JPS5818928A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To smooth the surface of a semiconductor thin film substrate by using partial etching. CONSTITUTION:While rotating an epitaxial wafer 1 having protrusion 2 at high speed a resist 3 is dropped to the wafer surface. The resultant film covering the surface of the protrusion is far thinner than other portion of the film. This thinner film portion is selectively removed, then the protrusion is etched with the resist 3 applied as a mask, and finally the resist 3 is removed, making the surface without any protrusion available. Therefore, pour contact with a mask and mask damage can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin film substrate, particularly a substrate (hereinafter referred to as a shrimp wafer) K in which a thin film is crystal-grown on a semiconductor substrate such as Si or GaAs.

When a thin film is grown as a crystal on a semiconductor substrate, protrusions are formed on the surface of the epitaxial wafer due to scraps and dust of the semiconductor material on the semiconductor substrate. These protrusions are caused by the fact that when semiconductor devices (hereinafter referred to as wafers) are manufactured using shrimp wafers, currently most wafers are made by photolithography using a mask to produce semiconductor devices (hereinafter referred to as pellets). Due to the manufacturing process, poor adhesion between the mask for photoetching and the wafer occurs, which in turn leads to defective formation of patterns and deterioration of product quality and productivity. For this reason.

Conventionally, this method was used to flatten the surface of shrimp wafers.

Unnecessary protrusions were crushed and removed by crimping a solid plate with a hardness higher than that on the surface of the shrimp wafer. However, with this method, fragments of the protrusions crushed during crimping may adhere to the shrimp wafer, and protrusions larger than a certain size cannot be completely crimped, making it impossible to completely remove the protrusions. There were some problems such as not having one.

The present invention provides a method for flattening the surface of a shrimp wafer with the aim of improving product quality and productivity by eliminating the above-mentioned problems.

That is, the present invention uses a partial etching method to achieve flattening, and the present invention will be explained below using examples. FIG. 1(a) is a plan view of an epiwafer with protrusions, and FIG. 1(b) is a side view thereof. FIG. 2 is a cross-sectional view of the above shrimp wafer showing an embodiment of the present invention.

First, a corrosion-resistant substance (hereinafter referred to as resist) 3 is applied to the surface of the shrimp wafer l having the projections 2 by dropping the resist while rotating the shrimp wafer at high speed. In coating according to this method, only a considerably thinner film is deposited on the surface of the protrusion than on other parts (FIG. 2(a)). next,
The resist on the wafer surface is removed until the thin resist attached to the surface of the protrusion 20 is removed (FIG. 2(b)).
. At this time, other parts of the resist are also removed, but since the resist film is thick, only a part of the surface layer is removed and most of it remains.Next, the protrusions are etched using the resist 3 as a protective film. (Fig. 2(C)). Finally, when the resist 3 is removed, only the unnecessary protrusions are removed and the protrusions on the surface of the shrimp wafer disappear.

As described above, according to the present invention, protrusions on the shrimp wafer surface can be removed regardless of the size of the protrusions, and problems such as poor adhesion with the mask and scratches on the mask caused by the protrusions are resolved. This makes it possible to improve pellet product quality and productivity.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a shrimp wafer having protrusions on its surface, and FIG. 1(b) is a sectional view thereof. FIGS. 2(a) to 2(d) are cross-sectional views showing a manufacturing method according to an embodiment of the present invention. 1...Semiconductor substrate (shrimp wafer) on which crystals have been grown, 2...Protrusions formed on the shrimp wafer,
3...Resist.

Claims (1)

[Claims] For obtaining surface flatness of semiconductor thin film substrates. A method for manufacturing a semiconductor device characterized by using a partial etching method.