Polishing head and chemical mechanical polishing apparatus

Abstract

The application provides a polishing head and a chemical mechanical polishing device. The polishing head comprises a polishing head body, an elastic air film, a first clamping device and a second clamping device. An installation space is formed at one end of the polishing head body in the axial direction. The elastic air film is arranged in the installation space, and the elastic air film forms a side film and a bottom film away from the bottom of the installation space. The first clamping device is in contact with the inner side surface of the side film, and the second clamping device is in contact with the outer side surface of the side film. The first clamping device and the second clamping device cooperate to clamp the side film. In the state of clamping the side film, the first clamping device and the second clamping device are annular structures. The circumferential dimensions of the annular structures of the first clamping device and the second clamping device can be adjusted to adjust the circumferential dimension of the elastic air film and change the edge stress of the polished wafer. The scheme can improve the compatibility of the polishing head.

Description

[0001] This application is a divisional application of the invention patent application filed on December 29, 2023, with application number 2023118455481. Technical Field

[0002] This application relates to the field of chemical mechanical polishing technology, and more particularly to a polishing head and chemical mechanical polishing equipment. Background Technology

[0003] Chemical mechanical polishing (CMP) equipment is commonly used for the chemical mechanical polishing of wafers. The polishing head is a crucial component of CMP. For example, some CMP equipment includes, in addition to the polishing head, a loading cup for holding the wafer and a polishing disc with a polishing pad. Some types of polishing heads incorporate a film gas system, which uses the film to adsorb the wafer and remove it from the loading cup. The film then applies appropriate pressure to press the wafer onto the polishing disc with the polishing pad, achieving CMP.

[0004] In this type of polishing head, to effectively transmit gas pressure to the wafer and apply pressure to it, the gas film is generally made of elastic, relatively soft rubber. To prevent the sides of the gas film from tipping over, a clamping device is needed to clamp the sides of the gas film, thereby increasing the rigidity of the sides and ensuring the stability of the gas film edges.

[0005] Third-generation semiconductor materials, with their wider bandgap, high thermal conductivity, high breakdown field strength, high saturated electron drift velocity, and high bonding energy, can meet the new requirements of modern electronic technology for harsh conditions such as high temperature, high power, high voltage, high frequency, and radiation resistance. As a result, third-generation semiconductor materials have wide applications in industries such as radio frequency communication, radar, satellite, power management, automotive electronics, and industrial power electronics.

[0006] However, third-generation semiconductor materials, such as gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), and diamond, are characterized by extremely high hardness and difficulty in polishing. Under certain special requirements, it is necessary to thin the edges of the wafer to a non-aligned state with other areas to form a trim wafer. When a conventional polishing head presses this wafer onto a polishing pad using a gas film for chemical mechanical polishing, the polishing rate at the wafer edges tends to increase sharply, resulting in poor chemical mechanical polishing performance. Furthermore, this sharp increase is difficult to mitigate by adjusting the gas pressure transmitted through the gas film.

[0007] Typically, different film gas sizes are designed for each trim wafer size, and sometimes even different polishing heads need to be developed. However, designing different film gas sizes and polishing heads for each trim wafer size significantly complicates polishing head management, increases the workload for R&D personnel, and makes cost control more difficult. Therefore, a new technical solution is needed to at least partially improve these issues. Summary of the Invention

[0008] This application provides a polishing head and a chemical mechanical polishing apparatus to at least partially improve the above-mentioned problems.

[0009] According to one aspect of this application, a polishing head is provided for use in a chemical mechanical polishing (CMP) apparatus. The polishing head includes: a polishing head body, an elastic gas film, a first clamping device, and a second clamping device. One end of the polishing head body has an installation space. The elastic gas film is disposed within the installation space, forming a side film and a bottom film away from the bottom of the installation space. The first clamping device contacts the inner surface of the side film, and the second clamping device contacts the outer surface of the side film. The first and second clamping devices cooperate to clamp the side film. When the side film is clamped, both the first and second clamping devices are annular structures, and the circumferential dimensions of the annular structures of both devices are adjustable to adjust the circumferential dimensions of the elastic gas film and change the edge force on the polished wafer.

[0010] According to another aspect of this application, a chemical mechanical polishing apparatus is provided, comprising: a polishing unit and the polishing head described above; the polishing head is configured with an elastic gas film whose circumferential dimension can be adjusted by a first clamping device and a second clamping device to change the edge force of the polished wafer.

[0011] The polishing head in this application has at least the following beneficial effects:

[0012] a. The first clamping device and the second clamping device can cooperate with each other to clamp the side membrane, thereby improving the rigidity of the side membrane of the elastic gas membrane and improving the stability of the edge of the elastic gas membrane;

[0013] b. Since both the first and second clamping devices are annular structures when the side film is clamped, and the circumferential dimensions of the annular structures of the first and second clamping devices are adjustable, when it is necessary to adsorb wafers of different sizes, the clamping state of the side film of the elastic gas film can be adjusted by adjusting the circumferential dimensions of the annular structure of the first clamping device and the annular structure of the second clamping device as needed. This changes the edge force of the polished wafer, allowing the elastic gas film to adapt to wafers of different sizes, solving the problem of a sharp increase in the wafer edge polishing rate, and improving the effect of chemical mechanical polishing.

[0014] c. Since the circumferential dimensions of the annular structures of the first and second clamping devices can be adjusted to accommodate trim wafers of different sizes, it is not necessary to design different elastic air films and polishing heads for trim wafers of different sizes. This improves the compatibility of the polishing heads, effectively reduces the complexity of polishing head management, reduces the workload of R&D personnel, and lowers the difficulty of cost control. 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 A cross-sectional schematic diagram of some of the optional polishing heads in this application is shown.

[0017] Figure 2 It shows Figure 1 A schematic diagram at point Q1.

[0018] Figure 3 A schematic diagram of an optional first type structure in this application is shown.

[0019] Figure 4 It shows Figure 3 A schematic diagram at point Q2.

[0020] Figure 5 A schematic diagram of the overlapping portion of the arc-shaped plate in this application is shown.

[0021] Figure 6 A cross-sectional schematic diagram of some other optional polishing heads in this application is shown.

[0022] Figure 7 A schematic diagram of an optional second type of structure in this application is shown.

[0023] Figure 8 A schematic diagram of one of the optional links in this application is shown.

[0024] Figure 9A A top view schematic diagram of the connection state between two adjacent links in this application is shown.

[0025] Figure 9B It shows Figure 9A Schematic diagram of the cross section along the AA direction.

[0026] Figure 9C It shows Figure 9B A schematic diagram at point Q4.

[0027] Figure 9D A schematic diagram is shown of the angle between the first and second limiting surfaces of two adjacent flush chain links.

[0028] Figure 10A A partial schematic diagram shows the base film pressing the wafer onto the polishing unit before the clamping device is adjusted.

[0029] Figure 10B A partial schematic diagram shows the bottom film after the clamping device is adjusted, pressing the wafer onto the polishing unit.

[0030] Figure 10C A schematic diagram showing the comparison of pressure curves at different radial positions of the wafer during chemical mechanical polishing before and after adjustment of the clamping device is presented.

[0031] Figure 11 A schematic diagram of an optional chemical mechanical polishing apparatus according to this application is shown. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in 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 in this application, all other embodiments obtained by those skilled in the art should fall within the scope of protection of this application.

[0033] The specific implementation of the polishing head 100 and the chemical mechanical polishing apparatus 200 of this application is described below with reference to the accompanying drawings. It should be noted that, for illustrative purposes, the structures in the following drawings are not necessarily drawn to scale.

[0034] Reference Figure 1 and Figure 2 As shown, according to one aspect of this application, a polishing head 100 is provided for a chemical mechanical polishing apparatus 200.

[0035] The polishing head 100 includes: a polishing head body 1, an elastic air film 2, a first clamping device 3 and a second clamping device 4. One end of the polishing head body 1 forms an installation space 11. The elastic air film 2 is disposed in the installation space 11 and forms a side film 21 and a bottom film 22 away from the bottom of the installation space 11.

[0036] The first clamping device 3 contacts the inner surface of the side film 21, and the second clamping device 4 contacts the outer surface of the side film 21. The first clamping device 3 and the second clamping device 4 cooperate with each other to clamp the side film 21. When the side film 21 is clamped, both the first clamping device 3 and the second clamping device 4 are annular structures. Furthermore, the circumferential dimensions of the annular structures of the first clamping device 3 and the second clamping device 4 can be adjusted, thereby adjusting the circumferential dimensions of the elastic gas film 2 to change the edge force of the polished wafer.

[0037] The polishing head 100 in this application will be described in detail below.

[0038] The polishing head 100 in this application can be used in a chemical mechanical polishing (CMP) apparatus 200, serving as an important component for wafer pick-up and CMP polishing. In this application, the CMP apparatus 200 may include one or more polishing heads 100, without limitation. For example, the number of polishing heads 100 may correspond to the number of polishing units 201 (e.g., polishing discs with polishing pads) in the CMP apparatus 200, meaning each polishing unit 201 may be equipped with one polishing head 100. Alternatively, each polishing unit 201 may be equipped with multiple polishing heads 100.

[0039] In this application, the polishing head body 1 is the main body portion of the polishing head 100. A mounting space 11 is formed at one end of the polishing head body 1; for example, the mounting space 11 may be located at one axially upward end of the polishing head body 1. Optionally, referring to… Figure 1As shown, a retaining ring 12 is disposed at the lower part of the polishing head body 1, and the mounting space 11 is enclosed by the retaining ring 12. The inner wall of the retaining ring 12 forms the side wall of the mounting space 11. An elastic gas film 2 is disposed within the mounting space 11 and its position is restricted by the mounting space 11. The elastic gas film 2 may be made of elastic, relatively soft rubber. Within the mounting space 11, the elastic gas film 2 forms a side film 21 and a bottom film 22 away from the bottom of the mounting space 11. The polishing head 100 can adsorb the wafer from the loading cup for holding the wafer in the chemical mechanical polishing apparatus 200 through the elastic gas film 2, thereby removing the wafer. When adsorbing the wafer, the wafer is located within the mounting space 11 and in contact with the bottom film 22. The polishing head 100 can then move the wafer to the polishing unit 201 (e.g., may include a polishing disc with a polishing pad), and pressure is transmitted to the wafer through the bottom film 22 of the elastic gas film 2 to press the wafer onto the polishing unit 201 of the chemical mechanical polishing apparatus 200 for corresponding chemical mechanical polishing. The principle by which the bottom film 22 transfers pressure to the wafer can be by transferring gas pressure, for example, referring to... Figure 1 As shown, the interior of the elastic gas film 2 is formed with multiple gas cavities 23. By adjusting the gas pressure of the multiple gas cavities 23, the pressure transmitted to each area of ​​the wafer corresponding to the bottom film 22 can be reasonably adjusted, thereby facilitating the pressing of the wafer onto the polishing pad for chemical mechanical polishing.

[0040] In this application, reference is made to Figure 1 and Figure 2 As shown, the first clamping device 3 is located inside the side membrane 21 of the elastic air membrane 2 and contacts the inner surface of the side membrane 21. The second clamping device 4 is located outside the side membrane 21 of the elastic air membrane 2 and contacts the outer surface of the side membrane 21. Through the cooperation of the first clamping device 3 and the second clamping device 4, the side membrane 21 can be clamped, thereby maintaining the rigidity of the side membrane 21 and improving the stability of the elastic air membrane 2.

[0041] The first clamping device 3 and the second clamping device 4 have a certain strength. When the side membrane 21 is clamped by the first clamping device 3 and the second clamping device 4, both the first clamping device 3 and the second clamping device 4 are annular structures. The annular structure of the first clamping device 3 can effectively push the side membrane 21 outward, while the annular structure of the second clamping device 4 can effectively clamp the side membrane 21 inward. Therefore, they can cooperate with each other to clamp the side membrane 21.

[0042] Optionally, refer to Figure 1 and Figure 2As shown, the outer surface of the annular structure of the first clamping device 3 can be fitted with the inner surface of the side membrane 21, and the inner surface of the annular structure of the second clamping device 4 can be fitted with the outer surface of the side membrane 21 to clamp the side membrane 21. Based on this, the side membrane 21 can be effectively stretched outward by the first clamping device 3 and effectively clamped inward by the second clamping device 4, thereby effectively meeting the requirement of the first clamping device 3 and the second clamping device 4 working together to clamp the side membrane 21.

[0043] In this application, the annular structures of the first clamping device 3 and the second clamping device 4 can be manufactured and adapted according to the actual shape of the elastic gas film 2. Optionally, the annular structures of the first clamping device 3 and the second clamping device 4 can both be circular annular structures. For example, the base film 22 of a conventional elastic gas film 2 can be circular to meet the wafer picking requirements, which are mostly circular. Therefore, the circular shape of the first clamping device 3 and the second clamping device 4 is also better suited to such requirements.

[0044] The circumferential dimensions of the annular structures of the first clamping device 3 and the second clamping device 4 can be adjusted. By adjusting the circumferential dimensions of the two annular structures, the clamping state of the side film 21 of the elastic gas film 2 can be adjusted to change the circumferential dimensions of the elastic gas film 2, thereby changing the edge force of the polished wafer, so that the elastic gas film 2 can be used for polishing trim wafers of different specifications and sizes.

[0045] The first clamping device 3 and the second clamping device 4 in this application can be configured in any structure that meets the requirements. In some optional embodiments, the first clamping device 3 can be configured as a first type structure, and the second clamping device 4 can be configured as either a first type structure or a second type structure.

[0046] Reference Figure 3 As shown, the first type of structure includes: at least one adjustment structure and at least one arc-shaped plate 31. The at least one adjustment structure is connected to the at least one arc-shaped plate 31. The at least one arc-shaped plate 31 is connected to form a ring structure through the at least one adjustment structure, and the circumferential dimension of the ring structure is adjusted through the at least one adjustment structure.

[0047] Reference Figure 7 As shown, the second type of structure includes: multiple links 41 and multiple shafts 42. The multiple links 41 are rotatably connected in sequence to form a ring structure through the multiple shafts 42. The circumferential dimension of the ring structure can be adjusted by changing the number of links 41 connected to form the ring structure.

[0048] In this application, the first clamping device 3 of the first type structure and the second clamping device 4 of the first type structure or the second type structure can effectively realize the circumferential dimension adjustment of the annular structure of the first clamping device 3 and the second clamping device 4, so as to adjust the clamping state of the side film 21 of the elastic gas film 2 by adjusting the circumferential dimension of the two annular structures, thereby changing the edge force of the polished wafer, so that the elastic gas film 2 can be used for wafers of different specifications and sizes.

[0049] It should be noted that the reason why the first clamping device 3 cannot adopt the second type of structure is that the second type of structure cannot effectively prop the side membrane 21 of the elastic air membrane 2 outward, resulting in poor clamping effect. The second clamping device 4, on the other hand, clamps the side membrane 21 inward, and the second type of structure can well meet the requirements.

[0050] In this application, for any first type of structure, the arc-shaped plate 31 has a certain strength, and the arc-shaped plate 31 can be made of any suitable material, such as metal or reinforced plastic.

[0051] This application does not limit the specific implementation of the first type structure; a suitable structure can be made as needed. The following describes some optional implementations of the first type structure in this application.

[0052] Optionally, refer to Figure 3 , Figure 4 and Figure 5 As shown, an optional first type of structure is illustrated. In this optional first type of structure: the arc-shaped plate 31 includes two overlapping portions for fixing, the two overlapping portions are located at both ends of the arc-shaped plate 31, and the overlapping portions have multiple locking holes 311; the adjustment structure includes an arc-shaped latch 32, which engages with the multiple locking holes 311 on the two overlapping portions to connect at least one arc-shaped plate 31 into a ring structure; the circumferential dimension of the ring structure can be adjusted by adjusting the arc-shaped latch 32 to engage with different multiple locking holes 311.

[0053] In this application, when the first clamping device 3 and / or the second clamping device 4 adopt such a first type of structure, the circumferential dimension adjustment of the annular structure of the first clamping device 3 and / or the second clamping device 4 can be effectively realized, so as to adjust the clamping state of the side membrane 21 of the elastic air membrane 2.

[0054] The keyhole 311 can be set into any suitable shape as needed. For example, it can be set into a parallelogram (specifically, it can be set into a rectangle). Or it can be other regular or irregular shapes. Optionally, when the keyhole 311 is set into a non-rectangular parallelogram, a certain range of slope can be set. The number of keyholes 311 on the curved plate 31 can be set as needed and is not limited here. In addition, the spacing between adjacent keyholes 311 on each overlapping part can also be set as needed to meet different adjustment requirements.

[0055] In some alternative embodiments, refer to Figure 5 As shown, the arc-shaped plate 31 also includes a main body portion disposed between the overlapping portions. The thickness of the overlapping portions is less than or equal to half the thickness of the main body portion. This avoids excessive thickness after the two overlapping portions overlap, improving the thickness uniformity of the annular structure formed by the first clamping device 3 and / or the second clamping device 4.

[0056] In this optional first type of structure, one or more arc-shaped plates 31 may be included, that is, a ring structure can be formed by one or more arc-shaped plates 31.

[0057] Optionally, refer to Figure 3 As shown, if the first type of structure includes a single arc-shaped plate 31 and a single adjustment structure, the arc-shaped latch 32 of the single adjustment structure engages with multiple locking holes 311 on the two overlapping portions of the single arc-shaped plate 31 to form a ring structure. With this structure, the single arc-shaped plate 31 can be effectively connected into a ring structure via the arc-shaped latch 32 of the single adjustment structure and the multiple locking holes 311, and the circumferential dimensions of the ring structure can be effectively adjusted.

[0058] Optionally, if the first type of structure includes multiple arc-shaped plates 31 and multiple adjustment structures, the multiple arc-shaped plates 31 are connected sequentially through multiple adjustment structures. Furthermore, the arc-shaped latches 32 of the adjustment structures connecting each pair of adjacent arc-shaped plates 31 engage with multiple locking holes 311 on the first overlapping portion of the first arc-shaped plate 31 and the second overlapping portion of the second arc-shaped plate 31 in the two adjacent arc-shaped plates 31, thus forming a ring structure. With this structure, the multiple arc-shaped plates 31 can be effectively connected into a ring structure through the arc-shaped latches 32 and multiple locking holes 311 of the multiple adjustment structures, and the circumferential dimension adjustment of the ring structure can be effectively achieved.

[0059] For example, if it includes four arc-shaped plates 31 and four arc-shaped latches 32, its structure can be as follows: the second overlapping portion of the first arc-shaped plate 31 and the first overlapping portion of the first arc-shaped plate 31 are connected by the first arc-shaped latch 32 after overlapping; the second overlapping portion of the second arc-shaped plate 31 and the first overlapping portion of the third arc-shaped plate 31 are connected by the second arc-shaped latch 32 after overlapping; the second overlapping portion of the third arc-shaped plate 31 and the first overlapping portion of the fourth arc-shaped plate 31 are connected by the third arc-shaped latch 32 after overlapping; the second overlapping portion of the fourth arc-shaped plate 31 and the first overlapping portion of the first arc-shaped plate 31 are connected by the fourth arc-shaped latch 32 after overlapping; thus forming a ring structure. The number of other arc-shaped plates 31 and adjustment structures can be deduced similarly, and will not be elaborated here.

[0060] This application does not limit the specific structure of the arc-shaped latch 32. In some alternative embodiments, refer to Figure 4 As shown, the arc-shaped latch 32 includes a locking piece 323, a setting hole 324, and a first arc wall 321 and a second arc wall 322 located on both sides of the setting hole 324 along the thickness direction of the arc-shaped latch 32. The thickness of the first arc wall 321 is greater than the thickness of the second arc wall 322. Two overlapping portions are intersected in the setting hole 324, so that the first arc wall 321 and the second arc wall 322 are located on both sides of the two overlapping portions. The locking piece 323 of the arc-shaped latch 32 engages with a plurality of locking holes 311 on the two overlapping portions of the setting hole 324 to connect at least one arc-shaped plate 31 into a ring structure. Wherein, if the first clamping device 3 is a first type structure, the first arc wall 321 is located on the inner side of the ring structure and the second arc wall 322 is located on the outer side of the ring structure; if the second clamping device 4 is a first type structure, the second arc wall 322 is located on the inner side of the ring structure and the first arc wall 321 is located on the outer side of the ring structure.

[0061] Based on the aforementioned optional arc-shaped latch 32 structure, at least one arc-shaped plate 31 can be effectively connected into an arc shape through multiple locking holes 311. Furthermore, since the thicker first arc wall 321 is located inside the annular structure and the thinner second arc wall 322 is located outside the annular structure when the first clamping device 3 adopts this structure, the thinner second arc wall 322 contacts the inner surface of the side membrane 21 of the elastic air membrane 2. Therefore, with this structure, the arc-shaped plate 31 of the first clamping device 3 can better fit with the side membrane 21, thereby improving the clamping effect.

[0062] Furthermore, since the thicker first arc wall 321 is located on the outside of the annular structure and the thinner second arc wall 322 is located on the inside of the annular structure when the second clamping device 4 adopts such a structure, the thinner second arc wall 322 contacts the outer side of the side membrane 21 of the elastic air membrane 2. Therefore, the arc-shaped plate 31 of the second clamping device 4 with such a structure can better fit with the side membrane 21 to improve the clamping effect.

[0063] Optionally, the first arc wall 321, the second arc wall 322, and the arc-shaped plate 31 are circular arc structures, and the circular arcs face the same direction; this arrangement can make the formed ring structure more effective.

[0064] For example, refer to Figure 3 In the first type of structure shown, the thicker first arc wall 321 is located on the outer side of the annular structure, while the thinner second arc wall 322 is located on the inner side of the annular structure, thus it can be applied to the first clamping device 3. For example, see reference... Figure 6 The polishing head 100 shown has a first clamping device 3 and a second clamping device 4, both of which adopt a first type structure including the above-mentioned arc-shaped latch 32. It can be seen that the thicker first arc wall 321 of the arc-shaped latch 32 does not directly contact the side film 21.

[0065] Reference Figure 7 and Figure 8 As shown, in this second type of structure: the link 41 includes a main body 411 and an extension 412. The extension 412 is connected to one side of the main body 411 along the width direction, and a notch 413 is provided on the other side of the main body 411 along the width direction. The extension 412 is provided with a first shaft hole, and a second shaft hole and a third shaft hole are provided on both sides of the notch 413 of the main body 411, respectively. In two adjacent links 41, the extension 412 of the first link 41 is disposed in the notch 413 of the second link 41, and the rotating shaft 42 is sequentially passed through the second shaft hole, the first shaft hole and the third shaft hole to rotatably connect the two adjacent links 41.

[0066] Based on this, the two links 41 are rotatably connected by the pivot 42 so that multiple links 41 and multiple pivots 42 can be connected to form a ring structure, and the circumferential size requirement of the ring structure can be adjusted by changing the number of links 41.

[0067] Optionally, the extension 412 extends from the main body 411, and the two are connected by an integral molding structure.

[0068] Optionally, refer to Figure 9A and Figure 9BAs shown, the link 41 in this application may include a first limiting surface B and a second limiting surface C, wherein the first limiting surface B is located at the extension 412 of the link 41, and the second limiting surface C is located at the notch 413 of the link 41; and, in this optional second type structure, referring to Figures 9A-9C As shown, in some states, in two adjacent links 41, the first limiting surface B of one link 41 can be limited by the second limiting surface C of the other link 41, so that the rotation angle of the link 41 relative to the other link 41 is not too large, thereby preventing the final connected ring structure from deforming too much.

[0069] Optionally, refer to Figure 9D As shown, when two adjacent links 41 are aligned, the angle between the first limiting surface B of the first link 41 and the second limiting surface C of the second link 41 is θ, and θ = 360° / a, where a is the minimum number of links required when the first limiting surface B on the extension 412 of each link 41 in the second type structure is limited by the second limiting surface C at the notch 413 of the adjacent link 41. That is, when θ = 360° / a, the second type structure connected into a ring structure requires at least a links 41; if the circumferential dimension of the ring structure needs to be increased, the number of links 41 needs to be increased. This application, through such a structure, can prevent the overall deformation of the ring structure of this optional second type structure from being too large.

[0070] It should be noted that the above-mentioned optional first type structure and second type structure can be selected and used as needed. The first clamping device 3 and the second clamping device 4 can be the same first type structure or different first type structures, as long as the usage needs can be met.

[0071] The following is combined Figure 10A , Figure 10B and Figure 10C To understand this application, please refer to the following: Figure 10A and Figure 10B As shown, wafer 300 is a trim wafer, where the thickness at the edge is less than the thickness at the inside. Figure 10A In the middle, it is the state before the circumferential dimension of the ring structure of the clamping device (i.e., the first clamping device 3 and the second clamping device 4) is adaptively adjusted. Figure 10B In the middle, it is the state after the circumferential dimension of the ring structure of the clamping device (i.e., the first clamping device 3 and the second clamping device 4) has been adaptively adjusted.

[0072] Reference Figure 10A As shown, before the clamping device is adaptively adjusted, the bottom film 22 of the elastic gas film 2 presses the wafer 300 onto the polishing unit 201 for chemical mechanical polishing, and the side film 21 and bottom film 22 of the elastic gas film 2 expand to the edge of the wafer 300. Figure 10C Curve P1 in the middle is Figure 10A In the pressure response of the corresponding embodiment, in curve P1, the larger the radius, the closer to the edge of wafer 300. As can be seen from pressure curve P1, the pressure at the edge of wafer 300 increases sharply and cannot be adjusted, which will cause the edge removal rate of wafer 300 to increase sharply.

[0073] Reference Figure 10B As shown, after the circumferential dimensions of the annular structure of the clamping device are adaptively adjusted, the side film 21 and bottom film 22 of the elastic gas film 2 expand only to the specified radial position of the wafer 300, and do not expand to the edge of the wafer 300. Figure 10C Curve P1 in the middle is Figure 10B Regarding the pressure response in the corresponding embodiment, in curve P2, a larger radius indicates that it is closer to the edge of wafer 300. As can be seen from pressure curve P2, the phenomenon of sharp pressure increase at the edge of wafer 300 is improved, and the problem of unadjustable pressure is solved. This improves the problem of sharp increase in removal rate at the edge of wafer 300, thus adapting to the chemical mechanical polishing requirements of trim wafer, and the polishing head 100 has good compatibility.

[0074] According to another aspect of this application, referring to Figure 11 As shown, a chemical mechanical polishing apparatus 200 is provided, which includes a polishing unit 201. The polishing unit 201 is configured with a polishing head 100 as described in any of the preceding claims. The elastic gas film 2 configured on the polishing head 100 can adjust its circumferential size through a first clamping device 3 and a second clamping device 4 to change the edge force of the polished wafer.

[0075] For example, in some alternative embodiments, the polishing unit 201 may include a polishing disc with a polishing pad, the polishing disc driving the polishing pad to rotate, and the bottom film 22 of the polishing head 100 transmitting pressure to the wafer to press the wafer onto the polishing pad of the polishing disc, thereby performing chemical mechanical polishing on the wafer through the polishing pad. Optionally, during chemical mechanical polishing, the polishing head 100 needs to drive the wafer to rotate. In addition, the polishing unit 201 also needs to be equipped with a liquid supply device, which drips polishing liquid for chemical mechanical polishing onto the polishing pad during chemical mechanical polishing. Optionally, the polishing unit 201 may also include a trimming device, which trims the polishing pad to improve the effect of chemical mechanical polishing.

[0076] In some optional embodiments, the chemical mechanical polishing apparatus 200 further includes a loading cup for carrying a wafer, with the polishing head 100 interacting with the loading cup to load the wafer. Optionally, the elastic gas film 2 can remove the wafer from the loading cup by adsorbing it. It should be understood that the polishing unit 201 and the loading cup for carrying the wafer described above can be implemented with any suitable structure, and can be understood with reference to related technologies, which will not be elaborated here.

[0077] Since the chemical mechanical polishing apparatus 200 of this application uses at least one of the aforementioned polishing heads 100, it improves the situation of a sharp increase in the polishing rate of the wafer edge when performing chemical mechanical polishing on trim wafers of different sizes, thereby improving the effect of chemical mechanical polishing.

[0078] Since the polishing head 100 can adapt to wafers of different sizes by adjusting the circumferential dimensions of the annular structures of the first clamping device and the second clamping device, the chemical mechanical polishing equipment 200 does not need to design different elastic gas films and polishing heads for wafers of different sizes. Therefore, it can effectively reduce the complexity of polishing head management, reduce the workload of R&D personnel, and reduce the difficulty of cost control.

[0079] It should be noted that the solution / equipment provided in this application is mainly used for chemical mechanical polishing of wafers made of third-generation semiconductor materials. Specifically, it can be used for 4-inch, 6-inch, or 8-inch wafers processed from third-generation semiconductor materials, such as 4-inch, 6-inch, or 8-inch GaN wafers, or 8-inch SiC wafers.

[0080] In addition, due to the high difficulty in growing third-generation semiconductor materials, there are problems such as difficulty in controlling the temperature field, slow growth rate, high requirements for yield parameters, and difficulty in crystal diameter expansion. As a result, the wafer size of third-generation semiconductor materials is mainly 6-8 inches. With the development of technology and the overcoming of growth problems, the wafer size of third-generation semiconductor materials may expand to 12 inches or even larger. The solutions / equipment provided in this application are also applicable and are all within the protection scope of this application.

[0081] The optional embodiments of this application have been described in detail above with reference to the accompanying drawings; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solutions of this application. The various technical features included in the different embodiments of this application can be combined in any suitable manner. To avoid unnecessary repetition, this application will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application.

[0082] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". It should be noted that the concepts of "first", "second", etc., mentioned in this application are only used to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies. It should be noted that the modifications "a" and "a plurality" mentioned in this application are illustrative rather than restrictive, and those skilled in the art should understand that, unless explicitly indicated in the context, they should be understood as "one or more".

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A polishing head for use in chemical mechanical polishing equipment, characterized in that, include: The polishing head body comprises an elastic air film, a first clamping device, and a second clamping device. One end of the polishing head body has an installation space, and the elastic air film is disposed within the installation space, forming a side film and a bottom film away from the bottom of the installation space. The first clamping device contacts the inner surface of the side membrane, and the second clamping device contacts the outer surface of the side membrane. The first clamping device and the second clamping device cooperate with each other to clamp the side membrane. Both the first clamping device and the second clamping device are ring structures, and at least one of the first clamping device and the second clamping device includes at least two rigid members that can be connected to each other to form the ring structure and whose connection position can be changed to adjust the circumferential dimension.

2. The polishing head according to claim 1, characterized in that, The rigid member includes at least one of the following two structures: The first type of structure includes at least one arc-shaped plate, the two ends of which have overlapping portions with multiple lock holes, and an arc-shaped latch capable of engaging with different lock holes; The second type of structure includes multiple links and multiple shafts. One end of each link is provided with a shaft hole, and the other end is provided with a notch. Adjacent links are rotatably connected by shafts.

3. The polishing head according to claim 2, characterized in that, When the rigid member adopts the first type of structure, the arc-shaped latch includes a locking piece, a setting hole, and a first arc wall and a second arc wall with different thicknesses. The arc wall with a larger thickness is located inside the annular structure when the clamping device is used as the first clamping device, and is located outside the annular structure when it is used as the second clamping device.

4. The polishing head according to claim 2, characterized in that, When the rigid member adopts the first type of structure, the arc-shaped plate also includes a main body located between the two overlapping portions, the thickness of the overlapping portions being less than or equal to half the thickness of the main body.

5. The polishing head according to claim 2, characterized in that, When the rigid member adopts the second type of structure, the link includes a main body and an extension, the extension is provided with a first shaft hole, and the notch of the main body is provided with a second shaft hole and a third shaft hole on both sides respectively.

6. The polishing head according to claim 5, characterized in that, In the second type of structure, two adjacent links are respectively provided with a first limiting surface and a second limiting surface to limit the maximum angle of relative rotation.

7. The polishing head according to claim 6, characterized in that, When two adjacent chain links are aligned, the angle θ between the first limiting surface and the second limiting surface satisfies θ = 360° / a, where a is the minimum number of chain links required to form a ring structure.

8. The polishing head according to claim 2, characterized in that, When the rigid member adopts the second type of structure, it also includes a locking structure disposed between two adjacent links to limit relative rotation after the circumferential dimension is adjusted.

9. The polishing head according to claim 2, characterized in that, The first clamping device adopts the first type of structure, and the second clamping device adopts the second type of structure.

10. A chemical mechanical polishing apparatus, characterized in that, It includes a polishing unit and a polishing head as described in any one of claims 1-9.

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