JPS62122120A - Manufacture of semiconductor substrate - Google Patents

Abstract

PURPOSE:To reduce the parasitic capacitance of a semiconductor device and a single crystal semiconductor substrate, and to increase working speed by burying a first single crystal semiconductor film up to the same height as an insulating film on the substrate to a window section formed to the insulating film, shaping a polycrystalline semiconductor film onto the fist single crystal semiconductor film and irradiating the polycrystalline semiconductor film by heat rays or beams to change the polycrystalline semiconductor film into a second single crystal semiconductor film. CONSTITUTION:An insulating film 12 is formed onto the surface of a single crystal semiconductor substrate 11, a window is bored to the insulating film through photo-etching, a first single crystal semiconductor film 13 is buried, and the surface of the film 13 is flattened approximately to the surface of the insulating film 12. A polycrystalline or amorphous silicon film 14 is shaped onto the surface of the substrate through a CVD method, etc., and heat rays or beams are projected, heating the substrate 11 from the surface of the film 14 to melt the silicon film 14. The film 14 is recrystallized in a cooling process to form a second single crystal semiconductor film 15, thus shaping the flat single crystal semiconductor film 15. Accordingly, the thickness of the insulating film can be thickened, thus reducing the parasitic capacitance of the semiconductor device and a single crystal semiconductor substrate, then further increasing working speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor substrate, and in particular, an insulating film is formed on a single-crystal semiconductor substrate by opening a window, and a single-crystal semiconductor film is formed on the window and the insulating film. The present invention relates to a method for manufacturing a semiconductor substrate comprising:

An insulating film is formed by opening a window on the surface of a single crystal semiconductor substrate,
Regarding a semiconductor substrate in which a single crystal semiconductor film is formed on the window portion and the insulating film, there has recently been published in Appl.

Phys, Lett, 38 f51, I Ma
There is a technique reported in RCH 1981.

However, the single crystal semiconductor film formed on the window-opened insulating film and the window portion on the single crystal semiconductor substrate using the above technique,
In order to reduce the step of the single crystal semiconductor film in the window area,
The thickness of the insulating film must be reduced, and when a semiconductor device is formed on the single crystal semiconductor film, the parasitic air capacitance between the single crystal semiconductor substrate and the semiconductor device cannot be reduced, and the air capacitance is reduced. If the thickness of the insulating film is increased in order to reduce the thickness of the insulating film, the step of the single crystal semiconductor film at the window portion becomes large, and when a semiconductor device is constructed using the single crystal semiconductor film, the difference between the step portion and the 5! : There is a drawback that the connecting T-pole wiring may break at the step and break.

The present invention eliminates the above-mentioned drawbacks, forms a high-speed semiconductor device with a small parasitic capacitance with a single-crystal semiconductor film in a single-crystal semiconductor film, and provides a highly reliable semiconductor device with no step breakage at the stepped portion of the TM wiring. The overall purpose is to provide a semiconductor substrate for manufacturing n.

The basic structure of the present invention for achieving the above object is that an insulating film is formed on the surface of a single crystal semiconductor substrate with a window, and a single crystal semiconductor film is formed on the window and on the insulating film. In the semiconductor substrate, the surface of the single crystal semiconductor film formed in the window portion of the insulating film is substantially flat with the surface of the single crystal semiconductor film on the peripheral insulating film.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows a cross-sectional view of a semiconductor substrate in order of steps in an embodiment showing a back-up method for manufacturing a semiconductor substrate of the present invention. In Figure 1, first, a single crystal semiconductor substrate (81%)
A 1 micron thick insulating film (S
(in, etc.) 12 is formed, and a window is opened in the insulating film by photo-etching. Next, a first single crystal semiconductor film 13 is buried in the window portion by an epitaxial method so that its surface is substantially flat with the surface of the insulating film 12. A polycrystalline or amorphous silicon film 14i with a thickness of 0.5 micron is formed on the surface of the substrate by an OVD method or the like,
The silico/film 14 is melted by irradiating heat rays or light rays while heating the substrate 11'i to about 1200° C. from its surface, and is recrystallized during the cooling process to form a second single crystal semiconductor film 15.
By forming , a flat single crystal semiconductor film 15 is formed.

In this way, an insulating film is formed by opening a window on the surface of a single-crystal semiconductor substrate, and a semiconductor device is formed on the single-crystal semiconductor film by using a single-crystal semiconductor film or a flat semiconductor substrate on the window and the insulating film. When forming an insulating film, the thickness of the insulating film can be increased, which reduces the parasitic capacitance between the semiconductor device and the single crystal semiconductor substrate, resulting in further high-speed performance1. 'lt+lI! The wiring In is not broken or broken at the step portion of the window portion, and there is an effect that a semiconductor device with high yield and high reliability can be provided.

[Brief explanation of drawings]

FIGS. 1(a) to 1(a) are cross-sectional views showing one manufacturing process for forming the present invention. 11... Semiconductor substrate 12... Insulating film 13... First single crystal semiconductor film 14... Polycrystalline or amorphous semi-quad film 15...
・Second single crystal semiconductor film or higher Applicant: Seiko Epson Corporation (α + φ ↓ ↓ ↓ ↓ ↓

Claims (1)

[Claims] a single-crystal semiconductor substrate, a step of forming an insulating film on the single-crystal semiconductor substrate, a step of forming a window by etching the insulating film, and a step of forming a first single-crystal semiconductor film in the window; a step of filling the insulating film to approximately the same height as the insulating film; a step of forming a polycrystalline or amorphous semiconductor film on the insulating film and the first single crystal semiconductor film;
A method for manufacturing a semiconductor substrate, comprising the step of irradiating the polycrystalline or amorphous semiconductor film with heat rays or light rays to form a second single-crystal semiconductor film.