An edge polishing adsorption chuck for improving ring defects on a wafer surface

Abstract

The utility model relates to a kind of edge polishing polishing adsorption chuck for improving wafer surface annular defect, including chuck body, chuck body is circular table structure, chuck body upper end is big, lower end is small, chuck body upper end is the adsorption mesa of flat, the vertical one vacuum hole is set in the upper end middle part of adsorption mesa, vacuum hole lower end penetrates chuck body bottom, adsorption mesa is evenly provided with several long recesses around vacuum hole upper end, several long recesses are radially arranged, and one end of long recess is communicated with vacuum hole.The utility model innovatively introduces integrated edge polishing chuck, the contact area of integrated edge polishing chuck and adsorption pad is the flat mesa of unified material quality, effectively solve the deformation problem caused by mesa uneven after long-term use of adsorption pad, wafer and adsorption pad are evenly stressed, eliminate the annular defect problem on wafer surface.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing equipment technology, and in particular to an edge polishing adsorption chuck for improving annular defects on wafer surfaces. Background Technology

[0002] Edge polishing machines are commonly used equipment in wafer fabrication, primarily for processing V-grooves and edge surfaces of wafers to reduce stress concentration and microcracks at the wafer edges. During edge surface processing, the front side of the wafer is vacuum-adsorbed onto an edge polishing chuck with an adsorption pad. In existing technology, the edge polishing chuck of edge polishing machines typically employs a combined structure, i.e., the edge polishing chuck body (refer to...) Figure 5 Plastic rings and V-rings are added to the edges (as shown) to assist in vacuum adsorption and positioning.

[0003] However, existing edge-polishing chucks have unevenness at the interface between the plastic ring and the chuck body. As the adsorption pad is used, it gradually deforms, resulting in a slight bulge in this annular area. This reduces the contact area between the wafer and this annular area, increasing the stress and forming annular defects on the wafer surface. These annular defects lead to particle defects, see... Figure 6 As shown, surface particles on wafers are the "invisible killers" of semiconductor back-end manufacturing yield. They can damage all critical processes, leading to various structural defects and electrical failures, ultimately causing chip malfunction or reliability issues. Therefore, optimizing the design of edge-throwing chucks and improving the reduction of annular defects are important measures to improve product quality and yield. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide an edge polishing adsorption chuck for improving annular defects on the wafer surface. In view of the shortcomings of existing edge polishing chucks, the plastic ring and V-ring design of the original edge polishing chuck are abandoned, and an integrated edge polishing chuck is innovatively introduced. The contact area between the integrated edge polishing chuck and the adsorption pad is a flat platform of the same material, which effectively solves the problem of deformation caused by unevenness of the adsorption pad after long-term use. The wafer and the adsorption pad are evenly stressed, eliminating the problem of annular defects on the wafer surface.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: A chuck for improving annular defects on wafer surfaces is provided, comprising a chuck body, the chuck body having a frustum-shaped structure, the upper end of the chuck body being larger than the lower end, the upper surface of the chuck body being a flat adsorption platform, a vacuum through hole vertically formed in the middle of the upper part of the adsorption platform, the lower end of the vacuum through hole penetrating the bottom of the chuck body, a plurality of elongated grooves evenly formed around the vacuum through hole on the adsorption platform, the plurality of elongated grooves being arranged radially, one end of the elongated groove communicating with the vacuum through hole, the other end of the elongated groove extending to the edge of the adsorption platform, and adsorption pads attached to the adsorption platform except for the elongated grooves and the vacuum through hole.

[0006] As a supplement to the technical solution described in this utility model, the chuck body is integrally molded from polytetrafluoroethylene material, and the flatness error of its adsorption platform is ≤0.01mm / m.

[0007] As a supplement to the technical solution described in this utility model, the bottom of the chuck body is provided with a number of connection holes around the lower port of the vacuum through hole. These connection holes are used in conjunction with fasteners to connect and fix the chuck body to the worktable of the edge polishing machine.

[0008] As a supplement to the technical solution described in this utility model, the number of elongated grooves is 6-8, the depth of the elongated grooves is 0.5-1mm, and the spacing between adjacent elongated grooves is 5-10mm.

[0009] As a supplement to the technical solution described in this utility model, the upper edge of the chuck body is provided with an arc-shaped chamfer with a radius of 0.5-1mm.

[0010] As a supplement to the technical solution described in this utility model, the upper port of the vacuum through hole is coaxially provided with an enlarged flared opening.

[0011] Beneficial effects: This utility model relates to an edge polishing adsorption chuck for improving annular defects on wafer surfaces, and has the following significant advantages:

[0012] 1. Elimination of ring defects: The integrated PTFE chuck structure avoids the splicing structure of traditional combined chucks. The flatness error of the adsorption stage is ≤0.01mm / m. There is no local deformation after the adsorption pad is attached. The incidence of ring defects on the wafer surface is reduced from 7%-10% to less than 0.5%.

[0013] 2. High vacuum adsorption efficiency: The radial strip grooves form an efficient vacuum conduction path, ensuring uniform adsorption force transmission. The contact area between the wafer and the adsorption pad increases by 20%-30%, and the local pressure deviation is controlled within ±5%.

[0014] 3. Long service life: The wear resistance of polytetrafluoroethylene material is 3-5 times that of traditional plastics. The service life of the chuck body can reach more than 100,000 wafers, and the replacement cycle of the adsorption pad is extended from 500 pads to 800-1000 pads, reducing consumable costs.

[0015] 4. Easy installation: The frustum-shaped structure and bottom connection hole ensure quick positioning of the chuck and polishing machine. The installation time is ≤10 minutes and the positioning accuracy is ≤0.02mm, reducing equipment debugging time.

[0016] 5. To address the shortcomings of existing edge polishing chucks, the original plastic ring and V-ring design of edge polishing chucks have been abandoned, and an innovative integrated edge polishing chuck has been introduced. The contact area between the integrated edge polishing chuck and the adsorption pad is a flat platform of the same material, which effectively solves the deformation problem caused by unevenness of the adsorption pad after long-term use. The wafer and the adsorption pad are evenly stressed, eliminating the problem of ring defects on the wafer surface. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a top view of the present invention;

[0019] Figure 3 This is the front view of this utility model;

[0020] Figure 4 This is a cross-sectional view of the present invention;

[0021] Figure 5 This is a schematic diagram of the chuck before the improvement of this utility model;

[0022] Figure 6 This is a schematic diagram of a ring-shaped defect wafer obtained after using the improved chuck according to this invention.

[0023] Illustration: 1. Chuck body, 2. Vacuum through hole, 3. Long groove, 4. Connecting hole, 5. Flared opening. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0025] The embodiments of this utility model relate to an edge polishing adsorption chuck for improving annular defects on wafer surfaces, such as... Figure 1-6As shown, the chuck body 1 is a frustum-shaped structure, wider at the top and narrower at the bottom. This frustum-shaped structure provides the chuck body 1 with good structural strength and resistance to deformation. The chuck body 1 is integrally molded from polytetrafluoroethylene (PTFE), a material known for its excellent wear resistance and chemical stability. The upper surface of the chuck body 1 is a flat adsorption platform, and a vacuum through-hole 2 is vertically formed in the center of the upper part of the adsorption platform. The vacuum through-hole 2... The bottom of the chuck body 1 is connected to the vacuum system of the edge polishing machine (working negative pressure -0.06 to -0.08 MPa). Several elongated grooves 3 are evenly distributed around the vacuum through hole 2 on the adsorption table surface. The elongated grooves 3 are arranged radially. One end of the elongated groove 3 is connected to the vacuum through hole 2, and the other end of the elongated groove 3 extends to the edge of the adsorption table surface (5-10 mm away from the edge). Adsorption pads are attached to the adsorption table surface except for the elongated grooves 3 and the vacuum through hole 2.

[0026] Several elongated grooves 3 are arranged radially to form a radial vacuum conduction path, ensuring that the adsorption force is evenly distributed.

[0027] The flatness error of the adsorption platform is ≤0.01mm / m (guaranteed by precision grinding), and the surface roughness Ra is ≤0.8μm, ensuring that the adsorption pad (nitrile rubber material, thickness 0.5-1mm) is not locally wrinkled or raised after being attached.

[0028] The bottom of the chuck body 1 is provided with several connection holes 4 around the lower port of the vacuum through hole 2. These connection holes 4 are used in conjunction with fasteners (bolts) to rigidly connect to the worktable of the edge polishing machine.

[0029] The number of the elongated grooves 3 is 6-8, the depth of the elongated grooves 3 is 0.5-1mm, and the spacing between adjacent elongated grooves 3 is 5-10mm.

[0030] The upper edge of the chuck body 1 is provided with a rounded chamfer with a radius of 0.5-1mm. The rounded chamfer is provided to prevent the sharp edge from scratching the adsorption pad or the edge of the wafer.

[0031] The vacuum through hole 2 is coaxially provided with a flared opening 5 with a larger diameter at the upper port. During processing, the vacuum through hole 2 and the elongated groove 3 are first machined on the chuck body 1. Then, the flared opening 5 is machined at the upper port of the vacuum through hole 2 so that the vacuum through hole 2 and the elongated groove 3 are connected. The flared opening 5 can reduce defects such as burrs at the connection between the vacuum through hole 2 and the elongated groove 3.

[0032] The working process of the adsorption chuck of this invention is as follows:

[0033] Adsorption pad bonding: The adsorption pad is flatly bonded to the adsorption platform of the chuck body 1. The flatness of the polytetrafluoroethylene platform ensures that the adsorption pad is free from local deformation. During the adsorption pad bonding process, the long groove 3 and the vacuum through hole 2 are avoided.

[0034] Wafer fixing: Place the wafer (12-300mm in diameter) on the adsorption pad, start the vacuum system of the edge polishing machine, and the air is collected through the long groove 3 and discharged through the vacuum through hole 2, forming a uniform adsorption force (pressure deviation per square centimeter ≤ ±5%), so that the wafer is tightly attached to the adsorption pad without local lifting.

[0035] Edge polishing: The chuck body 1 rotates at high speed with the worktable (300-500 r / min), and the polishing wheel processes the edge of the wafer. Because the adsorption table surface is flat and the adsorption force is uniform, there is no relative sliding between the wafer and the adsorption pad, avoiding ring defects caused by local friction.

[0036] This invention addresses the shortcomings of existing edge polishing chucks by abandoning the plastic ring and V-ring design of the original edge polishing chucks and innovatively introducing an integrated edge polishing chuck. The contact area between the integrated edge polishing chuck and the adsorption pad is a flat platform of the same material, which effectively solves the deformation problem caused by unevenness of the adsorption pad after long-term use. The wafer and the adsorption pad are evenly stressed, eliminating the problem of ring defects on the wafer surface.

[0037] After the integrated edge polishing chuck designed with this utility model is attached with an adsorption pad, it is installed on a 12-inch edge polishing machine for edge polishing of wafers. This can effectively solve the deformation problem after the adsorption pad has been used for a long time, thereby completely improving the wafer surface damage and ring defects caused by deformation.

[0038] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0039] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0040] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0041] The above provides a detailed description of an edge polishing adsorption chuck for improving annular defects on wafer surfaces, as provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A chuck for edge polishing and adsorption chuck for improving annular defects on wafer surfaces, comprising a chuck body (1), characterized in that: The chuck body (1) has a frustum-shaped structure. The chuck body (1) is larger at the top and smaller at the bottom. The upper surface of the chuck body (1) is a flat adsorption platform. A vacuum through hole (2) is vertically opened in the middle of the upper part of the adsorption platform. The lower end of the vacuum through hole (2) penetrates the bottom of the chuck body (1). Several long grooves (3) are evenly opened around the vacuum through hole (2) on the adsorption platform. The several long grooves (3) are arranged radially. One end of the long groove (3) is connected to the vacuum through hole (2), and the other end of the long groove (3) extends to the edge of the adsorption platform. In addition to the long grooves (3) and the vacuum through hole (2), the adsorption platform is covered with adsorption pads.

2. The edge polishing adsorption chuck for improving annular defects on wafer surfaces according to claim 1, characterized in that: The chuck body (1) is integrally molded from polytetrafluoroethylene material, and the flatness error of its adsorption platform is ≤0.01mm / m.

3. The edge polishing adsorption chuck for improving annular defects on wafer surfaces according to claim 1, characterized in that: The bottom of the chuck body (1) is provided with several connecting holes (4) around the lower port of the vacuum through hole (2). The connecting holes (4) are used to connect and fix the chuck body (1) to the worktable of the edge polishing machine with fasteners.

4. The edge polishing adsorption chuck for improving annular defects on wafer surfaces according to claim 1, characterized in that: The number of the elongated grooves (3) is 6-8, the depth of the elongated grooves (3) is 0.5-1mm, and the spacing between adjacent elongated grooves (3) is 5-10mm.

5. The edge polishing adsorption chuck for improving annular defects on wafer surfaces according to claim 1, characterized in that: The upper edge of the chuck body (1) is provided with an arc-shaped chamfer with a radius of 0.5-1mm.

6. The edge polishing adsorption chuck for improving annular defects on wafer surfaces according to claim 1, characterized in that: The upper port of the vacuum through hole (2) is coaxially provided with an enlarged flared opening (5).

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