Polishing head, polishing equipment, polishing method, processor and storage medium

Abstract

The embodiment of the invention provides a polishing head, polishing equipment, a polishing method, a processor and a storage medium. Wherein the polishing head comprises: a base; the retaining ring is arranged below the base; the polishing head gas film is arranged on the base, is arranged on the inner side of the retaining ring and is used for fixedly holding the wafer; the retaining ring gas film is arranged on the inner side of the retaining ring and is arranged between the retaining ring and the polishing head gas film, the retaining ring gas film is in contact with the edge of the wafer when the retaining ring gas film is pressurized and expanded so as to apply acting force to the edge of the wafer, and the acting force forms radial clamping force and axial downward pressure on the edge of the wafer. Radial clamping force and axial downward pressure are applied to the edge of the wafer through the retaining ring gas film, the wafer can be clamped through the radial clamping force, the wafer is prevented from moving in the polishing process, and the risk of wafer sliding is reduced; the axial downward pressure can apply pressing force to the edge of the wafer in the wafer polishing process, the polishing effect of the edge of the wafer can be controlled more accurately, and the polishing consistency of the surface of the whole wafer is guaranteed.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor processing technology, and in particular to a polishing head, a polishing device, a polishing method, a processor, and a storage medium. Background Art

[0002] In semiconductor processing technology, chemical mechanical polishing (CMP) is a global flattening ultra-precision surface processing technology. Chemical mechanical polishing usually involves sucking or clamping a wafer on the bottom surface of a carrier head, with the side of the wafer with a deposition layer pressed against the upper surface of a polishing pad. The carrier head rotates under the actuation of a drive assembly and applies a downward load to the wafer; at the same time, polishing liquid is supplied to the upper surface of the polishing pad and distributed between the wafer and the polishing pad, so that the wafer completes chemical mechanical polishing under the combined action of chemistry and mechanics.

[0003] During the chemical mechanical polishing process, the pressure exerted by the polishing head on the wafer is a direct factor affecting the wafer polishing effect. In order to more accurately control the wafer polishing effect, the internal partition of the polishing head is constantly optimized. However, the polishing head in the related technology still has difficulty in controlling the polishing of the wafer edge, resulting in unsatisfactory polishing effect of the wafer edge. In addition, during the polishing process, the back of the wafer or the surface of the polishing head air film may be damaged, resulting in the problem that the processed wafer cannot meet the requirements and the service life of the polishing head air film is low. At the same time, there is also a risk of fragmentation during the polishing process of the wafer. Summary of the invention

[0004] In view of this, embodiments of the present application provide a polishing head, a polishing device, a polishing method, a processor and a storage medium to at least partially solve the above problems.

[0005] According to a first aspect of an embodiment of the present application, a polishing head is provided for pressing a wafer against a polishing pad for polishing, the polishing head comprising: a base; a retaining ring, arranged below the base; a polishing head air film, arranged on the base and placed on the inner side of the retaining ring, for holding the wafer; a retaining ring air film, arranged on the inner side of the retaining ring and placed between the retaining ring and the polishing head air film, wherein the retaining ring air film contacts the edge of the wafer when pressurized and expanded to apply a force to the edge of the wafer, wherein the force forms a radial clamping force and an axial downward pressure on the edge of the wafer.

[0006] Furthermore, in the above-mentioned polishing head, the lower surface of the retaining ring air film is pressed against the polishing pad when it is pressurized and expanded, so as to control the polishing pad pressed against the edge of the wafer to bulge during the polishing process.

[0007] Furthermore, in the above-mentioned polishing head, there is a gap between the retaining ring air film and the polishing head air film; the retaining ring air film can reveal the gap when it shrinks under reduced pressure, so as to clean the gap.

[0008] Furthermore, in the above-mentioned polishing head, the retaining ring air film includes: an annular airbag, provided with an inflation interface for connecting to an inflation device; an annular inner support body, attached to the inner surface of the annular airbag close to the polishing head air film, so as to prop up the inner side of the annular airbag and avoid contact with the polishing head air film.

[0009] Furthermore, in the above-mentioned polishing head, a first recessed portion is formed on the inner surface of the annular airbag, and the annular inner support body is disposed in the first recessed portion.

[0010] Furthermore, in the above-mentioned polishing head, an annular support body is arranged on the outer surface of the polishing head air film facing the retaining ring air film; and the annular inner support body is arranged corresponding to the annular support body and has a gap therebetween.

[0011] Furthermore, in the above-mentioned polishing head, the materials of the annular inner support body and the annular support body are different non-metallic materials.

[0012] Furthermore, in the above-mentioned polishing head, the retaining ring air film further comprises: an annular outer support body, which is attached to a portion of the outer surface of the annular airbag close to the retaining ring to prop up the outer side of the annular airbag.

[0013] Furthermore, in the above-mentioned polishing head, a second recessed portion is formed on the outer surface of the annular airbag, and the annular outer support body is disposed in the second recessed portion.

[0014] Furthermore, in the above-mentioned polishing head, the annular airbag is in contact and connected with the retaining ring near the outer surface of the retaining ring; the retaining ring extends toward the direction of the polishing head air film at the end away from the base to form a boss, and the boss squeezes the retaining ring air film so that the retaining ring air film is bent toward the direction of the polishing head air film.

[0015] Furthermore, in the above-mentioned polishing head, there is a gap between the retaining ring air film and the polishing head air film; the bent part of the retaining ring air film forms a folding structure, which is used to shrink when the annular airbag is depressurized to reveal the gap between the retaining ring air film and the polishing head air film.

[0016] Furthermore, in the above-mentioned polishing head, a lower end surface of the annular inner support body away from the base is flush with an upper surface of the boss.

[0017] Furthermore, in the above-mentioned polishing head, the cross-sectional area of ​​the retaining ring air film at the point where it is bent due to compression with the boss is smaller than the cross-sectional area of ​​the portion of the retaining ring air film bent toward the polishing head air film.

[0018] According to a second aspect of an embodiment of the present application, a polishing device is provided, which includes: a base, a polishing disc disposed on the base, a polishing pad disposed on the polishing disc, and any one of the above-mentioned polishing heads.

[0019] According to the third aspect of the embodiment of the present application, a polishing method is provided, which includes the following steps: controlling any one of the above-mentioned polishing heads to load a wafer; controlling the polishing head loaded with the wafer to move toward the polishing pad and press against the polishing pad; controlling the supply of polishing liquid to the polishing pad; controlling the inflation and pressurization of the polishing head air film and the retaining ring air film to make the retaining ring air film expand and contact the edge of the wafer to apply a force to the edge of the wafer; the force forms a radial clamping force and an axial downward force on the edge of the wafer; controlling the polishing head and the polishing disk to rotate and start polishing the wafer; and controlling the polishing head to send the wafer to the loading and unloading platform after the polishing of the wafer is completed.

[0020] Furthermore, in the above-mentioned polishing method, after controlling the polishing head to send the wafer to the loading and unloading platform after the wafer polishing is completed, it also includes: controlling the decompression of the retaining ring air film to shrink the retaining ring air film to reveal the gap between the retaining ring air film and the polishing head air film; and cleaning the gap.

[0021] According to a fourth aspect of an embodiment of the present application, a processor is provided, which is used to execute relevant steps of any of the above-mentioned polishing methods.

[0022] According to a fifth aspect of an embodiment of the present application, a computer storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, any of the above-mentioned polishing methods is implemented.

[0023] In an embodiment of the present application, a radial clamping force and an axial downward pressure are applied to the edge of the wafer by maintaining the annular air film. The radial clamping force can clamp the wafer and radially fix the wafer to prevent the wafer from moving relative to the polishing head air film during the polishing process, thereby reducing the risk of the slide and avoiding damage to the back of the wafer or the lower surface of the polishing head air film. The axial downward pressure can apply a clamping force to the edge of the wafer during the wafer polishing process, which can more accurately control the polishing effect of the wafer edge and ensure the polishing consistency of the entire wafer surface. In addition, since the embodiment of the present application maintains a flexible contact between the annular air film and the wafer, stress concentration at the edge of the wafer during the polishing process can be avoided, reducing the risk of fragments.

[0024] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0026] Figure 1 An axial cross-sectional view of a polishing head shown in an embodiment of the present application;

[0027] Figure 2 for Figure 1 A local enlarged structural schematic diagram of the position A shown in FIG.

[0028] Figure 3 for Figure 2 A schematic diagram of the local enlarged structure at B shown in FIG.

[0029] Figure 4 A schematic diagram of a partial structure of a polishing head shown in an embodiment of the present application;

[0030] Figure 5 Another axial cross-sectional view of a polishing head shown in an embodiment of the present application;

[0031] Figure 6 for Figure 5 A schematic diagram of the local enlarged structure at C shown in FIG.

[0032] Figure 7 Another partial structural schematic diagram of a polishing head shown in an embodiment of the present application;

[0033] Figure 8 This is another partial structural schematic diagram of a polishing head shown in an embodiment of the present application;

[0034] Fig. 9 A schematic diagram of the structure of a polishing head air film in a polishing head shown in an embodiment of the present application;

[0035] Fig.10 A schematic diagram of the structure of a polishing head for maintaining an annular air film in an embodiment of the present application;

[0036] Fig.11 A schematic diagram of the structure of a polishing device shown in an embodiment of the present application;

[0037] Fig.12 A schematic diagram of the process structure of the polishing method provided in the embodiment of the present application;

[0038] Fig.13Another schematic diagram of the process structure of the polishing method provided in the embodiment of the present application;

[0039] In the figure:

[0040] Polishing head 100; base 110; disc-shaped body 111; connecting body 112; retaining ring 120; boss 121; polishing head air film 130; partition 131; annular support body 132; retaining ring air film 140; lower surface 141; annular airbag 142; inflation interface 1421; first sheet ring 1422; second sheet ring 1423; first recessed portion 1424; second recessed portion 1425; annular inner support body 143; annular outer support body 144; folding structure 145;

[0041] Wafer 200;

[0042] Polishing equipment 300; polishing disc 310; polishing pad 320; polishing liquid supply device 330; dresser 340; loading and unloading platform 350. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0044] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0045] It should be understood that although the terms "first", "second", "third", etc. may be used in the present application to describe various components, these components should not be limited to these terms. These terms are only used to distinguish components of the same type from each other. For example, without departing from the scope of the present application, the first component may also be referred to as the second component, and similarly, the second component may also be referred to as the first component. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0046] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0047] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0048] During the chemical mechanical polishing process, the role of the polishing head is to press the wafer against the rotating polishing pad. The polishing pad is fixed to the polishing plate and is driven to rotate by the polishing plate. At the same time, the polishing head also applies a rotational force to rotate the wafer relative to the polishing pad. During this process, the polishing liquid is evenly transported on the polishing pad to achieve chemical mechanical polishing of the wafer surface.

[0049] The pressure exerted by the polishing head on the wafer is a direct factor affecting the wafer polishing effect. Even if the internal partition of the polishing head is continuously optimized in order to more accurately control the wafer polishing effect, the polishing head in the related technology still finds it difficult to accurately control the polishing effect of the wafer edge, resulting in unsatisfactory polishing effect of the wafer edge. In addition, during the polishing process, the back of the wafer or the surface of the polishing head air film may be damaged, resulting in the problem that the wafer cannot meet the requirements after processing and the service life of the polishing head air film is low. At the same time, there is also a risk of fragmentation during the polishing process of the wafer.

[0050] In view of the above problems, an embodiment of the present application provides a polishing head. The technical solution of the embodiment of the present application is described in detail below in conjunction with the accompanying drawings.

[0051] See also Figures 1 to 6 , Figures 9 and 10 According to an embodiment of the present application, a polishing head 100 includes a base 110, a retaining ring 120, a polishing head air film 130 and a retaining ring air film 140. The polishing head 100 is used to press a wafer 200 against a polishing pad (not shown) for polishing.

[0052] The retaining ring 120 is disposed below the base 110 (relative to Figure 1The polishing head air film 130 is disposed on the base 110 and is placed on the inner side of the retaining ring 120 (relative to the state shown). Figure 1 status shown).

[0053] In a specific implementation, the retaining ring 120 may be an annular body, the base 110 may include a disc-shaped body 111 and a connecting body 112, and the retaining ring 120 and the polishing head air film 130 are both connected to the lower end surface (relative to the lower end surface) of the disc-shaped body 111. Figure 1 The polishing head air film 130 is used to hold the wafer 200, and the driving device drives the base 110 to rotate, thereby driving the retaining ring 120, the polishing head air film 130 and the wafer 200 to rotate.

[0054] The polishing head air film 130 expands when pressurized to make flexible contact with the wafer 200 and pressurize it to avoid damaging the wafer 200. It can be understood that in some examples, the polishing head air film 130 can be provided with multiple partitions 131, and each partition can apply different pressures to the wafer 200 during polishing to meet the polishing pressure requirements of different areas of the wafer 200.

[0055] The retaining ring air film 140 is arranged on the inner side of the retaining ring 120 (the side close to the polishing head air film 130) and is placed between the retaining ring 120 and the polishing head air film 130. When the retaining ring air film 140 is pressurized and expanded, it contacts the edge of the wafer 200 to apply a force F to the edge of the wafer 200. The force forms a radial clamping force F1 and an axial downward pressure F2 at the edge of the wafer 200 ( Figure 3 shown).

[0056] In a specific implementation, the air-retaining ring membrane 140 is an annular body, which expands when pressurized and contracts when depressurized. The air-retaining ring membrane 140 can be made of elastic materials, such as rubber, silicone, etc., or can be made of non-elastic materials, such as plastic, etc.

[0057] In this embodiment, see Figure 3 When the air-maintaining film 140 is pressurized and expanded, the air-maintaining film 140 will contact the edge of the wafer 200, and apply a downward tilt (relative to the edge of the wafer 200) to the edge of the wafer 200. Figure 3 The force F applied to the wafer 200 can be decomposed into a radial clamping force F1 and an axial downward pressure F2. The radial clamping force F1 can clamp the wafer 200, and the axial downward pressure F2 can apply a force pressing the wafer 200 against the polishing pad, thereby applying a compressive force to the wafer 200 during the polishing process.

[0058] During the polishing process of the wafer 200, the edge of the wafer 200 may extend beyond the edge of the polishing head air film 130 under certain conditions, such as Figure 4As shown, under this working condition, the air ring film 140 can also apply an oblique downward force F to the edge of the wafer 200 , and the oblique downward force can also be decomposed into a radial clamping force F1 and an axial downward force F2 on the wafer 200 .

[0059] In the embodiment of the present application, the radial clamping force and axial downward pressure are applied to the edge of the wafer 200 by maintaining the annular air film 140. The radial clamping force can clamp the wafer 200 and radially fix the wafer 200 to prevent the wafer 200 from moving relative to the polishing head air film 130 during the polishing process, thereby reducing the risk of sliding and avoiding damage to the back side of the wafer (the surface in contact with the polishing head air film) or the lower surface of the polishing head air film 130 (the surface in contact with the wafer); the axial downward pressure can apply a clamping force to the edge of the wafer 200 during the polishing process of the wafer 200, so as to more accurately control the polishing effect of the edge of the wafer 200 and ensure the polishing consistency of the entire wafer surface; in addition, since the embodiment of the present application maintains the annular air film 140 in flexible contact with the wafer 200, stress concentration at the edge of the wafer during the polishing process can be avoided, thereby reducing the risk of fragments.

[0060] In the related art, since the retaining ring air film 140 in the embodiment of the present application is not provided, the retaining ring is in rigid contact with the wafer. At the same time, the retaining ring, the wafer and the polishing pad are all rigidly pressed, which causes the polishing pad at the edge of the wafer to easily bulge during the polishing process. This will affect the load applied by the polishing head air film 130 to the edge area of ​​the wafer, such as causing the material removal rate in the edge area of ​​the wafer to be greater than the material removal rate in the center area of ​​the wafer, and the global flatness of the wafer cannot be obtained.

[0061] Based on this, in some embodiments, see Figure 2 , keep the lower surface 141 of the annular film 140 pressed against the polishing pad when it is pressurized and expanded, so as to suppress the degree of bulging of the polishing pad pressed against the edge of the wafer during the polishing process, thereby improving the force on the edge area of ​​the wafer and controlling the material removal rate at the edge of the wafer.

[0062] In a specific implementation, when the annular air membrane 140 is pressurized and expanded, the lower surface 141 (relative to Figure 2 The state shown) and the lower surface of the wafer 200 (relative to Figure 3 as shown).

[0063] In this embodiment, a retaining ring air film 140 is arranged between the retaining ring 120, the wafer 200 and the area where the polishing pad is rigidly pressed. The retaining ring air film 140 is flexibly pressed against the polishing pad. The flexible pressure effectively buffers the above-mentioned rigid pressure, reduces stress concentration at the edge of the wafer, and further controls the bulging of the polishing pad at the edge of the wafer during the polishing process.

[0064] In some embodiments, a gap D ( Figure 6 As shown), the retaining ring air film 140 is prevented from contacting the polishing head air film 130 when the film expands, thereby preventing the retaining ring air film 140 from affecting the polishing head air film 130 during use.

[0065] It should be noted that, in specific implementation, the specific value of the gap D can be determined according to actual conditions, and this embodiment does not impose any limitation on it.

[0066] In this embodiment, the gap D can be exposed when the retaining ring air film 140 shrinks under reduced pressure, so that the cleaning liquid can enter the gap D and clean the polishing liquid in the gap D, thereby preventing the contaminants on the outer peripheral side of the polishing head air film 130 and the retaining ring air film 140 from being cleaned in time and forming crystals. The crystals formed by the contaminants will fall onto the polishing pad during the operation and cause scratches on the wafer.

[0067] In some embodiments, see Figure 2 The ring air film 140 includes: an annular airbag 142 and an annular inner support 143. The annular airbag 142 is provided with an inflation interface 1421 for connecting with an inflation device. The annular inner support 143 is attached to the inner surface of the annular airbag 142 near the polishing head air film 130 to prop up the inner side of the annular airbag 142, thereby preventing the annular airbag 142 from contacting the polishing head air film 130 when inflating, and avoiding affecting the polishing head air film 130.

[0068] In a specific implementation, the annular airbag 142 is provided with a first sheet ring 1422 on the inner surface of the inflation interface 1421, and a second sheet ring 1423 on the outer surface, and the first sheet ring 1422 and the second sheet ring 1423 are connected to clamp the open end of the annular airbag 142 between the first sheet ring 1422 and the second sheet ring 1423 to form the inflation interface 1421. For better sealing, an annular groove may be provided in the first sheet ring 1422, and the annular airbag 142 is fixed in the groove by bonding, clamping, etc.

[0069] It can be understood that the inflation interface 1421 is connected to the inflation device through an airway (not shown in the figure). In specific implementation, the airway can be opened on the retaining ring 120 and the base 110. Of course, it can also be opened only on the retaining ring 120 or the base 110. When the airway is opened only on the base 110, the inflation interface 1421 needs to be configured on the top of the retaining ring air membrane 140. This embodiment does not impose any limitation on the specific arrangement of the airway.

[0070] Furthermore, in some embodiments, the inner surface of the annular airbag 142 is formed with a first concave portion 1424 (see Figure 8), the annular inner support body 143 is arranged in the first recessed portion 1424 to better fix the annular inner support body 143 on the inner surface of the annular airbag 142.

[0071] In specific implementation, the annular inner support body 143 can be directly embedded in the first recessed portion 1424, or fixed in the first recessed portion 1424 by means of gluing, snapping, etc. This embodiment does not impose any limitation on the specific setting form.

[0072] Further, in some embodiments, see Figure 2 The polishing head air membrane 130 is provided with an annular support body 132 on the outer surface facing the retaining ring air membrane 140, and the annular support body 132 supports the outer side surface of the polishing head air membrane 130; the annular inner support body 143 is arranged corresponding to the annular support body 132 and has a gap D, thereby ensuring that the gap D is set between the polishing head air membrane 130 and the retaining ring air membrane 140, avoiding the influence of the polishing head air membrane 130 when the retaining ring air membrane 140 is inflated.

[0073] In some embodiments, the annular inner support 143 may abut against the annular support 132. To avoid adhesion caused by abutment of the same materials, the annular inner support 143 and the annular support 132 need to be made of different non-metallic materials. In addition, metal ion contamination caused by metal materials is also avoided.

[0074] In this embodiment, the materials of the annular inner support body 143 and the annular support body 132 are different non-metals and have a certain hardness to play a supporting role. In specific implementation, they can be plastics, such as polyimide, etc., or rubber, such as fluororubber, etc., and ceramics, hard foam, etc. can also be selected. As long as they are non-metals and the annular inner support body 143 and the annular support body 132 have a certain hardness, this embodiment does not limit the specific materials.

[0075] In some embodiments, see Figure 2 , Figure 7 and Fig. 9 The retaining ring air film 140 further includes: an annular outer support 144. The annular outer support 144 is attached to the outer surface of the annular airbag 142 close to the retaining ring 120 to prop up the outer side of the annular airbag 142.

[0076] Furthermore, in some embodiments, the outer surface of the annular airbag 142 is formed with a second concave portion 1425, see Figure 8 The annular outer support body 144 is disposed in the second recessed portion 1425 .

[0077] In specific implementation, the annular outer support body 144 can be directly embedded in the second recessed portion, or fixed in the second recessed portion by bonding or the like. This embodiment does not impose any limitation on the specific setting form.

[0078] In some embodiments, see Figure 2 The annular airbag 142 is in contact and connected with the retaining ring 120 near the outer surface of the retaining ring 120; the retaining ring 120 extends toward the polishing head air film 130 at the end away from the base 110 to form a boss 121, and the boss 121 squeezes the retaining ring air film 140 so that the retaining ring air film 140 is bent toward the polishing head air film 130.

[0079] In this embodiment, the protective air-protection film 140 is squeezed by the boss 121, so that the air-protection film 140 is deformed and can better apply an inclined downward pressure to the wafer. The pressure can be transferred to the edge of the wafer 200 in a more uniform manner to control the polishing speed of the wafer edge, suppress the edge effect of wafer polishing, and improve the uniformity of polishing.

[0080] In some embodiments, see Figure 2 and Figure 6 There is a gap D between the maintaining ring air membrane 140 and the polishing head air membrane 130, and a retractable structure 145 is formed on the portion of the maintaining ring air membrane 140 bent toward the polishing head air membrane 130, which is used to shrink when the annular airbag 142 is depressurized to reveal the gap D between the maintaining ring air membrane 140 and the polishing head air membrane 130.

[0081] In a specific implementation, the retractable structure 145 may be a folding structure, and when the chamber pressure decreases, the folding structure can move closer to each other to form a fold. Figure 3 is the state where the retractable structure 145 is unfolded, Figure 7 The telescopic structure 145 is in a folded and contracted state.

[0082] In this embodiment, when the polishing head is cleaned, the annular airbag 142 can be evacuated through an independent air circuit to deform the annular airbag 142, thereby exposing the gap D between the ring air film 140 and the polishing head air film 130, so as to clean the polishing liquid or the crystals of the polishing liquid in the gap D and avoid contamination caused by the accumulation of polishing liquid crystals in the gap D.

[0083] In some embodiments, the lower surface (relative to the lower surface of the annular inner support body 143) Figure 3 The state shown) and the upper surface of the boss 121 (relative Figure 3The ring-shaped inner support body 143 and the boss 121 have a certain hardness, so they can work together to provide a stable support surface for the retaining ring film 140, ensuring that the retaining ring film 140 can bend evenly when subjected to pressure, thereby enabling the retaining ring film 140 to be more effectively tilted toward the polishing head air film 130, thereby applying a downward pressure on the wafer 200.

[0084] In some embodiments, see Figure 2 The cross-sectional area of ​​the annular air film 140 at the bending point where it is squeezed with the boss 121 is kept smaller than the cross-sectional area of ​​the portion of the annular air film 140 bent toward the polishing head air film 130, so that when the pressure changes, the pressure response of the portion bent toward the polishing head air film 130 is more sensitive, thereby better controlling the force on the edge of the wafer.

[0085] In some specific implementations, the cross-sectional area of ​​the bending portion of the annular air membrane 140 between the annular inner support body 143 and the boss 121 is smaller than the cross-sectional area of ​​other portions after being bent toward the polishing head air membrane 130 .

[0086] It can be seen that this embodiment adjusts the sensitivity and control force of pressure by changing the cross-sectional area, and can quickly respond to small adjustments in pressure, thereby improving the dynamic responsiveness of the entire system.

[0087] The present application also provides a polishing device 300, see Fig.11 The device includes: a base, a polishing disc 310 disposed on the base, a polishing pad 320 disposed on the polishing disc 310, and any one of the above-mentioned polishing heads 100.

[0088] It can be understood that in some embodiments, the polishing equipment 300 should also include a polishing liquid supply device 330 , a dresser 340 and a loading and unloading platform 350 .

[0089] The specific implementation process of the polishing head 100 can be found in the above description, and will not be elaborated herein.

[0090] The polishing liquid supply device 350 is used to deliver polishing liquid to the polishing pad, the dresser 340 is used to maintain and correct the polishing pad 320, the loading and unloading platform 350 is arranged on one side of the polishing disk 310, and the polishing head 100 is configured to receive the wafer to be polished from the loading and unloading platform 350 or transfer the polished wafer to the loading and unloading platform 350.

[0091] Since the polishing head 100 has the above-mentioned effects, the polishing device having the polishing head 100 also has corresponding technical effects.

[0092] The present application also provides a polishing method, see Fig.12 , the method comprises the following steps:

[0093] Step S1001, controlling the polishing head to load the wafer.

[0094] Specifically, any one of the polishing heads 100 in the above embodiments is controlled to load the wafer 200 .

[0095] Specifically, for example, the polishing head 100 may hold the wafer 200 by adsorption, clamping, or the like.

[0096] Step S1002 , controlling the polishing head 100 loaded with the wafer 200 to move toward the polishing pad 320 and to press against the polishing pad 320 .

[0097] Specifically, the polishing head 100 may press the wafer 200 against the polishing pad 320 to apply pressure required for polishing to the wafer 200 .

[0098] Step S1003 , controlling the supply of polishing liquid to the polishing pad 320 .

[0099] Specifically, the polishing liquid may be delivered to the polishing pad 320 through the polishing liquid supply device 350 .

[0100] Step S1004, control the polishing head air film 130 and the retaining ring air film 140 to be inflated and pressurized, so that the retaining ring air film 140 expands and contacts the edge of the wafer 200, so as to apply force to the edge of the wafer 200. The force forms a radial clamping force F1 and an axial downward pressure F2 on the edge of the wafer 200.

[0101] Specifically, the inflation device may be controlled to inflate and pressurize the air-maintaining ring membrane 140 .

[0102] Step S1005 , controlling the polishing head 100 and the polishing plate 310 to rotate, and starting to polish the wafer 200 .

[0103] Step S1006 , after the wafer 200 is polished, the polishing head 100 is controlled to send the wafer 200 to the loading and unloading platform 350 , and the robot sends the wafer 200 on the loading and unloading platform 350 to the next process.

[0104] In the embodiment of the present application, the radial clamping force and axial downward pressure are applied to the edge of the wafer 200 by maintaining the annular air film 140. The radial clamping force can clamp the wafer 200 and radially fix the wafer 200 to prevent the wafer 200 from moving relative to the polishing head air film 130 during the polishing process, thereby reducing the risk of sliding and avoiding damage to the back of the wafer or the lower surface of the polishing head air film 130; the axial downward pressure can apply a clamping force to the edge of the wafer 200 during the polishing process of the wafer 200, so as to more accurately control the polishing effect of the edge of the wafer 200 and ensure the polishing consistency of the entire wafer surface; in addition, since the annular air film 140 and the wafer 200 are maintained in flexible contact in the embodiment of the present application, stress concentration at the edge of the wafer during the polishing process can be avoided, thereby reducing the risk of fragments.

[0105] In some embodiments, Fig.12 After the polishing method shown in the figure completes polishing of one or more wafers, the polishing head 100 may be cleaned. Fig.13 , specifically including the following steps:

[0106] Step S1101 , controlling the pressure reduction of the retaining ring air film 140 to shrink the retaining ring air film 140 , thereby exposing a gap D between the retaining ring air film 140 and the polishing head air film 140 .

[0107] Specifically, the air retaining film 140 may be evacuated by a vacuum device to shrink the air retaining film 140 .

[0108] Step S1102, cleaning the gap.

[0109] Specifically, the polishing liquid in the gap is cleaned by the cleaning liquid.

[0110] In this embodiment, during cleaning, the annular airbag 142 can be evacuated through an independent air circuit to deform the annular airbag 142, thereby exposing a gap D between the retaining ring air film 140 and the polishing head air film 130, so as to clean the gap D and avoid contamination caused by accumulation of polishing liquid crystals in the gap D.

[0111] An embodiment of the present application also provides a processor, which is used to execute relevant steps of any of the above-mentioned polishing methods.

[0112] Specifically, the program may include program codes including computer operation instructions.

[0113] The processor may be a central processing unit CPU, or an application specific integrated circuit ASIC (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0114] An embodiment of the present application also provides a computer storage medium on which a computer program is stored, and when the program is executed by a processor, any of the above-mentioned polishing methods is implemented.

[0115] The above-described method according to the embodiment of the present application may be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-transitory machine-readable medium downloaded through a network and will be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an AS IC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor, or hardware, the polishing method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the polishing method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the polishing method shown herein.

[0116] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A polishing head for pressing a wafer against a polishing pad for polishing, characterized in that: include: Pedestal; A retaining ring, disposed below the base; A polishing head air film, disposed on the base and placed inside the retaining ring, for holding the wafer; A retaining ring air film is arranged on the inner side of the retaining ring and placed between the retaining ring and the polishing head air film. When the retaining ring air film is pressurized and expanded, it contacts the edge of the wafer to apply a force to the edge of the wafer, and the force forms a radial clamping force and an axial downward pressure on the edge of the wafer.

2. The polishing head according to claim 1, characterized in that: When the retaining ring air film is expanded under pressure, the lower surface thereof is pressed against the polishing pad, so as to control the polishing pad pressed against the edge of the wafer to bulge during the polishing process.

3. The polishing head according to claim 1, characterized in that: There is a gap between the retaining ring air film and the polishing head air film; The retaining ring air film can reveal the gap when it shrinks under reduced pressure, so as to clean the gap.

4. The polishing head according to claim 1, characterized in that: The air-retaining ring film comprises: The annular airbag is provided with an inflation interface for connecting with an inflation device; The annular inner support body is attached to the inner surface of the annular airbag close to the polishing head air film to prop up the inner side of the annular airbag and avoid contact with the polishing head air film.

5. The polishing head according to claim 4, characterized in that: A first concave portion is formed on the inner surface of the annular airbag, and the annular inner support body is arranged in the first concave portion.

6. The polishing head according to claim 4, characterized in that: The polishing head air film is provided with an annular support body on the outer surface facing the retaining ring air film; The annular inner support body is arranged corresponding to the annular support body and has a gap therebetween.

7. The polishing head according to claim 6, characterized in that: The annular inner support body and the annular support body are made of different non-metallic materials.

8. The polishing head according to claim 4, characterized in that: The retaining ring air film also includes: The annular outer support body is attached to the outer surface of the annular airbag close to the retaining ring to prop up the outer side of the annular airbag.

9. The polishing head according to claim 8, characterized in that: A second concave portion is formed on the outer surface of the annular airbag, and the annular outer support body is arranged in the second concave portion.

10. The polishing head according to claim 4, characterized in that: The annular airbag is close to the outer surface of the retaining ring and is in contact with the retaining ring; The retaining ring has a boss extending toward the polishing head air film at one end away from the base, and the boss presses the retaining ring air film to bend the retaining ring air film toward the polishing head air film.

11. The polishing head according to claim 10, characterized in that: There is a gap between the retaining ring air film and the polishing head air film; The bent portion of the retaining ring air film is formed with a retractable structure, which is used to shrink when the annular airbag is depressurized to reveal the gap between the retaining ring air film and the polishing head air film.

12. The polishing head according to claim 10, characterized in that: The lower end surface of the annular inner support body away from the base is flush with the upper surface of the boss.

13. The polishing head according to claim 10, characterized in that: The cross-sectional area of ​​the retaining ring air film at the point where it is bent due to being squeezed by the boss is smaller than the cross-sectional area of ​​the portion of the retaining ring air film that is bent toward the polishing head air film.

14. A polishing device, characterized in that: include: A base, a polishing disc arranged on the base, a polishing pad arranged on the polishing disc, and a polishing head according to any one of claims 1 to 13.

15. A polishing method, characterized in that: The steps include: Controlling the polishing head according to any one of claims 1 to 13 to load a wafer; Controlling the polishing head loaded with the wafer to move toward the polishing pad and press against the polishing pad; Controlling the delivery of polishing liquid to the polishing pad; Controlling the inflation and pressurization of the polishing head air film and the retaining ring air film so that the retaining ring air film expands and contacts the edge of the wafer, so as to apply a force to the edge of the wafer; the force forms a radial clamping force and an axial downward pressure at the edge of the wafer; Controlling the polishing head and the polishing disk to rotate and start polishing the wafer; After the wafer is polished, the polishing head is controlled to send the wafer to the loading and unloading platform.

16. The polishing method according to claim 15, characterized in that: After the wafer polishing is completed, the polishing head is controlled to send the wafer to the loading and unloading platform, and the following steps are further included: Controlling the decompression of the retaining ring air film to shrink the retaining ring air film and revealing the gap between the retaining ring air film and the polishing head air film; The gap is cleaned.

17. A processor, characterized in that: Used to perform relevant steps of the polishing method described in claim 15 or 16.

18. A computer storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the polishing method according to claim 15 or 16.

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