JP7154690B2 - Grinding wheel dressing method - Google Patents

Description

The present invention relates to a grinding wheel dressing method for dressing a grinding surface of a grinding wheel and a dressing wafer.

2. Description of the Related Art When grinding various plate-like workpieces such as semiconductor wafers, a grinding wheel is used in which a plurality of grinding wheels are arranged in an annular shape on a wheel base. Grinding wheels are formed by bonding diamond abrasive grains with a resin bond, vitrified bond, metal bond, etc., and good grinding results are obtained when the abrasive grains are in a so-called dressed state in which the abrasive grains partially protrude from the bond. be done.

Therefore, there is a dressing operation that consumes the bond and protrudes abrasive grains by grinding a workpiece other than the product before grinding, and a dressing operation (pre-grinding or pre-cutting) to optimize the protruding state for the product. need to do

Normally, the dressing work is performed by grinding a material similar to that of the product. For example, when the product is a silicon wafer, the dressing work is performed by grinding a plurality of dummy silicon wafers.

Japanese Patent Application Laid-Open No. 2008-221360

However, when a plurality of dummy silicon wafers are ground and a dressing operation is performed, there is a problem that the preparation of a plurality of dummy silicon wafers is costly.

SUMMARY OF THE INVENTION The present invention has been made in view of these points, and its object is to reduce the number of dummy wafers used in the dressing operation and to efficiently perform the dressing operation of the grinding wheel. To provide a method for dressing a grinding wheel.

According to the first aspect of the invention, a chuck table for holding a dummy silicon wafer on a holding surface and a grinding wheel having a plurality of grinding wheels arranged in an annular shape are mounted on a spindle having a rotation axis perpendicular to the holding surface. A method of dressing a grinding wheel using a grinding device comprising a grinding unit for grinding a dummy silicon wafer held on a chuck table and a grinding feed unit for grinding and feeding the grinding unit in the direction of the rotation axis, The grinding unit is fed while rotating the spindle to grind the dummy silicon wafer held on the chuck table without rotating the chuck table to form an arc-shaped grinding groove on the surface of the dummy silicon wafer . A method for dressing a grinding wheel is provided, characterized by forming a

Preferably, a plurality of arc-shaped grinding grooves are formed in the dummy silicon wafer to control the dressing state of the grinding wheel.

According to the grinding wheel dressing method of the present invention, since the workpiece is ground without rotating the chuck table holding the workpiece, the load applied to the grinding wheel is high and the grinding effect is high even if the grinding volume is small. can be obtained, the number of workpieces used in the dressing operation can be reduced. In addition, since a plurality of arc-shaped grinding grooves can be formed in one workpiece according to the dressing condition, there is an effect that the amount of dressing grinding can be adjusted without increasing the amount of workpiece used.

Furthermore, since the workpiece used in the dressing method of the present invention has an annular grinding groove and the grinding load is higher than that of a flat workpiece, the chuck table holding the workpiece is rotated and There is also the effect that it can also be used as a workpiece during a normal dressing operation in which a grinding wheel is ground to perform the dressing operation.

It is a perspective view of a grinding device. It is a partial cross-sectional side view which shows the grinding method of this invention. 1 is a schematic plan view showing a dressing method of the present invention; FIG. FIG. 4(A) is a plan view of a dummy silicon wafer after forming one arcuate grinding groove by the dressing method of the present invention, and FIG. 4(B) is a dummy after forming a plurality of arcuate grinding grooves. It is a top view of a silicon wafer. FIG. 4 is a partial cross-sectional side view showing how a dummy silicon wafer having a plurality of arcuate grinding grooves is used to rotate a chuck table and a grinding wheel together to perform a normal dressing operation.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown an external perspective view of a grinding apparatus 2 suitable for carrying out the dressing method of the present invention. A base 4 of the grinding device 2 has a column 6 erected behind the base 4 . A pair of guide rails 8 extending vertically is fixed to the column 6 .

Along the pair of guide rails 8, a grinding unit (grinding means) 10 is mounted so as to be vertically movable. The grinding unit 10 has a spindle housing 12 and a support portion 14 that holds the spindle housing 12. The support portion 14 is attached to a movable base 16 that moves vertically along a pair of guide rails 8. there is

The grinding unit 10 includes a spindle 18 rotatably housed in a spindle housing 12, a motor 20 for rotating the spindle 18, a wheel mount 22 fixed to the tip of the spindle 18, and detachable from the wheel mount 22. and a grinding wheel 24 mounted thereon.

The grinding apparatus 2 includes a grinding feed unit 34 composed of a ball screw 30 and a pulse motor 32 for vertically moving the grinding unit 10 along a pair of guide rails 8 . When the pulse motor 32 is driven, the ball screw 30 rotates and the movable base 16 is moved vertically.

A concave portion 4a is formed in the upper surface of the base 4, and a chuck table mechanism 36 is arranged in this concave portion 4a. The chuck table mechanism 36 has a chuck table 38 and is moved in the Y-axis direction between a wafer loading/unloading position A and a grinding position B facing the grinding unit 10 by a moving mechanism (not shown). 40 and 42 are bellows. An operation panel 44 is arranged on the front side of the base 4 for the operator of the grinding device 2 to input grinding conditions and the like.

Referring to FIG. 2, a dummy silicon wafer 11 on which a device such as an LSI is not formed on the surface is used as an object to be processed, and a method of dressing a grinding wheel 28 is carried out according to the method of the present invention. A partial cross-sectional side view is shown.

The chuck table 38 holds the dummy silicon wafer 11 on its holding surface, and the grinding wheel 24 detachably mounted on the wheel mount 22 is annularly fixed to the annular wheel base 26 and the lower end of the wheel base 26. It is composed of a plurality of grinding wheels 28 . The grinding wheel 28 is formed by bonding diamond abrasive grains with a resin bond, a vitrified bond, a metal bond, or the like.

The spindle 18 is rotated around a rotation axis perpendicular to the holding surface of the chuck table 38 . The grinding feed unit 34 feeds the grinding unit 10 in the rotation axis direction of the spindle 18 .

In the method of dressing the grinding wheel of the present invention, the chuck table 38 holding the dummy silicon wafer 11 is not rotated, and the spindle 18 is rotated in the direction of the arrow b at, for example, 6000 rpm, while the grinding feed unit 34 moves the grinding unit 10 toward the direction of the arrow Z. The dummy silicon wafer 11 held on the chuck table 38 is ground by feeding in the direction of grinding. That is, a major feature of the grinding wheel dressing method of the present invention is that the grinding wheel 28 is dressed without rotating the chuck table 38 .

FIG. 3 is a plan view schematically showing the method of dressing the grinding wheel of the present invention. In the grinding wheel dressing method of the present invention, only the grinding wheel 24 is rotated in the direction of arrow b without rotating the chuck table 38, and the dummy silicon wafer 11 is ground to dress the grinding wheel 28. An arc-shaped grinding groove 13 is formed in the wafer 11 .

Since the grinding wheel 28 is dressed by grinding the dummy silicon wafer 11 without rotating it, the load applied to the grinding wheel 28 is high, and a high dressing effect can be obtained even if the grinding volume of the dummy silicon wafer 11 is small. can be done. Therefore, the number of dummy silicon wafers 11 used for dressing the grinding wheel 28 can be reduced.

FIG. 4A is a plan view of the dummy silicon wafer 11 after forming one arc-shaped grinding groove 13 by dressing the grinding wheel 28. FIG. In this way, since only one arc-shaped grinding groove 13 is formed in one dressing operation of the grinding wheel 28, the chuck table 38 holding the dummy silicon wafer 11 is slightly rotated in the circumferential direction to set the grinding wheel. The 28 sharpening operations can be performed multiple times.

That is, since a plurality of arc-shaped grinding grooves 13 can be formed in one dummy silicon wafer 11 according to the sharpness of the grinding wheel 28 as shown in FIG. The amount of dressing can be adjusted without increasing the FIG. 4B is a plan view of the dummy silicon wafer 11 after forming a plurality of arcuate grinding grooves 13 in one dummy silicon wafer 11 .

The dummy silicon wafer 11 used in the grinding wheel dressing method of the present invention has one or more arc-shaped grinding grooves 13 formed therein, and has an uneven surface. Therefore, grinding is performed while the grinding wheel collides with the unevenness of the surface at high speed. It can also be used as a dressing wafer for a conventional dressing method in which the grinding wheel 28 is dressed.

Referring to FIG. 5, there is shown a partially cross-sectional side view showing how a dummy silicon wafer 1 in which a plurality of arcuate grinding grooves 13 are formed is used to perform dressing work according to the conventional method. .

In this conventional dressing method, a chuck table 38 holding a dummy silicon wafer 11 having a plurality of arc-shaped grinding grooves 13 is rotated in the direction of arrow a at, for example, 300 rpm, while rotating the grinding wheel 24 in the direction of arrow b. The dummy silicon wafer 11 is ground by feeding the grinding wheel 34 in the direction of the arrow Z by the grinding feed unit 34 while rotating at, for example, 6000 rpm.

Since a plurality of arc-shaped grinding grooves 13 are formed in the dummy silicon wafer 11, the grinding load is higher than that of a flat wafer, so the dressing work of the grinding wheel 28 can be efficiently performed. In addition, since the grinding load is high and the grindstone wears a lot, not only dressing, but also dressing, which is usually performed by grinding a dressing board containing abrasive grains, has a plurality of arcuate grinding grooves 13. The formed dummy silicon wafer 1 can also be used instead of the dressing board.

In the above-described embodiment, since the silicon wafer is used as the workpiece to be ground by the grinding device 2, a dummy silicon wafer is used for the dressing operation of the grinding wheel 28. If the workpiece is made of another material, it is preferable to use a workpiece of the same material as the workpiece to be ground as the dressing wafer.

10 Grinding Unit 11 Dummy Silicon Wafer 13 Arc Grinding Groove 18 Spindle 22 Wheel Mount 24 Grinding Wheel 26 Wheel Base 28 Grinding Wheel 34 Grinding Feeding Unit 38 Chuck Table

Claims (2)

A chuck table for holding a dummy silicon wafer on a holding surface, and a dummy silicon wafer held by the chuck table with a grinding wheel having a plurality of grinding wheels arranged in an annular shape mounted on a spindle having a rotation axis perpendicular to the holding surface. and a grinding feed unit that feeds the grinding unit for grinding in the direction of the rotation axis.
The grinding unit is fed while rotating the spindle to grind the dummy silicon wafer held on the chuck table without rotating the chuck table to form an arc-shaped grinding groove on the surface of the dummy silicon wafer. A method for dressing a grinding wheel, characterized by forming a 2. The method of dressing a grinding wheel according to claim 1, wherein a plurality of said arc-shaped grinding grooves are formed in said dummy silicon wafer, and the dressing state of said grinding wheel is controlled.

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