Wafer polishing head and polishing equipment

Abstract

The invention belongs to the technical field of semiconductor chip manufacturing, and particularly discloses a wafer polishing head and polishing equipment. According to the wafer polishing head provided by the invention, the first pressure applying element applies pressure to different areas of the transition disc in the radial direction of the mounting seat, and the second pressure applying element applies pressure to the transition disc in the same area range in the radial direction and at different positions in the circumferential direction; by means of the technical scheme, pressure is evenly applied to the transition disc in different areas in the radial direction and the circumferential direction, the non-uniformity of the pressure applied to the transition disc in the prior art is corrected and compensated, the polishing amount, the thickness size and the geometrical shape of the wafer are accurately controlled, and then the production quality of the wafer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor chip manufacturing, and in particular to a wafer polishing head and polishing equipment. Background Art

[0002] In the field of chemical mechanical polishing technology, the wafer is clamped at the lower end of a rotating polishing head, a polishing pad is provided at the upper end of a rotating polishing disk, and polishing liquid is provided between the wafer on the polishing head and the polishing pad. Under the combined action of chemistry and mechanics, the wafer is globally flattened.

[0003] Polishing heads in existing technology typically use a single flat plate for pressurization, which is unable to adjust for differences in polishing rate caused by factors such as differences in polishing linear speed, temperature, and polishing liquid flow rate in different areas of the wafer. This results in poor process flexibility and makes it difficult to effectively control polishing accuracy and polishing volume. To address the above technical issues, one or more airbags are installed on the polishing head for pressurization. The pressure applied by the polishing head to the wafer can be set separately in several annular areas where the airbags are fixed to compensate for the difference in polishing rate near the center and edge areas of the wafer. However, it is unable to correct for non-uniformity along the circumference of the airbag pressurization. As the polishing volume of the wafer increases, the difference in volume will accumulate, causing the wafer precision to deteriorate. Summary of the Invention

[0004] The purpose of the present invention is to provide a wafer polishing head and polishing equipment, which corrects and compensates for the unevenness of the pressure applied to the transition plate, thereby achieving precise control of the polishing removal, thickness size and geometric morphology of the wafer.

[0005] To achieve this object, the present invention adopts the following technical solutions:

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

[0007] a mounting seat, wherein a plurality of first pressure applying elements are provided on one side of the mounting seat, the plurality of first pressure applying elements are spaced apart along the radial direction of the mounting seat, and each of the first pressure applying elements extends along the circumference of the mounting seat;

[0008] a transition plate slidably connected to the mounting seat along an axis of the mounting seat, the first pressure applying element being disposed between the transition plate and the mounting seat, the first pressure applying element applying pressure to the transition plate, and a side of the transition plate facing away from the first pressure applying element being used to fix the wafer;

[0009] A second pressure-applying element is arranged between two adjacent first pressure-applying elements, and the second pressure-applying element is fixed to the mounting seat. The force-applying end of the second pressure-applying element is against the side of the transition plate facing the first pressure-applying element, and the second pressure-applying element is used to apply pressure to the transition plate.

[0010] As an optional technical solution for the above-mentioned wafer polishing head, a plurality of second pressure applying elements are provided between two adjacent first pressure applying elements, and the plurality of second pressure applying elements are arranged at circumferential intervals along the mounting seat, and the pressure applied by the second pressure applying elements on the transition plate is adjustable.

[0011] As an optional technical solution for the above-mentioned wafer polishing head, each of the second pressure-applying elements is correspondingly provided with a displacement detection element, which is used to detect the displacement of the transition plate relative to the mounting seat, and the second pressure-applying element is configured to be able to adjust the pressure applied to the transition plate in real time according to the displacement detected by the displacement detection element.

[0012] As an optional technical solution of the above-mentioned wafer polishing head, the second pressure applying element is a bidirectional cylinder.

[0013] As an optional technical solution for the above-mentioned wafer polishing head, the force-applying end of the second pressure-applying element passes through the mounting seat and is placed on the side of the mounting seat where the first pressure-applying element is provided. A buffer is provided at the end of the force-applying end of the second pressure-applying element, and the outer diameter of the buffer is larger than the outer diameter of the force-applying end of the second pressure-applying element.

[0014] As an optional technical solution of the above-mentioned wafer polishing head, the first pressure applying element is an airbag, the airbag has an inflation port, the inflation port is used to connect with an inflation device, and the pressure applied by the airbag on the transition plate is constant pressure.

[0015] As an optional technical solution for the above-mentioned wafer polishing head, the mounting seat includes a mounting seat body and a retaining ring, the retaining ring is arranged around the outer side wall of the mounting seat body, and one end of the retaining ring is connected to the mounting seat body, and the other end of the retaining ring is protruded on one side of the mounting seat body, the first pressure applying element, the second pressure applying element and the transition plate are arranged in the space enclosed by the retaining ring and the mounting seat body, and the transition plate is slidably connected to the retaining ring, and the first pressure applying element and the second pressure applying element are respectively connected to the mounting seat body.

[0016] As an optional technical solution of the above-mentioned wafer polishing head, one of the inner side wall of the retaining ring and the circumferential outer side wall of the transition plate is provided with a slider, and the other is provided with a slide groove, and the slider is provided in the slide groove.

[0017] As an optional technical solution for the above-mentioned wafer polishing head, the outer wall of the mounting seat body is provided with a mounting groove along the circumferential direction, one end of the retaining ring is placed in the mounting groove, and the outer wall of the retaining ring is flush with the outer wall of the mounting seat body.

[0018] In a second aspect, a polishing device is provided, comprising a polishing plate, a polishing head driving member and the above-mentioned wafer polishing head, wherein the polishing head driving member is used to drive the wafer polishing head to move toward the polishing plate, and the polishing plate is used to process the wafer fixed on the transition plate.

[0019] Beneficial effects of the present invention:

[0020] The wafer polishing head provided by the present invention has a first pressure-applying element that applies pressure to different areas of the transition plate along the radial direction of the mounting seat, and a second pressure-applying element that applies pressure to the transition plate within the same radial area and at different circumferential positions, thereby achieving uniform pressure application to the transition plate in different radial and circumferential areas, correcting and compensating for the unevenness of the pressure applied to the transition plate in the prior art, achieving precise control of the polishing removal, thickness size and geometric morphology of the wafer, and thereby improving the production quality of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a first isometric view of a wafer polishing head provided by an embodiment of the present invention;

[0022] Figure 2 is a second isometric view of a wafer polishing head provided by an embodiment of the present invention;

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

[0024] Figure 4 Schematic diagram of the internal structure of a wafer polishing head provided by an embodiment of the present invention;

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

[0026] In the picture:

[0027] 100, wafer;

[0028] 1. Mounting seat; 2. First pressure applying element; 3. Transition plate; 4. Second pressure applying element; 5. Displacement detecting element; 6. Slider; 7. Slide groove;

[0029] 11. Mounting seat body; 12. Retaining ring; 13. Mounting groove. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0031] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0032] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0034] like Figures 1 to 3As shown, this embodiment provides a wafer polishing head, which includes a mounting seat 1, a transition plate 3, a first pressure-applying element 2, and a second pressure-applying element 4. A plurality of first pressure-applying elements 2 are provided on one side of the mounting seat 1. 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 circumference of the mounting seat 1. The transition plate 3 is slidably connected to the mounting seat 1 along the axis of the mounting seat 1. The first pressure-applying element 2 is arranged between the transition plate 3 and the mounting seat 1. The first pressure-applying element 2 applies pressure to the transition plate 3. The side of the transition plate 3 facing away from the first pressure-applying element 2 is used to fix the wafer 100. The pressure applied by each first pressure-applying element 2 to the transition plate 3 is distributed around the circumference of the mounting seat 1, and the pressure applied by the plurality of first pressure-applying elements 2 to the transition plate 3 is distributed along the radial direction of the mounting seat 1. However, due to the interval between the two adjacent first pressure-applying elements 2, the pressure applied to the transition plate 3 still has the problem of unevenness. Therefore, a second pressure-applying element 4 is arranged between the two adjacent 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 is against the side of the transition plate 3 facing the first pressure-applying element 2. The second pressure-applying element 4 is used to apply pressure to the transition plate 3.

[0035] In the wafer polishing head provided in this embodiment, the first pressure-applying element 2 applies pressure to different areas of the transition plate 3 along the radial direction of the mounting seat 1, and the second pressure-applying element 4 applies pressure to the transition plate 3 within the same radial area and at different positions along the circumferential direction, thereby achieving uniform pressure on the transition plate 3 in different areas in the radial direction and in the circumferential direction, correcting and compensating for the unevenness of the pressure applied to the transition plate in the prior art, and achieving precise control of the polishing removal, thickness size and geometric morphology of the wafer 100, thereby improving the production quality of the wafer 100.

[0036] In some embodiments, as Figure 3 As shown, the mounting base 1 includes a mounting base body 11 and a retaining ring 12. The retaining ring 12 is arranged around the outer wall of the mounting base body 11, and one end of the retaining ring 12 is connected to the mounting base body 11. The other end of the retaining ring 12 is protruded from one side of the mounting base body 11. The first pressure applying element 2, the second pressure applying element 4, and the transition plate 3 are arranged in the space enclosed by the retaining ring 12 and the mounting base body 11. The transition plate 3 is slidably connected to the retaining ring 12. The first pressure applying element 2 and the second pressure applying element 4 are respectively connected to the mounting base body 11. The retaining ring 12 provides support for the installation of the transition plate 3 and provides space for the transition plate 3 to slide.

[0037] Optionally, one of the inner side wall of the retaining ring 12 and the circumferential outer side wall of the transition plate 3 is provided with a slider 6, and the other is provided with a slide groove 7. The slider 6 is arranged in the slide groove 7, thereby realizing a sliding connection between the transition plate 3 and the retaining ring 12.

[0038] The outer wall of the mounting seat body 11 is circumferentially recessed with a mounting groove 13, one end of the retaining ring 12 is placed in the mounting groove 13, and the outer wall of the retaining ring 12 is flush with the outer wall of the mounting seat body 11 to reduce the radial size of the mounting seat 1 and not occupy space.

[0039] In some embodiments, combined 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 bonding. Specifically, the airbag is connected to the mounting base body 11 by 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 the airbag is inflated, it drives the transition plate 3 to slide and applies pressure to the transition plate 3. However, the airbag is a flexible part. When polishing the wafer 100 fixed on the transition plate 3, a force can be applied to the transition plate 3. This force is opposite to the force applied by the airbag on the transition plate 3, causing the transition plate 3 to float up and down, thereby preventing a part of the wafer 100 from being over-polished and affecting the processing quality of the wafer 100. During the processing of the wafer 100, the pressure applied by the airbag on the transition plate 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 an annular structure, that is, the airbag is arranged around the circumference of the mounting seat 1. Alternatively, the airbag is arc-shaped and is arranged at intervals along the circumference of the mounting seat 1 to form an annular structure.

[0041] In some embodiments, see Figure 3 and Figure 4 As shown, a plurality of second pressure applying elements 4 are provided between two adjacent first pressure applying elements 2, and the plurality of second pressure applying elements 4 are arranged at intervals along the circumference of the mounting seat 1. The pressure applied by the second pressure applying elements 4 on the transition plate 3 is adjustable, and can be adjusted according to the polishing rate differences caused by factors such as the polishing line speed differences, temperature, and polishing liquid flow rate in different areas of the wafer 100, thereby improving the flexibility of the processing technology and effectively controlling the processing accuracy and removal amount of the wafer 100.

[0042] Optionally, the second pressure applying element 4 is a bidirectional cylinder, which can achieve relatively precise position and speed control, has a small size, does not occupy space, and can directly achieve bidirectional movement.

[0043] like Figure 4 and Figure 5As shown, each second pressure-applying element 4 is provided with a corresponding displacement detection element 5. The displacement detection element 5 is used to detect the displacement of the transition plate 3 relative to the mounting base 1. The second pressure-applying element 4 is configured to adjust the pressure applied to the transition plate 3 in real time based on the displacement detected by the displacement detection element 5. The displacement detection element 5 can detect in real time the force acting on the transition plate 3 that is opposite to that applied by the second pressure-applying element 4. By monitoring the data at each measurement point, the difference in the amount of polishing or removal rate in different areas of the wafer 100 can be understood. The removal rate of a specific area of ​​the wafer 100 can then be controlled by controlling the second pressure-applying element 4 corresponding to that measurement point. Ultimately, precise control of the polishing rate and amount of polishing in any area of ​​the wafer 100 is achieved, unaffected by the polishing fluid, preventing the wafer 100 from being over-polished and causing degradation in wafer 100 precision. It should be further explained that the displacement detection element 5 measures the change in position of the transition plate 3 relative to the mounting base 1. This change in position represents the amount of polishing of the wafer 100 in that area.

[0044] Optionally, the force-applying end of the second pressure-applying element 4 passes through the mounting seat 1 and is positioned on the side of the mounting seat 1 where the first pressure-applying element 2 is positioned. A buffer is provided at the end of the force-applying end of the second pressure-applying element 4, and the outer diameter of the buffer is larger than that of the force-applying end of the second pressure-applying element 4. This buffer serves to restrain the second pressure-applying element 4 and flexibly contacts the transition disc 3, applying a certain amount of force to cushion the displacement of the transition disc 3. The buffer can be made of rubber, which is not specifically limited here.

[0045] This embodiment also provides a polishing device, including a polishing plate, a polishing head driver, and the aforementioned wafer polishing head. The polishing head driver is used to drive the wafer polishing head toward the polishing plate, which is used to process the wafer 100 fixed on the transition plate 3. The polishing plate and the polishing head driver are both prior art and will not be described in detail here.

[0046] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A wafer polishing head, characterized in that: include: A mounting seat (1), wherein a plurality of first pressure applying elements (2) are provided on one side of the mounting seat (1), the plurality of first pressure applying elements (2) are arranged at intervals along the radial direction of the mounting seat (1), and each of the first pressure applying elements (2) extends along the circumference of the mounting seat (1); a transition plate (3) slidably connected to the mounting seat (1) along the axis of the mounting seat (1); the first pressure applying element (2) is arranged between the transition plate (3) and the mounting seat (1); the first pressure applying element (2) applies pressure to the transition plate (3); and a side of the transition plate (3) facing away from the first pressure applying element (2) is used to fix the wafer (100); A second pressure applying element (4) is arranged between two adjacent 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) is against the side of the transition plate (3) facing the first pressure applying element (2), and the second pressure applying element (4) is used to apply pressure to the transition plate (3).

2. The wafer polishing head according to claim 1, characterized in that: A plurality of second pressure applying elements (4) are provided between two adjacent first pressure applying elements (2), the plurality of second pressure applying elements (4) are arranged at intervals along the circumference of the mounting seat (1), and the pressure applied by the second pressure applying elements (4) to the transition disc (3) is adjustable.

3. The wafer polishing head according to claim 2, characterized in that: Each of the second pressure applying elements (4) is correspondingly provided with a displacement detecting element (5), the displacement detecting element (5) being used to detect the displacement of the transition plate (3) relative to the mounting seat (1), and the second pressure applying element (4) being configured to be able to adjust the pressure applied to the transition plate (3) in real time according to the displacement detected by the displacement detecting element (5).

4. The wafer polishing head according to claim 2, characterized in that: The second pressure applying element (4) is a bidirectional cylinder.

5. The wafer polishing head according to claim 1, wherein: The force-applying end of the second pressure-applying element (4) passes through the mounting seat (1) and is placed on the side of the mounting seat (1) where the first pressure-applying element (2) is provided. A buffer is provided at the end of the force-applying end of the second pressure-applying element (4), and the outer diameter of the buffer is larger than the outer diameter of the force-applying end of the second pressure-applying element (4).

6. The wafer polishing head according to claim 1, characterized in that: The first pressure applying element (2) is an airbag having an inflation port, the inflation port being used to connect to an inflation device, and the pressure applied by the airbag to the transition plate (3) is a constant pressure.

7. The wafer polishing head according to claim 1, wherein: The mounting seat (1) includes a mounting seat body (11) and a retaining ring (12), wherein the retaining ring (12) is arranged around the outer wall of the mounting seat body (11), and one end of the retaining ring (12) is connected to the mounting seat body (11), and the other end of the retaining ring (12) is protruded on one side of the mounting seat body (11), the first pressure applying element (2), the second pressure applying element (4) and the transition plate (3) are arranged in a space enclosed by the retaining ring (12) and the mounting seat body (11), and the transition plate (3) is slidably connected to the retaining ring (12), and the first pressure applying element (2) and the second pressure applying element (4) are respectively connected to the mounting seat body (11).

8. The wafer polishing head according to claim 7, characterized in that: One of the inner side wall of the retaining ring (12) and the circumferential outer side wall of the transition plate (3) is provided with a slider (6), and the other is provided with a slide groove (7), wherein the slider (6) is arranged in the slide groove (7).

9. The wafer polishing head according to claim 7, characterized in that: The outer wall of the mounting seat body (11) is provided with a mounting groove (13) along the circumferential direction, one end of the retaining ring (12) is placed in the mounting groove (13), and the outer wall of the retaining ring (12) is flush with the outer wall of the mounting seat body (11).

10. A polishing device, characterized in that: The invention comprises a polishing plate, a polishing head driving member and a wafer polishing head according to any one of claims 1 to 9, wherein the polishing head driving member is used to drive the wafer polishing head to move toward the polishing plate, and the polishing plate is used to process the wafer (100) fixed on the transition plate (3).

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