Carrier heads for wafer processing, chemical mechanical polishing equipment

Abstract

This application provides a carrier head and chemical mechanical polishing equipment for wafer processing. The carrier head includes: a main body; a first elastic membrane connected to the wafer-facing surface of the main body and defining a central cavity and multiple annular cavities between the membrane and the main body, wherein the central cavity and the multiple annular cavities are all connected to a first ventilation channel to enable the first elastic membrane to adsorb and release the wafer, and at least one of the multiple annular cavities has multiple pores on its wafer-facing surface; and a second elastic membrane located within the annular cavity with multiple pores, capable of expanding and contracting to seal and open the pores; when the second elastic membrane expands, it does not contact the inner wall of the annular cavity. This application provides a carrier head, device, and wafer polishing method for wafer processing, which avoids the second elastic membrane from expanding and contacting the first elastic membrane, thus preventing deformation of the first elastic membrane.

Description

Technical Field

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

[0002] In semiconductor manufacturing, wafer polishing is one of the process steps. Most current wafer carriers suffer from problems such as unstable adsorption and complex operation, affecting polishing efficiency and quality. The carrier can adjust the pressure of the elastic membrane to achieve a series of wafer pick-up and drop actions. However, when the wafer is thin or in high-pressure (HDF) processes, the wafer pick-up and drop failure rate increases significantly. For example, in the polishing process of third-generation semiconductor SiC wafers, due to the high elastic modulus, high specific stiffness, and stable chemical properties of the SiC substrate, high pressure (7 psi) and long polishing time (15-30 min) are required. This causes a "sticking" phenomenon between the elastic membrane and the wafer, making it impossible to smoothly place the wafer using conventional pick-up and drop settings. Summary of the Invention

[0003] In view of this, embodiments of this application provide a carrier head and chemical mechanical polishing equipment for wafer processing, which can prevent the second elastic membrane from expanding and contacting the first elastic membrane, thus avoiding deformation of the first elastic membrane.

[0004] According to a first aspect of this application, a carrier head for wafer processing is provided, comprising: a main body having a first ventilation channel and a second ventilation channel inside; a first elastic membrane connected to the wafer-facing surface of the main body and defining a central cavity and a plurality of annular cavities between the first elastic membrane and the wafer-facing surface, wherein the central cavity and the plurality of annular cavities are all connected to the first ventilation channel to enable the first elastic membrane to adsorb and release the wafer, and at least one of the plurality of annular cavities has a plurality of pores on its wafer-facing surface; a second elastic membrane located within the annular cavity having the plurality of pores, the second elastic membrane being connected to the second ventilation channel to expand and contract to block and open the pores; when the second elastic membrane expands, the second elastic membrane is not in 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, a plurality of 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 cavity. The plurality of inner peripheral longitudinal walls are all concentrically arranged inside the outer peripheral longitudinal wall, and the diameters of the plurality of inner peripheral longitudinal walls are different, so as to divide the internal cavity into a circular central cavity located in the middle and a plurality of annular cavities concentric with the central cavity.

[0006] Optionally, the second elastic membrane includes a second elastic bottom wall, a pleated 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 by the pleated side wall to form an inflation chamber. The inflation chamber is connected to the second ventilation pipe.

[0007] Optionally, 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 the width of the first top wall, and the width of the second elastic bottom wall is two-thirds the width of the first elastic bottom wall.

[0008] Optionally, the sidewall of the second elastic membrane is a pleated sidewall.

[0009] Optionally, the second elastic membrane and the first elastic membrane satisfy the following relationship: Wherein, t1 is the thickness of the sidewall 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; where t1 is the thickness of the sidewall of the second elastic membrane; t2 is the thickness of the inner circumferential longitudinal wall; and b is the width of a single fold of the folded sidewall.

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

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

[0013] According to a second aspect of this application, a chemical mechanical polishing apparatus is provided, including a support head, said support head being the support head described in the first aspect above.

[0014] According to the carrier head provided in the embodiments of this application, the first elastic bottom wall of the annular cavity with a second elastic membrane has vent holes. These vent holes can be sealed and opened by the expansion and contraction of the second elastic membrane, thereby enabling the wafer to be pressed onto the polishing pad or adsorbed. Gas can also be blown out through the vent holes to detach the wafer from the carrier head. Furthermore, when the second elastic membrane expands, it does not contact the inner wall of the annular cavity. The width of the bottom wall of the second elastic membrane's cross-section is smaller than the width of the bottom wall of the annular cavity's cross-section, and the width of the top wall of the second elastic membrane's cross-section is smaller 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 smaller than the width of the bottom wall of the first elastic membrane. This further avoids contact between the second elastic membrane and the side wall of the first elastic membrane when the second elastic membrane expands, preventing pressure from being transmitted to the first elastic membrane due to contact. This avoids uneven pressure transmission from the first elastic membrane, leading to unstable pressure transmitted to the wafer, resulting in low efficiency or wafer damage during wafer polishing. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0016] Figure 1 This is a structural side view of the bearing head according to the first aspect of this application;

[0017] Figure 2 This is a schematic diagram illustrating pressure transmission in an embodiment of this application;

[0018] Figure 3 This is a cross-sectional view along line AA of one embodiment of the bearing head according to the first aspect of this application;

[0019] Figure 4 for Figure 3 A magnified view of a section at point B in the middle;

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

[0021] Figure 6 for Figure 5 A magnified view of a section at point C;

[0022] Figure 7 A schematic diagram of a chemical mechanical polishing apparatus according to the second aspect of this application;

[0023] Explanation of reference numerals in the attached figures:

[0024] Chemical mechanical polishing equipment 1000;

[0025] 100 bearing head;

[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; vent 3021;

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

[0030] Inflatable chamber 50;

[0031] Polishing pad 200; Polishing disc 300; Dresser 400; Liquid supply unit 500;

[0032] Wafer W; Axis Ax. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0034] As mentioned earlier, wafer polishing is one of the process steps in semiconductor manufacturing. Most current wafer carriers 100 suffer from problems such as unstable adsorption and complex operation, affecting polishing efficiency and quality. The wafer carrier 100 can achieve a series of actions for picking up and placing wafers W by adjusting the pressure of the elastic membrane. However, when the wafer W is thin or when using high-pressure (HDF) processes, the failure rate of picking up and placing wafers W increases significantly. For example, in the polishing process of third-generation semiconductor SiC wafers, due to the high elastic modulus, high specific stiffness, and stable chemical properties of the SiC substrate, high pressure (7 psi) and long polishing time (15-30 min) are required. This causes a "sticking" phenomenon between the elastic membrane and the wafer W, making it impossible to smoothly place the wafer W using conventional pick-and-place settings.

[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 been polished, so as to prevent the wafer W from being difficult to detach due to excessive pressure adsorbed by the carrier head 100, or from being damaged when detached.

[0036] Therefore, this application proposes a carrier head 100 and a chemical mechanical polishing device 1000 for wafer processing. The following is a description of the appendix to the specification. Figures 1-7 The present application describes in detail the carrier head 100 for wafer processing according to an embodiment of the present application.

[0037] According to a first aspect of the present invention, a carrier head 100 for wafer processing, Figure 1 The diagram shows the overall external structure of the bearing head 100. (See diagram for reference.) 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 can be a circular structure, and its bottom surface is circular to facilitate the adsorption of the wafer W.

[0038] like Figure 3 As shown, the main body 10 has a first vent pipe (not shown) and a second vent pipe (not shown). The first vent pipe can provide positive or negative pressure gas to the cavity formed between the first elastic membrane 20 and the main body 10. The second vent pipe can provide positive 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 defines a central cavity 301 and a plurality of annular cavities 302 between itself and the main body 100. The central cavity 301 and the plurality of annular cavities 302 are all connected to a first venting conduit, thereby allowing gas to be supplied to the central cavity 301 and the annular cavities 302 through the first venting conduit to create positive or negative pressure inside the cavities. It is understood that when positive pressure is created by supplying gas inside the cavities, the first elastic membrane 20 expands and presses the wafer W against the polishing pad 200. When negative pressure is created inside the cavities, the first elastic membrane 20 contracts and adsorbs the wafer W.

[0040] In other words, positive or negative pressure can be created inside the central cavity 301 and the annular cavity 302 through the first ventilation pipe to achieve the adsorption or detachment of the wafer W. For example, when positive pressure gas is introduced, the first elastic membrane 20 can be filled with gas, thereby pressing the wafer W onto the polishing pad 200 during the polishing process, thus preventing the wafer W from slipping and ensuring uniform polishing of the wafer W. When negative pressure gas is introduced, the bottom surface of the first elastic membrane 20 can contract, thereby adsorbing the wafer W and realizing the transport of the wafer W.

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

[0042] In some embodiments of the present invention, such as Figure 3 As shown, at least one of the annular cavities 302 has multiple air holes 3021 on its surface facing the wafer W. When it is necessary to detach the wafer W, air can be blown through the air holes 3021 to detach the wafer W from the carrier head 100. This avoids the problem of difficulty in detaching the carrier head 100 from the wafer W due to prolonged polishing operations, and prevents the wafer W from being unable to be smoothly placed down. Furthermore, by providing multiple air holes 3021 on the annular cavity 3021 for simultaneous air blowing, the detachment of the wafer W is more stable, preventing damage to the wafer W due to uneven force.

[0043] like Figure 3 As shown, the bearing head 100 also has a second elastic membrane 40, which is located within an annular cavity 302 having multiple vents 3021. The second elastic membrane 40 can communicate with the second ventilation pipe, allowing it to expand and contract to block and open the vents 3021. That is, when gas is introduced into the second elastic membrane 40 to create positive pressure, the second elastic membrane 40 expands, and its bottom surface abuts against the bottom surface of the first elastic membrane 20, thereby enabling the second elastic membrane 40 to block the vents 3021.

[0044] Therefore, during the polishing of wafer W, both the first elastic film 20 and the second elastic film 40 expand. The expansion of the second elastic film 40 seals the pores, preventing the filling of the space inside the first elastic film 20 with gas and preventing gas leakage through the pores 3021, thus ensuring that the first elastic film 20 can stably press against wafer W. It also prevents liquids (such as water or polishing fluid) and debris or particles generated during the polishing process from entering the annular cavity 302 through the pores 3021, thereby preventing corrosion of the metal structure inside the support head 100.

[0045] When the second elastic membrane 40 expands, it does not contact the inner wall of the annular cavity 302, and as... Figure 3As shown, 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-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. This further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when it expands, thereby preventing the second elastic membrane 40 from applying pressure to the side wall of the first elastic membrane 20 after contact, which could cause the side wall of the first elastic membrane 20 to bend and thus affect the pressure control when adsorbing the wafer W.

[0046] Therefore, when the second elastic membrane 40 expands and seals the pores 3021, it avoids contact with the inner wall of the first elastic membrane 20. This prevents pressure from being transmitted to the first elastic membrane 40 due to contact between the second elastic membrane 20 and the first elastic membrane 40, thus avoiding uneven pressure transmission to the first elastic membrane 20. This, in turn, leads to unstable pressure transmitted from the first elastic membrane 20 to the wafer W, resulting in low efficiency during wafer W polishing or even damage to the wafer W. (See also...) Figure 2 The diagram illustrates a pressure transmission process where, when the second elastic membrane 40 expands and comes into contact with the sidewall of the first elastic membrane 20, the pressure transmitted from the sidewall of the first elastic membrane 20 to the wafer will fluctuate as shown in the diagram. Figure 2 The horizontal axis represents the radius, and the vertical axis represents the pressure.

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

[0048] In this embodiment of the invention, the bottom wall width of the cross-section of the first elastic membrane 20 is denoted by D3, the bottom wall width of the cross-section of the second elastic membrane 40 is denoted by D2, and the top wall width of the cross-section of the second elastic membrane 40 is denoted by D1. Furthermore, D1 < D2 < D3. D1, D2, and D3 are all within... Figure 4 The text is represented in Chinese and will not be labeled in other accompanying figures.

[0049] According to the carrier head 100 provided in the embodiments of this application, the first elastic bottom wall 202 of the annular cavity 302, which is provided with a second elastic membrane 40, has vent holes 3021. The vent holes 3021 can be sealed and opened by the expansion and contraction of the second elastic membrane 40, thereby enabling the wafer W to be pressed onto the polishing pad 200 or adsorbed. Gas can also be blown out through the vent holes 3021 to detach the wafer W from the carrier head 100. Furthermore, when the second elastic membrane 40 expands, the second elastic membrane 40 does not contact 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. This further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when it expands. It can also prevent the pressure from being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40. This would cause uneven pressure transmission to the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, which would lead to low efficiency or damage to the wafer W during polishing.

[0050] In some embodiments of the present invention, such as Figure 3 As shown, the first elastic membrane 20 includes an outer peripheral longitudinal wall 201, a first elastic bottom wall 202, multiple 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, forming an internal cavity 30. Multiple inner peripheral longitudinal walls 203 are concentrically arranged inside the outer peripheral longitudinal wall 201, and the diameters of the multiple inner peripheral longitudinal walls 203 are different, thus dividing the internal cavity 30 into a central cavity 301 and multiple annular cavities 302. The width between two adjacent inner peripheral longitudinal walls 203 is as follows: Figure 4 As shown in D3.

[0051] Specifically, an internal cavity 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 via a 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. The internal cavity 30 has multiple inner peripheral longitudinal walls 203, each with a different diameter. Therefore, the inner peripheral longitudinal walls 203 divide the internal cavity 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 pleated 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 by the pleated side wall 402 to form an inflation chamber 50. The inflation chamber 50 is connected to the second ventilation pipe.

[0053] like Figures 4-6 As shown, in some embodiments of the present invention, the second elastic membrane 40 includes a second elastic bottom wall 401, a pleated 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 by the pleated side wall 402 to form an inflation chamber 50. The inflation chamber 50 is connected to the second ventilation pipe.

[0054] Specifically, the pleated sidewall 402 of the second elastic membrane 40 can unfold during inflation, and the second elastic bottom wall 401 expands downward to block the vents 3021 on the first elastic bottom wall 202. This ensures that the first elastic bottom wall 202 can expand and press the wafer W onto the polishing pad 200 when positive pressure gas is input. Alternatively, after the wafer W is polished and needs to be removed from the first elastic membrane 20, the second elastic membrane 40 can contract through the pleated sidewall 402, opening the vents 3021 that were originally blocked, allowing gas to be blown out through the vents 3021, thus blowing the wafer W off the first elastic membrane 20 and achieving smooth separation of the wafer W from the carrier head 100.

[0055] Furthermore, the design of the pleated sidewall 402 of the second elastic film 40 prevents it from touching or abutting the inner circumferential longitudinal wall 203 or outer circumferential longitudinal wall 201 of the first elastic film 20 after inflation. This would prevent the inner circumferential longitudinal wall 203 and outer circumferential longitudinal wall 201 from bending, which would cause the first elastic bottom wall 202 of the first elastic film 20 to be unable to stably press the wafer W onto the polishing pad 200, resulting in uneven polishing of the wafer W.

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

[0057] Specifically, the cross-sectional structure of the second elastic membrane 40 is trapezoidal. This allows the second elastic membrane 40 to seal the pores 3021 when it is inflated, and also prevents the second elastic membrane 40 from contacting the inner wall of the first elastic membrane 20 after expansion. This would prevent the pressure on the outer peripheral longitudinal wall 201 and inner peripheral longitudinal wall 203 of the first elastic membrane 20 from becoming unstable, which would cause changes in the pressure transmission to the wafer W, resulting in a reduction in the polishing effect of the wafer W or damage to the wafer W.

[0058] Among them, such as Figures 3-6 As shown, the width of the second top wall 403 is half the width of the first top wall 204, and the width of the second elastic bottom wall 401 is two-thirds 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 both the first elastic bottom wall 202 and the first top wall 204.

[0059] In some embodiments of the present invention, such as Figure 5 and Figure 6 As shown, the sidewall of the second elastic membrane 40 is a pleated sidewall 402. By setting the sidewall of the second elastic membrane 40 to a pleated sidewall 402, it is possible to further prevent the second elastic membrane 40 from contacting the sidewall of the first elastic membrane 20 after it expands.

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

[0063] Specifically, such as Figure 4 As shown, the sidewall of the second elastic membrane 40, represented by the waist of the trapezoid in its cross-section, has a thickness of t1. The thickness of the inner longitudinal wall 203 is t2. Therefore, it can be seen that the sidewall thickness of the second elastic membrane 40 is thinner than the inner longitudinal wall 203 of the first elastic membrane 20. Consequently, its elasticity is higher than that of the inner longitudinal wall 203. This allows for better elastic deformation, effectively sealing the pores 3021 and preventing their expansion from putting pressure on the first elastic membrane 20.

[0064] In some embodiments of the present invention, such as 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] Where t1 is the thickness of the sidewall 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 fold in the folded sidewall 402.

[0069] Specifically, such as Figure 4 As shown, the sidewall of the second elastic membrane 40, represented by the waist of the trapezoid in its cross-section, has a thickness of t1. The thickness of the inner longitudinal wall 203 is t2. Therefore, it can be seen that the sidewall thickness of the second elastic membrane 40 is thinner than the inner longitudinal wall 203 of the first elastic membrane 20. Consequently, its elasticity is higher than that of the inner longitudinal wall 203. This allows for better elastic deformation, effectively sealing the pores 3021 and preventing their expansion from putting pressure on the first elastic membrane 20.

[0070] In addition, the sidewalls of the second elastic membrane 40 can also be like Figure 6 The diagram shows a pleated sidewall. The number and width of the pleats in the pleated sidewall 402 of the second elastic membrane 40 can be determined by satisfying the formula above. b>5t1, ensuring that the second elastic membrane 40 seals the pores 3021 when it expands, and also preventing the folded sidewall 402 from touching or abutting the inner circumferential longitudinal wall 203 after expansion. For example... Figure 6 As shown, the width of the folds in the folded sidewall 402 is as follows: Figure 6 As shown in H in the diagram. After the second elastic membrane 40 is pressurized and expanded, it can completely cover the chamber, and the pressure can be applied evenly to the air film base plate without affecting the sidewalls of the elastic membrane.

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

[0072] Specifically, the second elastic film 40 has a lower hardness than the first elastic film 20, meaning it possesses greater elasticity. The hardness of the second elastic film 40 ranges from 37HA to 42HA. Therefore, when gas is introduced, the second elastic film 40 can be more flexible and elastic, thus preventing it from pressing against the first elastic bottom wall 202 after inflation. This avoids excessive pressure on the second elastic bottom wall 202, which could lead to pressure changes and reduced polishing effect or fluctuations in the polishing rate of the wafer W. In other words, the better elasticity of the second elastic film 40 reduces the pressure impact on the first elastic film 20.

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

[0074] Specifically, the surface roughness of the anti-adhesive layer 404 is 1.0, which is a relatively small value, making it smoother. Therefore, even if the second elastic membrane 40 expands and comes into contact with the inner wall of the first elastic membrane 20, the high smoothness will prevent pressure from affecting the first elastic membrane 20.

[0075] In some embodiments of the present invention, such as Figures 3-6 As shown, the anti-adhesion layer 404 covers the sidewall of the second elastic membrane 40 and the outer surface of the pleated sidewall 402, thereby preventing the sidewall of the second elastic membrane 40 or the pleated sidewall 402 from adhering to the inner wall of the sidewall of the first elastic membrane 20.

[0076] In some embodiments of the present invention, such as Figures 3-6 As shown, the anti-adhesion layer 404 can cover the outer surface of the sidewalls of the second elastic film 40 and the outer surface of the pleated sidewalls 402. Simultaneously, the anti-adhesion layer 404 can also cover the outer surface of the second elastic bottom wall 401. Because the carrier head 100 applies significant pressure during the prolonged adsorption of the wafer W for polishing, the second elastic bottom wall 401 and the first elastic bottom wall 202 may adhere together due to prolonged close contact when separation is required. Therefore, covering the outer surface of the second elastic bottom wall 401 with the anti-adhesion layer 404 is equivalent to adding an anti-adhesion structure between the second elastic bottom wall 401 and the first elastic bottom wall 202, thus preventing adhesion between them due to prolonged close contact and ensuring stable separation between the second elastic film 40 and the first elastic film 20.

[0077] Among them, such as Figures 3-6 The thickness of the anti-stick layer 404 shown is for illustrative purposes only and does not represent its actual size.

[0078] In some embodiments of the present invention, the anti-adhesion layer 404 may be a thin film with a shallow texture, thereby further preventing adhesion between the first elastic film 40 and the first elastic film 20.

[0079] The following will first introduce how... Figure 7 As shown, the chemical mechanical polishing apparatus 1000 according to the second aspect of this application.

[0080] In some embodiments of the present invention, the chemical mechanical polishing apparatus 1000 may include a support head 100. The support head 100 may be the support head 100 of the first aspect embodiment described above. Furthermore, the chemical mechanical polishing apparatus 1000 may also include a polishing pad 200, a polishing disc 300, a dresser 400, and a liquid supply unit 500. The polishing pad 200 is disposed on the upper surface of the polishing disc 300 and rotates together with it along an axis Ax. The axis Ax is as follows... Figure 7 As shown in the diagram. The carrier head 100 is horizontally movable and positioned above the polishing pad 200. The lower surface of the carrier head 100 can hold the wafer W to be polished. The dresser 400 includes a dresser arm and a dresser head, which are disposed on one side of the polishing disk 300. The dresser arm drives the rotating dresser head to swing and dress the surface of the polishing pad 200. The liquid supply unit 500 is disposed above the polishing pad 200 to distribute the polishing liquid onto the surface of the polishing pad 200.

[0081] The chemical mechanical polishing apparatus 1000 according to the second aspect of this application, having the support head 100 described in the first aspect, has the same beneficial effects as the support head 100 described in the first aspect. The first elastic bottom wall 202 of the annular cavity 302, which has a second elastic membrane 40, has vent holes 3021. These vent holes 3021 can be sealed and opened by the expansion and contraction of the second elastic membrane 40, thereby enabling the wafer W to be pressed onto the polishing pad 200 or adsorbed. Gas can also be blown out through the vent holes 3021 to detach the wafer W from the support head 100. Furthermore, when the second elastic membrane 40 expands, it does not contact 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. This further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when it expands. It can also prevent the pressure from being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40. This would cause uneven pressure transmission to the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, which would lead to low efficiency or damage to the wafer W during polishing.

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

[0083] Step S1: The second vent pipe of the bearing head 100 inflates the second elastic membrane 40 so that the second elastic membrane 40 expands and seals the air hole 3021, and the second elastic membrane 40 does not contact the inner circumferential longitudinal wall 203 when it expands.

[0084] Specifically, in this step, the second elastic membrane 40 is inflated through the second vent pipe, causing it to expand and seal the vent 3021, thereby forming a sealed cavity in the annular cavity 302. Furthermore, when the second elastic membrane 40 expands, it does not come into contact with the inner circumferential longitudinal wall 203, thus preventing the second elastic membrane 40 from exerting pressure on the first elastic membrane 20 and causing pressure changes on the inner circumferential longitudinal wall 203 of the first elastic membrane 20.

[0085] Step S2: The carrier head 100 moves to the wafer W pick-up position, and the first elastic bottom wall 202 of the first elastic film 20 adheres to the wafer W;

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

[0087] Step S3: The first ventilation pipe creates 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.

[0088] Specifically, in this step, the first ventilation pipe creates a negative pressure in the internal chamber 30 of the first elastic membrane 20, and the middle part of the first elastic bottom wall 202 of the first elastic membrane 20 separates from the wafer, thereby adsorbing the wafer W.

[0089] Step S4: The carrier head 100 moves the wafer W to the polishing pad 300 and lowers the height of the carrier head 100 so that the wafer W fits against the polishing pad 200;

[0090] Specifically, the carrier head 100 drives the wafer W to move synchronously to the polishing pad 300. The carrier head 100 lowers its height so that the wafer W fits against the polishing pad 200, which facilitates the subsequent polishing operation of the wafer W.

[0091] Step S5: The first venting pipe creates positive pressure on the internal chamber 30, causing the first elastic bottom wall 202 to contact the surface of the wafer W and press the wafer W onto the polishing pad 200. At the same time, the second venting pipe inflates the second elastic membrane 40 to seal the vent 3021. The polishing pad 200 polishes the surface of the wafer W.

[0092] Specifically, in this step, positive pressure gas is injected 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, pressing the wafer W onto the polishing pad 200. The second elastic membrane 40 inflates and seals the vent 3021, thereby enabling the wafer W to be stably pressed onto the polishing pad 200, thus stabilizing the position of the wafer W and ensuring uniform surface polishing.

[0093] Step S6: After polishing, the first ventilation pipe creates 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, adsorbs the wafer W and moves it to the wafer W placement location.

[0094] Specifically, in this step, after polishing is completed, the internal chamber 30 forms a negative pressure, causing the middle part of the first elastic bottom wall 202 to detach from the wafer W and re-adsorb the wafer W. The wafer W is then moved to the wafer placement location by the movement of the polishing head.

[0095] Step S7: The second ventilation line stops filling with gas, so that the second elastic membrane 40 contracts and opens the vent 3021. The first ventilation line blows out gas through the vent 3021, so that the wafer W is separated from the first elastic bottom wall 202 of the first elastic membrane 20.

[0096] Specifically, in this step, the second elastic membrane 40 contracts and opens the vent 3021, allowing gas to be blown out through the vent 3021. Therefore, the wafer W can be smoothly detached from the carrier head 100 by the gas being blown out through the vent 3021. This enables rapid gripping and placement of the wafer W and also prevents damage to the wafer W during removal.

[0097] According to the wafer polishing method of the third aspect of this application, the wafer polishing method is applicable to controlling the carrier head 100 of the first aspect embodiment, and therefore 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, which is provided with a second elastic membrane 40, has vent holes 3021. The vent holes 3021 can be sealed and opened by the expansion and contraction of the second elastic membrane 40, thereby enabling the wafer W to be pressed onto the polishing pad 200 or adsorbed. Gas can also be blown out through the vent holes 3021 to detach the wafer W from the carrier head 100. Furthermore, when the second elastic membrane 40 expands, the second elastic membrane 40 does not contact 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. This further avoids the second elastic membrane 40 from contacting the side wall of the first elastic membrane 20 when it expands. It can also prevent the pressure from being transmitted to the first elastic membrane 40 due to the contact between the second elastic membrane 20 and the first elastic membrane 40. This would cause uneven pressure transmission to the first elastic membrane 20, resulting in unstable pressure transmitted from the first elastic membrane 20 to the wafer W, which would lead to low efficiency or damage to the wafer W during polishing.

[0098] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A carrier head for wafer processing, characterized in that, include: The main body has a first vent pipe and a second vent pipe inside; A first elastic membrane is connected to the wafer-facing surface of the main body and defines a central cavity and a plurality of annular cavities between the membrane and the main body. The central cavity and the plurality of annular cavities are all connected to a first ventilation pipe so that the first elastic membrane can adsorb and detach the wafer. At least one of the plurality of annular cavities has a plurality of pores on its wafer-facing surface. 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 cavity. Multiple inner peripheral longitudinal walls are concentrically arranged to the inside of the outer peripheral longitudinal wall, and the diameters of the multiple inner peripheral longitudinal walls are different, so as to divide the internal cavity into a circular central cavity located in the middle and multiple annular cavities concentric with the central cavity. The second elastic membrane is located in an annular cavity with multiple pores. The second elastic membrane can be connected to the second ventilation tube, 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 does not contact 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. The second elastic membrane has a pleated sidewall with a thinner inner longitudinal wall than the first elastic membrane, and its elasticity is higher than that of the inner longitudinal wall, and it satisfies the following conditions: ,in, t 1 represents the thickness of the sidewall of the second elastic membrane. ，b The width of a single fold in the folded sidewall.

2. The bearing head according to claim 1, characterized in that, The second elastic membrane includes a second elastic bottom wall, a pleated 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 by the pleated side wall to form an inflation chamber. The inflation chamber is connected to the second ventilation pipe.

3. The bearing head according to claim 2, characterized in that, The second elastic membrane has a trapezoidal cross-section. When the second elastic membrane expands, the width of the second top wall is half the width of the first top wall, and the width of the second elastic bottom wall is two-thirds the width of the first elastic bottom wall.

4. The bearing head according to any one of claims 1-3, characterized in that, The hardness of the second elastic membrane is less than that of the first elastic membrane, and the hardness of the second elastic membrane ranges from 37HA to 42HA.

5. The bearing head according to any one of claims 1-3, characterized in that, The outer surface of the second elastic membrane is covered with an anti-adhesive layer, which is a silicone rubber layer. The thickness of the anti-adhesive layer is between 0.3 mm and 0.5 mm. The anti-adhesive layer has a texture and a surface roughness of 1.

0.

6. A chemical mechanical polishing apparatus, characterized in that, Includes a bearing head, wherein the bearing head is the bearing head according to any one of claims 1-5.

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