JP2013184240A - Method for cutting by cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cutting by a cutting tool, capable of efficiently cutting a workpiece irrespective of a size of the workpiece.SOLUTION: A method for cutting by a cutting tool includes: a workpiece determination step of determining whether a workpiece 11 wholly covers over a holding part when the workpiece is held by a chuck table; an adhesive sheet attaching step of attaching the workpiece to an adhesive sheet 13 with a size of covering over the holding part when it is determined that the workpiece does not wholly cover over the holding part in the workpiece determination step; a holding step of sucking and holding the workpiece by the chuck table via the adhesive sheet after performing the adhesive sheet attaching step; and a cutting step of positioning a cutting tool wheel at a height where a cutting blade cuts into the workpiece held to the chuck table by a predetermined depth, and then moving linearly the rotating cutting tool wheel and the chuck table relative to each other so that the workpiece is subjected to rotation cutting.

Description

  The present invention relates to a cutting tool for turning a workpiece such as a wafer with a cutting tool.

  There are various techniques for realizing light and thin semiconductor devices. As an example, a flip in which a plurality of metal protrusions called bumps having a height of about 10 to 100 μm are formed on the surface of a device formed on a semiconductor wafer, and these bumps are directly bonded to an electrode formed on a wiring board. A mounting technique called chip bonding has been put into practical use.

  The bump formed on the device surface of the semiconductor wafer is formed by a method such as plating or stud bump. For this reason, the heights of the individual bumps are non-uniform, and it is difficult to uniformly bond the plurality of bumps to the electrodes of the wiring board as they are.

  In order to realize high-density wiring, there is an integrated circuit mounting technique in which an anisotropic conductive film (ACF) is sandwiched and bonded between a bump and a wiring board. In the case of this mounting technique, if the height of the bump is insufficient, a bonding failure is caused, so that a certain bump height is required.

  Therefore, it is desired to cut a plurality of bumps formed on the surface of the semiconductor wafer to a desired height. As a method of cutting the bumps to a desired height, a method of scraping the bumps using a bite wheel is proposed in, for example, Japanese Patent Application Laid-Open No. 2004-319697.

  The bite wheel includes a wheel base and a bite unit including a cutting blade disposed on the wheel base. The bite wheel and the workpiece are in contact with the workpiece while rotating the bite wheel while the cutting blade is in contact with the workpiece. Cutting is performed by sliding the workpiece.

  The workpiece is sucked and held by a chuck table as disclosed in Japanese Patent Application Laid-Open No. 2008-140832 or Japanese Patent Application Laid-Open No. 5-023941, and the chuck table is linearly processed and fed while rotating the bite wheel. To be cut.

  If the size of the workpiece is smaller than the size of the chuck table suction holding area, the negative pressure leaks and the workpiece cannot be sucked and held by the chuck table, so the chuck table is changed according to the size of the workpiece. There is a need.

JP 2004-319697 A JP 2008-140832 A JP-A-5-023941

  After changing the chuck table, so that the chuck table holding surface and the cutting surface of the cutting tool of the bite wheel are parallel, so-called self-cutting that cuts the chuck table with the bite wheel or setting the cutting depth Therefore, there is a problem that if the chuck table is changed for each workpiece, the work becomes very complicated and troublesome.

  In particular, when cutting a damaged workpiece, it is impractical to form the holding surface of the chuck table according to the damaged shape, and it is possible to cut a workpiece that has been damaged and has an irregular shape. A cutting method is desired.

  The present invention has been made in view of these points, and an object of the present invention is to provide a cutting tool capable of efficiently cutting a workpiece regardless of the size of the workpiece.

  According to the present invention, there is provided a tool cutting method for cutting a workpiece with a cutting tool means having a tool wheel including a cutting blade, the size of the holding portion of the chuck table having a holding portion for sucking and holding the workpiece. A workpiece discrimination step for comparing the size of the workpiece and determining whether or not the workpiece covers the entire holding portion when the workpiece is held by the chuck table; and the workpiece When it is determined that the workpiece does not cover the entire holding portion in the determination step, an adhesive sheet attaching step for attaching the workpiece to an adhesive sheet having a size covering the holding portion, and the adhesive sheet attaching step. After performing, the holding step of sucking and holding the workpiece through the adhesive sheet by the chuck table, and the height position at which the cutting blade cuts into the workpiece held by the chuck table to a predetermined depth. A tool cutting method comprising: a cutting step of turning a workpiece by rotating the tool wheel and the chuck table relatively linearly moved after the wheel is positioned. .

  Preferably, the adhesive sheet has a base material and a paste layer made of an ultraviolet curable resin disposed on the base material and cured by irradiation of ultraviolet light, and the cutting tool method includes an adhesive sheet attaching step. Then, at least before performing the cutting step, it further comprises a curing step of irradiating the adhesive sheet with ultraviolet rays to cure the glue layer.

  According to the cutting tool method of the present invention, there is no need to change the chuck table in accordance with the size of the work piece, so there is no need to store and manage a plurality of chuck tables, regardless of the size of the work piece. The workpiece can be cut efficiently.

  According to the second aspect of the present invention, by irradiating ultraviolet rays before cutting to cure the glue layer, the movement of the workpiece during cutting can be suppressed, and variation in the cutting depth can be reduced. Processing becomes possible.

It is a perspective view of a cutting tool suitable for carrying out the cutting method of the present invention. It is a perspective view explaining a workpiece discrimination step. It is a disassembled perspective view which shows an adhesive sheet sticking step. It is a perspective view which shows a hardening step. It is a perspective view which shows a holding | maintenance step. It is a partial cross section side view which shows a cutting step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a perspective view of a cutting tool 2 suitable for carrying out the cutting method of the present invention is shown. The housing 4 of the cutting tool 2 comprises a horizontal housing part 6 and a vertical housing part 8.

  A pair of guide rails 12 and 14 extending in the vertical direction are fixed to the vertical housing portion 8. A cutting tool unit 16 is mounted along the pair of guide rails 12 and 14 so as to be movable in the vertical direction. The cutting tool unit 16 is attached to a moving base 18 that moves up and down along a pair of guide rails 12 and 14 via a support portion 20.

  The cutting tool unit 16 includes a spindle housing 22 attached to the support portion 20, a spindle 24 rotatably accommodated in the spindle housing 22, and a servo motor 26 that rotationally drives the spindle 24.

  A wheel mount 28 is fixed to the tip of the spindle 24, and a bite wheel 30 having a bite tool 32 is attached to the wheel mount 28. The cutting tool 32 has a cutting blade formed of diamond at its tip.

  The cutting tool 2 includes a cutting tool feed mechanism 34 that moves the cutting tool 16 in the vertical direction along the pair of guide rails 12 and 14. The cutting tool unit feed mechanism 34 includes a ball screw 36 and a pulse motor 38 fixed to one end of the ball screw 36. When the pulse motor 38 is pulse-driven, the ball screw 36 rotates and the moving base 18 is moved in the vertical direction via the nut of the ball screw 36 housed in the moving base 18.

  A chuck table 40 is disposed in the recess 10 of the horizontal housing portion 6. The chuck table 40 is moved in the Y-axis direction by a chuck table moving mechanism (not shown). 44 and 46 are bellows. A cutting water supply nozzle 42 that supplies cutting water toward the workpiece being cut and the bite wheel 30 is disposed adjacent to the chuck table 40.

  The horizontal housing portion 6 of the housing 4 includes a first cassette 48, a second cassette 50, a workpiece transfer robot 52, a temporary placement table 54 having a plurality of positioning pins 56, and a temporary placement table 54. A workpiece loading means 58 for loading the workpiece onto the chuck table 40, a workpiece unloading means 60 for unloading the workpiece from the chuck table 40, and a cleaning unit 62 are provided. Further, an operation panel 64 is provided in front of the housing 4 for an operator to input cutting conditions and the like.

  A gate-type frame 70 is disposed in the horizontal housing portion 6 so as to straddle the recess 10, and the chuck table 40 can pass through a space below the gate-type frame 70.

  A first height position detector 72 and a second height position detector 74 are attached to the portal frame 70. Each of the first and second height position detectors 72 and 74 has a contact needle at the tip. For example, the first height position detector 72 detects the height position of the holding surface of the chuck table 40, and the second height position detector 72 and 74 has a second height. A position detector 74 detects the height position of the upper surface of the workpiece held on the chuck table 40.

  In the cutting tool method of the present invention, first, as shown in FIG. 2, the size of the holding portion 40a of the chuck table 40 having the holding portion 40a for sucking and holding the workpiece 11 such as a semiconductor wafer, and the size of the workpiece 11 Are compared, and a workpiece discrimination step for discriminating whether or not the workpiece 11 covers the entire holding portion 40a when the workpiece 11 is held by the chuck table 40 is performed. This workpiece discrimination step is performed visually by the operator of the cutting tool 2.

  The suction holding portion 40a of the chuck table 40 is formed of porous ceramics or the like, or is formed of a pin chuck that holds a workpiece with a plurality of pins. The outer periphery of the holding portion 40a is surrounded by a frame body 40b made of SUS or the like.

  When it is determined in the workpiece discrimination step that the workpiece 11 does not cover the entire holding portion 40a of the chuck table 40, the workpiece 11 is applied to the adhesive sheet 13 having a size covering the holding portion 40a as shown in FIG. The adhesive sheet sticking step for sticking is carried out.

  The pressure-sensitive adhesive sheet 13 is composed of a base material 13a formed of a material transparent to ultraviolet rays, and a paste layer 13b made of an ultraviolet curable resin that is cured by irradiation with ultraviolet rays disposed on the base material 13a.

  After the workpiece 11 is adhered to the pressure-sensitive adhesive sheet 13, as shown in FIG. 4, a curing step is performed in which ultraviolet rays are irradiated from below the pressure-sensitive adhesive sheet 13 by an ultraviolet lamp 15 to cure the glue layer 13b.

  In this curing step, it is desirable to completely cure the glue layer 13b made of an ultraviolet curable resin, but it may be cured to a semi-cured state. When the workpiece 11 is formed of a material transparent to ultraviolet rays, a curing step by ultraviolet irradiation may be performed from above the workpiece 11.

  After performing the curing step, as shown in FIG. 5, a holding step for sucking and holding the workpiece 11 through the adhesive sheet 13 is performed by the chuck table 40 of the cutting tool 2. Since the size of the adhesive sheet 13 is equal to or larger than the size of the suction holding unit 40a of the chuck table 40, the suction holding unit 40a is connected to the suction source 70 (see FIG. 6) to apply a negative pressure to the suction holding unit 40a. When applied, negative pressure will not leak.

  When the workpiece 11 is made of a material transparent to ultraviolet rays, after the holding step shown in FIG. 5 is performed, ultraviolet rays are irradiated from above the workpiece 11 to form the glue layer 13b. A curing step for curing may be performed.

  After the workpiece 11 is sucked and held by the chuck table 40 via the adhesive sheet 13, the chuck table 40 is moved below the first and second height position detectors 72 and 74, and the first height position detector is detected. The upper surface height position of the pressure-sensitive adhesive sheet 13 is detected at 72, and the upper surface height position of the workpiece 11 is detected by the second height position detector 74.

  Then, the thickness of the workpiece 11 is calculated by subtracting the upper surface height position of the adhesive sheet 13 from the upper surface height position of the workpiece 11. Based on the calculated thickness of the workpiece 11, the target cutting height of the workpiece 11 held on the chuck table 40 via the adhesive sheet 13 is set.

  After setting the target cutting height, the chuck table moving mechanism in FIG. 1 is driven to move the chuck table 40 to the back side (right side) in the Y-axis direction, and then the cutting tool feed unit 34 is driven to operate the cutting tool 32. The cutting blade is moved to the set target cutting height and cut into the workpiece by a predetermined depth.

  Then, as shown in FIG. 6, the workpiece 11 held on the chuck table 40 is moved while moving the chuck table 40 in the direction of the arrow Y1, that is, while pulling the chuck table 40 forward in the Y-axis direction in FIG. Carry out swivel cutting. Cutting is performed while supplying cutting fluid from the cutting fluid supply nozzle 42.

  In this cutting step, since the adhesive layer 13b of the pressure-sensitive adhesive sheet 13 is cured by irradiation with ultraviolet rays, the movement of the workpiece 11 during cutting can be suppressed, and the variation in the cutting depth can be reduced. Cutting is possible.

  After the workpiece 11 is cut to a desired thickness, the chuck table 40 is returned to the workpiece loading / unloading area, the suction holding of the suction holding unit is released, and the adhesive sheet 13 is removed from the chuck table 40. Since the adhesive layer 13 b of the pressure-sensitive adhesive sheet 13 is cured by irradiation with ultraviolet rays, the workpiece 11 can be easily peeled from the pressure-sensitive adhesive sheet 13.

2 Bite cutting device 11 Work piece 13 Adhesive sheet 13a Base material 13b Glue layer 15 Ultraviolet lamp 16 Bite cutting unit 30 Bite wheel 32 Bite tool 40 Chuck table 40a Suction holding part 72 First height position detector 74 Second height Position detector

Claims (2)

A tool cutting method for cutting a workpiece with a cutting tool means having a tool wheel including a cutting blade,
The size of the holding portion of the chuck table having a holding portion for holding the workpiece by suction is compared with the size of the workpiece, and the workpiece is held by the holding portion when the workpiece is held by the chuck table. A workpiece discrimination step for discriminating whether or not to cover the whole; and
When it is determined that the workpiece does not cover the entire holding portion in the workpiece discrimination step, an adhesive sheet attaching step for attaching the workpiece to an adhesive sheet having a size covering the holding portion;
A holding step of sucking and holding the workpiece through the adhesive sheet with the chuck table after performing the adhesive sheet attaching step;
After a bite wheel is positioned at a height position where a cutting blade cuts a predetermined depth into the workpiece held on the chuck table, the rotating bite wheel and the chuck table are relatively linearly moved to move the workpiece. A cutting step for turning and turning,
A tool cutting method characterized by comprising: The pressure-sensitive adhesive sheet has a base material and a paste layer made of an ultraviolet curable resin that is cured by irradiation with ultraviolet light disposed on the base material,
2. The method according to claim 1, further comprising a curing step of irradiating the pressure-sensitive adhesive sheet with ultraviolet rays to harden the adhesive layer after performing the pressure-sensitive adhesive sheet attaching step and before performing the cutting step. The cutting tool described.

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