JPS60197372A - Dicing blade for semiconductor substrate - Google Patents

Abstract

PURPOSE:To reduce the formation of chipping by making the thickness of the peripheral edge part of a wafer thinner than that of the holding part and increasing the grinding amount on the uppersurface of the wafer with the increase of the depth of cutting-in, thus reducing the resistance in cutting operation. CONSTITUTION:The peripheral edge part 11a of a blade 11 is formed thinner than the thickness of a nipping part which does not cut a wafer 4 and is held by a holder 2, and the thickness of the blade 11 is varied into straight-line form from the peripheral edge part 11a towards the holding part 11b in symmetrical form with respect to the center of thickness of the blade 11, as shown on the side 11c, and the shape of the section of the blade 11 is formed into isosceles trapezoid. When the wafer 4 is cut by using the blade 11 thus formed, the taper coinciding with the shape of the blade 11 is formed on the wafer edge surfaces on the both sides of the cut part 12, and the amount of cutting-in gradually increases as the depth of cutting-in increases, and the formation of chipping on the uppersurface of the wafer 4 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a grade for semiconductor substrate dicing, which is used in the manufacture of semiconductor devices.

[Technical background of the invention and its problems]

To manufacture semiconductor devices, a large number of identical elements (tips) are formed on a semiconductor substrate (wafer) made of silicon, germanium, etc. using litho-daraphy technology, and after the wafer process is completed, dicing is used to cut and separate the wafer into chips. Then, each chip is packaged and manufactured into a product.

To cut the wafer, a rotating blade made of diamond R powder and a binder formed into a thin disk shape is used.
Figures 1 and 2 are diagrams showing the structure and function of a conventional dicing blade. FIG. 3 is a diagram showing the state of the wafer after dicing as seen from the circumferential direction of the blade.

According to these, the dicing blade has a thickness of 20 mm.
The blade is a circular plate having a uniform thickness of 100 μm to 100 μm, and for stable support, it is held between a holder 2, which is a metal disk, except for the peripheral edge of the blade, and is further rotated at high speed by a rotating shaft 3.

However, with such equal thickness blades, the holder
Stress from the holder is concentrated on the part of the blade that protrudes from the blade, making it easy for the blade to chip.

For this reason, the blade thickness cannot be made very thin, and it is therefore necessary to have a large cutting allowance during cutting, which means that the chips must be placed with plenty of room in the wafer, and the chip formation rate per unit area (yield rate) cannot be set high.

Also, after cutting, the width can be cut with equal width as shown in Fig. 2, but when this cut part is viewed from above as shown in Fig. 3, the cut part! There are many defects on the edge surfaces of the wafer on both sides.

For example, when using a blade with a thickness of SOμm, the width of the cut portion is approximately 70-10μm, but the width of the unusable portion due to chipping reaches 100-120μm.

This chipping may spread to the vicinity of the semiconductor element area of each chip, reducing the reliability of the semiconductor device, and the semiconductor element formation area must be arranged with more margin, making it difficult to increase the yield. The problem is that it can't be done.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a blade for dicing a semiconductor substrate that reduces the cutting width and does not cause chipping on the cut surface.

[Summary of the invention]

In order to achieve the above object, in the present invention, the cross-sectional shape of the dicing blade is changed between the peripheral edge part and the holding part held by the holding plate on the inner side of the wedge. [Embodiments of the Invention] Some embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 is a diagram showing the configuration and operation of an embodiment of the semiconductor substrate dicing blade according to the present invention, in which the dicing blade // is held by the holder λ and does not cut into the wafer. It has a holding part //1) and a peripheral part //a thinner than this part.

This tip part //a is located at the center of the dicing blade // in the thickness direction, and the inner part from the peripheral edge //a //
The change in thickness to 1) is v-F//. Tsuu, 1. nika,, 1ka, 97. . .

As you can see, it is in a straight line. That is, the cross-sectional shape of the blade // is an isosceles trapezoidal shape.

When such a dicing blade is used, a taper matching the shape of the blade // is formed on the wafer end faces on both sides of the cutting portion /2 of wafer≠. In such a cut surface, the depth of cut gradually increases as the depth of cut increases. As in the case of Fig. ≠, the blade holder is a peripheral part 2/b that is thinner than the clamping part J/b and is located at the center of the blade thickness.
a, but its thickness changes linearly from the uniform thickness part 2/a, which has a length smaller than the wafer thickness, to the clamping part 2/1). This is achieved by the thickness changing portion 2/d.

Therefore, when this dicing blade is used, the wafer≠ cutting portion 22. As shown in FIG. 5, the cross-section of is shaped such that the vicinity of the bottom surface is spaced at equal intervals and the vicinity of the top surface is tapered and widened. In this case as well, since the depth of cut gradually increases while the upper end of the cut portion is being diced, chipping is less likely to occur.

Figure 5 is a plan view showing how the wafer is cut in Figure 5, where the cut edge ≠a on the upper surface of the wafer is substantially straight, and no chipping is observed.

Uha Tsukuda 11fr winter trip using the dicing blade according to the present invention. Here is a comparison of the results using I ishing blades according to the method.

According to the table, it is recognized that the occurrence of chipping has been reduced, and as a result, the rate of non-defective products as finished semiconductor devices has improved, the life of the blade has been extended, and the yield has also improved.

In the above actual travel example, there was no change in the thickness of the dicing blade and the dicing was linear, but it is not limited to this and may change according to each if curve such as a quadratic curve, a parabola, a circle, an ellipse, etc. You can do it like this.

〔Effect of the invention〕

As described above, in the present invention, the shape of the semiconductor substrate dicing blade is not uniform in thickness as in the conventional case, but the thickness of the wafer peripheral part is thinner than the thickness of the clamping part held by the holding plate. In addition, since the amount of cutting on the upper surface of the wafer increases as the depth of cut increases, the resistance during cutting is reduced, the occurrence of chipping is reduced, and the life of the blade is extended. ′! In addition, since the machining allowance during cutting can be reduced, the thickness of the blade can be further reduced, and there is no need to provide sufficient margin for chipping, and this also reduces the formation area of the semiconductor tip. can be increased and the yield can be improved. Furthermore, the reliability of the semiconductor device can be improved by reducing the occurrence of chipping.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing the configuration of a conventional semiconductor substrate dicing blade, Figure 3 is a plan view showing the wafer surface after cutting by the conventional dicing blade, and Figures ≠ and 5 are from this book. FIG. 6 is a diagram showing the structure and function of the semiconductor substrate dicing blade of the invention, and FIG. 6 is a plan view showing the wafer surface after being cut by the dicing blade of the invention. /, //, 2/... dicing blade, 2...
Holder, 3... Rotating shaft, G... Wafer, s, ix
, w... cut section, Otsu... chip, //a, t/a-periphery, //1). 2/b... clamping part. Applicant's ear embedded boar crotch bleached 1 to b2 Figure 63 Figure b4 Figure

Claims (1)

[Scope of Claims] 1. A jig blade in which the thickness of the peripheral edge of a thin disk is determined by the thickness of the holding portions held by p holding plates on both sides of the thin disk. 2. The semiconductor substrate dicing blade according to claim 1, wherein the thickness of the λ1 peripheral portion and the thickness of the holding portion change linearly symmetrically with respect to the blade thickness center. 3. The blade for dicing a semiconductor substrate according to claim 1, wherein the thickness of the peripheral edge portion and the thickness of the holding portion change curved symmetrically with respect to the center of blade thickness. The blade for dicing semiconductor substrates described above. 2. The blade for dicing a semiconductor substrate according to claim 1, wherein the upper peripheral edge portion has a portion having a thickness equal to at least H, which is a Quafer thickness.