JPH0448751A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a short-circuit of a wiring to a semiconductor substrate by burying a contact opening to the substrate formed by overetching of anisotropically etching of the opening with an insulating film when the film for forming a sidewall at the side of the opening is isotropically deposited. CONSTITUTION:A thin oxide film 2, a polysilicon layer 3, a thick oxide film 4 are formed on a silicon substrate 1, and a resist pattern 6 is formed on the film 4. Then, a contact opening 7 is formed at the thick film 4 by anisotropically etching using reactive ion etching by using the pattern 6. In this case, if an oxide 5 exists in the layer 3 directly under the opening 7, the oxide 5 is etched to form an opening 8 to the substrate 1. An oxide film 10 of the thickness of the degree of the diameter of the opening 8 is formed. A sidewall 11 of the oxide film is formed at the film 4 by etching it in thickness of the film 10 by anisotropically etching, and the opening 8 is simultaneously buried with an oxide film 12. Then, an aluminum wiring 9 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device having a contact structure.

[Conventional technology]

FIGS. 3A to 3C are cross-sectional views showing each step of a conventional method for manufacturing a semiconductor device. In Fig. 3, 1 is a single crystal silicon substrate (hereinafter simply referred to as silicon substrate) 2
is a thin oxide film, 3 is a polyrecon layer, 4 is a thick oxide film,
5 is an oxide present in the polysilicon layer 3; 6 is a resist pattern obtained by patterning a resist; 7 is a contact opening formed in the thick M film 4; 8 is an etching of the contact opening 7. The opening 9 formed during the step is an aluminum wiring which is a metal #film wiring.

Next, the manufacturing method will be explained.

A thermal oxidation method or a chemical vapor deposition method (
After forming a thin oxide film 2 by a CVD method (hereinafter referred to as CVD method), a polysilicon layer 3 is formed by a CVD method. A thick oxide film 4 is formed. In this process, if heat treatment is performed at about 820° C. in an oxidizing atmosphere, oxide 5 will be formed in the polysilicon layer 3. Further, through a photoresist process, a resist pattern 6 is formed by patterning the resist at a location z om (FIG. 3(a)). Using this resist pattern 6, anisotropic etching using reactive ion etching is performed. A contact opening 7 is formed in the thick oxide film 4 by etching. At this time, if an oxide 5 exists in the polysilicon layer 3 directly under the contact opening 7, the oxide 5 will be etched due to overetching of the anisotropic etching, and the opening will reach the silicon substrate 1. 8 will be formed. After forming the contact hole 7 in this manner, the resist pattern 6 is removed, and aluminum is formed by the spacking method to form the aluminum wiring 9 (FIG. 3(C)). Issue] Since conventional semiconductor devices are configured as described above,
When forming a contact with an aluminum wiring 9 on a polysilicon layer 3 formed on a silicon substrate 1 via a thin oxide film 2, a contact is formed in a region where an oxide 5 exists in the polysilicon layer 3. , Contact l-Due to over-etching when opening the opening 7, the contact penetrates to the silicon substrate 1, causing a short circuit between the aluminum arrangement i19 and the silicon substrate 1.

This invention was made to solve the above-mentioned problems, and when a contact is formed between a polycrystalline semiconductor layer formed on a semiconductor substrate via a thin insulating film and a metal thin film wiring, The object of the present invention is to obtain a semiconductor device in which the metal F4 film wiring and the semiconductor substrate do not short-circuit.

[Means to solve the problem]

In the semiconductor device according to the present invention, when an insulating film for forming a sidewall is isotropically deposited on the side surface of the contact opening, the insulating film is formed by overetching the contact opening by anisotropic etching and soching. The opening leading to the semiconductor substrate is filled with an insulating film.

[Effect]

In this invention, the contact hole formed by over-etching of anisotropic etching for forming the contact hole is formed by contact 1 - the sidewall of the hole, and the hole leading to the semiconductor substrate directly under the hole. Since it is embedded in the insulating film during formation, it prevents the gap between the metal FIIP film and the semiconductor substrate.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor device which is an embodiment of the present invention. In this figure, the same reference numerals as in FIG. 3 indicate the same parts, and 11 is an oxide film sidewall.

FIGS. 2(a) to 2(e) are cross-sectional views showing each step of the method for manufacturing a semiconductor device of the present invention.

First, as shown in FIG. 2(a), a thin oxide film 2° polysilicon M3. A thick oxide film 4 is formed, and this thick oxide film 4 is further
Form a pattern 6 on top. Next, see Figure 2 (
As shown in b), contact openings 7 are formed in the thick oxide film 4 by anisotropic etching using reactive ion etching using the resist pattern 6. At this time, if an oxide 5 exists in the polysilicon layer 3 directly under the contact opening 7 (FIG. 2(a)), the oxide 5 is etched by overetching in the anisotropic etching.
is etched to form an opening 8 that reaches the silicon substrate 1. In this state, continue as shown in Figure 2 (C).
As shown in FIG. 3, an oxide film 10 having a thickness approximately equal to the diameter of the opening 8 is formed by the CVD method. Next, Figure 2(d)
As shown in FIG. 3, by etching the oxide film 10 by the thickness of the oxide film 10 by anisotropic etching using reactive ion etching, an oxide film sidewall 11 is formed on the thick oxide film 4, and at the same time, the opening 8 is etched. is also filled with an oxide film 12. Next, as shown in FIG. 2(e), aluminum is formed by sputtering to form an anodized wiring 9. Then, as shown in FIG.

〔Effect of the invention〕

As explained above, the present invention is advantageous in that when an insulating film for forming a sidewall is isotropically deposited on the side surface of a contact opening, an insulating film is formed by over-etching the anisotropic etching of the contact opening. Since the opening leading to the semiconductor substrate is filled with an insulating film, it is possible to prevent the aluminum wiring formed in the subsequent process from shorting with the semiconductor substrate, resulting in a high quality semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a semiconductor device showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of each step showing a method of manufacturing the semiconductor device of this invention, and FIG. 3 is a cross-sectional view of a conventional semiconductor device showing each step. It is a diagram. In the figure, 1 is a single crystal silicon substrate, 2 is a thin oxide film, 3 is a polysilicon layer, 4 is a thick oxide film, 5 is an oxide,
6 is a resist pattern, 7 is a contact opening, 8 is an opening, 9 is an aluminum wiring, 10 is an oxide film, 11 is a sidewall of the oxide film, and 12 is an oxide film. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure No. 2 o12 Oxidation gradient Figure 3 1991

Claims (1)

[Claims] A polycrystalline semiconductor wiring formed on a semiconductor substrate with a thin insulating film interposed therebetween and a thick insulating film formed on the polycrystalline semiconductor wiring, a contact hole formed in the thick insulating film, and a contact hole formed in the thick insulating film. In a semiconductor device in which the polycrystalline semiconductor wiring and the metal thin film wiring are electrically connected through a semiconductor device, an insulating film is isotropically deposited on a side surface of the contact opening,
A semiconductor device characterized in that an opening extending to the semiconductor substrate formed by anisotropic removal and over-etching of the anisotropic etching of the contact opening is filled with the insulating film.