JPS59129431A - Manufacture of semiconductor device protected by glass film - Google Patents

Abstract

PURPOSE:To provide a microscopic electrode window by a method wherein a low temperature CVD SiO film, which does not react to HF acid, is superposed on the oxide film located on the exposed part of a P-N junction, and an etching is performed thereon using HF acid. CONSTITUTION:An Si3N4 or poly Si 6 or CVD SiO2 7 film is superposed on the oxide film5 located on an Si substrate whereon the specified diffusion has been completed. A groove 8 is provided on the substrate by performing a photoetching, lead glass or zinc glass is adhered by performing an electrophoretic method, a heat treatment is performed, and a glass layer 9 is formed. At this time, glass particulates 10 are adhered to the SiO2 film 7 too. Then, a CVD SiO2 film 11 is covered on the whole surface, the particulates 10 are removed together with the films 7 and 11 by performing a photoetching method using HF acid, a window 6 is provided, and the film 6 is exposed. Subsequently, when an electrode pattern 13 is formed in the manner as specified, a highly accurate microscopic pattern can be obtained without having oozing out etchant caused by glass particulates, thereby enabling to obtain the semiconductor device of high reliability and efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a semiconductor device such as a transistor, a thyristor, or an IC using a glass material for a passivation film.

When a low-melting glass such as lead glass or zinc glass is used as a passivation film by depositing it on a semiconductor device, there are various methods for manufacturing it, such as electrophoresis.
When the field oxide film is selectively opened with nitrogen by photoetching and glass is selectively deposited on the nitrogen portion, some glass particles are also deposited on the field oxide film.

Etching accuracy may deteriorate when forming electrode chambers due to unnecessary glass particles, especially for transistors,
This is considered an obstacle when forming fine patterns such as IO.

An object of the present invention is to provide a new method for manufacturing a semiconductor device that makes it possible to remove glass particles remaining on an oxide film after forming a passivation glass film and form a fine electrode contact chamber.

In order to achieve such an object, in the present invention, a silicon nitride film (SigN+) or polycrystalline silicon, etc., is reacted with hydrofluoric acid on a semiconductor substrate having one or more PN junctions and a field oxide film on the entire surface. a step of forming a silicon oxide film, etc., by an OVD method, which is relatively easily soluble in hydrofluoric acid, on the silicon oxide film, and a photoetching method of a part of the superimposed film on the silicon substrate. To open the window, the silicon surface is exposed, glass is applied by electrophoresis, heat treatment is performed, and O2 is applied to protect the glass.
In the process of forming a VD oxide film on the entire surface, it is attached to the fine pattern forming part. Unnecessary glass particles are removed by photo-etching together with the OVD oxide film using a hydrofluoric acid-based etching solution to the top of the nitride film or polycrystalline silicon layer, and a thermal oxide film and a nitride film or polycrystalline silicon layer are applied to the fine pattern formation area. A method for manufacturing a semiconductor device, comprising a step of leaving a superimposed thin film, and a step of forming an electrode contact window, coating the entire surface with electrode metal, and forming a fine electrode pattern by photo-etching. It is something.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing an NPN transistor as a specific embodiment of the present invention will be described below in detail with reference to the drawings. In addition, the present invention also relates to transistors using passivation glass backing,
It can also be applied to thyristors, IOs, etc.

FIG. 1 A schematic cross-section of a transistor, which serves as the base of an element subjected to Niglass passivation, has a structure as shown in FIG. An NN+ type silicon wafer 1.degree. 2 has impurities selectively diffused therein to form two layers 3 to serve as a paste and an N+ layer 4 to serve as an emitter, and the surface is covered with a silicon thermal oxide film 5.

FIG. 2: A silicon nitride film (81fiN4) 6. is formed on the oxide film 5 by OVD method or the like. 300~500'7L or several thousand x polycrystalline silicon 6 and then OV on top of it.
A silicon oxide film 7 having a thickness of about 500X is formed by method D. Next, the oxide film, nitride film, or polycrystalline silicon in the portion where the glass film will be formed is removed by photo-etching, and the silicon is further etched to form grooves 8.

FIG. 3: Lead glass or zinc glass is deposited in the groove 8 by electrophoresis and heat treated to form a glass layer 9. At this time, the glass adheres not only to the groove portion 8 but also to the oxide film 7 as fine glass particles (1 to 5 μm in diameter) 10 . After this, a silicon oxide film 11 is further deposited over the entire surface by OVD method.
Form about 00X. This is to protect the glass from acids in later steps.

FIG. 4: Stain by photo-etching method. Glass particles 10 are etched away together with 0V7) oxide film 7°11 in the fine pattern portion which will become the electrode contact chamber, using hydrofluoric acid, and window 12 is opened. The nitride film or polycrystalline silicon 6 is exposed on the surface of the window portion.

FIG. 5: An electrode contact window is formed by photo-etching, and then aluminum, which will serve as an electrode, is formed on the entire surface by vapor deposition, and then a fine pattern 13 of the electrode is formed by photo-etching. After forming an electrode on the front surface, a collector electrode on the back surface is formed, and the transistor pellets are obtained by dividing.

By using the above-mentioned manufacturing method, it is possible to obtain a fine pattern with a fineness of 5 degrees without leaking the etching liquid due to the glass particles, and it is possible to obtain a highly reliable and high-performance device using glass padding. It becomes like this.

[Brief explanation of drawings]

1 to 5 are cross-sectional views showing an embodiment of the present invention in the order of steps. In the figure, 1 to 2...NN+ type silicon wafer, 3...P type base layer, 4...
N+ type emitter layer, 5...Field thermal oxidation silicon film, 6° old. Silicon nitride film or polycrystalline silicon layer, 7...
・OVD silicon oxide film layer, 8...Glass coating groove, 9...Low melting point glass film, 10...
・Residual glass particles, 11...OVD silicon oxide film layer, 12...Glass particle removal chamber section, 13
・・・・・・Aluminum electric sign. 6-

Claims (1)

[Claims] In a method for manufacturing a semiconductor device in which the surface of an exposed portion of a PN junction is protected with glass, there is a step of forming a film that does not react with hydrofluoric acid on an oxide film before forming a glass film, and then OVD silicon oxide film is formed at a low temperature, and after the glass film is deposited, the glass particles adhering to the OVD silicon oxide film are removed together with the oxide film using hydrofluoric acid. A method for manufacturing a semiconductor device.