Chuck cleaning device

Abstract

To provide a chuck cleaning device capable of efficiently removing not only foreign matter that has entered into pores on the chucking surface of a chuck but also foreign matter that has become lodged in the pores by brushing. [Solution] A chuck cleaning device that cleans a chuck that holds a wafer by vacuum suction using a porous structure when grinding the wafer, the chuck cleaning device having a scraping brush that scrapes out foreign matter that has gotten into the pores of the suction surface of the chuck, and a dressing brush that has a larger wire diameter than the scraping brush and removes the portion of the foreign matter that has gotten caught in the pores of the suction surface of the chuck and protrudes from the suction surface.

Description

[Technical field]

[0001] The present invention relates to a chuck cleaning device. [Background technology]

[0002] 2. Description of the Related Art There is known a chuck cleaning device that cleans a chuck that holds a wafer by vacuum suction using a porous structure when grinding the wafer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-237108 A Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a chuck cleaning device which is capable of efficiently removing not only foreign matter that has entered the pores of the suction surface of the chuck, but also foreign matter that has become lodged in the pores by brushing. [Means for solving the problem]

[0005] One aspect of the present invention is as follows.

[0006] [1] A chuck cleaning device for cleaning a chuck that holds a wafer by vacuum suction using a porous structure when grinding the wafer, comprising: a scraping brush for scraping out foreign matter that has entered into pores in the suction surface of the chuck; a dressing brush having a wire diameter larger than that of the scraping brush and for removing a protruding portion of the foreign matter lodged in the pores of the suction surface of the chuck.

[0007] [2] The chuck cleaning device described in [1] has a brush extra length, which is the difference between the brush length (the length from the base end of the brush to the tip of the brush before the chuck is cleaned) and the distance from the base end of the brush to the suction surface when the chuck is cleaned, which is longer for the scraping brush than for the dressing brush.

[0008] [3] The chuck cleaning device according to [1] or [2], wherein the brush length of the scraping brush is longer than that of the dressing brush.

[0009] [4] The chuck cleaning device described in any one of [1] to [3], wherein the brush length of the scraping brush is equal to or greater than the distance from the brush base end to the deepest part of the pores of the suction surface when cleaning the chuck.

[0010] [5] The chuck cleaning device according to any one of [1] to [4], wherein the wire diameter of the scraping brush is 0.09 to 0.3 mm.

[0011] [6] The chuck cleaning device according to any one of [1] to [5], wherein the dressing brush has a wire diameter of 0.3 to 1.6 mm.

[0012] [7] a brush holding member having a flat brush holding surface that faces the suction surface when the chuck is cleaned; the brush holding surface holds the scraping brush and the dressing brush, The scraping brush has a radial wire bundle row made up of a plurality of wire bundles arranged radially along the brush holding surface, The chuck cleaning device described in any one of [1] to [6], wherein the dressing brush has a radial wire bundle row consisting of a plurality of wire bundles arranged radially along the brush holding surface concentrically with the center of the radial arrangement of the scraping brush.

[0013] [8] the brush holding member rotates in one circumferential direction about the center of the radial arrangement of the scraping brushes to clean the chuck; The radial wire bundle rows of the scraping brush are arranged such that each of the wire bundle rows arranged in the radial direction is curved toward the other circumferential side toward the radially outward side, The chuck cleaning device described in [7], wherein the radial wire bundle rows of the dressing brush are arranged so that each of the wire bundle rows arranged in the radial direction is curved radially outward toward the other circumferential side.

[0014] [9] the brush holding member rotates in one circumferential direction about the center of the radial arrangement of the scraping brushes to clean the chuck; The chuck cleaning device described in [7] or [8], wherein the radial wire bundle row of the scraping brush and the radial wire bundle row of the dressing brush are adjacent to each other so as to be arranged radially in two rows, and the radial wire bundle row of the dressing brush is located on the other circumferential side. Effect of the Invention

[0015] According to the present invention, a chuck cleaning device can be provided that can efficiently remove not only foreign matter that has entered the pores of the suction surface of the chuck, but also foreign matter that has become lodged in the pores by brushing. [Brief description of the drawings]

[0016] [Figure 1] 2 is a bottom view of a chuck cleaning device according to an embodiment of the present invention; FIG. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] 2 is an explanatory diagram illustrating a chuck cleaning function of the chuck cleaning device of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] 1 to 3, in one embodiment of the present invention, a chuck cleaning device 1 cleans a chuck 2 that holds a wafer on an adsorption surface 2a by vacuum adsorption using a porous structure when grinding the wafer. In this embodiment, the chuck cleaning device 1 and the chuck 2 constitute a chuck system 3. The chuck system 3 may be built into a grinding device that grinds the wafer.

[0019] In this embodiment, the chuck 2 is used for high-grit grinding of silicon wafers as wafers, and the porous structure of the chuck 2 has a grit size of #100 to #1000 in this embodiment. The chucking surface 2a of the chuck 2 has a porous structure, which has a pore group 2a2 consisting of a plurality of pores 2a1.

[0020] When grinding a wafer, foreign matter 4, such as abrasive grains that fall off a grinding wheel serving as a grinding tool and chips generated from the wafer, enters or gets caught in the group of pores 2a2 on the chucking surface 2a of the chuck 2. The chuck cleaning device 1 removes such foreign matter 4 remaining on the chucking surface 2a of the chuck 2 by cleaning.

[0021] The orientation of the chucking surface 2a of the chuck 2 is not particularly limited, but in this embodiment, the chucking surface 2a is the upper surface of the chuck 2 and is perpendicular to the vertical direction. In this embodiment, the chucking surface 2a is planar. The shape of the chucking surface 2a in a top view is not particularly limited, but in this embodiment, it is circular. In this embodiment, the wafer has a disk shape that is arranged concentrically with the chuck 2 when chucking to the chuck 2, and has, for example, the same diameter as the chuck 2.

[0022] The chuck cleaning device 1 has a scraping brush 5 for scraping out foreign matter 4 that has entered the air pores 2a1 of the suction surface 2a of the chuck 2, and a dressing brush 6 for removing the portion of the foreign matter 4 that has become lodged in the air pores 2a1 of the suction surface 2a of the chuck 2 and protrudes from the suction surface 2a, the dressing brush 6 having a wire diameter φ (see FIG. 3) larger than that of the scraping brush 5.

[0023] According to the above-mentioned configuration, the foreign matter 4 that has entered the pores 2a1 of the suction surface 2a can be scraped out and removed by the scraping brush 5, and the foreign matter 4 that has become lodged in the pores 2a1 of the suction surface 2a can be removed by scraping out the portion protruding from the suction surface 2a by the dressing brush 6, which has a larger wire diameter φ and is less likely to bend than the scraping brush 5. Therefore, not only the foreign matter 4 that has entered the pores 2a1 of the suction surface 2a of the chuck 2 but also the foreign matter 4 that has become lodged in the pores 2a1 can be efficiently removed by brushing.

[0024] The foreign matter 4 produced by grinding causes the following problems. Dimples that occur on the wafer due to foreign matter 4 remaining on the chucking surface 2a of the chuck 2 A wide range of dimples formed by the accumulation of foreign matter 4 on the chucking surface 2a of the chuck 2 Changes in wafer accuracy caused by deposits on the chucking surface 2a of the chuck 2

[0025] Foreign matter 4 remaining on the chucking surface 2a of the chuck 2 may become lodged in the pores 2a1 of the chucking surface 2a. Once foreign matter 4 has become lodged in the pores 2a1, dimples are likely to occur continuously on the wafer that is subsequently ground using the chuck 2. In order to detect the continuous occurrence of dimples at an early stage, it is necessary to frequently inspect the wafer surface using a magic mirror or the like.

[0026] If dimples are found, a dressing operation is required to remove the protruding portion from the suction surface 2a by scraping it off using a dresser such as a grinding wheel. The dressing operation is performed at an appropriate frequency to remove deposits on the suction surface 2a. The dressing operation has an impact on productivity because it requires stopping the grinding device. In addition, once the dressing operation is performed, the flatness of the suction surface 2a of the chuck 2 changes, so the precision of the grinding device must be adjusted for each dressing operation.

[0027] In this embodiment, the dressing brush 6 removes not only the protruding portion of the foreign matter 4 caught in the pores 2a1 of the adsorption surface 2a but also the deposits on the adsorption surface 2a. Therefore, according to this embodiment, the frequency of inspection and dressing work that stops the device can be reduced.

[0028] 2, the brush extra length L3, which is the difference between the brush length L1, which is the length from the brush base end to the brush tip before the chuck 2 is cleaned, and the distance L2 from the brush base end to the adsorption surface 2a when the chuck 2 is cleaned, is longer for the scraping brush 5 than for the dressing brush 6. In this embodiment, the brush extra length L3 of the scraping brush 5 (L3 on the left side in FIG. 2) is 3 mm longer than the brush extra length L3 of the dressing brush 6 (L3 on the right side in FIG. 2). This configuration makes it easier for the scraping brush 5 to enter the pore portion 2a1.

[0029] The brush length L1 of the scraping brush 5 is longer than that of the dressing brush 6. According to the above-mentioned configuration, the scraping brush 5 is easily flexible, so that the foreign matter 4 can be easily scraped out from the pores 2a1.

[0030] The brush length L1 of the scraping brush 5 is equal to or greater than the distance L4 from the brush base end to the deepest part of the pores 2a1 of the suction surface 2a when cleaning the chuck 2. According to the above-described configuration, the scraping brush 5 can reach the deepest part of the pores 2a1, making it easier to scrape out the foreign matter 4 from the pores 2a1.

[0031] The wire diameter φ of the scraping brush 5 is 0.09 mm in this embodiment, but is not limited to this, and is preferably 0.09 to 0.3 mm in diameter. The material of the scraping brush 5 is nylon in this embodiment, but is not limited to this, and may be, for example, polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), acrylic, etc.

[0032] The wire diameter φ of the dressing brush 6 is 0.3 mm in this embodiment, but is not limited to this, and is preferably 0.3 to 1.6 mm in diameter. The material forming the dressing brush 6 is nylon in this embodiment, but is not limited to this, and may be, for example, a material containing abrasive grains (such as nylon or aramid fiber) or a metal.

[0033] The chuck cleaning device 1 has a brush holding member 7 having a flat brush holding surface 7a that faces the suction surface 2a when cleaning the chuck 2. The brush holding surface 7a holds the scraping brush 5 and the dressing brush 6. As shown in FIG. 1, the scraping brush 5 has a radial wire bundle row 5b consisting of a plurality of wire bundles 5a arranged radially along the brush holding surface 7a. The radial wire bundle row 5b of the scraping brush 5 has a plurality of wire bundle rows 5b1 arranged in the radial direction. The dressing brush 6 has a radial wire bundle row 6b consisting of a plurality of wire bundles 6a arranged radially along the brush holding surface 7a concentrically with the center of the radial arrangement of the scraping brush 5. The radial wire bundle row 6b of the dressing brush 6 has a plurality of wire bundle rows 6b1 arranged in the radial direction. According to the above configuration, by rotating the brush holding member 7 around the center O of the radial arrangement of the scraping brushes 5 as the center of rotation, as shown in FIG. 3, the foreign matter 4 is scraped out from the air holes 2a1 of the suction surface 2a of the chuck 2 and the protruding portions of the trapped foreign matter 4 are removed, and the scraped out foreign matter 4 and the foreign matter 4 scraped off by the dressing brush 6 are transported radially outward from the center of rotation (center O) by centrifugal force along the radial directions of the radial wire bundle rows 5b of the scraping brush 5 and the radial wire bundle rows 6b of the dressing brush 6, and are removed from the scraping brush 5 and the dressing brush 6.

[0034] The brush holder 7 cleans the chuck 2 by rotating in one circumferential direction (rotation direction R) around the center O of the radial arrangement of the scraping brushes 5. That is, the chuck cleaning device 1 has a rotation shaft (not shown) that rotates the brush holder 7 in the rotation direction R around the center O of the radial arrangement of the scraping brushes 5. As shown in FIG. 1, the radial wire bundle rows 5b of the scraping brush 5 are arranged so that each of the wire bundle rows 5b1 arranged in the radial direction curves toward the other circumferential direction toward the radial outside. The radial wire bundle rows 6b of the dressing brush 6 are arranged so that each of the wire bundle rows 6b1 arranged in the radial direction curves toward the other circumferential direction toward the radial outside. According to the above configuration, the scraped out foreign matter 4 and the foreign matter 4 scraped off by the dressing brush can be easily transported radially outward along the radial wire bundle rows 5b of the scraping brush 5 and the radial wire bundle rows 6b of the dressing brush 6.

[0035] The radial wire bundle rows 5b of the scraping brush 5 and the radial wire bundle rows 6b of the dressing brush 6 are adjacent to each other so as to be radially arranged in two rows, and the radial wire bundle rows 6b of the dressing brush 6 are located on the other circumferential side. According to the above configuration, as shown in Fig. 3, the foreign matter 4 scraped out by the radial wire bundle rows 5b of the scraping brush 5 can be received by the radial wire bundle rows 6b of the dressing brush 6 located adjacent to each other on the rear side in the rotation direction R, and quickly carried radially outward.

[0036] It is preferable that the wire bundle row 5b1 of the scraping brush 5 and the wire bundle row 6b1 of the dressing brush 6 are curved in an arc shape. In this case, the radius of curvature of the curvature of the scraping brush 5 and the dressing brush 6 is equivalent to the diameter of the chuck 2 (300 mm in this embodiment) in this embodiment, but is not limited thereto, and is preferably equal to or larger than the radius of the chuck 2 (150 mm in this embodiment). The radius of curvature of the scraping brush 5 and the dressing brush 6 is equivalent in this embodiment.

[0037] In this embodiment, the brush holding member 7 is disposed during cleaning such that the center of rotation (center O) of the brush holding member 7 coincides with the center of the circular chuck 2. The outer diameter D1 of the radial wire bundle rows 5b of the scraping brush 5 and the outer diameter D2 of the radial wire bundle rows 6b of the dressing brush 6 are not particularly limited, but both are preferably equal to or larger than the outer diameter of the circular chuck 2.

[0038] The chuck 2 may be configured to rotate in the opposite direction to the rotation direction R of the brush holding member 7 during cleaning, or may be configured not to rotate during cleaning.

[0039] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be modified in various ways without departing from the gist of the present invention. [Explanation of symbols]

[0040] 1 Chuck cleaning device 2 Chuck 2a Adsorption surface 2a1 Pore 2a2 Pore group 3 Chuck System 4 Foreign object 5. Scraping brush 5a Wire bundle 5b Radial wire bundle row 5b1 Wire bundle row 6 Dress Brush 6a Wire bundle 6b Radial wire bundle row 6b1 Wire bundle row 7 Retaining member 7a Brush holding surface D1 Outer diameter D2 outer diameter R Rotation direction L1 Brush length L2 distance L3 Brush extra length L4 Distance O center φ Wire diameter

Claims

1. A chuck cleaning device for cleaning a chuck that holds a wafer by vacuum suction using a porous structure when grinding the wafer, comprising: a scraping brush for scraping out foreign matter that has entered into pores in the suction surface of the chuck; a dressing brush having a wire diameter larger than that of the scraping brush and for removing a protruding portion of the foreign matter lodged in the pores of the suction surface of the chuck.

2. 2. The chuck cleaning device according to claim 1, wherein a brush extra length, which is a difference between a brush length, which is a length from a brush base end to a brush tip end before the chuck is cleaned, and a distance from the brush base end to the suction surface when the chuck is cleaned, is longer for the scraping brush than for the dressing brush.

3. 2. The chuck cleaning device according to claim 1, wherein the length of said scraping brush is longer than that of said dressing brush.

4. 2. The chuck cleaning device according to claim 1, wherein the brush length of the scraping brush is equal to or greater than the distance from a base end of the brush to the deepest part of the pores of the suction surface when the chuck is cleaned.

5. 2. The chuck cleaning device according to claim 1, wherein the wire diameter of the scraping brush is 0.09 to 0.3 mm.

6. 2. The chuck cleaning device according to claim 1, wherein the dressing brush has a wire diameter of 0.3 to 1.6 mm.

7. a brush holding member having a flat brush holding surface that faces the suction surface when the chuck is cleaned; the brush holding surface holds the scraping brush and the dressing brush, The scraping brush has a radial wire bundle row made up of a plurality of wire bundles arranged radially along the brush holding surface, 2. The chuck cleaning device according to claim 1, wherein the dressing brush has a radial wire bundle row consisting of a plurality of wire bundles arranged radially along the brush holding surface concentrically with a center of the radial arrangement of the scraping brush.

8. the brush holding member rotates in one circumferential direction about the center of the radial arrangement of the scraping brushes to clean the chuck; The radial wire bundle rows of the scraping brush are arranged such that each of the wire bundle rows arranged in the radial direction is curved toward the other circumferential side toward the radially outward side, 8. The chuck cleaning device according to claim 7, wherein the radial wire bundle rows of the dressing brush are arranged such that each of the wire bundle rows aligned in the radial direction is curved radially outward toward the other circumferential side.

9. the brush holding member rotates in one circumferential direction about the center of the radial arrangement of the scraping brushes to clean the chuck; 8. The chuck cleaning device according to claim 7, wherein the radial wire bundle rows of the scraping brush and the radial wire bundle rows of the dressing brush are adjacent to each other so as to be radially arranged in two rows, and the radial wire bundle rows of the dressing brush are located on the other circumferential side.

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