the present application, the wafer polishing method is applicable to controlling the carrier head 100 of the first aspect embodiment, and thus has the same beneficial effects as the carrier head 100 of the first aspect. The first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with an air hole 3021, and the air hole 3021 can be blocked and opened by the expansion and contraction of the second elastic membrane 40, thereby enabling the wafer W to be pressed on the polishing pad 200 or adsorbed. Gas can also be blown out through the air hole 3021 to detach the wafer W from the carrier head 100. And when the second elastic membrane 40 expands, the second elastic membrane 40 has no contact with the inner wall of the annular cavity 302, the width of the bottom wall of the cross section of the second elastic membrane 40 is smaller than the width of the bottom wall of the cross section of the annular cavity 302, and the width of the top wall of the cross section of the second elastic membrane 40 is smaller than the width of its bottom wall. That is, the cross-sectional shape of the second elastic membrane 40 can be a trapezoidal structure, and the width of its bottom wall is smaller than the width of the bottom wall of the first elastic membrane 20, which further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when expanding, and can avoid the pressure being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40, thereby causing uneven pressure transmission of the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, resulting in low efficiency during the polishing operation of the wafer W or causing damage to the wafer W.

[0098] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A carrier head for wafer processing, characterized in that: include: A main body having a first ventilation pipeline and a second ventilation pipeline inside thereof; a first elastic membrane connected to the surface of the main body facing the wafer, and defining a central cavity and a plurality of annular cavities between the main body and the first elastic membrane, wherein the central cavity and the plurality of annular cavities are both in communication with the first ventilation pipeline, so that the first elastic membrane can absorb and release the wafer, and at least one of the plurality of annular cavities is provided with a plurality of air holes on its surface facing the wafer; a second elastic membrane, which is located in the annular cavity having the plurality of pores, and the second elastic membrane can be in communication with the second ventilation pipeline, so that the second elastic membrane can expand and contract to block and open the pores; When the second elastic membrane expands, the second elastic membrane has no contact with the inner wall of the annular cavity, and the width of the bottom wall of the cross section of the second elastic membrane is smaller than the width of the bottom wall of the cross section of the annular cavity, and the width of the top wall of the cross section of the second elastic membrane is smaller than the width of its bottom wall.

2. The carrier head according to claim 1, characterized in that: The first elastic membrane includes an outer peripheral longitudinal wall, a first elastic bottom wall, multiple inner peripheral longitudinal walls and a first top wall. The first top wall is connected to the lower surface of the main body. The first elastic bottom wall is connected to the lower surface of the main body through the outer peripheral longitudinal wall to form an internal chamber. The multiple inner peripheral longitudinal walls are concentrically arranged to the inner side of the outer peripheral longitudinal wall, and the diameters of the multiple inner peripheral longitudinal walls are different to divide the internal chamber into the circular central cavity located in the middle and multiple annular cavities concentric with the central cavity.

3. The carrier head according to claim 3, characterized in that: The second elastic membrane includes a second elastic bottom wall, a corrugated side wall and a second top wall, the second top wall is connected to the lower surface of the main body, the second top wall and the second elastic bottom wall are connected through the corrugated side wall to form an inflation chamber, and the inflation chamber is connected to the second ventilation duct.

4. The carrier head according to claim 3, characterized in that: The cross section of the second elastic membrane is trapezoidal. When the second elastic membrane expands, the width of the second top wall is half of the width of the first top wall, and the width of the second elastic bottom wall is two-thirds of the width of the first elastic bottom wall.

5. The carrier head according to claim 1, characterized in that: The side wall of the second elastic film is a corrugated side wall having corrugations.

6. The carrier head according to claim 5, characterized in that: The second elastic film and the first elastic film satisfy the following relationship: Wherein, t1 is the thickness of the side wall of the second elastic membrane, and t2 is the thickness of the inner circumferential longitudinal wall.

7. The carrier head according to claim 6, characterized in that: The second elastic film and the first elastic film satisfy the following relationship: Wherein, t1 is the thickness of the side wall of the second elastic membrane; t2 is the thickness of the inner longitudinal wall; b is the width of a single fold of the fold sidewall.

8. The carrier head according to any one of claims 1 to 7, characterized in that: The hardness of the second elastic film is smaller than that of the first elastic film, and the hardness of the second elastic film ranges from 37HA to 42HA.

9. The carrier head according to any one of claims 1 to 7, characterized in that: The outer surface of the second elastic film is covered with an anti-sticking layer, the anti-sticking layer is a silicone rubber layer, the thickness of the anti-sticking layer is between 0.3 mm and 0.5 mm, the anti-sticking layer has a texture, and the surface roughness of the anti-sticking layer is 1.

0.

10. A chemical mechanical polishing device, characterized in that: It comprises a carrier head, and the carrier head is the carrier head according to any one of claims 1-8.

Images