JP2010247311A - Workpiece grinding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding method capable of grinding a plurality of workpieces simultaneously.
A method for grinding a workpiece, wherein a workpiece pasting step for pasting a plurality of workpieces on an adhesive tape having an outer peripheral portion stuck to an annular frame, and on the adhesive tape A holding step for holding the attached workpieces on a holding table; a thickness measuring step before processing for measuring a thickness of the workpiece held on the holding table by a thickness measuring means; and the holding table A grinding step for grinding the plurality of workpieces held in step to a predetermined thickness by a grinding means, and a finishing thickness measurement step for measuring the thickness of the workpiece by a thickness measurement means after performing the grinding step And re-grinding step of regrinding the plurality of workpieces to a predetermined thickness by the grinding means when the thickness of the workpiece measured in the finishing thickness measurement step does not reach the predetermined thickness. And equipped with And features.
[Selection] Figure 5

Description

  The present invention relates to a workpiece grinding method for grinding a plurality of workpieces at a time.

  A workpiece such as a semiconductor wafer on which a plurality of devices such as IC and LSI are formed is ground to a predetermined thickness by a grinding device and then cut into individual devices by a cutting device. . The divided devices are widely used for electric devices such as mobile phones and personal computers.

  The grinding apparatus measures a thickness of the workpiece, a holding table for holding the workpiece, a grinding means rotatably mounted with a grinding wheel having a grinding wheel for grinding the workpiece held on the holding table. And a contact-type measuring device that can grind the workpiece to a desired thickness with high accuracy.

  During grinding, grinding is performed while measuring the thickness of the workpiece while the contact needle (probe) of the measuring device is in contact with the workpiece. By stopping grinding when the desired thickness is reached, the workpiece can be ground to the desired thickness.

  On the other hand, in recent years, various electronic components are becoming lighter, thinner, and smaller, and in addition to semiconductor wafers, grinding of sapphire substrates used for optical devices and package substrates in which semiconductor devices are molded with mold resin is also possible. Demand is increasing.

  Sapphire substrates, which are more expensive than semiconductor wafers, are mainly in the size of φ6 inches to φ12 inches, whereas small diameter substrates of φ2 inches and φ3 inches are mainstream. A general package substrate has a rectangular shape and is often smaller than a semiconductor wafer.

JP 2002-200545 A

  Conventionally, even a small substrate such as a sapphire substrate or a small substrate such as a package substrate has been ground by holding the small substrate and the small substrate individually with a chuck table of a grinding apparatus. However, grinding such small workpieces individually is very time consuming and has a problem of poor productivity.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the grinding method which can grind several workpieces simultaneously.

  According to the present invention, there is provided a grinding method for a workpiece, the workpiece pasting step for pasting a plurality of workpieces on an adhesive tape having an outer peripheral portion stuck to an annular frame, and on the adhesive tape. A holding step for holding the plurality of workpieces adhered to the holding table with a holding table; a thickness measuring step before measuring the thickness of the workpiece held on the holding table with a thickness measuring means; and A grinding step for grinding the plurality of workpieces held by a holding table to a predetermined thickness by a grinding means, and a finishing thickness for measuring the thickness of the workpiece by a thickness measurement means after performing the grinding step When the thickness of the workpiece measured in the measuring step and the finished thickness measuring step does not reach the predetermined thickness, the plurality of workpieces are ground again to the predetermined thickness by the grinding means. A grinding step. Grinding method of the workpiece are provided, characterized in that the.

  According to the present invention, since a plurality of workpieces are attached with an adhesive tape and ground simultaneously, productivity can be improved. Furthermore, since the holding surface side of the workpiece is adhered to the adhesive tape, it is not damaged during grinding, and the adhesive tape can be peeled only once, leading to a reduction in man-hours.

1 is an external perspective view of a grinding apparatus suitable for carrying out the grinding method of the present invention. It is a flowchart which shows the grinding method of this invention embodiment. It is a perspective view which shows the some small workpiece supported by the annular frame via the adhesive tape. It is explanatory drawing of the grinding method of this invention. It is explanatory drawing of the thickness measurement step of a to-be-processed object.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external perspective view of a grinding apparatus suitable for carrying out the grinding method of the present invention. Reference numeral 4 denotes a housing of the grinding apparatus 2, and a column 6 is erected on the rear side of the housing 4. A pair of guide rails 8 extending in the vertical direction is fixed to the column 6.

  A grinding unit (grinding means) 10 is mounted along the pair of guide rails 8 so as to be movable in the vertical direction. The grinding unit 10 includes a spindle housing 12 and a support portion 14 that supports the spindle housing 12. The support portion 14 is attached to a moving base 16 that moves in the vertical direction along a pair of guide rails 8. Yes.

  The grinding unit 10 includes a spindle 18 rotatably accommodated in a spindle housing 12, a wheel mount 20 fixed to the tip of the spindle 18, and a plurality of grinding wheels 24 screwed to the wheel mount 20 and arranged annularly. A grinding wheel 22 having (see FIG. 4) and an electric motor 26 for rotating the spindle 18 are included.

  The grinding apparatus 2 includes a grinding unit moving mechanism 32 including a ball screw 28 that moves the grinding unit 10 in the vertical direction along a pair of guide rails 8 and a pulse motor 30. When the pulse motor 30 is driven, the ball screw 28 rotates and the moving base 16 is moved in the vertical direction.

  A recess 4a is formed on the upper surface of the housing 4, and a chuck table mechanism 34 is disposed in the recess 4a. The chuck table mechanism 34 has a chuck table (holding table) 36, and is moved in the Y-axis direction between a workpiece attaching / detaching position A and a grinding position B facing the grinding unit 10 by a moving mechanism (not shown). 38 and 40 are bellows. On the front side of the housing 4, an operation panel 42 on which an operator of the grinding device 2 inputs grinding conditions and the like is disposed.

  The chuck table 36 has a suction chuck (holding surface) 44 for sucking and holding a workpiece. A thickness measuring device 46 has two contact needles (probes) 47 and 48 as shown in FIG. Around the chuck table 36, four permanent magnets 50 for magnetically adsorbing an annular frame F that supports a workpiece 52 via an adhesive tape T are disposed as shown in FIG.

  Next, with reference to the flowchart of FIG. 2, the grinding method of the workpiece of this embodiment is demonstrated. First, in step S10, a workpiece pasting step is performed in which a plurality of workpieces are stuck to an adhesive tape and supported by an annular frame.

  That is, as shown in FIG. 3, a plurality of small workpieces 52 such as sapphire substrates are stuck on the adhesive tape T whose outer periphery is stuck to the annular frame F. As a result, the plurality of small workpieces 52 are supported by the annular frame F via the adhesive tape T.

  Examples of the workpiece 52 include a sapphire substrate, a gallium arsenide wafer, a Si wafer, a package substrate in which a semiconductor device is molded with a mold resin, and the like.

  The adhesive tape T includes a base material made of PO (polyolefin), PVC (polyvinyl chloride), PET (polyethylene terephthalate) or the like having a thickness of about 100 μm, and an acrylic system having a thickness of about 5 to 40 μm formed on the base material. And rubber glue layer.

  Next, the plurality of workpieces attached on the adhesive tape in step S11 are held by a holding table (chuck table). That is, as shown in FIG. 4, a plurality of workpieces 52 are sucked and held by the chuck table 36 via the adhesive tape T, and the annular frame is formed by the permanent magnet 50 provided below the holding surface 44 of the chuck table 36. F is pulled down and adsorbed. This prevents the annular frame F from being ground by the grinding wheel 24.

  Next, the thickness of the workpiece 52 held by the holding table 36 is measured by the thickness measuring device 46 in step S12. That is, as shown in FIG. 5, one probe 47 of the thickness measuring device 46 is brought into contact with the upper surface of the workpiece 52 to measure its height, and the other probe 48 is brought into contact with the adhesive tape T. Measure its height.

  By measuring the difference between the measured values of both probes 47 and 48, the thickness of the workpiece 52 before processing is measured. Since all the workpieces 52 have the same thickness in principle, this pre-processing thickness measurement step may be performed on one workpiece 52.

  Next, the chuck table 36 is moved to a grinding position facing the grinding unit 10 indicated by an arrow B in FIG. 1 by a moving mechanism (not shown), and the grinding step of Step S13 is performed. That is, as shown in FIG. 4, while rotating the chuck table 36 in the direction of arrow A at 300 rpm, for example, and rotating the grinding wheel 22 in the direction of arrow B at, for example, 6000 rpm, the chuck table 36 is ground and fed downward by a predetermined feed amount. In order to grind the workpiece 52 to a desired thickness, the grinding step is stopped when a predetermined grinding time elapses while paying attention to excessive grinding.

  Next, after the chuck table 36 is moved to the workpiece attaching / detaching position indicated by the arrow A by a moving mechanism (not shown), the finishing thickness measuring step of Step S14 is performed. That is, as shown in FIG. 5, one probe 47 of the thickness measuring device 46 is brought into contact with the ground surface of the workpiece 52 and the height thereof is measured, and the other probe 48 is brought into contact with the adhesive tape T. And measure its height. By taking the difference between the measured values of both probes 47 and 48, the thickness of the ground workpiece 52 can be measured. The workpiece to be measured here is preferably the same as the workpiece whose thickness was measured in the thickness measurement step S12 before processing.

  By this measurement, it is determined whether or not the ground workpiece 52 has reached a predetermined thickness (step S15). When the predetermined thickness is reached, the grinding is terminated. On the other hand, when the thickness of the workpiece 52 after grinding does not reach the predetermined thickness, the grinding step in step S13 and the finishing thickness measurement step in step S14 are performed again. Steps S13 and S14 are repeated until the thickness of the workpiece 52 reaches a predetermined thickness.

  In the grinding step of step S13, since the plurality of workpieces 52 adhered to the adhesive tape T are ground at the same time, the degree of the grinding process is considered to be equivalent. Therefore, the finishing thickness measurement step of step S14 is: What is necessary is just to implement with respect to the one to-be-processed object 52. FIG.

  In the grinding apparatus 2 shown in FIG. 1, the thickness measuring device 46 is disposed at the workpiece attaching / detaching position A. However, if the thickness measuring device 46 is disposed at the grinding position B, a predetermined time is provided. After the workpiece 52 is ground, the finishing thickness measuring step of step S14 can be performed immediately.

  In the workpiece grinding method of the embodiment of the present invention described above, productivity is improved because a plurality of workpieces 52 are adhered to the adhesive tape T and simultaneously ground by the grinding wheel 22 having the grinding wheel 24. can do.

2 Grinding device 10 Grinding unit 22 Grinding wheel 24 Grinding wheel 36 Chuck table 46 Thickness measuring devices 47 and 48 Contact needle (probe)
50 Permanent magnet 52 Work piece

Claims (2)

A method of grinding a workpiece,
A workpiece pasting step for pasting a plurality of workpieces on the adhesive tape whose outer peripheral portion is stuck to the annular frame;
A holding step of holding the plurality of workpieces adhered on the adhesive tape with a holding table;
A thickness measuring step before processing for measuring the thickness of the workpiece held by the holding table with a thickness measuring means;
A grinding step of grinding the plurality of workpieces held by the holding table to a predetermined thickness by a grinding means;
After performing the grinding step, a finished thickness measuring step for measuring the thickness of the workpiece by a thickness measuring means;
A re-grinding step of regrinding the plurality of workpieces to a predetermined thickness by the grinding means when the thickness of the workpiece measured in the finishing thickness measurement step does not reach the predetermined thickness;
A method of grinding a workpiece, comprising:   2. The workpiece grinding method according to claim 1, wherein the workpieces whose thicknesses are measured in the pre-machining thickness measuring step and the finished thickness measuring step are the same.

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