Multi-cavity polishing head and polishing equipment

Abstract

The multi-cavity polishing head comprises a polishing base, a retaining ring and an elastic film assembly, the retaining ring is connected to the lower portion of the polishing base, the elastic film assembly is arranged in a mounting cavity, lower cavities and upper cavities are formed in the elastic film assembly, an inner ring frame is connected to the inner circumferential wall of the lower cavity located on the outermost ring, and an outer ring frame is connected to the inner circumferential wall of the upper cavity located on the outermost ring. And an air guide groove is formed in the inner ring frame. According to the multi-cavity polishing head provided by the invention, the upper cavity acts on the lower cavity at the edge of the outermost ring, and the inner ring frame is structurally optimized to form reliable support for the lower cavity, so that the forced fluctuation degree of the adjacent lower cavities during pressurization is reduced; the structure and the position of the air guide groove are improved, so that the air flow circulation is improved, the air flow in the lower chamber can be diffused to the position closer to the outermost ring, the pressure effect of the lower chamber at the edge is met, and the effective removal of the wafer edge is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer polishing, and more specifically, relates to a multi-chamber polishing head and polishing equipment. Background Art

[0002] Chemical Mechanical Polishing (CMP) is an ultra-precision surface processing technology for global flattening. This method places the wafer under the polishing head, which drives the wafer downward so that its bottom surface abuts against the top of the polishing pad. The nozzle supplies polishing liquid to the polishing pad. Under the action of the driving component, the polishing head drives the wafer and the polishing pad to rotate in the same direction, achieving material removal from the wafer under the combined action of chemistry and mechanics.

[0003] When polishing a wafer, multiple chambers are often required to act on the wafer to form a zoned pressure control effect. In this process, zone back pressure control technology is inevitably involved. The part between the two chambers and in contact with the wafer is a flexible diaphragm. When the chamber is inflated, the chamber pressure increases, the chamber volume also increases, and the adjacent chambers are squeezed, so a coupling effect occurs between the two adjacent chambers, and even spreads to other chambers. As the inflation pressure increases, the coupling effect will become obvious, which is easy to increase the degree of forced fluctuations between chambers at the edge, resulting in the problem of difficult to control the amount of wafer removal at the edge, which in turn affects the polishing quality at the edge of the wafer. Summary of the invention

[0004] The object of the present invention is to provide a multi-chamber polishing head and polishing equipment, which can reduce the degree of forced fluctuation of the chamber at the edge, facilitate the control of the removal amount at the edge of the wafer, and help improve the polishing quality of the wafer.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a multi-chamber polishing head, including a polishing base, a retaining ring and an elastic membrane assembly, the retaining ring is connected to the bottom of the polishing base, and forms a downward-opening mounting cavity with the polishing base, the elastic membrane assembly is arranged in the mounting cavity, and a lower chamber and an upper chamber are formed in the elastic membrane assembly, the lower chamber is provided with a plurality of chambers, and are arranged in sequence from the center to the periphery of the mounting cavity, the upper chamber is provided at the top of the chamber of the outermost circle, and an inner ring frame is connected to the inner peripheral wall of the lower chamber located in the outermost circle, the inner ring frame is located on the side of the lower chamber away from the center of the mounting cavity, and the inner ring frame is provided with an air guide groove extending downward.

[0006] In a possible implementation, the lower chamber includes an inner chamber, a middle chamber and an outer chamber. The middle chamber is sleeved on the outer periphery of the inner chamber, the outer chamber is sleeved on the outer periphery of the middle chamber, and an outer ring frame is embedded on the outer peripheral wall of the outer chamber.

[0007] In a possible implementation, the outer chamber has an extension chamber extending toward one side of the center of the installation chamber to above the middle chamber, and the upper chamber is located above the outer chamber and the extension chamber.

[0008] In some embodiments, the bottom of the polishing base is provided with a central base extending into the mounting cavity, the outer periphery of the central base is provided with a supporting ring plate extending into the extension cavity, the supporting ring plate is supported under the inner top wall of the extension cavity, and the extension chamber and the outer peripheral wall of the central base are sealed and connected.

[0009] In some embodiments, the middle chamber is arranged higher than the inner chamber, and the outer periphery of the central base is also provided with a lower ring plate extending into the middle chamber. The lower ring plate is supported below the inner top wall of the middle chamber, and the middle chamber is sealed and connected to the outer peripheral wall of the central base.

[0010] In a possible implementation, a plurality of intermediate chambers are provided, and the plurality of intermediate chambers are arranged in sequence from the center to the periphery of the installation cavity.

[0011] In a possible implementation, a boss ring for mounting an inner ring frame is provided on the inner circumferential wall of the outer chamber, the inner ring frame is connected to the inner circumferential wall of the boss ring, and the upper end of the air guide groove extends toward the center of the mounting cavity.

[0012] In some embodiments, the lower end surface of the boss ring gradually extends outward and downward to connect with the inner bottom wall of the outer chamber, and a gap is provided between the lower edge of the inner ring frame and the inner bottom wall of the outer chamber.

[0013] In some embodiments, an extended ring plate bent horizontally outward is provided on the upper edge of the inner ring frame, and the extended ring plate is located between the upper end surface of the boss ring and the inner top wall of the outer chamber.

[0014] Compared with the prior art, the solution shown in the embodiment of the present application utilizes the upper chamber to act on the lower chamber at the edge of the outermost circle, and realizes reliable support for the lower chamber by structural optimization of the inner ring frame, thereby reducing the degree of forced fluctuation of the adjacent lower chamber when pressurized; improves the structure and position of the air guide groove, and then improves the fluidity of the airflow, so that the airflow inside the lower chamber can diffuse to a position closer to the outermost circle, thereby satisfying the pressure effect of the lower chamber at the edge, realizing effective removal of the wafer edge, and ensuring the processing quality of the wafer.

[0015] The present invention also provides a polishing device, which includes a multi-chamber polishing head. The polishing device forms a reliable support for the lower chamber by arranging an inner ring frame in the lower chamber of the outermost circle, improves the structure and position of the air guide groove, and further improves the flowability of the airflow, so that the airflow inside the lower chamber can diffuse to a position closer to the outermost circle, satisfies the pressure effect of the lower chamber at the edge, realizes the effective removal of the wafer edge, and ensures the processing quality of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 A schematic structural diagram of a multi-chamber polishing head provided by an embodiment of the present invention; Figure 2 For the embodiment of the present invention Figure 1 The partially enlarged structural diagram of middle Ⅰ; Figure 3 For the embodiment of the present invention Figure 1 A schematic diagram of the structure of the middle inner ring frame when viewed from above; Figure 4 It is a diagram of wafer morphology and polishing data obtained by using the multi-chamber polishing head provided by an embodiment of the present invention; Figure 5 This is a diagram of wafer morphology and polishing data obtained using a traditional structure.

[0018] Among them, the reference numerals in the figure are: 1. Polishing base; 11. Mounting cavity; 2. Retaining ring; 3. Elastic membrane assembly; 31. Upper chamber; 32. Inner chamber; 33. Middle chamber; 34. Outer chamber; 35. Boss ring; 36. Extension cavity; 4. Outer ring frame; 5. Center base; 51. Supporting ring plate; 52. Lower ring plate; 6. Inner ring frame; 61. Air guide groove; 62. Extension ring plate. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on another element or indirectly on another element. It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0021] Please also read Figures 1 to 3 , the multi-chamber polishing head and the polishing equipment provided by the present invention are now described. The multi-chamber polishing head comprises a polishing base 1, a retaining ring 2 and an elastic membrane assembly 3. The retaining ring 2 is connected to the bottom of the polishing base 1 and forms a downwardly opening mounting cavity 11 with the polishing base 1. The elastic membrane assembly 3 is arranged in the mounting cavity 11. A lower chamber and an upper chamber 31 are formed in the elastic membrane assembly 3. The lower chamber is provided with a plurality of chambers and arranged in sequence from the center to the periphery of the mounting cavity 11. The upper chamber 31 is arranged at the top of the chamber of the outermost circle. An inner ring frame 6 is connected to the inner peripheral wall of the lower chamber located in the outermost circle. The inner ring frame 6 is located on the side of the lower chamber away from the center of the mounting cavity 11. The inner ring frame 6 is provided with an air guide groove 61 extending downward.

[0022] Compared with the prior art, the multi-chamber polishing head provided in this embodiment utilizes the upper chamber 31 to act on the lower chamber at the edge of the outermost circle, and realizes reliable support for the lower chamber by structurally optimizing the inner ring frame 6, thereby improving the structure and position of the air guide groove 61, thereby improving the fluidity of the airflow, so that the airflow inside the lower chamber can diffuse to a position closer to the outermost circle, thereby satisfying the pressure effect of the lower chamber at the edge, realizing effective removal of the wafer edge, and ensuring the processing quality of the wafer.

[0023] In this embodiment, the elastic membrane assembly 3 is made of a rubber material with good elasticity, and the upper chamber 31 is connected to a gas flow channel (not shown in the figure), and the pressure of the upper chamber 31 can be adjusted by controlling the pressure of the supplied gas. The pressure of the upper chamber 31 forms a load on the outermost lower chamber, which is convenient for adjusting the polishing pressure at the edge of the wafer in coordination with the pressure of the lower chamber, and can reduce the forced fluctuation degree between adjacent lower chambers at the edge, thereby controlling the polishing pressure at the edge and achieving effective removal of the wafer edge material.

[0024] Specifically, the number of lower chambers is set according to parameters such as the wafer size and the polishing amount. Three, four, five, six or seven lower chambers can be set from the center of the installation cavity 11 to the periphery. By applying different pressures to multiple lower chambers, the pressure in different areas of the wafer can be controlled to ensure the polishing effect of the wafer.

[0025] There should be a certain gap between the elastic membrane assembly 3 and the inner wall of the retaining ring 2, but the gap should not be too large to avoid a large amount of particles adhering to the gap position, thereby avoiding scratches on the wafer surface caused by falling during polishing. Therefore, the gap value can meet the installation requirements of the elastic membrane assembly 3.

[0026] It should be noted that when pressurizing the upper cavity, the standard pressure value should be selected first, and then, based on the above standard pressure value, a parameter with a fluctuation of 20% should be selected for testing. The final pressure value of the upper cavity 31 should be selected based on the minimum degree of forced fluctuation between the upper cavity 31 and the outermost lower cavity.

[0027] In one possible implementation, see Figures 1 to 3 The lower chamber includes an inner chamber 32, a middle chamber 33 and an outer chamber 34. The middle chamber 33 is sleeved on the outer periphery of the inner chamber 32, and the outer chamber 34 is sleeved on the outer periphery of the middle chamber 33. An outer ring frame 4 is embedded on the outer peripheral wall of the outer chamber 34.

[0028] In this embodiment, the lower chamber is a combination of an inner chamber 32, an intermediate chamber 33 and an outer chamber 34. The inner chamber 32 is a cylindrical chamber, and the intermediate chamber 33 and the outer chamber 34 are also cylindrical cavities. The intermediate chamber 33 is located between the inner chamber 32 and the outer chamber 34. The inner chamber 32 and the outer chamber 34 may be provided with one intermediate chamber 33, or may be provided with two, three or more intermediate chambers 33, so as to realize the partitioning of different areas of the wafer and ensure the overall polishing effect of the wafer.

[0029] Specifically, the inner ring frame 6 is arranged on the inner wall of the outer chamber 34 close to the periphery, and the outer ring frame 4 is correspondingly provided on the outer peripheral wall of the outer chamber 34, that is, it is located on the outer peripheral wall of the outer chamber 34 away from the center of the installation cavity 11. The inner ring frame 6 and the outer ring frame 4 form a common support from the inner and outer sides of the side wall of the outer chamber 34, and then effectively transfer the downward pressure of the upper cavity on the outer chamber 34 to the edge area of ​​the wafer, so as to improve the pressure state of the edge area of ​​the wafer, avoid interference between the outer chamber 34 and the adjacent middle chamber 33, reduce the degree of forced fluctuation of the two, and realize effective control of the removal amount of the wafer edge area.

[0030] Furthermore, the height of the outer ring frame 4 in the axial direction of the elastic membrane assembly 3 is smaller than the height of the inner ring frame 6 in the corresponding direction, and the outer peripheral wall of the inner ring frame 6 abuts against the inner wall of the inner chamber 32, thereby forming effective support for the corresponding position of the outer chamber 34 through the abutment between the two.

[0031] In one possible implementation, see Figures 1 to 3 The outer chamber 34 has an extension chamber 36 extending toward one side of the center of the mounting chamber 11 to above the middle chamber 33 , and the upper chamber 31 is located above the outer chamber 34 and the extension chamber 36 .

[0032] In this embodiment, the setting of the extension chamber 36 can enable the outer chamber 34 to fully withstand the downward pressure during the pressurization of the upper chamber, reduce the impact of the middle chamber 33 on the outer chamber 34 during the pressurization process, ensure the force effect at the edge of the wafer, and achieve effective removal of material in the edge area of ​​the wafer.

[0033] For some examples, see Figures 1 to 3 The bottom of the polishing base 1 is provided with a central base 5 extending into the mounting cavity 11, and the outer periphery of the central base 5 is provided with a supporting ring plate 51 extending into the extension cavity 36. The supporting ring plate 51 is supported under the inner top wall of the extension cavity 36, and the extension cavity 36 and the outer peripheral wall of the central base 5 are sealed and connected.

[0034] In this embodiment, the central base 5 at the bottom of the polishing base 1 is located at the center of the mounting cavity 11, and the supporting plate on the outer periphery of the central base 5 can be supported under the upper chamber 31 to ensure the structural stability of the outer chamber 34. At the same time, a reliable seal is formed between the central substrate and the outer chamber 34, ensuring the sealing performance inside the outer chamber 34, making it easy to form a stable internal pressure when airflow is supplied, thereby achieving effective pressure on the edge of the wafer.

[0035] On this basis, the setting of the supporting ring plate 51 can also ensure the stability of the structure of the outer chamber 34, thereby reducing the degree of forced fluctuation between the outer chamber 34 and the adjacent middle chamber 33, achieving effective pressure on the edge area of ​​the wafer by the outer chamber 34, and ensuring the removal efficiency and quality of the material in the edge area of ​​the wafer.

[0036] For some examples, see Figures 1 to 3The middle chamber 33 is arranged higher than the inner chamber 32. The outer periphery of the central base 5 is also provided with a lower ring plate 52 extending into the middle chamber 33. The lower ring plate 52 is supported below the inner top wall of the middle chamber 33. The middle chamber 33 is sealed and connected to the outer peripheral wall of the central base 5. By arranging the lower ring plate 52 on the outer periphery of the central base, the middle chamber 33 of the outermost circle is effectively supported, and the structural stability of the middle chamber 33 of the outermost circle is ensured. The arrangement method of the lower ring plate 52 is basically the same as that of the supporting plate, and will not be repeated here. The forced fluctuation degree between the middle chamber 33 and the outer chamber 34 can be effectively reduced, and the pressure on the edge area of ​​the wafer can be effectively applied, so as to achieve effective control of the removal amount of the edge area of ​​the wafer.

[0037] In one possible implementation, see Figures 1 to 3 There are several intermediate chambers 33, which are arranged from the center to the periphery of the mounting cavity 11. According to the size of the wafer and other parameters, multiple intermediate chambers 33 can be set, and the intermediate chambers 33 are arranged from the center to the periphery of the mounting cavity 11. The intermediate chambers 33 located in the outer circle are sleeved on the periphery of the intermediate chambers 33 located in the inner circle, forming a zoned pressure control on the wafer surface, which is convenient for ensuring the polishing quality of the wafer.

[0038] In one possible implementation, see Figures 1 to 3 The inner circumferential wall of the outer chamber 34 is provided with a boss ring 35 for mounting the inner ring frame 6, the inner ring frame 6 is connected to the inner circumferential wall of the boss ring 35, and the upper end of the air guide groove 61 extends toward the center of the mounting cavity 11. The lower end surface of the boss ring 35 gradually extends outward and downward to meet the inner bottom wall of the outer chamber 34, and a gap is provided between the lower edge of the inner ring frame 6 and the inner bottom wall of the outer chamber 34.

[0039] In this embodiment, a circumferentially extending boss ring 35 is provided in the outer chamber 34. The boss ring 35 can greatly enhance the structural strength of the peripheral wall of the outer chamber 34 on the one hand, and can provide a reliable installation foundation for the installation of the inner ring frame 6 and the outer ring frame 4 on the other hand.

[0040] The bottom wall of the boss ring 35 gradually extends outward and downward until it meets the inner bottom wall of the outer chamber 34, so that the inner bottom wall of the outer chamber 34 can be fully affected by the internal air pressure of the chamber. On this basis, a gap is provided between the lower edge of the inner ring frame 6 and the inner bottom wall of the outer chamber 34 to prevent the inner ring frame 6 from acting on the inner bottom wall of the outer chamber 34 and directly acting on the outer edge area of ​​the outer chamber 34, providing sufficient space for the introduction of the airflow in the air guide groove 61 on the outer ring frame 4, achieving effective guidance of the gas action position outward and downward, and reducing the degree of forced fluctuation between the outer chamber 34 and the adjacent intermediate chamber 33.

[0041] For some examples, see Figures 1 to 3The upper edge of the inner ring frame 6 is provided with an extension ring plate 62 that is horizontally bent outward, and the extension ring plate 62 is located between the upper end surface of the boss ring 35 and the inner top wall of the outer chamber 34. By arranging the extension plate that extends horizontally outward on the inner ring frame 6, the bottom of the upper chamber 31 can be reliably supported, and the structural stability of the outer chamber 34 itself can be further improved, which can meet the load effect of the upper chamber 31 on the outer chamber 34, ensure the effective transmission of the force to the edge position of the wafer, and improve the polishing effect of the edge area of ​​the wafer.

[0042] For details, please refer to Figure 4 and Figure 5 , Figure 4 This is a diagram of wafer morphology and polishing data obtained using a multi-chamber polishing head. Figure 5 The figure is a graph of wafer morphology and polishing data obtained using a traditional structure (the ordinate is the normalized data of wafer removal; the abscissa is the radius of the wafer, in mm). The vertical value floating range of the curve in the figure reflects the degree of forced fluctuation between adjacent chambers. Figure 4 and Figure 5 It can be seen that when a multi-chamber polishing head is used, the degree of forced fluctuation between adjacent chambers is significantly smaller than when the existing structure is used. Therefore, the above-mentioned multi-chamber polishing head can effectively improve the degree of forced fluctuation and help improve the processing quality at the edge of the wafer.

[0043] Based on the same inventive concept, the embodiment of the present application also provides a polishing device, which includes a multi-chamber polishing head. The above-mentioned polishing device forms a reliable support for the lower chamber by arranging an inner ring frame 6 in the lower chamber of the outermost circle, improves the structure and position of the air guide groove 61, and further improves the flowability of the airflow, so that the airflow can diffuse to the inner part of the lower chamber near the outer periphery, satisfies the pressure effect of the lower chamber at the edge, realizes the effective removal of the wafer edge, and ensures the processing quality of the wafer.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Multi-chamber polishing head, characterized in that: The invention comprises a polishing base (1), a retaining ring (2) and an elastic membrane assembly (3), wherein the retaining ring (2) is connected to the bottom of the polishing base (1) and forms a downwardly opening mounting cavity (11) with the polishing base (1), the elastic membrane assembly (3) is arranged in the mounting cavity (11), and a lower chamber and an upper chamber (31) are formed in the elastic membrane assembly (3), the lower chambers are provided with a plurality of them and are arranged in sequence from the center to the periphery of the mounting cavity (11), the upper chamber (31) is arranged at the top of the chamber in the outermost circle, an inner ring frame (6) is connected to the inner peripheral wall of the lower chamber located in the outermost circle, the inner ring frame (6) is located on a side of the lower chamber away from the center of the mounting cavity (11), and the inner ring frame (6) is provided with an air guide groove (61) extending downward.

2. The multi-chamber polishing head according to claim 1, characterized in that: The lower chamber comprises an inner chamber (32), an intermediate chamber (33) and an outer chamber (34); the intermediate chamber (33) is sleeved on the outer periphery of the inner chamber (32); the outer chamber (34) is sleeved on the outer periphery of the intermediate chamber (33); and an outer ring frame (4) is embedded on the outer peripheral wall of the outer chamber (34).

3. The multi-chamber polishing head according to claim 2, characterized in that: The outer chamber (34) has an extension chamber (36) extending toward one side of the center of the installation chamber (11) to above the middle chamber (33), and the upper chamber (31) is located above the outer chamber (34) and the extension chamber (36).

4. The multi-chamber polishing head according to claim 3, characterized in that: The bottom of the polishing base (1) is provided with a central base (5) extending into the mounting cavity (11); the outer periphery of the central base (5) is provided with a supporting ring plate (51) extending into the extension cavity (36); the supporting ring plate (51) is supported below the inner top wall of the extension cavity (36); and the extension cavity (36) is sealedly connected to the outer peripheral wall of the central base (5).

5. The multi-chamber polishing head according to claim 4, characterized in that: The intermediate chamber (33) is arranged higher than the inner chamber (32), and the outer periphery of the central base (5) is also provided with a lower ring plate (52) extending into the intermediate chamber (33). The lower ring plate (52) is supported below the inner top wall of the intermediate chamber (33), and the intermediate chamber (33) is sealedly connected to the outer peripheral wall of the central base (5).

6. The multi-chamber polishing head according to claim 2, characterized in that: A plurality of the intermediate chambers (33) are provided, and the plurality of the intermediate chambers (33) are arranged in sequence from the center to the periphery of the installation chamber (11).

7. The multi-chamber polishing head according to claim 2, characterized in that: A boss ring (35) for mounting the inner ring frame (6) is provided on the inner peripheral wall of the outer chamber (34); the inner ring frame (6) is connected to the inner peripheral wall of the boss ring (35); and the upper end of the air guide groove (61) extends toward the center of the mounting cavity (11).

8. The multi-chamber polishing head according to claim 7, characterized in that: The lower end surface of the boss ring (35) gradually extends outward and downward to connect with the inner bottom wall of the outer chamber (34), and a gap is provided between the lower edge of the inner ring frame (6) and the inner bottom wall of the outer chamber (34).

9. The multi-chamber polishing head according to claim 8, characterized in that: An extended ring plate (62) that is bent outward horizontally is provided on the upper edge of the inner ring frame (6), and the extended ring plate (62) is located between the upper end surface of the boss ring (35) and the inner top wall of the outer chamber (34).

10. Polishing equipment, characterized in that The polishing device comprises the multi-chamber polishing head according to any one of claims 1-9.

Images