CN112053987A - Porous chuck table and method for manufacturing porous chuck table - Google Patents

Porous chuck table and method for manufacturing porous chuck table Download PDF

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Publication number
CN112053987A
CN112053987A CN202010460784.1A CN202010460784A CN112053987A CN 112053987 A CN112053987 A CN 112053987A CN 202010460784 A CN202010460784 A CN 202010460784A CN 112053987 A CN112053987 A CN 112053987A
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CN
China
Prior art keywords
chuck table
porous
aggregate
porous plate
workpiece
Prior art date
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Pending
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CN202010460784.1A
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Chinese (zh)
Inventor
马路良吾
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Disco Corp
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Disco Corp
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Publication of CN112053987A publication Critical patent/CN112053987A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6838—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping with gripping and holding devices using a vacuum; Bernoulli devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
    • B23Q3/02—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine for mounting on a work-table, tool-slide, or analogous part
    • B23Q3/06—Work-clamping means
    • B23Q3/08—Work-clamping means other than mechanically-actuated
    • B23Q3/088—Work-clamping means other than mechanically-actuated using vacuum means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/06—Work supports, e.g. adjustable steadies
    • B24B41/061—Work supports, e.g. adjustable steadies axially supporting turning workpieces, e.g. magnetically, pneumatically
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/0058—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material
    • B28D5/0082—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material for supporting, holding, feeding, conveying or discharging work
    • B28D5/0094—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material for supporting, holding, feeding, conveying or discharging work the supporting or holding device being of the vacuum type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67092—Apparatus for mechanical treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68757—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a coating or a hardness or a material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68785—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by the mechanical construction of the susceptor, stage or support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68327—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used during dicing or grinding
    • H01L2221/68336—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used during dicing or grinding involving stretching of the auxiliary support post dicing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68381—Details of chemical or physical process used for separating the auxiliary support from a device or wafer
    • H01L2221/68386—Separation by peeling

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Jigs For Machine Tools (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Dicing (AREA)
  • Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

Abstract

Provided are a porous chuck table and a method for manufacturing the porous chuck table, which can restrain the damage generated on the chip when cutting the processed object to form the chip. The porous chuck table is configured to suck and support a workpiece when the workpiece is cut by a cutting tool, and includes a porous plate having an aggregate, a binder for fixing the aggregate, and pores, a frame having a concave portion into which the porous plate is fitted, and a suction passage having one end communicating with the concave portion and the other end connectable to a suction source, wherein the aggregate having a flat upper surface is exposed to the support surface of the porous plate. The aggregate comprises particles made of silicon, glass, boron carbide, zirconia or silicon carbide. The particle size of the particles is F80 or more and F400 or less.

Description

Porous chuck table and method for manufacturing porous chuck table
Technical Field
The present invention relates to a porous chuck table which is incorporated in a cutting device for cutting a workpiece and which sucks and holds the workpiece, and a method for manufacturing the porous chuck table.
Background
Chips such as device chips mounted on electronic devices are formed by cutting and dividing a workpiece such as a semiconductor wafer, a glass substrate, a ceramic substrate, or a resin package substrate with an annular cutting tool. The cutting of the workpiece is performed by a cutting apparatus having a cutting unit to which a cutting tool is attached. The cutting device includes a chuck table for holding a workpiece to be cut by a cutting tool.
An adhesive tape called a dicing tape is attached to the back surface side of the work cut by the cutting device before the work is carried into the cutting device. The outer peripheral portion of the adhesive tape is attached to the annular frame so as to overlap the outer peripheral portion of the adhesive tape. Then, a frame unit is formed in which the workpiece, the adhesive tape, and the annular frame are integrated. The workpiece is carried into the cutting device in a state of the frame unit and is held on the chuck table. At this time, the workpiece is sucked and held on the chuck table through the adhesive tape.
When a chip is formed by cutting a workpiece, damage such as chipping or cracking may occur in the formed chip. Such damage tends to occur relatively easily on the back side of the workpiece (chip). Further, in order to form a high-quality chip with less damage accompanying cutting, improvements have been made to a cutting tool and an adhesive tape. Further, a chuck table mechanism capable of suppressing the occurrence of damage has also been developed (for example, see patent document 1).
Patent document 1: japanese laid-open patent publication No. 2009-76773
The chuck table is, for example, a porous chuck table having: a plate-like porous member called a porous plate; and a frame body having a recess formed therein, the frame body having a shape corresponding to the shape of the porous plate and being capable of accommodating the porous plate. The upper surface of the porous plate serves as a support surface for holding the work by suction via the adhesive tape, and the work is sucked through the numerous pores formed in the porous plate. The porous plate is composed of, for example, an aggregate, a binder for fixing the aggregate, and pores, and the aggregate is dispersed and fixed in the binder.
When the porous chuck table is formed, the porous plate thicker than the depth of the recess of the frame is accommodated in the recess of the frame, and the porous plate is ground from above by the grinding wheel to be thin, so that the height of the upper surface of the porous plate is made to be equal to the height of the upper surface of the frame. At this time, when the grinding stone comes into contact with the aggregate exposed on the upper surface of the porous plate, the aggregate is ejected from the binder. Therefore, numerous recesses were observed in the upper surface of the porous plate as the support surface of the porous chuck table, which were left in the binder due to the ejection of the aggregate.
When numerous concave portions are formed on the upper surface of a porous plate that supports a workpiece via an adhesive tape, a part of the workpiece cannot be appropriately supported. Therefore, when the workpiece is cut from the front side, damage is likely to occur on the back side of the workpiece due to a load applied to the workpiece. This tendency is more remarkable as the size of a chip formed from a work piece is smaller.
Disclosure of Invention
The present invention has been made in view of the above problems, and an object of the present invention is to provide a chuck table and a method of manufacturing the chuck table, in which when a chip is formed by cutting a held workpiece, damage is not easily generated on the chip.
According to one aspect of the present invention, there is provided a multi-hole chuck table that sucks and supports a workpiece to be machined when the workpiece is cut by a cutting tool, the multi-hole chuck table including a multi-hole plate and a frame, the multi-hole plate including: an aggregate; a binder for fixing the aggregate; and an air hole, wherein the porous plate has a support surface capable of supporting the processed object on the upper surface, the frame body has a concave part for the porous plate to be embedded in, and has an absorption path with one end communicated with the concave part and the other end capable of being connected with an absorption source, and the aggregate with a flat upper surface is exposed on the support surface of the porous plate.
Preferably the aggregate comprises particles made of silicon, glass, boron carbide, zirconia or silicon carbide. Further, the particle size of the particles is preferably F80 or more and F400 or less.
According to another aspect of the present invention, there is provided a method for manufacturing a porous chuck table, including the steps of: a preparation step of preparing a porous plate having aggregate, a binder, and pores, and a frame having a recess into which the porous plate is fitted, and having an aspiration path having one end communicating with the recess and the other end connectable to an aspiration source; a fixing step of fitting and fixing the porous plate in the recess of the frame; and a grinding step of grinding the upper surface of the porous plate and the upper surface of the frame to be flush with each other after the fixing step, wherein an upper portion of the aggregate fixed to the binder is ground on the upper surface of the porous plate to form a flat surface on the upper portion of the aggregate, and the flat surface is exposed on the upper surface of the porous plate.
Preferably the aggregate comprises particles made of silicon, glass, boron carbide, zirconia or silicon carbide. Further, the particle size of the particles is preferably F80 or more and F400 or less.
A porous chuck table and a porous plate of a porous chuck table manufactured by a method of manufacturing a porous chuck table according to an aspect of the present invention have a support surface on an upper surface thereof, the support surface being capable of supporting a workpiece. The aggregate having a flat upper surface is exposed to the support surface of the porous plate.
In this porous chuck table, when the upper surface of the porous plate is flattened, the aggregate is not ejected from the binder, and a concave portion formed by the falling-off of the aggregate is not formed on the upper surface of the binder. Therefore, the upper surface of the porous plate becomes flat. In addition, the aggregate having a flat upper surface is disposed in a portion where the aggregate on the upper surface of the conventional binder comes off and becomes a concave portion. Therefore, the upper surface of the porous plate becomes more flat.
In this porous chuck table, the area of a flat region constituting a support surface for supporting a workpiece is significantly larger than that of a conventional porous chuck table. Therefore, when the workpiece is placed on the support surface, a wider area for supporting the back surface of the workpiece can be provided, and the back surface can be supported more uniformly. Therefore, when a chip is manufactured by holding a workpiece on the porous chuck table and cutting the workpiece, damage is less likely to occur on the back surface of the chip, including when the chip is small in size.
Therefore, according to one aspect of the present invention, there is provided a chuck table and a method of manufacturing the chuck table, in which damage is not easily generated on a chip when the chip is formed by cutting a held workpiece.
Drawings
Fig. 1 is a perspective view showing a configuration example of a cutting device.
Fig. 2 is a perspective view schematically showing the porous chuck table and the workpiece.
Fig. 3 (a) is a sectional view schematically showing a molding step, and fig. 3 (B) is a sectional view schematically showing a firing step.
Fig. 4 (a) is a sectional view schematically showing a fixing step, and fig. 4 (B) is a sectional view schematically showing a porous plate fixed to a frame and a sectional view schematically showing an enlarged upper surface of the porous plate.
Fig. 5 (a) is a sectional view schematically showing a grinding step, and fig. 5 (B) is a sectional view schematically showing a porous chuck table and a sectional view schematically showing an upper surface of a porous plate in an enlarged manner.
Fig. 6 is a cross-sectional view schematically showing a case where the workpiece held by the porous chuck table is cut by the cutting tool, and a cross-sectional view schematically showing the workpiece cut by the cutting tool in an enlarged manner.
Fig. 7 (a) is a flowchart showing a flow of each step of the method for manufacturing the porous chuck table, and fig. 7 (B) is a flowchart showing a flow of each step in the preparation step.
Fig. 8 (a) is a photomicrograph obtained by observing the front surface of an example of a multi-well plate at a low magnification, and fig. 8 (B) is a photomicrograph obtained by observing the front surface of an example of a multi-well plate at a high magnification.
Fig. 9 (a) is a photomicrograph obtained by observing the front surface of another example of the multi-well plate at a low magnification, and fig. 9 (B) is a photomicrograph obtained by observing the front surface of another example of the multi-well plate at a high magnification.
Fig. 10 (a) is a photomicrograph showing the workpiece cut on the porous chuck table, and fig. 10 (B) is a photomicrograph showing the workpiece cut on another porous chuck table.
Fig. 11 (a) is a photomicrograph obtained by observing the front surface of a conventional multi-well plate at a low magnification, and fig. 11 (B) is a photomicrograph obtained by observing the front surface of a conventional multi-well plate at a high magnification.
Fig. 12 (a) is a photomicrograph showing the workpiece cut on the conventional porous chuck table, and fig. 12 (B) is a photomicrograph showing the other region of the workpiece cut on the conventional porous chuck table.
Description of the reference symbols
1: a workpiece; 1a, 42 a: a front side; 1b, 42 b: a back side; 1 c: dividing the predetermined line; 1 d: a device; 3: an adhesive tape; 5: an annular frame; 7: a frame unit; 2: a cutting device; 4: a base station; 6: an X-axis moving table; 6 a: a table base; 8: a chuck table; 8 a: a bearing surface; 8 b: an attraction source; 8 c: a switching unit; 10: a clamp; 12. 24, 30: a guide rail; 14. 28, 34: a ball screw; 16. 28a, 36: a pulse motor; 18: a cutting unit; 18 a: a main shaft; 18 b: a cutting tool; 20: a water drainage path; 22: a support structure; 26. 32: moving the plate; 38: a shooting unit (camera); 40: a blade edge detection unit; 42: a perforated plate; 42 c: mixing; 42 d: a shaped body; 44: a frame body; 46: a recess; 48: an aspiration path; 50: an aggregate; 50 a: a flat surface; 52: a binding agent; 54: air holes; 56: a cross shaft grinding device; 56 a: a support table; 58: a main shaft; 60: grinding the grinding tool; 62. 64, 66, 68, 70, 76, 78, 80, 84, 86: a photomicrograph; 72: a chip; 74: cutting a groove; 82: a recess; 88: edge breakage; 90: a pressure forming device; 92: a mold; 94: a plate-like pressing member; 96: pressing the shaft; 98: firing the furnace; 100: a container; 102: a cover body.
Detailed Description
An embodiment of one embodiment of the present invention will be described with reference to the drawings. First, a cutting apparatus to which the porous chuck table of the present embodiment is attached and used will be described with reference to fig. 1. Fig. 1 is a perspective view schematically showing a cutting apparatus 2 that cuts a workpiece 1. The workpiece 1 is a plate-like substrate made of a material such as silicon, silicon carbide (SiC), or another semiconductor, or a material such as sapphire, glass, or quartz, for example. The workpiece 1 may be a package substrate in which a plurality of chips are sealed with resin.
Fig. 2 shows a perspective view schematically illustrating the workpiece 1. A plurality of lines to divide 1c are set on the front surface 1a of the workpiece 1 so as to intersect with each other, and devices 1d such as ICs (Integrated circuits) are formed in respective regions partitioned by the lines to divide 1 c. Finally, the object 1 is cut and divided along the lines 1c to form the device chips.
For example, when cutting a region from the front surface 1a to the back surface 1b of the workpiece 1 along the line to divide 1c, a dividing groove is formed from the front surface 1a to the back surface 1b to divide the workpiece 1. However, instead of forming dividing grooves from the front surface 1a to the back surface 1b of the workpiece 1 by cutting, grooves that do not reach the back surface 1b may be formed by cutting. When a groove that does not reach the back surface 1b is formed by cutting, the workpiece 1 is divided by forming a dividing groove or the like from the bottom of the groove to the back surface 1b of the workpiece 1 by a method other than cutting or slicing.
For example, the workpiece 1 and the adhesive tape 3 attached to the annular frame 5 are integrated to form a frame unit 7. The workpiece 1 is conveyed and cut in a state of the frame unit 7. When the workpiece 1 is divided in the state of the frame unit 7, the formed chips are supported by the adhesive tape 3. Further, when the adhesive tape 3 is spread radially outward in the opening of the annular frame 5, the space between the chips is spread, and the chips are easily peeled off from the adhesive tape 3.
As shown in fig. 1, the cutting apparatus 2 includes a base 4 that supports each component. The base 4 is provided with: an X-axis moving table 6; an X-axis direction moving mechanism that moves the X-axis moving table 6 in an X-axis direction (a machining feed direction); and a water discharge path 20 covering the X-axis direction moving mechanism. The X-axis direction moving mechanism includes a pair of X-axis guide rails 12 parallel to the X-axis direction, and the X-axis moving table 6 is slidably attached to the X-axis guide rails 12.
A nut portion (not shown) is provided on the lower surface side of the X-axis moving table 6, and an X-axis ball screw 14 parallel to the X-axis guide rail 12 is screwed to the nut portion. An X-axis pulse motor 16 is connected to one end of the X-axis ball screw 14. When the X-axis ball screw 14 is rotated by the X-axis pulse motor 16, the X-axis moving table 6 moves in the X-axis direction along the X-axis guide rail 12.
A table base 6a is provided on the X-axis moving table 6. A porous chuck table 8 for sucking and holding the workpiece 1 is attached to the table base 6 a. The porous chuck table 8 is connected to a rotation drive source (not shown) such as a motor incorporated in the table base 6a, and is rotatable about a rotation axis perpendicular to the upper surface of the porous chuck table 8. Further, the porous chuck table 8 is fed in the X-axis direction together with the table base 6a by the above-described X-axis direction moving mechanism.
The front surface (upper surface) of the porous chuck table 8 serves as a support surface 8a for sucking and holding the workpiece 1. The support surface 8a is connected to a suction source 8b (see fig. 6) via a suction passage 48 (see fig. 6 and the like) formed inside the porous chuck table 8. Around the support surface 8a, a jig 10 is disposed, and the jig 10 is used to fix the annular frame 5 that holds the workpiece 1 via a belt.
A support structure 22 for supporting the two cutting units 18 that cut the workpiece 1 is disposed on the upper surface of the base 4 so as to straddle the X-axis direction movement mechanism. A cutting unit moving mechanism for moving the two cutting units 18 in the Y-axis direction (indexing direction) and the Z-axis direction is provided on the upper front surface of the support structure 22.
The cutting unit moving mechanism includes a pair of Y-axis guide rails 24 disposed on the front surface of the support structure 22 and parallel to the Y-axis direction. Two Y-axis moving plates 26 corresponding to the cutting units 18, respectively, are slidably attached to the Y-axis guide rails 24. On the back surface side of each Y-axis moving plate 26, a nut portion (not shown) is provided, and a Y-axis ball screw 28 parallel to the Y-axis guide rail 24 is screwed to the nut portion.
A Y-axis pulse motor 28a is connected to one end of the Y-axis ball screw 28. When the Y-axis ball screw 28 is rotated by the Y-axis pulse motor 28a, the corresponding Y-axis moving plate 26 moves in the Y-axis direction along the Y-axis guide rail 24. A pair of Z-axis guide rails 30 parallel to the Z-axis direction are provided on the front surface (front surface) of the Y-axis moving plate 26. The Z-axis moving plate 32 is slidably attached to each Z-axis guide rail 30.
A nut portion (not shown) is provided on the back surface side (rear surface side) of the Z-axis moving plate 32, and a Z-axis ball screw 34 parallel to the Z-axis guide rail 30 is screwed into the nut portion. A Z-axis pulse motor 36 is connected to one end of the Z-axis ball screw 34. When the Z-axis ball screw 34 is rotated by the Z-axis pulse motor 36, the Z-axis moving plate 32 moves in the Z-axis direction (the direction of feed) along the Z-axis guide 30.
A cutting unit 18 for machining the workpiece 1 and an imaging unit (camera) 38 capable of imaging the workpiece 1 held by the porous chuck table 8 are fixed to the lower portions of the two Z-axis moving plates 32. When the Y-axis moving plate 26 is moved in the Y-axis direction, the cutting unit 18 and the imaging unit 38 are moved in the Y-axis direction (index feed direction), and when the Z-axis moving plate 32 is moved in the Z-axis direction, the cutting unit 18 and the imaging unit 38 are moved in the Z-axis direction (incision feed direction).
A side view schematically showing the structure of a part of the cutting unit 18 is included in fig. 6. The cutting unit 18 has a spindle 18a constituting a rotation axis parallel to the Y-axis direction. A tool attachment seat is attached to a distal end portion of the spindle 18a, and an annular cutting tool 18b is attached to a distal end of the spindle 18a via the tool attachment seat.
A rotation drive source (not shown) such as a motor housed in a spindle case (not shown) is connected to the other end side of the spindle 18 a. When the spindle 18a is rotated by using the rotary drive source, the cutting tool 18b attached to the spindle 18a can be rotated.
The cutting tool 18b has, for example, a disk-shaped base and an annular grindstone portion fixed to an outer peripheral portion of the base. A substantially circular mounting hole penetrating the base is provided in the center of the base, and a protruding portion of the tool mounting seat attached to the spindle 18a penetrates the mounting hole when the cutting tool 18b is mounted to the cutting unit 18.
The grinding tool portion of the cutting tool 18b includes a bonding material made of metal, resin, or the like, and a plurality of abrasive grains made of diamond or the like fixed to the bonding material. The abrasive grains are exposed from the bonding material, and when the cutting tool 18b is rotated and cut into the workpiece 1, the exposed abrasive grains contact the workpiece 1 and cut the workpiece 1.
When cutting and cutting the workpiece 1, the height of the cutting unit 18 is adjusted so that the lower end of the grindstone portion of the cutting tool 18b reaches a position lower than the lower surface of the workpiece 1. When a groove that does not reach the lower surface side is formed in the workpiece 1, the height of the cutting unit 18 is adjusted so that the lower end of the grinder portion is positioned at a height between the upper surface and the lower surface of the workpiece 1.
When the workpiece 1 is cut by the cutting tool 18b, the abrasive grains are chipped or dropped. However, since the bonding material is gradually consumed and new abrasive grains are gradually exposed, the cutting ability of the cutting tool 18b can be maintained. At this time, the diameter of the cutting insert 18b gradually decreases. Therefore, the height of the lower end of the grinding wheel portion of the cutting tool 18b changes.
Therefore, the cutting apparatus 2 performs the following installation steps at predetermined timings: the position of the lower end of the grinding wheel portion of the cutting tool 18b is detected, and the Z-axis direction moving mechanism is adjusted so that the lower end reaches a predetermined height. As shown in fig. 1, a cutting edge detection unit 40 used in the setting step is provided below the cutting unit 18.
Next, the porous chuck table 8 of the present embodiment will be described. Fig. 2 is a perspective view schematically showing the porous chuck table 8 and the object 1 to be processed. Fig. 5 (B) shows a cross-sectional view of the porous chuck table 8. As shown in fig. 2, the upper surface of the porous chuck table 8 is a support surface 8a on which the workpiece 1 is placed. When cutting the workpiece 1, for example, the workpiece 1 is placed on the support surface 8a of the porous chuck table 8 in a state of the frame unit 7, and is sucked and held by the porous chuck table 8.
The porous chuck table 8 includes a disk-shaped porous plate 42 having a diameter corresponding to the diameter of the workpiece 1, and a frame 44 having a recess 46 (see fig. 4 a) into which the porous plate 42 is fitted. In the multi-well chuck table 8, the upper surface of the multi-well plate 42 and the upper surface of the frame 44 are flush with each other. In the porous chuck table 8, the porous plate 42 is exposed upward, and the upper surface of the porous plate 42 serves as a support surface 8a capable of supporting the workpiece 1.
Fig. 4 (a) shows a cross-sectional view schematically showing the frame 44. The frame 44 is made of, for example, stainless steel. As shown in fig. 4 (a), a suction passage 48 is formed in the bottom of the frame 44. One end of the suction passage 48 communicates with the recess 46. When the porous chuck table 8 formed of the frame 44 and the porous plate 42 is attached to the table base 6a of the cutting apparatus 2, the other end of the suction path 48 is connected to the suction source 8b (see fig. 6).
A switching unit 8c (see fig. 6) for switching connection and disconnection between the suction path 48 and the suction source 8b is provided therebetween. When the switching portion 8c is operated to connect the suction source 8b to the suction passage 48, negative pressure is applied to the workpiece 1 placed on the support surface 8a of the porous chuck table 8 through the air holes 54 of the porous plate 42 to be described later, and the workpiece 1 is sucked and held by the porous chuck table 8.
Fig. 5 (B) is an enlarged schematic cross-sectional view of the vicinity of the support surface 8a, which is the upper surface of the porous plate 42. As shown in fig. 5 (B), the porous plate 42 includes aggregates 50, a binder 52 for fixing the aggregates 50, and pores 54. As will be described in detail later, the porous plate 42 is formed by mixing and solidifying the granular aggregate 50 and the binder 52 at a predetermined ratio.
When the porous chuck table 8 is formed, for example, a porous plate 42 having a thickness larger than the depth of the recess 46 of the frame 44 is prepared. The porous plate 42 is accommodated in the concave portion 46. In this case, the upper portion of the porous plate 42 protrudes above the upper surface of the frame 44.
When the porous plate 42 is thinned by grinding from above, the height of the upper surface 42a of the porous plate 42 is matched with the height of the upper surface of the frame 44, and the upper surface 42a of the porous plate 42 and the upper surface of the frame 44 are ground at the same time. When the grinding is stopped, the upper surface 42a of the porous plate 42 becomes the support surface 8a, and the porous chuck table 8 is formed to be flush with the upper surface of the frame 44.
Here, when the upper surface 42a of the porous plate 42 is ground, the grinding wheel contacts the binder 52 to scrape the binder 52 off from the upper surface, and a part of the aggregate 50 is exposed upward from the binder 52. And, the grinding tool is in contact with the exposed aggregate 50. Conventionally, a material having high toughness such as alumina has been used as the aggregate 50. Therefore, when the grindstone comes into contact with the exposed aggregate 50, the aggregate 50 is ejected from the binder 52 without being broken by the grindstone, and a concave portion corresponding to the shape of the aggregate 50 is formed in the upper surface 42a of the porous plate 42 at a position where the aggregate 50 has previously passed.
Therefore, numerous concave portions remaining in the binder 52 due to the ejection of the aggregate 50 were confirmed on the support surface 8a of the porous chuck table 8. When the frame unit 7 is placed on the porous chuck table 8 having numerous concave portions formed on the support surface 8a and the workpiece 1 is sucked and held on the porous chuck table 8 via the adhesive tape 3, the workpiece 1 cannot be uniformly supported over the entire back surface 1 b.
Therefore, in a region of the workpiece 1 that cannot be appropriately supported by the support surface 8a, when the workpiece 1 is cut from the front surface 1a, a load applied to the workpiece 1 tends to cause a damage called a chipping or a chipping on the rear surface 1b side of the workpiece 1. This tendency becomes more remarkable as the size of the chip formed from the workpiece 1 becomes smaller. That is, in the conventional porous chuck table, when the workpiece 1 is cut and divided to produce chips, the chips are easily damaged.
In contrast, in the porous chuck table 8 of the present embodiment, a material having relatively low toughness is used as the aggregate 50. In this case, when the porous plate 42 is ground from the upper surface in the process of manufacturing the porous chuck table 8, the aggregate 50 is not ejected from the binder 52 and grinding work is performed while the grinding tool is in contact with the aggregate 50. That is, the upper portion of the aggregate 50 is removed to form a planarized upper surface. Fig. 5 (B) includes a cross-sectional view schematically showing an enlarged upper portion of the porous plate 42 of the porous chuck table 8 according to the present embodiment.
Fig. 5 (B) schematically shows the aggregate 50 with the flat surface 50a exposed upward. As shown in fig. 5 (B), in the porous chuck table 8, the aggregates 50 are not ejected from the binder 52, and the concave portions formed by the falling-out of the aggregates 50 are not formed on the upper surface of the binder 52. The aggregates 50 having a flat upper surface are disposed in a portion where the aggregates 50 on the upper surface of the conventional binder 52 come out to form a concave portion. Therefore, the support surface 8a becomes more flat.
In other words, in the porous chuck table 8, the area of the flat region constituting the support surface 8a for supporting the workpiece 1 is significantly larger than that of the conventional porous chuck table 8. When the workpiece 1 is placed on the support surface 8a, a wider area of the back surface 1b of the workpiece 1 can be supported, and the back surface 1b can be supported more uniformly.
Therefore, when the workpiece 1 is held on the porous chuck table 8 and chips are manufactured by cutting the workpiece 1, the chips are not easily damaged on the back surface thereof, including the case where the size of the chips is small. That is, when the workpiece 1 is cut using the porous chuck table 8 of the present embodiment, the defective rate of chips to be formed can be reduced.
As the aggregate 50 constituting the porous plate 42 of the porous chuck table 8 of the present embodiment, for example, silicon, glass typified by barium titanium glass, or boron carbide (B) is used4C) Zirconium oxide or silicon carbide (SiC)And (4) forming particles. The aggregate 50 made of these materials has a relatively high brittleness, and is easily removed by grinding the upper portion. For example, SiC is a hard material, but has a surface that is easily broken in crystal structure, and therefore is easily broken and flattened during grinding with a grinder.
The binder 52 constituting the porous plate 42 may be made of a glass material such as quartz glass, soda-lime glass, borosilicate glass, or alkali-free glass. The porous plate 42 has pores 54, and the pores 54 serve as suction paths when the workpiece 1 is sucked and held on the porous chuck table 8 through the adhesive tape 3. In forming the porous plate 42, the aggregate 50, the binder 52, and the pore-forming material are mixed at a predetermined ratio and sintered at a high temperature. At this time, the pore forming material disappears to form pores 54.
In the porous plate 42, the area occupied by the pores 54 is secured to such an extent that a sufficient suction force can be applied to the workpiece 1. Then, a binder 52 is bonded to the outer surface of the aggregate 50, and the aggregate 50 is held in a dispersed state by the binder 52. For example, when the binder 52 is too small, the aggregate 50 cannot be sufficiently supported by the binder 52, and it is not easy to maintain the shape of the porous plate 42, for example, in the process of manufacturing the porous plate 42. On the other hand, if the binder 52 is contained excessively, the area occupied by the pores 54 cannot be sufficiently secured.
Here, the particle size of the aggregate 50 is noted. Particle size refers to the nominal size of the particle. The particle size described in the present embodiment and the like is referred to JIS Standards established by the Japanese Industrial Standards Committee (JIS C). Specifically, refer to JIS R6001-1: 2017 (particle size of grinding material for grinding abrasive-part 1: coarse grain) and JIS R6001-2: 2017 (particle size of grinding material for grinding abrasive-part 2: fine powder), according to or according to the expression generally used in the industry of manufacturing and selling grinding tools.
The details of the method for determining the particle size are described in the above-mentioned JIS R6001-1: 2017 and JIS R6001-2: 2017. For example, the particle size of the abrasive particles is determined by using a particle size distribution test or a settling leg test method, or the like. The particle size of the particles of the present embodiment is determined by, for example, a particle size distribution test or a settling leg test method. In the porous chuck table 8 of the present embodiment, the particles of the aggregate 50 used in the porous plate 42 are not used as a grinding material for a grinding stone, but JIS standard is applied as an expression of the particle size.
Specifically, in the porous chuck table 8 of the present embodiment, it is preferable to use particles having a particle size of F80 or more and F400 or less as the particles of the aggregate 50 used in the porous plate 42. The "upper" and "lower" in "F80 or more and F400 or less" indicate the lower limit and the upper limit of the particle size. The smaller the number, the larger the maximum diameter of the particle, and the larger the number, the smaller the maximum diameter of the particle.
Here, particles having a particle size of F80 or more and F400 or less mean particles having a particle size of F80 or less according to JIS R6001-1: 2017 of any one of particles of particle size F80, F90, F100, F120, F150, F180 or F220. Alternatively, it means a composition represented by JIS R6001-2: 2017 of any one of particles of the particle sizes of F230, F240, F280, F320, F360 or F400.
For example, in the case where the volumes of the aggregate 50 and the binder 52 in the porous plate 42 are made constant, when the aggregate 50 is composed of particles having a particle size smaller than F80, that is, when particles having a relatively large diameter are used as the aggregate 50, it is not easy to sufficiently support the aggregate 50 with the binder 52. This is considered to be because the increase in the surface area is small compared to the increase in the weight of the particles when the diameter is increased, and the contact area of the binder 52 with the aggregate 50 is insufficient to hold the aggregate 50. In this case, it is not easy to maintain the shape of the porous plate 42 in the process of manufacturing the porous plate 42, or the like.
On the other hand, when the aggregate 50 is a particle having a particle size larger than F400, that is, when particles having a relatively small diameter are used as the aggregate 50, the surface area of the particles becomes small, and the adhesion between the binder 52 and the aggregate 50 is reduced. In this case, when the porous plate 42 is ground from the upper surface 42a, the aggregate 50 is easily ejected from the binder 52 by the grinding wheel. Therefore, the concave portion formed by the falling-off of the aggregate 50 is easily generated on the support surface 8a of the porous chuck table 8. When the concave portion is formed on the support surface 8a, it is not easy to cut the workpiece 1 with high quality.
Therefore, in the porous chuck table 8 of the present embodiment, it is preferable to use particles having a particle size of F80 or more and F400 or less as the particles of the aggregate 50.
In particular, when barium titanate glass or soda lime glass is used as the aggregate 50, particles having the quality of the test powder 2 that is JIS Z8901 (test powder and test particles) as JIS standard can be used. For example, particles having a particle size distribution (based on the resistance test method) of any one of GBM20, GBL30, GBM30, GBL40, GBM40, GBL60, and GBL100 may be used for the aggregate 50. In addition, in the case where the aggregate 50 is not a barium titanium glass, the quality of the particles can be expressed by this standard.
Next, a method for manufacturing the porous chuck table 8 according to the present embodiment will be described. Fig. 7 (a) is a flowchart showing a flow of each step of the method for manufacturing the porous chuck table 8. In the description of the method for manufacturing the porous chuck table 8, the description of the porous chuck table 8 can be referred to as appropriate.
In this manufacturing method, first, the preparation step S1 is performed to prepare the porous plate 42 and the frame 44. Here, as described above, the porous plate 42 has the aggregate 50, the binder 52, and the pores 54. As described above, the frame 44 has the concave portion 46 into which the porous plate 42 is fitted, and has the suction passage 48 having one end communicating with the concave portion 46 and the other end connectable to the suction source 8 b. Here, in this manufacturing method, the porous plate 42 may be manufactured in the preparation step S1.
Here, a case where the porous plate 42 is produced in the preparation step S1 will be described. Fig. 7 (B) is a flowchart showing the flow of the steps performed in the preparation step S1 when the porous plate 42 is produced in the preparation step S1. First, a mixing step S11 is performed to produce a mixture of the materials of the porous plate 42, and then a molding step S12 is performed to mold the mixture into a predetermined shape to produce a molded body. Then, a firing step S13 of firing the molded body is performed.
In the mixing step S11, a plurality of aggregate particles as a raw material of the aggregate 50, a raw material member as a binder of a material of the binder 52, and a granular pore-forming material for causing spaces to be finally removed to become pores 54 to appear in the porous plate 42 are mixed to produce a mixture. The mixing ratio of the aggregate particles, the raw material components of the binder, and the pore-forming material is appropriately determined depending on the properties of the porous plate 42 to be manufactured.
As described above, the plurality of aggregate particles are made of a material such as silicon carbide (SiC). In addition, particles having a particle size of F80 or more and F400 or less can be used as the plurality of aggregate particles. Here, the particle size distribution in the aggregate particles of each particle size was measured in accordance with JIS R6001-1: 2017 (particle size of grinding material for grinding abrasive-part 1: coarse grain) and JIS R6001-2: 2017 (particle size of grinding material for grinding abrasive-No. 2: micropowder). However, the particle size distribution of the aggregate particles is not limited to the standard.
The pore-forming material may have an average particle diameter of 100 μm or more and 150 μm or less, for example. The pore-forming material is particles of an organic material that is burned and disappears in the firing step S13 described later, and can form spaces to be the pores 54 in the porous plate 42. In addition, the glass material can be used as the material member of the binder. The raw material components of the binder are, for example, in the form of powder or slurry.
After the mixing step S11, a molding step S12 of molding the mixture into a predetermined shape is performed.
Fig. 3 (a) is a sectional view schematically showing the molding step S12. For example, a press molding apparatus 90 is used for molding the mixture 42c, and the press molding apparatus 90 includes: a concave die 92 having a disc-shaped space therein; a plate-shaped pressing member 94 having a shape corresponding to the space inside the mold 92; and a pressing shaft 96 capable of pressing the plate-like pressing member 94 downward. The space inside the die 92 is, for example, a substantially disk-like shape corresponding to the shape of the porous plate 42.
In the molding step S12, the mixture 42c produced in the mixing step S11 is introduced into the space inside the mold 92, and the mixture 42c is pressed by the plate-like pressing member 94 to be compression molded. After molding, the molded body is taken out from the mold 92.
After the molding step S12 is performed, a firing step S13 is performed. Fig. 3 (B) is a cross-sectional view showing the firing step S13. In the firing step S13, for example, a firing furnace 98 shown in fig. 3 (B) is used.
In the firing step S13, first, the molded body 42d is placed in a concave portion of the container 100 made of metal or ceramic that can withstand firing at a high temperature of 1300 ℃. The molded body 42d is sealed in the recess of the container 100 by a lid 102 made of the same material as the container 100. Next, the molded body 42d sealed with the container 100 and the lid 102 is put into a firing furnace 98, and the molded body 42d is fired. The firing temperature is, for example, a predetermined temperature of 800 ℃ to 1000 ℃. Thereby, the disc-shaped porous plate 42 is formed.
During the firing, the pore-forming material is burned and gasified, and is released into the atmosphere, so that pores 54 corresponding to the size of the pore-forming material are formed in the porous plate 42. After the firing step S13, the porous plate 42 is taken out from the container 100. Then, the upper surface 42a, the back surface 42b, and the side surfaces of the porous plate 42 may be ground to adjust the shape of the porous plate 42. The porous plate 42 produced in the above steps is produced, and the preparation step S1 is ended.
The porous plate 42 prepared in the preparation step S1 is ground from the upper surface to be thinned as described later. Therefore, in the preparation step S1, the porous plate 42 thicker than the porous plate 42 included in the manufactured porous chuck table 8 is prepared. For example, in the preparation step S1, the porous plate 42 having a thickness larger than the depth of the recess 46 (see fig. 4 a) of the frame 44 is prepared. When the porous plate 42 is manufactured in the preparation step S1, the thickness of the porous plate 42 is adjusted by adjusting the amount of the mixture.
In the method of manufacturing the porous chuck table 8 according to the present embodiment, after the preparation step S1, a fixing step S2 is performed in which the porous plate 42 is fitted and fixed to the recess 46 of the frame 44. Fig. 4 (a) is a sectional view schematically showing the fixing step S2. As shown in fig. 4 (a), in the fixing step S2, the porous plate 42 is fitted into the recess 46 of the frame 44. At this time, the porous plate 42 may be bonded to the frame 44 using an adhesive.
Fig. 4 (B) is a sectional view schematically showing the porous plate 42 fitted into the recess 46 of the frame 44. As described above, since the thickness of the porous plate 42 is larger than the depth of the concave portion 46, the upper portion of the porous plate 42 protrudes upward of the frame 44. Fig. 4 (B) is an enlarged schematic cross-sectional view of the upper surface 42a of the porous plate 42. As shown in the enlarged view, in the porous plate 42, the aggregates 50 are held by the binder 52 in a dispersed manner, and pores 54 are formed in the gaps between the aggregates 50 and the binder 52.
In the method of manufacturing the porous chuck table according to the present embodiment, after the fixing step S2, a grinding step S3 is performed in which the upper surface 42a of the porous plate 42 and the upper surface of the frame 44 are ground to be flush with each other. Fig. 5 (a) is a sectional view schematically showing the grinding step S3. The grinding step S3 is performed by, for example, the lateral axis grinding device 56 shown in fig. 5 (a).
The lateral shaft grinding device 56 has: a support table 56a for supporting a grinding object; and an annular grinding wheel 60 for grinding the object to be ground placed on the support table 56 a. A through hole (not shown) through which the spindle 58 passes is formed in the center of the annular grinding wheel 60, and the spindle 58 is attached to the lateral grinding device 56 through the through hole.
In the grinding step S3, the frame 44 with the porous plate 42 fitted therein is first placed on the support table 56a of the lateral grinding device 56. At this time, the frame 44 faces upward toward the porous plate 42. Then, the grinding wheel 60 is brought into contact with the upper surface 42a of the porous plate 42 while rotating the spindle 58 and rotating the annular grinding wheel 60. At this time, the grinding stone 60 is relatively moved in the direction along the upper surface 42a of the porous plate 42 while grinding is performed so as to grind the entire upper surface 42a of the porous plate 42.
When the porous plate 42 is thinned by grinding, the upper surface 42a of the porous plate 42 and the upper surface 44a of the frame 44 have the same height. Further, grinding is performed so that the grinding stone 60 is in contact with the upper surface 42a of the porous plate 42 and the upper surface 44a of the frame 44, and the upper surface 42a of the porous plate 42 and the upper surface 44a of the frame 44 are flush with each other. When grinding is performed until the upper surface 42a of the porous plate 42 reaches a predetermined height position, the porous chuck table 8 is manufactured, the upper surface of which serves as a support surface 8a for supporting the workpiece 1.
Fig. 5 (B) is a sectional view schematically showing the porous chuck table 8 manufactured by the method for manufacturing a porous chuck table according to the present embodiment. Fig. 5 (B) includes a cross-sectional view schematically showing an upper surface 42a of the porous plate 42 in an enlarged manner. In the method for manufacturing the porous chuck table according to the present embodiment, the aggregate 50 is made of a material having relatively high brittleness. Therefore, the aggregate 50 is not ejected from the binder 52 when the grinding stone 60 is brought into contact with the upper surface 42a of the porous plate 42.
In the grinding step S3 of the method for manufacturing a porous chuck table according to the present embodiment, as shown in fig. 5 (B), the upper portion of the aggregate 50 fixed by the binder 52 is ground on the upper surface 42a of the porous plate 42. A flat surface 50a is formed on the upper portion of the aggregate 50, and the flat surface 50a is exposed on the upper surface 42a of the porous plate 42.
The flat surface 50a of the aggregate 50 does not need to be flat like a mirror surface. For example, it may be flatter than the other surface of the aggregate 50, i.e., the non-ground surface. The flat surfaces 50a of the aggregates 50 are located at substantially the same height, and are substantially contained in the upper surface 42a of the porous plate 42.
Here, in the grinding step S3, the porous plate 42 and the frame 44 may be ground by a grinding wheel having a ceramic bond grinding wheel arranged in a ring shape. In this case, the abrasive grains dispersed and fixed in the grindstone of the grinding wheel may have a grain size of about #600 (JIS R6001-2: 2017).
For example, if the abrasive grains contained in the grindstone are large and the grain size of the abrasive grains is about #320, the aggregate 50 in contact with the grindstone of the grinding wheel is likely to fall off from the porous plate 42, and the aggregate 50 ground and flattened is unlikely to remain on the upper surface 42a of the porous plate 42. Further, for example, if the abrasive grains contained in the grindstone are small and the grain size of the abrasive grains is about #2000, the frame 44 cannot be ground properly, and therefore, it is not easy to make the upper surface 44a of the frame 44 flush with the upper surface 42a of the porous plate 42 by only grinding the porous plate 42.
The porous chuck table 8 thus manufactured is attached to the upper portion of the table base 6a of the cutting apparatus 2 shown in fig. 1 and the like, and used. Fig. 6 is a cross-sectional view schematically showing a case where the workpiece 1 is cut by the cutting device 2.
When the workpiece 1 is cut by the cutting device 2, first, the frame unit 7 is carried onto the porous chuck table 8. Then, the negative pressure from the suction source 8b is applied to the adhesive tape 3 adhered to the back surface 1b side of the workpiece 1 through the suction path 48 of the frame 44 and the air holes 54 of the porous plate 42 by operating the switching portion 8 c. Then, the workpiece 1 is attracted to and held by the porous chuck table 8.
Next, the workpiece 1 is cut by the cutting unit 18. The cutting unit 18 has: a main shaft 18a extending in the Y-axis direction parallel to the support surface 8a (see fig. 1); and a cutting tool 18b attached to a tip of the spindle 18 a. A rotation drive source such as a motor is connected to the base end side of the main shaft 18 a. When the rotary drive source is operated to rotate the main spindle 18a and cut the cutting tool 18b from the front surface 1a side of the workpiece 1, the workpiece 1 is cut and divided.
Fig. 6 includes a cross-sectional view schematically showing the workpiece 1 cut by the cutting tool 18b and the support surface 8a of the porous chuck table 8 in an enlarged manner. As shown in fig. 6, when cutting the workpiece 1, the lower end of the cutting tool 18b reaches the adhesive tape 3 in order to reliably divide the workpiece 1. Here, the adhesive tape 3 is in contact with the flat surface 50a of the aggregate 50 on the support surface 8a of the porous chuck table 8, and the work 1 is sufficiently supported by the porous chuck table 8.
Conventionally, since the aggregates 50 exposed on the upper surface 42a are ejected from the binder 52 when the porous plate 42 is ground on the support surface 8a of the porous chuck table 8, numerous recesses corresponding to the traces of the falling-off of the aggregates 50 are included on the support surface 8 a. Therefore, the workpiece 1 cannot be sufficiently supported by the porous chuck table 8, and damage such as chipping tends to occur around the chip formed when the workpiece 1 is cut.
In contrast, in the porous chuck table 8 manufactured by the method for manufacturing a porous chuck table according to the present embodiment, when grinding the porous plate 42, the aggregate 50 is not detached from the binder 52, and the upper portion of the aggregate 50 is ground to form the flat surface 50 a. Therefore, as shown in fig. 6, since the workpiece 1 is sufficiently supported by the support surface 8a of the porous chuck table 8, damage such as chipping is unlikely to occur in the chips formed by dividing the workpiece 1.
[ example 1 ]
In this example, as the porous chuck table 8 of the present embodiment, two porous chuck tables 8 were manufactured using silicon carbide (SiC) as the aggregate 50 and alkali-free glass as the binder 52, and the support surface 8a was observed with an optical microscope. Here, the porous chuck table 8 manufactured is a porous chuck table using the aggregate 50 having the particle size of F80 and a porous chuck table using the aggregate 50 having the particle size of F220. As example porous chuck table a and example porous chuck table B, respectively.
For comparison, a porous chuck table a of a comparative example was prepared using alumina as the aggregate 50, and the supporting surface 8a was photographed by an optical microscope in the same manner.
In the perforated plate 42 of the perforated chuck table a of the example, the volume ratio (porosity) of the pores 54 in the perforated plate 42 was about 40%, and the volume ratio of the aggregate in the total volume of the aggregate 50 and the binder 52 was about 60%. That is, in the production of the porous plate 42, the proportions of the plurality of aggregate particles as the raw material of the aggregate 50, the raw material component of the binder as the material of the binder 52, and the pore-forming material are adjusted so as to form the porous plate 42 under these conditions. The particle size of a plurality of aggregate particles as a raw material of the aggregate 50 was F80.
After the mixed material is molded, the porous plate 42 is sintered at a temperature of about 1000 ℃ for 10 hours to manufacture the porous plate. Then, the porous plate 42 is fitted into the frame 44, and the upper surface of the porous plate 42 is ground to form the support surface 8 a.
The photograph shown in fig. 8 (a) is a photomicrograph 62 obtained by taking a photograph of the support surface 8a of the porous chuck table a of the example at a low magnification by an optical microscope. The photograph shown in fig. 8 (B) is a photomicrograph 64 obtained by taking an image of the support surface 8a of the porous chuck table a of the example at a high magnification by an optical microscope. The microscopic photographs 62 and 64 show the flat surface 50a of the aggregate 50 ground at the top, the binder 52 surrounding the aggregate 50 around the flat surface 50a, and the pores 54.
The micrographs 62 and 64 are photographs taken in a state of being focused on the flat surface 50a of the aggregate 50. Further, since the focus is not focused on the structure existing at the bottom of the air hole 54, it can be understood that the height of the structure is different from that of the flat surface 50 a. On the other hand, the entire area of the photomicrographs 62, 64 is focused on the flat surface 50 a. Therefore, it can be understood that the height of the flat surface 50a is substantially uniform at each portion, and the flat surface 50a constitutes the support surface 8a of the porous chuck table a of the embodiment.
Particularly, when the micrograph 64 is carefully observed, streaky marks that are considered to be formed by grinding are recognized on the flat surface 50 a. Therefore, it was confirmed that the upper portion of the aggregate 50 was removed by grinding to form the flat surface 50 a.
The example porous chuck table B was fabricated in the same manner as the example porous chuck table a. However, when the porous plate 42 is manufactured, the particle size of the aggregate particles is set to F220. The photograph shown in fig. 9 (a) is a photomicrograph 66 obtained by taking a photograph of the support surface 8a of the porous chuck table B of the example at a low magnification by an optical microscope. The photograph shown in fig. 9 (B) is a photomicrograph 68 obtained by taking an image of the support surface 8a of the porous chuck table B of the example at a high magnification by an optical microscope.
In the example porous chuck table B, the number indicating the particle size of the aggregate 50 was higher than that of the example porous chuck table a, and the size of the particles constituting the aggregate 50 was relatively small as a whole. It was confirmed from the photomicrographs 66 and 68 that the upper portion of the aggregate 50 was removed by grinding to form the flat surface 50a of the aggregate 50. In addition, it was confirmed that the support surface 8a of the porous chuck table B of the example was constituted by the flat surface 50a of the aggregate 50.
The comparative example porous chuck table a was produced in the same manner as the example porous chuck table a and the like. However, alumina is used as the aggregate 50 of the porous plate 42. The photograph shown in fig. 11 (a) is a photomicrograph 78 obtained by taking a photograph of the support surface 8a of the porous chuck table a of the comparative example at a low magnification by an optical microscope. The photograph shown in fig. 11 (B) is a photomicrograph 80 obtained by taking an image of the support surface 8a of the porous chuck table a of the comparative example at a high magnification by an optical microscope.
As can be understood from the photomicrographs 78, 80, when the porous chuck table a of the comparative example was observed from the upper surface, numerous concave portions 82 were observed on the upper surface of the binder 52, and the concave portions 82 were considered to be formed by the grinding ejection of the aggregate 50 formed of alumina. Thus, the following is suggested: the example porous chuck table a and the example porous chuck table B can support the object 1 and the like more appropriately than the comparative example porous chuck table a.
In the present example, for comparison, the porous plate 42 was produced using aggregate particles having a particle size of F60, and the production of the porous chuck table was attempted in the same manner as in the porous chuck table a of the example. However, in the process of forming and firing a mixture of materials to produce the porous plate 42, a part of the mixture tends to be separated before and after firing, and the mixture tends to be naturally collapsed. This is believed to be because the proportion of binding agent 52 is insufficient to maintain the shape of the perforated plate 42.
In the present example, for comparison, the porous plate 42 was produced using aggregate particles having a particle size of F2000, and the porous chuck table was produced in the same manner as the porous chuck table a in the example. However, when the porous plate 42 was ground from the upper surface 42a and then the upper surface 42a was observed with a microscope, numerous concave portions 82 that were regarded as traces of falling-off of the aggregates 50 were observed. This is considered to be because the aggregate 50 has a small diameter and an insufficient contact area with the binder 52, and therefore the aggregate particles are not ground and detached from the binder 52.
[ example 2 ]
In this example, as the porous chuck table 8 of the present embodiment, two porous chuck tables 8 were manufactured, in which silicon carbide (SiC) was used as the aggregate 50 and alkali-free glass was used as the binder 52. The multi-hole chuck tables were attached to the cutting device 2, and LiTaO was placed on the multi-hole chuck tables3The wafer is cut by the cutting tool 18b as the object 1. Then, the LiTaO was observed in the vicinity of the formed cut groove by an optical microscope3The wafers were evaluated for the occurrence of damage such as edge chipping.
The two porous chuck tables 8 used for the production are each a porous chuck table using an aggregate 50 having a grain size of F150, and the aggregate 50 in the porous plate 42 has different volume ratios in the total volume of the aggregate 50 and the binder 52. As example porous chuck stage C and example porous chuck stage D, respectively. The volume ratio of the aggregate 50 to the total volume of the aggregate 50 and the binder 52 was adjusted so that the example porous chuck table C was 2 times as large as the example porous chuck table D.
For comparison, a porous chuck table B of comparative example was prepared using alumina as the aggregate 50, and the same procedure was applied to the cutting apparatus 2 for LiTaO3The wafer is cut. Then, the LiTaO was observed in the vicinity of the formed cut groove by an optical microscope3The wafers were evaluated for the occurrence of damage such as edge chipping.
The cut workpiece 1 was LiTaO having a diameter of 4 inches and a thickness of 0.35mm3A wafer. A tape "D-628" manufactured by LINTEC corporation as an adhesive tape 3 was attached to the back surface 1b side of the object 1 to form a frame unit 7, and the frame unit 7 was carried into the cutting device 2 and sucked and held on the porous chuck table. Then, the workpiece 1 was cut on each porous chuck table to cut out chips having a planar size of 1.0mm × 0.8 mm.
As the cutting tool 18b, "ZH 05-SD3000-N1-50 DD" manufactured by Di Cico of Kabushiki Kaisha was used. The workpiece 1 was cut with the rotation speed of the spindle 18a set at 20,000 revolutions per minute, the machining feed speed set at 10mm per second, and the depth of cut of the cutting blade 18b into the adhesive tape 3 set at 20 μm. At this time, 1.5L/min of cutting water was sprayed toward the cutting blade 18b, and 1.0L/min of cutting water was sprayed to the workpiece 1.
Fig. 10 (a) is a photomicrograph 70 of the back side of the workpiece 1 cut on the porous chuck table C of the example taken with an optical microscope. Fig. 10 (B) is a photomicrograph 76 of the back side of the workpiece 1 cut on the porous chuck table D of the example taken with an optical microscope. The microscopic photographs 70 and 76 show the chips 72 obtained by dividing the workpiece 1 and the cut grooves 74 formed between the chips 72.
Fig. 12 (a) is a photomicrograph 84 of the back side of the workpiece 1 cut on the porous chuck table B of the comparative example, taken with an optical microscope. Fig. 12 (B) is a photomicrograph 86 of another region on the back side of the workpiece 1 cut on the porous chuck table B of the comparative example, taken with an optical microscope. The microscopic photographs 84 and 86 show the chips 72 obtained by dividing the workpiece 1 and the cut grooves 74 formed between the chips 72. In addition, in the vicinity of the cut groove 74, the chipping 88 formed in the chip 72 is imaged.
As can be understood from comparison of the photomicrographs 70, 76, 84, and 86, the workpiece 1 can be processed with high quality on the example porous chuck table C and the example porous chuck table D, as compared with the comparative example porous chuck table B.
The cut workpiece 1 was observed over a wide range with an optical microscope, and the number of defective chips of the formed chips 72 was counted to calculate the defective rate. Here, the chips 72 that have been damaged by chipping 88 or chipping, which is a distance exceeding 20 μm from the cut groove 74, are regarded as defective chips.
As a result, the defective rate of the chips 72 formed on the porous chuck table C of the example was about 7%. In addition, the defective rate of the chips 72 formed on the example porous chuck table D was about 11%. On the other hand, the defective rate of the chips 72 formed on the porous chuck table B of the comparative example was about 25%. From the above results, it was confirmed that the porous chuck table 8 of the present embodiment can support the workpiece 1 more appropriately, and can cut the workpiece 1 of higher grade.
In addition, the structure, method, and the like of the above embodiments may be modified and implemented as appropriate without departing from the scope of the object of the present invention.

Claims (6)

1. A porous chuck table for sucking and supporting a workpiece to be machined when the workpiece is cut by a cutting tool,
the porous chuck worktable is provided with a porous plate and a frame body,
the porous plate has:
an aggregate;
a binder for fixing the aggregate; and
an air hole is formed in the upper surface of the shell,
the porous plate has a support surface on the upper surface thereof capable of supporting the object to be processed,
the frame body has a concave portion for fitting the porous plate, and has a suction passage having one end communicating with the concave portion and the other end connectable to a suction source,
the aggregate having a flat upper surface is exposed to the support surface of the porous plate.
2. The multi-hole chuck table according to claim 1,
the aggregate comprises particles made of silicon, glass, boron carbide, zirconia or silicon carbide.
3. The multi-hole chuck table according to claim 2,
the particle size of the particles is F80 or more and F400 or less.
4. A method for manufacturing a porous chuck table, characterized in that,
the manufacturing method of the porous chuck worktable comprises the following steps:
a preparation step of preparing a porous plate having aggregate, a binder, and pores, and a frame having a recess into which the porous plate is fitted, and having an aspiration path having one end communicating with the recess and the other end connectable to an aspiration source;
a fixing step of fitting and fixing the porous plate in the recess of the frame; and
a grinding step of grinding the upper surface of the porous plate and the upper surface of the frame to be flush with each other after the fixing step,
in the grinding step, an upper portion of the aggregate fixed by the binder is ground on the upper surface of the porous plate to form a flat surface on the upper portion of the aggregate, and the flat surface is exposed on the upper surface of the porous plate.
5. The method of manufacturing a multi-hole chuck table according to claim 4,
the aggregate comprises particles made of silicon, glass, boron carbide, zirconia or silicon carbide.
6. The method of manufacturing a multi-hole chuck table according to claim 5,
the particle size of the particles is F80 or more and F400 or less.
CN202010460784.1A 2019-06-07 2020-05-27 Porous chuck table and method for manufacturing porous chuck table Pending CN112053987A (en)

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JP2019106874A JP2020199564A (en) 2019-06-07 2019-06-07 Porous chuck table and porous chuck table manufacturing method
JP2019-106874 2019-06-07

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KR (1) KR20200140712A (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001341042A (en) * 2000-06-01 2001-12-11 Nanotemu:Kk Vacuum chuck and method for manufacturing the same
JP2009076773A (en) 2007-09-21 2009-04-09 Disco Abrasive Syst Ltd Chuck table mechanism
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