Retaining ring for polishing head

Abstract

The utility model provides a retaining ring for a polishing head. The retaining ring comprises a structural plate, a supporting film, a supporting pad and a polishing plate. The structural plate and the polishing plate are annular and are coaxially arranged; a first groove extending in the annular direction is formed in the bottom face of the structural plate. The upper portion of the polishing plate is provided with a protruding structure matched with the first groove, and the protruding structure is embedded into the first groove. A supporting film is arranged on the inner circle part of the structural plate; the edge of the supporting film extends in the radial direction and is fixedly arranged between the structural plate and the polishing plate. A supporting pad is arranged below the supporting film; the bottom surface of the supporting pad is in contact with the top surface of the wafer; the inner circle side face of the polishing plate makes contact with the side face of the wafer. The retaining ring provided by the utility model can effectively fix the wafer and enable the wafer to be tightly attached to the polishing pad, is favorable for improving the removal rate and the polishing uniformity of the wafer, and has good stability in the polishing process.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical mechanical polishing, in particular to a retaining ring for a polishing head. Background Art

[0002] Chemical mechanical polishing (CMP) is a precision surface treatment technology used in semiconductor manufacturing. It achieves global flattening of the wafer surface by combining chemical etching and mechanical friction. During the CMP process, the polishing head support ring secures the wafer and applies pressure, rotating it and bringing it into contact with the rotating polishing pad. The chemical components of the polishing slurry and the abrasive particles act together on the wafer surface, removing material.

[0003] The design of the polishing head support ring needs to consider multiple factors, including: (1) the ability to apply uniform pressure on the wafer to ensure consistency and flatness during the polishing process; (2) good stability. During high-speed rotation and continuous polishing, the support ring needs to maintain high stability to avoid uneven polishing due to vibration or deviation; (3) good durability to withstand long-term polishing operations without deformation or damage.

[0004] Therefore, providing a retaining ring for a polishing head that is conducive to achieving global flattening of the wafer surface and has a stable structure is a technical problem that needs to be solved in the current field. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a retaining ring for a polishing head, which can effectively fix the wafer and make it fit tightly with the polishing pad, which is beneficial to improving the wafer removal rate and polishing uniformity, and has good stability during the polishing process.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] The utility model provides a retaining ring for a polishing head, the retaining ring comprising a structural plate, a supporting film, a supporting pad and a polishing plate;

[0008] The structural plate and polishing plate are both annular and coaxially arranged;

[0009] The bottom surface of the structural plate is provided with a first groove extending in a circumferential direction;

[0010] The upper portion of the polishing plate is provided with a protrusion structure matching the first groove, and the protrusion structure is embedded in the first groove;

[0011] A supporting membrane is provided on the inner circular portion of the structural plate;

[0012] The edge of the support film extends radially and is fixedly disposed between the structural plate and the polishing plate;

[0013] A support pad is provided below the support film;

[0014] The bottom surface of the support pad contacts the top surface of the wafer;

[0015] The inner circular side surface of the polishing plate contacts the side surface of the wafer.

[0016] In the support ring provided by the utility model, the inner circular side surface of the polishing plate contacts the side surface of the wafer, which plays a role in limiting the wafer; through the matching arrangement of the first groove and the convex structure, the position of the retaining ring can be limited to avoid vibration or deviation, thereby ensuring the uniformity and stability of the polishing effect; the structural plate plays a role in fixing the support ring on the polishing device, and is connected to the rotating shaft of the polishing device, so that the support ring drives the wafer to rotate; the support pad provides polishing pressure for the wafer, the upper surface of the wafer contacts the support pad, and the lower surface contacts the polishing pad, so that the lower surface of the wafer is globally flattened after chemical mechanical grinding; the support film plays a role in fixing the support pad.

[0017] Preferably, the edge of the supporting film is fixed between the structural plate and the polishing plate by screws.

[0018] Preferably, the radial cross-section of the first groove is a right-angled trapezoid.

[0019] Preferably, an annular mounting groove is provided on the upper outer circle of the structural plate.

[0020] Preferably, the annular mounting groove is connected to the rotating shaft of the polishing device.

[0021] Preferably, the bottom surface of the polishing plate is provided with first grooves spaced circumferentially.

[0022] Preferably, the number of the first grooves is at least 2, for example, 2, 3, 4, 5 or 6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the first grooves are arranged radially outward from the center of the polishing plate.

[0024] Preferably, a second groove is formed on the upper surface of the first groove, and the second groove is located above the protruding structure.

[0025] Preferably, the support pad and the support film are fixedly connected by double-sided tape.

[0026] In the present invention, holes can be provided on the support pad, and the support ring can be used to absorb and transfer wafers by cooperating with other devices having a suction function.

[0027] The operation process of the support ring provided by the utility model for chemical mechanical polishing is as follows:

[0028] Place the upper surface of the wafer under the support pad so that the inner circular side of the polishing plate contacts the side of the wafer, thereby limiting the position of the wafer. Connect the annular mounting groove of the structural plate to the rotating shaft of the polishing device so that the rotating shaft can drive the wafer to rotate through the support ring. At the same time, the lower surface of the wafer contacts the polishing pad. The polishing pad rotates and grinds the wafer at the same time. Polishing liquid is applied during the grinding process. The polishing liquid enters the interface between the polishing pad and the wafer through the first groove. The polishing liquid corrodes the wafer to further remove material.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The support ring provided by the utility model can effectively fix the wafer, make the wafer fit tightly against the polishing pad, and is conducive to the transportation of polishing liquid to the interface between the wafer and the polishing pad, thereby improving the removal rate and uniformity of the wafer. Moreover, through the matching arrangement of the first groove and the convex structure, the position of the polishing plate can be limited to avoid vibration or deviation, thereby ensuring the uniformity and stability of the polishing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of the support ring described in Example 1 of the present utility model;

[0032] Figure 2 This is a schematic diagram of the bottom surface structure of the polishing plate described in Example 1 of the present utility model;

[0033] In the figure: 1-structural plate; 2-support membrane; 3-support pad; 4-polishing plate; 5-second groove; 6-first groove; 7-annular mounting groove. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0035] The following is a further detailed description of the present invention. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0036] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] It should be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0038] Those skilled in the art should understand that the present invention must include necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not constitute the main innovation of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements or specific limitations on this.

[0039] In a specific embodiment, the present invention provides a retaining ring for a polishing head, such as Figure 1 As shown, the retaining ring includes a structural plate 1, a support film 2, a support pad 3 and a polishing plate 4. The structural plate 1 and the polishing plate 4 are both annular and coaxially arranged. The bottom surface of the structural plate 1 is provided with a first groove extending in the annular direction, and the upper part of the polishing plate 4 is provided with a convex structure matching the first groove, and the convex structure is embedded in the first groove. The inner circle part of the structural plate 1 is provided with a support film 2, and the edge of the support film 2 extends radially and is fixedly provided between the structural plate 1 and the polishing plate 4. A support pad 3 is provided below the support film 2, and the bottom surface of the support pad 3 contacts the top surface of the wafer, and the inner circle side surface of the polishing plate 4 contacts the side surface of the wafer.

[0040] The support ring provided by the utility model can effectively fix the wafer, is conducive to improving the removal rate and polishing uniformity of the wafer, and has good stability during the polishing process.

[0041] In some embodiments, the edge of the support film 2 is fixed between the structural plate 1 and the polishing plate 4 by screws.

[0042] In the present invention, the edge of the support film 2 is fixed between the structural plate 1 and the polishing plate 4 by using locking screws, which can ensure the stability of the support film 2, thereby stably fixing the support pad 3 and making the wafer evenly stressed.

[0043] In some embodiments, a radial cross-section of the first groove is a right-angled trapezoid.

[0044] In some embodiments, an annular mounting groove 7 is provided on the upper outer circle of the structural plate 1 .

[0045] In some embodiments, the annular mounting groove 7 is connected to the rotating shaft of the polishing device.

[0046] In the present invention, the annular mounting groove 7 is provided to be connected to the rotating shaft of the polishing device, so that the support ring can drive the wafer to rotate.

[0047] In some embodiments, such as Figure 2 As shown, the bottom surface of the polishing plate 4 is provided with first grooves 6 spaced apart in the circumferential direction.

[0048] In some embodiments, the number of the first grooves 6 is at least 2, for example, 2, 3, 4, 5 or 6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In some embodiments, the first grooves 6 are radially arranged from the center of the polishing plate 4 outward.

[0050] In the present invention, the provision of the first groove 6 enables the polishing liquid to continuously enter between the polishing pad and the wafer through the first groove 6, thereby improving the removal effect on the wafer.

[0051] In some embodiments, a second groove 5 is formed on the upper surface of the first groove, and the second groove 5 is located above the protruding structure.

[0052] In the present invention, the provision of the second groove 5 helps to reduce the change in air pressure between the first groove and the protruding structure during the polishing process.

[0053] In some embodiments, the support pad 3 and the support film 2 are fixedly connected by double-sided tape.

[0054] In the present invention, the double-sided adhesive tape can stably fix the support pad 3 on the support film 2, and also has good waterproof and acid-proof functions.

[0055] The technical effects of the present invention are described in detail below through Example 1:

[0056] Example 1

[0057] This embodiment provides a retaining ring for a polishing head, such as Figure 1 As shown, the retaining ring includes a structural plate 1, a supporting film 2, a supporting pad 3 and a polishing plate 4, the structural plate 1 and the polishing plate 4 are both annular and coaxially arranged, the bottom surface of the structural plate 1 is provided with a first groove extending in the annular direction, the radial cross-section of the first groove is a right-angled trapezoid, the upper part of the polishing plate 4 is provided with a convex structure matching the first groove, the convex structure is embedded in the first groove, the inner circle part of the structural plate 1 is provided with a supporting film 2, the edge of the supporting film 2 extends radially and is fixed between the structural plate 1 and the polishing plate 4 by screws, the supporting film 2 is fixedly connected to the supporting pad 3 by double-sided tape, the supporting pad 3 is arranged below the supporting film 2, the bottom surface of the supporting pad 3 contacts the top surface of the wafer, the inner circle side surface of the polishing plate 4 contacts the side surface of the wafer, the upper outer circle of the structural plate 1 is provided with an annular mounting groove 7, and the annular mounting groove 7 is connected to the rotating shaft of the polishing device, as shown Figure 2 As shown, the bottom surface of the polishing plate 4 is provided with first grooves 6 spaced circumferentially thereon, the number of the first grooves 6 is 8, and the first grooves 6 are arranged radially outward from the center of the polishing plate 4, and the upper top surface of the first groove is provided with second grooves 5, and the second grooves 5 are located above the raised structure.

[0058] The operation process of the support ring provided in the above embodiment for chemical mechanical polishing is as follows:

[0059] The upper surface of the wafer is placed under the support pad 3, so that the inner circular side of the polishing plate 4 contacts the side of the wafer, thereby limiting the position of the wafer, and the annular mounting groove 7 of the structural plate 1 is connected to the rotating shaft of the polishing device, so that the rotating shaft can drive the wafer to rotate through the support ring, and at the same time the lower surface of the wafer contacts the polishing pad, and the polishing pad rotates and grinds the wafer at the same time. Polishing liquid is applied during the grinding process, and the polishing liquid enters the interface between the polishing pad and the wafer through the first groove 6. The polishing liquid corrodes the wafer to further remove the material.

[0060] In summary, the retaining ring provided by the present invention can effectively fix the wafer and make it fit tightly with the polishing pad, which is beneficial to improving the removal rate and polishing uniformity of the wafer, and has good stability during the polishing process.

[0061] The applicant declares that the above is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Technicians in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technicians in the relevant technical field within the technical scope disclosed in the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A retaining ring for a polishing head, characterized in that: The retaining ring includes a structural plate, a support film, a support pad and a polishing plate; The structural plate and polishing plate are both annular and coaxially arranged; The bottom surface of the structural plate is provided with a first groove extending in a circumferential direction; The upper portion of the polishing plate is provided with a protrusion structure matching the first groove, and the protrusion structure is embedded in the first groove; A supporting membrane is provided on the inner circular portion of the structural plate; The edge of the support film extends radially and is fixedly disposed between the structural plate and the polishing plate; A support pad is provided below the support film; The bottom surface of the support pad contacts the top surface of the wafer; The inner circular side surface of the polishing plate contacts the side surface of the wafer.

2. The retaining ring for a polishing head according to claim 1, characterized in that: The edge of the supporting film is fixed between the structural plate and the polishing plate by screws.

3. The retaining ring for a polishing head according to claim 1, characterized in that: The cross section of the first groove along the radial direction is a right-angled trapezoid.

4. The retaining ring for a polishing head according to claim 1, characterized in that: An annular mounting groove is provided on the outer circle of the upper portion of the structural plate.

5. The retaining ring for a polishing head according to claim 4, characterized in that: The annular mounting groove is connected to the rotating shaft of the polishing device.

6. The retaining ring for a polishing head according to claim 1, characterized in that: The bottom surface of the polishing plate is provided with first grooves spaced apart in the circumferential direction.

7. The retaining ring for a polishing head according to claim 6, characterized in that: The number of the first grooves is at least 2.

8. The retaining ring for a polishing head according to claim 7, characterized in that: The first grooves are arranged radially outward from the center of the polishing plate.

9. The retaining ring for a polishing head according to claim 1, characterized in that: A second groove is formed on the upper surface of the first groove, and the second groove is located above the protruding structure.

10. The retaining ring for a polishing head according to claim 1, characterized in that: The support pad and the support film are fixedly connected by double-sided tape.

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