Wafer polishing head and polishing apparatus

Abstract

The application belongs to the technical field of semiconductor chip manufacturing, and particularly discloses a wafer polishing head and a polishing device. The wafer polishing head provided by the application exerts pressure on different areas of the transition disc by the first pressure exerting element along the radial direction of the mounting seat, and exerts pressure on the transition disc at different positions in the same area range in the radial direction and along the circumferential direction by the second pressure exerting element, so that the pressure is uniformly exerted on the transition disc in different areas in the radial direction and in the circumferential direction, the non-uniformity of the pressure exerted on the transition disc in the prior art is corrected and compensated, the polishing amount, thickness size and geometric appearance of the wafer are accurately controlled, and the production quality of the wafer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor chip manufacturing, and in particular to a wafer polishing head and a polishing device. BACKGROUND

[0002] In the field of chemical mechanical polishing technology, a wafer is clamped at the lower end of a rotating polishing head, and a polishing pad is arranged at the upper end of a rotating polishing disc. A polishing liquid is arranged between the wafer on the polishing head and the polishing pad. Under the combined action of chemical and mechanical forces, the wafer is globally planarized.

[0003] The polishing head in the prior art usually uses a whole flat plate for pressing, and cannot adjust the polishing rate caused by the polishing linear velocity difference, temperature, polishing liquid flow and other factors in different areas of the wafer. The process flexibility is poor, and it is difficult to effectively control the precision and amount of polishing. In order to solve the above technical problems, one or more air bags are arranged on the polishing head for pressing. The pressure applied by the polishing head to the wafer in the several annular areas fixed by the air bags can be set respectively to make up for the polishing rate difference of the wafer near the central area and the edge area. However, the non-uniformity of the air bag pressure cannot be corrected and made up. When the polishing amount of the wafer increases, the amount difference will be accumulated to cause the wafer precision to deteriorate. SUMMARY

[0004] The purpose of the present application is to provide a wafer polishing head and a polishing device, which corrects and makes up the non-uniformity of the pressure applied to the transition disc, and realizes accurate control of the polishing amount, thickness size and geometric appearance of the wafer.

[0005] To achieve this purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, a wafer polishing head is provided, comprising:

[0007] A mounting seat, one side of the mounting seat is provided with a plurality of first pressure applying elements, the plurality of first pressure applying elements are arranged at intervals along the radial direction of the mounting seat, and each first pressure applying element extends along the circumferential direction of the mounting seat;

[0008] A transition disc is slidably connected to the mounting seat along the axis of the mounting seat, the first pressure applying elements are arranged between the transition disc and the mounting seat, the first pressure applying elements apply pressure to the transition disc, and the side of the transition disc away from the first pressure applying elements is used to fix a wafer;

[0009] A second pressure applying element is arranged between two adjacent first pressure applying elements, the second pressure applying element is fixed to the mounting base, the force applying end of the second pressure applying element abuts the side of the transition disc facing the first pressure applying element, and the second pressure applying element is used to apply pressure to the transition disc.

[0010] As an optional technical solution of the wafer polishing head, a plurality of second pressure applying elements are arranged between two adjacent first pressure applying elements, the plurality of second pressure applying elements are arranged at intervals along the circumference of the mounting base, and the pressure applied by the second pressure applying elements to the transition disc is adjustable.

[0011] As an optional technical solution of the wafer polishing head, each second pressure applying element is correspondingly provided with a displacement detection member, the displacement detection member is used to detect the displacement of the transition disc relative to the mounting base, and the second pressure applying element is configured to adjust the pressure applied to the transition disc in real time according to the displacement detected by the displacement detection member.

[0012] As an optional technical solution of the wafer polishing head, the second pressure applying element is a double-acting pneumatic cylinder.

[0013] As an optional technical solution of the wafer polishing head, the force applying end of the second pressure applying element penetrates the mounting base and is arranged on the side of the mounting base provided with the first pressure applying element, an end portion of the force applying end of the second pressure applying element is provided with a buffer member, and the outer diameter of the buffer member is greater than the outer diameter of the force applying end of the second pressure applying element.

[0014] As an optional technical solution of the wafer polishing head, the first pressure applying element is an air bag, the air bag has an inflation port for connecting with an inflation device, and the pressure applied by the air bag to the transition disc is constant pressure.

[0015] As an optional technical solution of the wafer polishing head, the mounting base comprises a mounting base body and a retaining ring, the retaining ring is arranged around the outer sidewall of the mounting base body, one end of the retaining ring is connected with the mounting base body, and the other end of the retaining ring protrudes from one side of the mounting base body, the first pressure applying element, the second pressure applying element, and the transition disc are arranged in the space enclosed by the retaining ring and the mounting base body, the transition disc is in sliding connection with the retaining ring, and the first pressure applying element and the second pressure applying element are respectively connected with the mounting base body.

[0016] As an optional technical scheme of the wafer polishing head, one of the inner side wall of the retaining ring and the circumferential outer side wall of the transition disc is provided with a sliding block, and the other is provided with a sliding groove, and the sliding block is arranged in the sliding groove.

[0017] As an optional technical scheme of the wafer polishing head, the outer side wall of the mounting seat body is recessed in the circumferential direction to form a mounting groove, one end of the retaining ring is arranged in the mounting groove, and the outer side wall of the retaining ring is flush with the outer side wall of the mounting seat body.

[0018] In a second aspect, a polishing device is provided, comprising a polishing disc, a polishing head driving member and the wafer polishing head, the polishing head driving member is used to drive the wafer polishing head to move towards the polishing disc, and the polishing disc is used to process the wafer fixed on the transition disc.

[0019] The wafer polishing head provided by the present application has the following beneficial effects:

[0020] The wafer polishing head provided by the present application has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a first axial side view of the wafer polishing head provided by the embodiment of the present application;

[0022] Figure 2 is a second axial side view of the wafer polishing head provided by the embodiment of the present application;

[0023] Figure 3 is a first cross-sectional view of the wafer polishing head provided by the embodiment of the present application;

[0024] Figure 4 is a schematic view of the internal structure of the wafer polishing head provided by the embodiment of the present application;

[0025] Figure 5 is a second cross-sectional view of the wafer polishing head provided by the embodiment of the present application.

[0026] In the drawings:

[0027] 100, wafer;

[0028] 1, mounting seat; 2, first pressure applying element; 3, transition disc; 4, second pressure applying element; 5, displacement detecting piece; 6, sliding block; 7, sliding groove;

[0029] 11, mounting seat body; 12, retaining ring; 13, mounting groove. DETAILED DESCRIPTION

[0030] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended for the purpose of interpretation of the application and are not intended to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for the purpose of description.

[0031] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrated; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0032] In the application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0033] In the description of the embodiments, the terms "upper", "lower", "right", and other orientation or position relationships are based on the orientation or position relationship shown in the drawings, and are only for the purpose of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0034] As Figures 1 to 3As shown, the embodiment provides a wafer polishing head, which comprises a mounting seat 1, a transition disc 3, a first pressure applying element 2 and a second pressure applying element 4. The mounting seat 1 is provided with a plurality of first pressure applying elements 2 on one side thereof, the plurality of first pressure applying elements 2 are arranged at intervals along the radial direction of the mounting seat 1, and each first pressure applying element 2 extends along the circumferential direction of the mounting seat 1. The transition disc 3 is slidably connected to the mounting seat 1 along the axis of the mounting seat 1, the first pressure applying elements 2 are arranged between the transition disc 3 and the mounting seat 1, the first pressure applying elements 2 apply pressure to the transition disc 3, and the side of the transition disc 3 away from the first pressure applying elements 2 is used to fix a wafer 100. The pressure applied by each first pressure applying element 2 to the transition disc 3 is distributed along the circumferential direction of the mounting seat 1, and the pressure applied by the plurality of first pressure applying elements 2 to the transition disc 3 is distributed along the radial direction of the mounting seat 1. However, due to the interval arrangement between adjacent two first pressure applying elements 2, the pressure applied to the transition disc 3 is still uneven, so the second pressure applying element 4 is arranged between adjacent two first pressure applying elements 2, the second pressure applying element 4 is fixed to the mounting seat 1, the force applying end of the second pressure applying element 4 abuts against the side of the transition disc 3 facing the first pressure applying elements 2, and the second pressure applying element 4 is used to apply pressure to the transition disc 3.

[0035] The wafer polishing head provided by the embodiment applies pressure to different areas of the transition disc 3 by the first pressure applying elements 2 along the radial direction of the mounting seat 1, applies pressure to the transition disc 3 at different positions along the circumferential direction within the same area range along the radial direction by the second pressure applying element 4, realizes uniform application of pressure to the transition disc 3 at different areas along the radial direction and along the circumferential direction, corrects and makes up the unevenness of the pressure applied to the transition disc in the prior art, realizes accurate control of the polishing amount, thickness size and geometric appearance of the wafer 100, and further improves the production quality of the wafer 100.

[0036] In some embodiments, as shown, Figure 3 As shown, the mounting seat 1 comprises a mounting seat body 11 and a retaining ring 12, the retaining ring 12 is arranged around the outer sidewall of the mounting seat body 11, one end of the retaining ring 12 is connected to the mounting seat body 11, the other end of the retaining ring 12 protrudes from one side of the mounting seat body 11, the first pressure applying elements 2, the second pressure applying elements 4 and the transition disc 3 are arranged in the space surrounded by the retaining ring 12 and the mounting seat body 11, the transition disc 3 is slidably connected to the retaining ring 12, and the first pressure applying elements 2 and the second pressure applying elements 4 are respectively connected to the mounting seat body 11. The retaining ring 12 provides support for the mounting of the transition disc 3 and provides space for the sliding of the transition disc 3.

[0037] Optionally, a slider 6 is provided on one of the inner sidewall of the retaining ring 12 and the circumferential outer sidewall of the transition disk 3, and a groove 7 is provided on the other. The slider 6 is disposed in the groove 7, thereby realizing the sliding connection between the transition disk 3 and the retaining ring 12.

[0038] The outer side wall of the mounting base body 11 is recessed with a mounting groove 13 along the circumference. One end of the retaining ring 12 is placed in the mounting groove 13, and the outer side wall of the retaining ring 12 is flush with the outer side wall of the mounting base body 11, so as to reduce the radial dimension of the mounting base 1 and not occupy space.

[0039] In some embodiments, combined with Figure 3 and Figure 4 As shown, the first pressure applying element 2 is an airbag, which can be connected to the mounting base 1 by adhesive bonding. Specifically, the airbag is connected to the mounting base body 11 by adhesive bonding. The airbag has an inflation port, which is used to connect to an inflation device. The inflation device inflates the airbag through the inflation port. After being inflated, the airbag drives the transition disk 3 to slide and applies pressure to the transition disk 3. However, the airbag is a flexible component. When polishing the wafer 100 fixed on the transition disk 3, a force can be applied to the transition disk 3. This force is opposite to the force applied to the transition disk 3 by the airbag, allowing the transition disk 3 to float up and down, preventing localized over-polishing of the wafer 100 and affecting the processing quality of the wafer 100. During the processing of the wafer 100, the pressure applied by the airbag to the transition disk 3 is constant and does not change. After the wafer 100 is processed, the air in the airbag can be discharged through the inflation port.

[0040] Optionally, the airbag is a ring-shaped structure, that is, the airbag is arranged around the circumference of the mounting base 1. Alternatively, the airbag is arc-shaped and is arranged at intervals along the circumference of the mounting base 1 to form a ring structure.

[0041] In some embodiments, see continue to see Figure 3 and Figure 4 As shown, multiple second pressure applying elements 4 are provided between two adjacent first pressure applying elements 2. The multiple second pressure applying elements 4 are arranged at intervals along the circumference of the mounting base 1. The pressure applied by the second pressure applying elements 4 to the transition disk 3 is adjustable. It can adjust the polishing rate caused by factors such as the difference in polishing line speed, temperature, and polishing fluid flow rate in different areas of the wafer 100, thereby improving the flexibility of the processing technology and effectively controlling the precision and quantity of wafer 100 processing.

[0042] Optionally, the second pressure application element 4 is a two-way cylinder, which can achieve relatively precise position and speed control, is small in size, does not occupy space, and can directly achieve two-way movement.

[0043] like Figure 4 and Figure 5As shown, each second pressure applying element 4 is correspondingly provided with a displacement detecting piece 5 for detecting the displacement of the transition disc 3 relative to the mounting base 1, and the second pressure applying element 4 is configured to adjust the pressure applied on the transition disc 3 in real time according to the displacement detected by the displacement detecting piece 5. The displacement detecting piece 5 can detect the force acting on the transition disc 3 in real time and opposite to the force applied by the second pressure applying element 4. By monitoring the data of each measuring point, the difference of the removal or removal rate of the wafer 100 in different areas can be known, and then the removal rate of the wafer 100 in a specific area is controlled through the control of the second pressure applying element 4 corresponding to the measuring point, so as to finally realize the accurate control of the polishing rate and removal of the wafer 100 in any area, which is not affected by the polishing liquid and avoids the precision degradation of the wafer 100 caused by over-polishing. It needs to be further explained that the displacement detecting piece 5 measures the position change of the transition disc 3 relative to the mounting base 1, and the position change is the removal of the wafer 100 in the corresponding area during polishing.

[0044] Optionally, the force applying end of the second pressure applying element 4 penetrates the mounting base 1 and is arranged on the side of the mounting base 1 provided with the first pressure applying element 2, and the end of the force applying end of the second pressure applying element 4 is provided with a buffer piece, and the outer diameter of the buffer piece is greater than the outer diameter of the force applying end of the second pressure applying element 4. The buffer piece is arranged to limit the second pressure applying element 4, and the buffer piece is in flexible contact with the transition disc 3 to apply a certain buffer force to the displacement change of the transition disc 3. The buffer piece can be made of rubber, which is not limited here.

[0045] The embodiment also provides a polishing device, which comprises a polishing disc, a polishing head driving piece and the wafer polishing head, the polishing head driving piece is used to drive the wafer polishing head to move towards the polishing disc, and the polishing disc is used to process the wafer 100 fixed on the transition disc 3. The polishing disc and the polishing head driving piece are both prior art, which will not be specifically introduced here.

[0046] Obviously, the above embodiment of the present application is only an example for clearly illustrating the present application, and is not a limitation on the embodiments of the present application. Those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the protection scope of the present application. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent substitution and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A wafer polishing head, comprising: The utility model relates to a wafer fixing device, which comprises: a mounting seat (1) provided with a plurality of first pressure applying elements (2) on one side thereof, the first pressure applying elements (2) being spaced apart along the radial direction of the mounting seat (1), and each of the first pressure applying elements (2) extending along the circumferential direction of the mounting seat (1); a transition disc (3) slidably connected to the mounting seat (1) along the axis of the mounting seat (1), the first pressure applying elements (2) being arranged between the transition disc (3) and the mounting seat (1), the first pressure applying elements (2) applying pressure to the transition disc (3), and the side of the transition disc (3) facing away from the first pressure applying elements (2) being used for fixing a wafer (100); a second pressure applying element (4) arranged between two adjacent first pressure applying elements (2), the second pressure applying element (4) being fixed to the mounting seat (1), the force applying end of the second pressure applying element (4) abutting against the side of the transition disc (3) facing the first pressure applying elements (2), and the second pressure applying element (4) being used for applying pressure to the transition disc (3); a plurality of second pressure applying elements (4) being arranged between two adjacent first pressure applying elements (2), the second pressure applying elements (4) being spaced apart along the circumferential direction of the mounting seat (1), and the pressure applied by the second pressure applying elements (4) to the transition disc (3) being adjustable; the second pressure applying element (4) being a bidirectional air cylinder; the first pressure applying element (2) being an air bag, the air bag being provided with an inflation port for connecting to an inflation device, and the pressure applied by the air bag to the transition disc (3) being constant.

2. The wafer polishing head of claim 1, wherein Each of the second pressure applying elements (4) is correspondingly provided with a displacement detection member (5) for detecting the displacement of the transition disc (3) relative to the mounting seat (1), and the second pressure applying element (4) is configured to adjust the pressure applied to the transition disc (3) in real time according to the displacement detected by the displacement detection member (5).

3. The wafer polishing head of claim 1, wherein The force applying end of the second pressure applying element (4) penetrates through the mounting seat (1) and is arranged on the side of the mounting seat (1) provided with the first pressure applying elements (2), and the end of the force applying end of the second pressure applying element (4) is provided with a buffer member, the outer diameter of the buffer member being greater than the outer diameter of the force applying end of the second pressure applying element (4).

4. The wafer polishing head of claim 1, wherein The mounting seat (1) comprises a mounting seat body (11) and a retaining ring (12), the retaining ring (12) is arranged around the outer side wall of the mounting seat body (11), one end of the retaining ring (12) is connected with the mounting seat body (11), the other end of the retaining ring (12) is arranged on one side of the mounting seat body (11), the first pressure applying element (2), the second pressure applying element (4) and the transition disc (3) are arranged in the space surrounded by the retaining ring (12) and the mounting seat body (11), the transition disc (3) is slidingly connected with the retaining ring (12), and the first pressure applying element (2) and the second pressure applying element (4) are respectively connected with the mounting seat body (11).

5. The wafer polishing head of claim 4, wherein One of the inner side wall of the retaining ring (12) and the circumferential outer side wall of the transition disc (3) is provided with a sliding block (6), and the other is provided with a sliding groove (7), the sliding block (6) is arranged in the sliding groove (7).

6. The wafer polishing head of claim 4, wherein The outer side wall of the mounting seat body (11) is recessed in the circumferential direction to form a mounting groove (13), one end of the retaining ring (12) is arranged in the mounting groove (13), and the outer side wall of the retaining ring (12) is flush with the outer side wall of the mounting seat body (11).

7. A polishing apparatus characterized by comprising: The polishing head comprises a polishing disc, a polishing head driving element and the wafer polishing head according to any one of claims 1-6, the polishing head driving element is used for driving the wafer polishing head to move towards the polishing disc, and the polishing disc is used for processing the wafer (100) fixed on the transition disc (3).

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