Method for forming scribed groove and scribing apparatus

Abstract

A method for forming scribed grooves on a wafer and an apparatus for implementing the method. The method moves the cutting part such that its cutting edge forms an inverted trapezoid-shaped path, thereby reducing the scribing angle of the cutting edge to an acute angle. Consequently, the stress produced by the mechanical shock at the time of the scribing can be dispersed in the moving direction of the cutting edge and in a direction perpendicular to the surface of the wafer. The horizontal movement of the scribing cutting edge in the wafer enables the application of a sufficient load in a direction perpendicular to the scribing plane in the wafer. Consequently, vertical cracks are sufficiently generated, and the amount of dimensional deviation between the scribed groove and the cleaved plane is reduced. This method can produce chips featuring outside dimensions with higher precision and cleaved surfaces with high-quality mirror finish.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for forming a scribed groove at the surface portion of a wafer so that the groove can act as the starting point for splitting the wafer to obtain chips by exploiting the cleaving property of the wafer and a scribing apparatus for implementing the method. The present invention particularly relates to a method for forming a scribed groove that can considerably reduce the amount of dimensional deviation between the scribed groove and the cleaved plane and a scribing apparatus for implementing the method. [0003] 2. Description of the Background Art [0004] Semiconductor chips are produced by separating them from a wafer such as a laser diode wafer. In this case, scribed grooves are first formed at the surface portion of the wafer with a scribing apparatus. Then, a cleaving prism performs the cleaving work by concentrating the stress on the scribed groove. This is a well known tec...

AI Technical Summary

Benefits of technology

The present invention offers a method for forming a scribed groove on a wafer that reduces the amount of dimensional deviation between the groove and the cleaving plane, resulting in higher precision and a better mirror finish on the chip. This is achieved by moving the cutting part along a path with the shape of an inverted trapezoid, which produces a large number of vertical cracks while reducing the number of horizontal cracks. The invention also offers a scribing apparatus that includes a cutting part, a horizontally moving portion, and a vertically moving portion for the formation of the scribed groove. The coordinates of the cutting edge are automatically operated by the controlling section, allowing for independent horizontal and vertical movements.

Problems solved by technology

However, the foregoing conventional groove-forming method has a drawback of a large amount of dimensional deviation between the scribed groove and the cleaved plane. FIG. 14 is a plan view showing a bar-shaped wafer which is cleaved after scribed grooves are formed by the conventional method.

As a result, the large deviation in the outside dimensions makes it difficult to produce chips with high yield ratio, and it is difficult to obtain chips having cleaved surfaces with high-quality mirror finish.

When the amount of dimensional deviation in cleavage 112 is large, another problem is created.

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