JPS62213954A - Method and device for grinding peripheral surface of hard and brittle material - Google Patents

Abstract

PURPOSE:To shorten grinding time and lessen the finish coarseness greatly by allowing a work to be processed to rotate at a low speed, engaging a coarse grinding element in high speed rotation with the peripheral surface of the work as coarse grinding, and at the same time, engaging a finish grinding element in high speed rotation with the peripheral surface of the coarse ground work as finish grinding. CONSTITUTION:A coarse grinding element 201 advances in the A direction and is engaged with a work to be processed W as start of coarse grinding. At the same time, the work W begins rotating counterclockwise at a low speed, and thus the periphery of the work W is coarse ground, and when the coarse grinding wheel 201 starts coarse grinding of the periphery (3), a finish grinding wheel 301 advances in the B direction to engage with the work W, and thus finish grinding will start. That is, the periphery (1) already coarse ground undergoes finish grinding. While the work W then makes one turn, the finish grinding wheel 301 performs finish grinding of peripheries (1)-(4) one after another. The work W makes a rotation a little more than one turn after start of the finish grinding. Thus concurrent performance of coarse and finish grinding shortens the processing time as well as provides selectively for finish grinding element, which gives finer coarseness of the finished surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and an apparatus for grinding the outer peripheral surface of a hard brittle material such as a silicon wafer used for, for example, an IC chip.

[Conventional technology]

Ic chip wafers have chamfers on the outer periphery to prevent the outer periphery from chipping, and to make it easier for abrasive (lap agent) to enter between the surface plate and the wafer surface during surface finishing. administered. As a device for grinding and chamfering the outer peripheral surface of hard brittle materials such as wafers, Utility Model Application No. 60-149749
The one described in the No. Publication is known.

[Problem that the invention seeks to solve]

Conventional outer peripheral surface grinding equipment uses one grindstone to grind the outer peripheral surface of the wafer, and in order to complete the grinding process within a certain amount of time, it is necessary to use a grindstone with a certain degree of roughness. Therefore, there is a problem that there is a certain limit to the finish roughness of the outer peripheral surface of the wafer.

The present invention was made for the purpose of shortening grinding time and improving machined surface roughness.

[Means for solving problems]

The first invention relates to a method for grinding the outer peripheral surface of a hard and brittle material, and this method involves rotating a workpiece made of a hard and brittle material at a low speed, and engaging the outer peripheral surface of the workpiece with a high-speed rotating rough grindstone for rough grinding. At the same time as this rough grinding, a finishing grindstone that rotates at high speed is brought into engagement with the rough-ground outer peripheral surface of the workpiece to perform finish grinding.

The second invention relates to an apparatus directly used for carrying out the above-mentioned outer circumferential surface grinding method, and this apparatus includes a means for rotatably supporting a workpiece made of hard and brittle material, and a means for freely moving toward and away from the workpiece, and a high-speed It is equipped with a rough grinding wheel that rotates to roughly grind the outer circumferential surface of the workpiece, and a finishing grindstone that is provided so as to be able to move toward and away from the workpiece and rotates at high speed to finish grind the outer circumferential surface of the workpiece. The outer circumferential surface of the workpiece is ground, and the finishing whetstone is characterized in that it performs finish grinding on the outer circumferential surface of the workpiece that has been ground by the rough grindstone.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

FIG. 2 shows an embodiment of the device of the present invention. For example, a workpiece W such as a silicon wafer having a disk shape is held at the upper chuck 10.
1 and the lower chuck 102, and are rotated at low speed around the axis together with the coaxially provided model M. A rough grindstone 201 and a finishing grindstone 301 are provided at the same height as the workpiece W, and stylus rollers 202 and 302 are provided at the same height as the model M, respectively. These stylus rollers 202 and 302 are provided coaxially with the rough whetstone 201 and the finishing whetstone 301, respectively. The rough grindstone 201 engages with the outer peripheral surface of the workpiece W while rotating at high speed, while the stylus roller 202 engages with the model M at all times. Therefore, the rough grindstone 201 roughly grinds the workpiece W along the shape of the model M. The finishing whetstone 301 performs finishing grinding on the rough-ground outer peripheral surface of the workpiece W along the shape of the model M.

The workpiece support mechanism 100 includes a lower shaft portion 110 provided on a base 90 and an upper shaft portion 120 mounted on a fixed frame 91 via a connecting member (not shown).

The lower shaft portion 110 is a cylinder device 11 fixed to the base 90.
1, and the piston rod 1 of this cylinder device 111
A lower shaft 113 connected to the fixed frame 91 passes through a bearing member 92 provided on the fixed frame 91 and projects above the fixed frame 91 . The lower chuck 102 is attached to the upper end of the lower shaft 113.
13 so as to be relatively rotatable around the axis. Thus, the lower chuck 102 can be moved up and down, and can be rotated about its axis. On the other hand, the upper shaft portion 120 has a motor 122 within a housing 121. This motor 12
The second drive shaft 123 extends downward and protrudes from the housing 121, the model M is fixed to the protruding end thereof, and the upper chuck 101 is provided on the lower surface of the model M. Thus, the model M and the upper chuck 101 are rotated at low speed by the motor 122.

Before the workpiece W is supplied, the lower chuck 102 is in the lowered position, and when the workpiece W is supplied onto the lower chuck 102 by a supply mechanism (not shown), the workpiece W is moved onto the lower chuck 10.
2 is adsorbed and positioned by the negative pressure generated on the upper surface. The lower chuck 102 then rises and clamps the workpiece W together with the upper chuck 101. Then motor 1
22 starts and rotates the workpiece W.

A copying mechanism 200 having a rough whetstone 201 and a finishing whetstone 301
Since it has the same configuration as the copying mechanism 300 having
Here, the latter copying mechanism 300 will be explained.

The grindstone head 310 is mounted on rails 312 on a pair of brackets 311 provided on the fixed frame 91, and is movable forward and backward relative to the workpiece support mechanism 100. Grinding wheel head 31
0 is a feed cylinder device 320 fixed to the fixed frame 91
It is driven back and forth by. A cylindrical member 322 is slidably fitted to the tip of the piston rod 321 of the feed cylinder device 320, and this cylindrical member 322 is connected to a connecting member 313 fixed to the lower surface of the grindstone stock 310. The cylindrical member 322 has an elongated hole 323 formed therein, and a pin 324 erected on the piston rod 321 engages with the elongated hole 323 .

When not in operation, the piston rod 321 moves backward and the grindstone head 3
10 is located at the rear. Here, high pressure air is introduced from a pressure source (not shown) into a chamber (not shown) on the rear side of the piston of the feed cylinder device 320, and the piston rod 320
1 starts moving forward. At the start of this forward movement, the grindstone head 310 is still stopped, but when the pin 324 engages with the front end of the elongated hole 323, the piston rod 321 then moves to the pin 324.
The grindstone head 310 is advanced through the. Finishing whetstone 301
After contacting the workpiece W, the piston rod 321 moves forward by about half the length of the elongated hole 323, and the pin 324 moves into the elongated hole 3.
It stops when it reaches approximately the center of 23. In this state, work W
Grinding is performed. When the grinding is completed, high pressure air is introduced into the chamber (not shown) in front of the piston of the feed cylinder device 320, and the piston rod 321 begins to retreat.
First, the pin 324 engages with the rear end of the elongated hole 323, and then the piston rod 321 is connected to the grindstone head 31 via the pin 324.
Retract 0. The feed cylinder device 320 is configured to rapidly feed the grindstone head 310 when the finishing whetstone 301 is away from the workpiece W by a certain value or more, and to slowly feed the whetstone head 310 when the finishing whetstone 301 is close to the workpiece W. It has become.

The pressing balance cylinder device 325 includes a bracket 326
The piston rod 3 is attached to the fixed frame 91 by
27 always presses the rear surface of the grindstone head 310 with a constant pressure.

Therefore, the workpiece W is ground by slidingly contacting the finishing whetstone 301 with a constant pressure.

The grindstone support frame 330 is attached to the front surface of the grindstone shaft stand 310 so as to be vertically movable. A bracket 3 is placed on the top surface of the grindstone head 310.
Drive screw shaft 33 of motor 332 fixed via 31
3 is screwed into a threaded hole (not shown) provided in the whetstone support frame 330, and by rotation, the whetstone support frame 330 can be moved up and down. The grindstone support frame 330 has a rotating shaft 334 that extends in the vertical direction. The rotating shaft 334 protrudes below the grindstone support frame 330, and a finishing grindstone 301 is fixed to the protruding end thereof, and a stylus roller 302 is coaxially provided above the finishing grindstone 301. Further, a pulley 335 is fixed to a portion of the rotating shaft 334 that projects upward from the grindstone support frame 330. This boob 17335 is connected via a belt 338 to a pulley 337 of a drive shaft of a motor 336 attached to the grindstone stock 310.

Therefore, when the motor 336 is rotated, the pulley 337
, belt 338, and pulley 335 to the rotating shaft 3.
34 rotates at high speed, and the finishing whetstone 301 is rotationally driven.

FIG. 3 shows the configuration of the rough whetstone 201 and the finishing whetstone 301. The outer circumferential surfaces 201 a and 301 a of the roughing whetstone 201 and the finishing whetstone 301 shown in this figure have the same shape as the outer circumferential surface of the workpiece W after grinding, that is, an annular groove with a semicircular bottom section. Therefore, such a grindstone 2
01 and 301, the grindstone support frames 230 and 330 are not raised or lowered.

FIG. 4 shows another configuration of the rough whetstone 201 and the finishing whetstone 301. In this example, the workpiece W has an upper edge W1
The lower edge W2 is chamfered. The rough whetstone 201 includes a cylindrical part 201b for grinding the cylindrical outer peripheral surface W3 of the workpiece W, an upper conical part 201C for grinding the upper edge W1, and a lower conical part 201C for grinding the lower edge W2. A columnar portion 201b is formed, and a columnar portion 201d is formed.
The width of the workpiece W is formed to be thicker than the thickness of the workpiece W. Similarly, the finishing whetstone 301 has a cylindrical portion 301 thicker than the workpiece W.
b, an upper conical portion 301c, and a lower conical portion 301d.

Thus, the workpiece W is first ground on its outer circumferential surface W3, and then on its upper edge W and lower edge W2. The upper edge W is lower than the grinding wheels 201 and 3 when grinding the outer peripheral surface W3.
The lower edge W2 is ground by moving the grindstone 201° 301 upwards compared to when grinding the outer circumferential surfaces W and l. In this way, in the example of FIG. 4, the grindstone support frames 230 and 330 move up and down.

FIGS. 1(a) to (e) show the grindstone 201 shown in FIG.
3 shows a process of grinding a workpiece W according to an embodiment of the method of the present invention using a grinder 301. To make it easier to understand the rotational angular position of the workpiece W, the outer circumference of the workpiece W is divided into four equal parts in the circumferential direction.
Each point is marked with symbols ■ to ■ in a clockwise direction.

FIG. 1(a) shows the state of the workpiece W before grinding, and the grinding wheel 2
01 and 301 have started high speed rotation. Here, the rough grindstone 201 moves forward in the direction of the arrow as shown in FIG. 1(b), engages with the workpiece W, and starts rough grinding. At the same time, the workpiece W begins to rotate counterclockwise at low speed. Thus, the outer peripheral portions (■, ■, ■) of the workpiece W are roughly ground. When the rough grinding wheel 201 starts rough grinding of the outer peripheral part (■), that is, when the work W rotates half a turn and the outer peripheral part (■) reaches the finishing whetstone 301 side, the finishing whetstone 301 starts grinding as shown in FIG. 1(C). It moves forward in the direction of arrow B, engages with the workpiece W, and starts finish grinding. That is, the outer circumferential portion (2), which has already been roughly ground, is subjected to finish grinding. After that, while the workpiece W rotates once, as shown in Fig. 1(d),
As shown in , the finishing whetstone 301 sequentially performs finishing grinding on the outer circumferential parts (1) to (2). At this time, the rough whetstone 201 is in the forward position, but the outer peripheral surface of the work W adjacent to the rough whetstone 201 has already been ground, and the stylus roller 202 engages with the model M, so the rough whetstone 201 and the work W do not touch.

The workpiece W rotates a little more than one revolution after the start of finish grinding until the outer circumferential part (2) passes a little past the finishing grindstone 301 again. This is to ensure that finish grinding is performed over the entire circumference of the workpiece W. However, work W
When the grinding process is completed after approximately 1.5 rotations, the image shown in Figure 1 (e
), the rough whetstone 201 retreats in the direction of arrow C, and the finishing whetstone 301 retreats in the direction of arrow C. Thereafter, the workpiece W rotates about half a rotation and returns to the original rotation angle position.

As described above, according to this embodiment, finish grinding can be performed simultaneously with rough grinding, so that machining time can be shortened. Furthermore, in this embodiment, grinding can be performed by rotating the workpiece W approximately twice, and compared to the conventional example in which the upper and lower edges are chamfered separately, the machining time is greatly shortened. I can do it. This is because the present embodiment is configured to perform grinding using a rough whetstone and a finishing whetstone separately. It becomes possible to use a grindstone with a grain size of 11,000 or more as a finishing grindstone, and the finished surface roughness of the workpiece W can be significantly improved. When two types of grindstones are used in this way, it is only necessary to replace the grindstones depending on the state of wear, and the management thereof is easy. Further, by using a grindstone having a cross-sectional shape corresponding to the final shape of the outer peripheral surface of the workpiece W, such as the grindstone 201° 301 in FIG. 3, the outer peripheral surface shape of the workpiece W can be determined with high precision.

In addition, when grinding with the whetstone shown in Fig. 4, the grinding wheel shown in Fig. 1 (
According to the steps shown in a) to (e), first the outer circumferential surface W3 is ground, then the upper edge W1 is similarly ground, and finally the lower edge W8 is ground.

〔Effect of the invention〕

As described above, according to the present invention, in grinding the outer circumferential surface of a workpiece made of a hard and brittle material, it is possible to significantly improve the finish roughness and shorten the grinding time.

[Brief explanation of drawings]

FIGS. 1(a) to (e) are plan views showing the workpiece grinding process according to an embodiment of the method of the present invention, FIG. 1(a) is the process before the start of grinding, and FIG. 1(b) is the A process where only rough grinding is performed,
Figure 1 (C) shows the process of performing rough grinding and finish grinding at the same time, Figure 1 (d) shows the process of performing only finish grinding, Figure 1 (e) shows the process of finishing the grinding, and Figure 2 shows the process of finishing grinding. FIG. 3 is a side view showing one embodiment of the inventive device, FIG. 3 is a side view showing one embodiment of a rough grinding wheel and a finishing grindstone, and FIG. 4 is a side view showing another embodiment of the rough grinding wheel and finishing grindstone. 201... Rough grinding, 301... Finishing whetstone,
W...Work.

Claims (1)

[Claims] 1. A workpiece made of a hard and brittle material is rotated at a low speed, and a rough grindstone rotating at a high speed is engaged with the outer peripheral surface of the workpiece for rough grinding,
A method for grinding the outer circumferential surface of a hard brittle material, which is characterized in that, at the same time as this rough grinding, a finishing grindstone rotating at high speed is engaged with the outer circumferential surface of the rough-ground workpiece to perform finish grinding. 2. A means for rotatably supporting a workpiece made of hard and brittle material, a rough grindstone that is provided so as to be able to move toward and away from the workpiece and rotate at high speed to roughly grind the outer circumferential surface of the workpiece, and a means that can move toward and away from the workpiece. It is equipped with a finishing whetstone that is freely provided and rotates at high speed to finish grind the outer circumferential surface of the workpiece, and the outer circumferential surface of the workpiece is ground while being rotated and displaced. A device for grinding the outer peripheral surface of hard and brittle materials.