JPS5859764A - Lapping surface plate - Google Patents

Abstract

PURPOSE:To improve the lapping efficiency and reduce the frequency for correcting the lapping surface plate body and reduce the number of flaws formed on the ground surface of an article by forming radial grooves on the surface of the device itself. CONSTITUTION:Radial grooves 12 are formed on the body 11 of a lower lapping surface plate, in order to facilitate discharge of the free grinding grains and the grinding scrap which are sunk into the grooves 12 and reduce the generation rate of flaws on a semiconductor wafer. As the number of grooves on the lower lapping surface plate is reduced, the number of grinding grains sunk in the grooves 12 is reduced, and the number of grinding grains which contact the ground surface of the semiconductor wafer is increased, and the working time for lapping can be reduced. As radial grooves 12 are formed on the body 11' of the upper lapping surface plate and a grinding-grain feeding hole 13 is formed at the center of the grooves 12, the crossing part of the grooves is not formed, and generation of burr is eliminated in the grinding grain feeding hole 13, and generation of flaws on the semiconductor wafer can be reduced.

Description

[Detailed description of the invention] The present invention relates to improvements in lap plates.

A lapping machine is a machine that finishes the surface of a workpiece flat, smooth, and with high precision. For example, when applying photographic technology to transfer a very fine pattern onto the surface of a semiconductor wafer, The presence of local irregularities on the surface causes image blurring of the transferred pattern, which adversely affects the performance of the manufactured semiconductor device.
Extremely high-precision surfaces are required, and lapping is performed as a step in finishing the four surfaces.

For example, when performing double-sided lapping of semiconductor wafers, a rotating shaft that interlocks with the lower lap surface plate is inserted into the central opening of the lower lap surface plate, and a wafer carrier having a wafer installation hole is placed on the lower lap surface plate. The wafer is installed in the wafer installation hole, and the upper lap surface plate is placed on top of it. While supplying abrasive grains from the abrasive grain supply hole of the upper lap surface plate, the lower lap surface plate linked to the rotating shaft is rotated. and then wrap it.

By the way, conventionally, for lapping, a lower lapping surface plate having a structure as shown in FIG. 1, for example, has been used. J in FIG. 1 is a surface plate main body, and the surface of this main body J is provided with a large number of grooves 2 in a lattice pattern for discharging free abrasive grains and polishing debris.

However, when lapping is performed using a conventional lower lapping surface plate, the grooves 2... are provided in a grid pattern, so loose abrasive grains and abrasive debris that have entered the grooves 2... are removed from the surface plate. These are likely to cause scratches on the polished surface of the object to be polished. In addition, the surface plate body is also susceptible to scratches, so the surface plate body must be repaired frequently. In addition, since there are many grooves, many abrasive grains enter the grooves 2, etc., and fewer abrasive grains come into contact with the polished surface of the object to be polished, so there is a drawback that lapping efficiency is poor. Furthermore, if the abrasive grain supply hole is drilled at the intersection of the grooves on the upper lap surface plate which has the same grooves as the lower lap surface plate, burrs are likely to occur and the polished surface of the object to be polished will be scratched. This is likely to occur, and it is necessary to modify the upper lap surface plate to remove this burr.

The present invention was made in view of the above-mentioned problems, and it reduces the number of corrections of the surface plate body, improves lapping efficiency, and reduces scratches on the polished surface of the object to be polished, thereby producing a high-quality coating. The object of the present invention is to provide a lapping surface plate that can obtain an abrasive object.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in Figure 2 (al), the lower lap surface plate is located at the surface plate body 11.
It has a structure in which a large number of straight grooves J2... are provided radially. In addition, as shown in Fig. 2, the upper lap surface plate, like the lower lap surface plate, has a large number of linear grooves 12 radially formed in the surface plate body and the surface J', and is further polished. It has a structure in which a plurality of grain supply holes 13 are bored.

By performing double-sided lapping of a semiconductor wafer using the lapping platen having the above-described structure, the following effects can be obtained.

(1) By providing the grooves 12 radially in the lower lap surface plate, free abrasive grains and abrasive debris contained in the grooves 12 can be easily discharged outside the surface plate, thereby preventing scratches on the semiconductor wafer. The occurrence rate has been reduced by 50%, and the number of corrections to the surface plate body 11 has been reduced to less than 1/2.

(2) Due to the reduced number of grooves on the lower lapping surface plate, fewer abrasive grains enter the grooves 12, and more abrasive grains come into contact with the polished surface of the semiconductor wafer, which reduces the lapping work time by 20%. The length can be shortened, the amount of abrasive grains can be reduced, and the cost required for processing the grooves 12 has been reduced by 15%.

(3) Groove 12' on the surface plate body in the upper lap surface plate.
...ζ has no intersection, and the abrasive grain supply holes 13... are all drilled in the center of the grooves 12', which reduces the occurrence of paris in the abrasive grain supply holes 13. As a result, the occurrence of scratches on semiconductor wafers has been reduced, and the number of corrections to the surface plate body has also been reduced.

The lap surface plate according to the present invention is shown in FIG. 2(a).

(Limited to those shown in bl, lower lap surface plate with many curved grooves J2'... radially provided as shown in Fig. 3, or extending from the outer periphery to the inner periphery as shown in Fig. 4) A lower lap surface plate may be used, in which a large number of straight grooves 12 extending from the outer circumference to the inner circumference and a plurality of linear grooves 12 extending from the outer circumference to the inner circumference are provided alternately in a radial manner.

Further, the lapping surface plate according to the present invention is not limited to double-sided lapping as in the above Re embodiment, but can be similarly applied to single-sided lapping.

As described in detail above, according to the present invention, it is possible to reduce corrections to the surface plate body, improve lapping efficiency, and reduce scratches on the polished surface of the object to be polished, thereby obtaining a high-quality object to be polished. It is possible to provide a lap surface plate that can perform

[Brief explanation of drawings]

Figure 1 is a plan view showing the conventional lower lap surface plate, Figure 2
．． (bl is a plan view showing a lower rack surface plate according to an embodiment of the present invention.) -7, 7'... Surface plate main body, 12, 12', 12''
- Clear, 13...Abrasive grain supply hole. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure 4 1 1

Claims (1)

[Claims] A lap surface plate characterized by having radial grooves on the surface of the surface plate body.