Bearing head for wafer processing, chemical mechanical polishing equipment and method

Abstract

The embodiment of the invention provides a bearing head for wafer processing and chemical mechanical polishing equipment and method.The bearing head comprises a circular main body part, and a first ventilation pipeline and a second ventilation pipeline are arranged in the circular main body part; a central cavity and a plurality of annular cavities are defined between the first elastic film and the surface of the main body part, the annular cavities are concentric with the central cavity, and the central cavity and the annular cavities are communicated with the first ventilation pipeline, so that the lower surface of the first elastic film adsorbs or loosens 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 communicates with the second ventilation pipeline so as to block and open the air holes. According to the bearing head, the device and the wafer polishing method provided by the embodiment of the invention, the wafer can be stably adsorbed, and the wafer is separated from the bearing head after the wafer polishing operation is completed.

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, chemical mechanical polishing equipment and method 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, chemical mechanical polishing equipment and method for wafer processing, which can stably adsorb the wafer and separate the wafer from the carrier head after the wafer polishing operation is completed.

[0004] According to the first aspect of the present application, an embodiment provides a carrier head for wafer processing, comprising a circular main body with a first ventilation duct and a second ventilation duct inside; a first elastic membrane, which defines a central cavity and a plurality of annular cavities between the first elastic membrane and the surface of the main body, the plurality of annular cavities are all concentric with the central cavity, the central cavity and the plurality of annular cavities are all connected to the first ventilation duct, so that the lower surface of the first elastic membrane can adsorb or release the wafer, and at least one of the plurality of annular cavities is provided with a plurality of air holes facing the surface of the wafer; a second elastic membrane, which is located in the annular cavity having the plurality of air holes, and the second elastic membrane is connected to the second ventilation duct to block and open the air holes.

[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 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 a central cavity and multiple annular cavities.

[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, when the inflation chamber is inflated, the second elastic membrane expands, and the width of the second elastic bottom wall is the same as the width of the first elastic bottom wall.

[0008] Optionally, the second top wall and the second elastic bottom wall of the second elastic membrane have the same width.

[0009] Optionally, the width of the second top wall of the second elastic membrane 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.

[0010] Optionally, the second elastic membrane and the first elastic membrane satisfy the following relationship: b>5t1;

[0011] Wherein, t1 is the thickness of the side wall of the second elastic membrane; t2 is the thickness of the inner peripheral longitudinal wall; and b is the width of a single fold of the fold side wall.

[0012] 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.

[0013] According to a second aspect of the present application, a wafer polishing method is provided, and the wafer polishing method is suitable for controlling the carrier head described in the first aspect of the present application, including: the second ventilation pipeline of the carrier head inflates the second elastic membrane to expand and block the air hole; the carrier head moves to a wafer picking position, and the first elastic bottom wall of the first elastic membrane fits with the wafer; the first ventilation pipeline forms a negative pressure in the internal chamber to separate the middle part of the first elastic bottom wall from the wafer and adsorb the wafer; the carrier head drives the wafer to move to the polishing disk, and lowers the height of the carrier head to fit the wafer with the polishing pad; A ventilation pipe forms a positive pressure on the internal chamber, so that the first elastic bottom wall contacts the surface of the wafer and presses the wafer to the polishing pad, and at the same time the second ventilation pipe inflates the second elastic membrane to seal the air hole, and the polishing pad polishes the surface of the wafer; after polishing, the first ventilation pipe forms a negative pressure in the internal chamber to separate the middle part of the first elastic bottom wall from the wafer, adsorbs the wafer and moves it to the wafer placement location; the second ventilation pipe stops inflating to shrink the second elastic membrane and open the air hole, and the first ventilation pipe blows out the gas through the air hole to separate the wafer from the first elastic bottom wall of the first elastic membrane.

[0014] According to a third 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 of the present application.

[0015] Optionally, the chemical mechanical polishing equipment is characterized in that it also includes: a controller for performing the following steps: inflating the second elastic membrane through the second ventilation pipeline of the carrier head so that the second elastic membrane expands and blocks the air hole; controlling the carrier head to move to the wafer picking position, and the first elastic bottom wall of the first elastic membrane fits with the wafer; controlling the first ventilation pipeline to form a negative pressure in the internal chamber, so that the middle part of the first elastic bottom wall is separated from the wafer and adsorbs the wafer; controlling the carrier head to drive the wafer to move to the polishing disk, and lowering the height of the carrier head so that the wafer fits with the polishing pad; controlling the first ventilation pipeline to The internal chamber forms a positive pressure, so that the first elastic bottom wall contacts the surface of the wafer and presses the wafer to the polishing pad, and at the same time the second ventilation pipe inflates the second elastic membrane to seal the air hole, and the polishing pad polishes the surface of the wafer; after polishing, the first ventilation pipe is controlled to form a negative pressure in the internal chamber, so that the middle part of the first elastic bottom wall is separated from the wafer, the wafer is adsorbed and moved to the wafer placement position; the second ventilation pipe is stopped from inflating, so that the second elastic membrane contracts and the air hole is opened, and the first ventilation pipe blows out the gas through the air hole to separate the wafer from the first elastic bottom wall of the first elastic membrane.

[0016] According to a fourth aspect of the present application, a computer storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the method for determining the wafer grinding time as described above is implemented.

[0017] According to a fifth aspect of the present application, a computer program product is provided, including computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the wafer grinding time determination method as described above.

[0018] According to the carrier head provided in the first aspect of the present application, the first ventilation pipeline can provide positive pressure and negative pressure gas for the central cavity and multiple annular cavities between the first elastic membranes, and the second ventilation pipeline can provide positive pressure and negative pressure gas for the interior of the second elastic membrane. The first elastic bottom wall of the annular cavity provided with the second elastic membrane is provided with air holes, so that when the wafer is adsorbed, the air holes can be blocked by the expansion of the second elastic membrane, thereby ensuring stable adsorption of the wafer, and preventing liquid (such as water or polishing liquid) during wafer polishing and debris or particles generated during the polishing process from entering the annular cavity through the air holes, thereby corroding the metal structure inside the carrier head. After the polishing operation is completed, gas can be blown out through the air holes to make the wafer detach from the first elastic bottom wall of the first elastic membrane. In addition, the overall structure is simple, and there is no need to add too much equipment and structure, which is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 A structural side view of a carrier head according to the first aspect of the present application;

[0021] Figure 2 is a cross-sectional view of an embodiment of the carrier head along line AA according to the first aspect of the present application;

[0022] Figure 3 for Figure 2 A partial enlarged view of point B in the middle;

[0023] Figure 4 is a cross-sectional view of another embodiment of the carrier head along line AA according to the first aspect of the present application;

[0024] Figure 5 for Figure 4 A partial enlarged view of point C in the middle;

[0025] Figure 6 is a cross-sectional view of another embodiment of the carrier head along line AA according to the first aspect of the present application;

[0026] Figure 7 for Figure 6 A partial enlarged view of point E in the middle;

[0027] Figure 8 is a schematic diagram of a chemical mechanical polishing device according to the second aspect of the present application;

[0028] Fig. 9 The present invention is a flowchart of a wafer polishing method according to the third aspect of the present invention.

[0029] Description of reference numerals:

[0030] Chemical mechanical polishing equipment 1000;

[0031] Carrier Head 100:

[0032] Main body 10;

[0033] first elastic membrane 20; outer peripheral longitudinal wall 201; first elastic bottom wall 202; inner peripheral longitudinal wall 203; first top wall 204;

[0034] Internal chamber 30; central cavity 301; annular cavity 302; air hole 3021;

[0035] Second elastic membrane 40; second elastic bottom wall 401; pleated side wall 402; second top wall 403;

[0036] A gas-filled chamber 50;

[0037] Polishing pad 200; polishing plate 300; dresser 400; liquid supply unit 500;

[0038] Wafer W; axis Ax. DETAILED DESCRIPTION

[0039] 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.

[0040] 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 W, 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, and the conventional pick-and-place setting cannot smoothly put down the wafer W.

[0041] 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.

[0042] Therefore, the first aspect of the present application provides a carrier head 100, a chemical mechanical polishing device 1000 and a method for wafer processing. Figure 1-Figure 7 The carrier head 100 for wafer processing according to the first aspect of the present application is described in detail.

[0043] like Figure 1 FIG. 1 is a schematic diagram of the overall structure of a carrier head 100 for wafer processing according to the first aspect of the present application. Figure 2As shown, the carrier head 100 for wafer processing according to the first aspect of the present application includes a circular main body 10, a first elastic membrane 20 and a second elastic membrane 40. The main body 10 has a first ventilation pipeline and a second ventilation pipeline inside, and the first ventilation pipeline can provide positive pressure or negative pressure gas for the cavity formed between the first elastic membrane 20 and the main body 10.

[0044] The second ventilation line can provide positive pressure or negative pressure gas in the cavity formed between the second elastic membrane 40 and the main body 10. The main body 10 is a disc-shaped structure in a top view, which is convenient for its rotation.

[0045] like Figure 2 As shown, a central cavity 301 and a plurality of annular cavities 302 are defined between the first elastic membrane 20 and the surface of the main body 10. The central cavity 301 is a cavity corresponding to the middle area of ​​the main body 10 among the plurality of 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. The central cavity 301 and the plurality of annular cavities 302 are all connected to the first ventilation pipeline, so that positive pressure gas or negative pressure gas can be transported through the first ventilation pipeline, so that the lower surface of the first elastic membrane 20 can absorb or release 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 the negative pressure gas is connected, the middle portion of the first elastic membrane 20 is sunken, so that the wafer W can be adsorbed, making it easier to transport the wafer W.

[0046] like Figure 3 , Figure 5 and Figure 7 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, and when the wafer W needs to be loosened from the lower surface of the first elastic membrane 20, air can be blown toward the wafer W through the air holes 3021, thereby ensuring that the wafer W is stably separated from the first elastic membrane 20. This prevents the wafer W from being unable to be smoothly separated from the first elastic membrane 20 due to long pressing time and high pressure when grinding the wafer W, or prevents the wafer W from being broken due to uneven force when the wafer W is separated.

[0047] like Figure 2-Figure 7As shown, the carrier head 100 also has a second elastic membrane 40, which is located in the annular cavity 302 having a plurality of air holes 3021, and the second elastic membrane 40 is connected to the second ventilation pipeline to block and open the air holes 3021. Specifically, when the wafer W is polished, positive pressure gas is filled into the first elastic membrane 20, and the first elastic membrane 20 expands. The second elastic membrane 40 also passes positive pressure gas through the second ventilation pipeline, so that it can expand and block the air holes 3021, thereby preventing the gas filled in the first elastic membrane 20 from leaking out, and ensuring that the first elastic membrane 20 can stably press the wafer W. In addition, the second elastic membrane 40 blocks the air holes 3021, and 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 air holes 3021, thereby corroding the metal structure inside the carrier head 100.

[0048] Furthermore, the structure of the first elastic membrane 20 and the second elastic membrane 40 is adopted, and the elastic membrane and the wafer W are loosened by the expansion and contraction of multiple sets of elastic membranes, rather than the need to adjust the pressure of the elastic membranes multiple times. This avoids the problem that the elasticity of the elastic membrane deteriorates rapidly with the increase of the number of polishing times, and the prolongation of the wafer placement time affects the polishing efficiency and the poor effect.

[0049] 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 3 It is indicated in the figure and is not marked in other figures.

[0050] According to the carrier head 100 provided in the embodiment of the present application, the first ventilation pipeline can provide positive pressure and negative pressure gas for the central cavity 301 and the plurality of annular cavities 302 between the first elastic membrane 20, and the second ventilation pipeline can provide positive pressure and negative pressure gas for the interior of the second elastic membrane 40. The first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with air holes 3021, so that when the wafer W is adsorbed, the air holes 3021 can be blocked by the expansion of the second elastic membrane 40, thereby ensuring stable adsorption of the wafer W, and preventing the liquid (such as water or polishing liquid) 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 air holes 3021, thereby corroding the metal structure inside the carrier head 100. After the polishing operation is completed, the gas can be blown out through the air holes 3021 to make the wafer W detach from the first elastic bottom wall 202 of the first elastic membrane 20. In addition, the overall structure is simple, and there is no need to add too many equipment and structures, which is convenient and fast.

[0051] like Figure 2As 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 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 to divide the internal chamber 30 into a central cavity 301 and a plurality of annular cavities 302.

[0052] 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.

[0053] like Figure 3 , Figure 5 and Figure 7 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] Furthermore, if Figure 2 As shown, when the inflation chamber 50 is inflated, the second elastic membrane 40 expands, the width of the second elastic bottom wall 401 is the same as the width of the first elastic bottom wall 202, and the second elastic bottom wall 401 blocks the air hole 3021. The fold side wall 402 is non-contact with the inner peripheral longitudinal wall 203.

[0057] Specifically, when the second elastic membrane 40 expands, its second elastic bottom wall 401 stretches to a structure with the same width as the first elastic bottom wall 202, which can not only make the pressure evenly distributed on the first elastic bottom wall 202 corresponding to the annular cavity 302, but also ensure that the pores 3021 on the first elastic bottom wall 202 are completely blocked, so as to avoid incomplete blocking of the pores 3021, which causes liquid (such as water or polishing liquid) and debris or particles generated during the polishing process of the wafer W to enter the annular cavity 302 through the pores 3021, thereby corroding the metal structure inside the carrier head 100. After the second elastic membrane 40 expands, the folded side wall 402 of the second elastic membrane 40 does not contact the inner circumferential longitudinal wall 203, so as to avoid the inner circumferential longitudinal wall 203 from bending, thereby causing the first elastic bottom wall 202 of the first elastic membrane 20 to bend due to the bending of the inner circumferential longitudinal wall 203. Therefore, the wafer W cannot be stably pressed onto the polishing pad 200 , resulting in uneven polishing of the wafer W and difficulty in controlling the adsorption pressure of the first elastic bottom wall 202 on the wafer W.

[0058] In some embodiments of the present invention, Figure 7 As shown, the second top wall 403 of the second elastic membrane 40 has the same width as the second elastic bottom wall 401 .

[0059] Specifically, at this time, the width of the second top wall 403 of the second elastic membrane 40 is the same as the width of the second elastic bottom wall 401, thereby forming Figure 7The cross section shown is a rectangular structure with certain wrinkles on the long side. The second top wall 403 and the second elastic bottom wall 401 are connected by the wrinkled side wall 402. This structural form can ensure that the second elastic membrane 40 can block the air hole 3021 when it expands, and can also prevent the wrinkled side wall 402 from touching or abutting against the inner peripheral longitudinal wall 203. At the same time, due to the effect of the wrinkled side wall 402, when the second elastic membrane 40 contracts, the second elastic bottom wall 401 can open the air hole 3021.

[0060] In some embodiments of the present invention, Figure 3 and Figure 5 As shown, the width of the second top wall 403 of the second elastic membrane 40 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 .

[0061] Specifically, the cross-sectional structure of the second elastic membrane 40 is a trapezoidal structure with folds on both sides. This can ensure that the second elastic membrane 40 can block the air hole 3021 when it expands, and can also prevent the folded side wall 402 from touching or abutting against the inner circumferential longitudinal wall 203. At the same time, due to the effect of the folded side wall 402, when the second elastic membrane 40 contracts, the second elastic bottom wall 401 can open the air hole 3021. At the same time, the overall structure saves more raw materials.

[0062] Among them, Figure 3 and Figure 5 As shown, the width of the second top wall 403 is half of the width of the first top wall 204 , the width of the second elastic bottom wall 401 is two-thirds of the width of the first elastic bottom wall 202 , and the second elastic bottom wall 401 has an open air hole 3021 .

[0063] Specifically, when the second elastic film 40 is in the contracted state, the second elastic bottom wall 401 is also contracted to a structure with a width of two-thirds of the width of the first elastic bottom wall 202, so that the air hole 3021 can be opened. At this time, gas is allowed to pass through the air hole 3021. When the polishing operation of the wafer W is completed, when the wafer W needs to be placed at a predetermined position, the second elastic film 40 can be contracted, the air hole 3021 is opened, and the gas is blown onto the wafer W through the air hole 3021, so that the wafer W can be smoothly separated from the carrier head 100. It is prevented that the wafer W is pressed by the carrier head 100 for a long time and with a large pressure, so that it cannot be smoothly separated.

[0064] Further, in this embodiment, 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;

[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 3 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 5 and Figure 7 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.

[0071] like Figure 5 and Figure 7 As shown, the width of the folds of the fold side wall 402 is as shown in FIG. Figure 5 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.

[0072] 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.

[0073] Specifically, the elasticity of the second elastic film 40 is smaller than the hardness of the first elastic film 20, that is, the second elastic film 40 has greater elasticity. The hardness of the second elastic film 40 ranges from 37HA to 42HA. Therefore, when the gas is filled, the second elastic film 40 can undergo greater elastic deformation. As a result, when the first elastic film 20 and the second elastic film 40 are deformed due to the pressure change of the gas, the deformation degree of the first elastic film 20 and the second elastic film 40 can be more consistent, thereby avoiding the pressure difference between the internal chamber 30 of the first elastic film 20 and the gas-filled chamber 50 of the second elastic film 40, which causes the wafer W to be damaged.

[0074] The present invention is not limited thereto, and in some embodiments of the present invention, a plurality of concentric annular cavities 302 are provided, and the second elastic membrane 40 can be disposed in the annular cavity 302 of the second outer layer, thereby a plurality of air holes 3021 can be opened on the first elastic bottom wall 202 corresponding to the annular cavity 302, so that when the wafer W is separated from the carrier head 100, the blown gas can make it easier for the wafer W to be separated from the carrier head 100, and the force applied to the wafer W is more uniform.

[0075] A chemical mechanical polishing device 1000 according to an embodiment of the second aspect of the present invention includes a carrier head 100 , and the carrier head 100 is the carrier head 100 of the embodiment of the first aspect.

[0076] In some embodiments of the present invention, Figure 8 As shown, 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 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 along the axis Ax together with the polishing disc 300. The axis Ax is as shown in FIG. Figure 8 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.

[0077] According to the chemical mechanical polishing device 1000 provided in the embodiment of the present application, since it has the carrier head 100 of the embodiment of the first aspect, it has the same beneficial effects as the carrier head 100 of the embodiment of the first aspect. The first ventilation pipeline can provide positive pressure and negative pressure gas for the central cavity 301 and the plurality of annular cavities 302 between the first elastic membrane 20, and the second ventilation pipeline can provide positive pressure and negative pressure gas for the inside of the second elastic membrane 40. The first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with air holes 3021, so that when the wafer W is adsorbed, the air holes 3021 can be blocked by the expansion of the second elastic membrane 40, thereby ensuring stable adsorption of the wafer W, and preventing liquid (such as water or polishing liquid) during the polishing process of the wafer W and debris or particles generated during the polishing process from entering the inside of the annular cavity 302 through the air holes 3021, thereby corroding the metal structure inside the carrier head 100. After the polishing operation is completed, gas can be blown out through the air holes 3021 to separate the wafer W from the first elastic bottom wall 202 of the first elastic membrane 20. In addition, the overall structure is simple, and there is no need to add too much equipment and structure, which is convenient and fast.

[0078] According to a third aspect of the present invention, a wafer polishing method is Fig. 9 As shown, the wafer polishing method is suitable for controlling the carrier head 100 of the first aspect embodiment, and its process is as follows Fig. 9 As shown, including:

[0079] Step S1: inflating the second elastic membrane through the second ventilation pipeline of the carrier head so that the second elastic membrane expands and blocks the air hole;

[0080] 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.

[0081] Step S2: Control the carrier head to move to the wafer W picking position, and the first elastic bottom wall of the first elastic film is attached to the wafer W;

[0082] Specifically, in this step, the carrier head 100 moves to the wafer W grabbing position, and the first elastic film 20 contacts the wafer W. 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 W.

[0083] Step S3: controlling the first ventilation pipeline to form a negative pressure in the internal chamber, so that the middle portion of the first elastic bottom wall is separated from the wafer W and the wafer W is adsorbed;

[0084] Specifically, in this step, the first ventilation line forms a negative pressure in the internal chamber 30 in 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 W, thereby adsorbing the wafer W.

[0085] Step S4: Control the carrier head to drive the wafer W to move to the polishing plate, and lower the height of the carrier head to make the wafer W fit the polishing pad;

[0086] Specifically, the carrier head 100 is controlled to drive the wafer W to move synchronously to the polishing plate 300 , and the carrier head 100 is lowered to make the wafer W fit with the polishing pad 200 , so as to facilitate the subsequent wafer W polishing operation.

[0087] Step S5: controlling the first ventilation pipeline to form a positive pressure on the internal chamber, so that the first elastic bottom wall contacts the surface of the wafer W and presses the wafer W onto the polishing pad, while the second ventilation pipeline inflates the second elastic membrane to block the pores, and the polishing pad performs a polishing operation on the surface of the wafer W;

[0088] 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 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.

[0089] Step S6: After polishing is completed, the first ventilation pipeline is controlled to form a negative pressure in the internal chamber, so that the middle part of the first elastic bottom wall is separated from the wafer W, the wafer W is adsorbed and moved to the wafer W placement position;

[0090] 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 W placement position.

[0091] Step S7: Stop inflating the second ventilation pipeline to shrink the second elastic membrane and open the air holes. The first ventilation pipeline blows out the gas through the air holes to separate the wafer W from the first elastic bottom wall of the first elastic membrane.

[0092] 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.

[0093] According to the wafer polishing method of the third embodiment of the present application, the wafer polishing method is suitable for controlling the carrier head 100 of the first embodiment, and thus has the same beneficial effects as the carrier head 100 of the first embodiment. The first ventilation pipeline can provide positive pressure and negative pressure gas for the central cavity 301 and the plurality of annular cavities 302 between the first elastic membrane 20, and the second ventilation pipeline can provide positive pressure and negative pressure gas for the interior of the second elastic membrane 40. The first elastic bottom wall 202 of the annular cavity 302 provided with the second elastic membrane 40 is provided with air holes 3021, so that when the wafer W is adsorbed, the air holes 3021 can be blocked by the expansion of the second elastic membrane 40, thereby ensuring stable adsorption of the wafer W, and preventing liquid (such as water or polishing liquid) during the polishing process of the wafer W and debris or particles generated during the polishing process from entering the interior of the annular cavity 302 through the air holes 3021, thereby corroding the metal structure inside the carrier head 100. After the polishing operation is completed, gas can be blown out through the air holes 3021 to separate the wafer W from the first elastic bottom wall 202 of the first elastic membrane 20. In addition, the overall structure is simple, and there is no need to add too much equipment and structure, which is convenient and fast.

[0094] In another embodiment of the present application, the chemical mechanical polishing device may further include a controller, the controller being used to execute the following steps: Fig. 9 The method shown.

[0095] Another embodiment of the present application provides a computer storage medium having a computer program stored thereon, which, when executed by a processor, implements the wafer grinding time determination method as described above.

[0096] Another embodiment of the present application provides a computer program product, including computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the wafer grinding time determination method as described above.

[0097] 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 circular main body having a first ventilation pipeline and a second ventilation pipeline inside thereof; A first elastic membrane, wherein a central cavity and a plurality of annular cavities are defined between the first elastic membrane and the surface of the main body, wherein the plurality of annular cavities are all concentric with the central cavity, and the central cavity and the plurality of annular cavities are all connected to the first ventilation pipeline, so that the lower surface of the first elastic membrane can absorb or release the wafer, and at least one of the plurality of annular cavities is provided with a plurality of air holes on a surface facing the wafer; The second elastic membrane is located in the annular cavity having the plurality of air holes, and the second elastic membrane is communicated with the second ventilation pipeline to block and open the air holes.

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 a central cavity and multiple annular cavities.

3. The carrier head according to claim 2, 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: When the inflation chamber is inflated, the second elastic membrane expands, the width of the second elastic bottom wall is the same as that of the first elastic bottom wall, and the second elastic bottom wall blocks the air hole.

5. The carrier head according to claim 4, characterized in that: The second top wall and the second elastic bottom wall of the second elastic film have the same width.

6. The carrier head according to claim 4, characterized in that: The width of the second top wall of the second elastic film 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.

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. A wafer polishing method, characterized in that: The wafer polishing method is applicable to controlling the carrier head according to any one of claims 1 to 8, comprising: Inflate the second elastic membrane through the second ventilation pipeline of the carrier head so that the second elastic membrane expands and blocks the air hole; Controlling the carrier head to move to a wafer picking position, so that the first elastic bottom wall of the first elastic film is in contact with the wafer; Controlling the first ventilation pipeline to form a negative pressure in the internal chamber, so that the middle portion of the first elastic bottom wall is separated from the wafer and the wafer is adsorbed; Controlling the carrier head to drive the wafer to move to the polishing plate, and lowering the height of the carrier head to make the wafer fit with the polishing pad; Controlling the first ventilation pipeline to form a positive pressure on the internal chamber, so that the first elastic bottom wall contacts the surface of the wafer and presses the wafer onto the polishing pad, while the second ventilation pipeline inflates the second elastic membrane to block the pores, and the polishing pad performs a polishing operation on the wafer surface; After polishing is completed, the first ventilation pipeline is controlled to form a negative pressure in the internal chamber, so that the middle part of the first elastic bottom wall is separated from the wafer, the wafer is adsorbed and moved to the wafer placement position; The second ventilation pipeline stops inflating to make the second elastic membrane contract and open the air hole, and the first ventilation pipeline blows out the gas through the air hole to separate the wafer from the first elastic bottom wall of the first elastic membrane.

10. A chemical mechanical polishing device, characterized in that: include: A carrier head, wherein the carrier head is the carrier head according to any one of claims 1 to 8.

11. The chemical mechanical polishing equipment according to claim 10, characterized in that: Also includes: A controller that performs the following steps: Inflate the second elastic membrane through the second ventilation pipeline of the carrier head so that the second elastic membrane expands and blocks the air hole; Controlling the carrier head to move to a wafer picking position, so that the first elastic bottom wall of the first elastic film is in contact with the wafer; Controlling the first ventilation pipeline to form a negative pressure in the internal chamber, so that the middle portion of the first elastic bottom wall is separated from the wafer and the wafer is adsorbed; Controlling the carrier head to drive the wafer to move to the polishing plate, and lowering the height of the carrier head to make the wafer fit with the polishing pad; Controlling the first ventilation pipeline to form a positive pressure on the internal chamber, so that the first elastic bottom wall contacts the surface of the wafer and presses the wafer onto the polishing pad, while the second ventilation pipeline inflates the second elastic membrane to block the pores, and the polishing pad performs a polishing operation on the wafer surface; After polishing is completed, the first ventilation pipeline is controlled to form a negative pressure in the internal chamber, so that the middle part of the first elastic bottom wall is separated from the wafer, the wafer is adsorbed and moved to the wafer placement position; The second ventilation pipeline stops inflating to make the second elastic membrane contract and open the air hole, and the first ventilation pipeline blows out the gas through the air hole to separate the wafer from the first elastic bottom wall of the first elastic membrane.

12. A computer storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method for determining the wafer grinding time according to claim 9 is implemented.

13. A computer program product, comprising computer instructions, wherein the computer instructions instruct a computing device to perform operations corresponding to the wafer grinding time determination method according to claim 9.

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