JPS60134445A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable to improve the reliability of a semiconductor device as well as to upgrade the yield thereof by a method wherein, when an interlayer insulating film to be used for insulation-isolating conductive layers is formed, a polycrystalline Si film containing impurities is deposited first on a conductor layer by a low-pressure CVD method and the polycrystalline Si film is converted into an oxide by performing a thermal treatment. CONSTITUTION:Thick field oxide films 8 are formed one by one in the peripheral parts of a P type semiconductor substrate 1, N<+> type regions 2 and 3 are formed by diffusion in the surface layer part of the substrate 1 being surrounded with the oxide films 8 and a gate electrode 5 consisting of polycrystalline Si is provided between these regions 2 and 3 through a gate oxide film 4. Then, a polycrystalline Si layer 6 of a thickness of about 500-3,000Angstrom is deposited on the whole surface by a low-pressure CVD method. The reason why the low-pressure CVD method is applied here is that the film thickness of the polycrystalline Si layer 6 is not unirformly formed by the CVD method and the reason why the SiO2 film is directly adhered is that the excellent electrical insulating properties are not obtained. After that, N type impurities are doped on the layer 6 for accelerating the rate of thermal oxidation, a thermal treatment is performed at low temperatures of 700-900 deg.C and the layer 6 is converted into an interlayer insulating film 6. Then, apertures are bored in the insulating film 6 and Al wiring layers 7 are respectively installed on the regions 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device having a glabella insulating film that insulates between conductive layers.

[Technical background of the invention and its problems]

Figure 1 shows NIViO8FET as a specific example of a semiconductor device.
shows. Impurity diffusion layers 2.3 as a source and r-rain are formed on a semiconductor substrate 1, and a gate oxide film 4 and a polycrystalline silicon electrode 5 are formed between these impurity diffusion layers 2.3. An interlayer insulating film 6 is formed thereon, and a thin aluminum wiring layer 7 is formed thereon.

8 is an element isolation oxide film.

To form this interlayer insulating film 6, conventional normal pressure CVD is used.
I was accumulating more Sioz than I was before. However, in such a conventional manufacturing method, as shown in FIG.
There were problems such as poor registration of the D film and the formation of cavities (A), excessive thinning at the step portion of the base (B), and poor electrical characteristics. In addition, in the normal CVD method, clumps of oxide film deposited on the walls of the manufacturing equipment adhere to the semiconductor substrate.
There is a problem in that hillocks are likely to occur in the CVD film. These hillocks increase in proportion to the number of times the manufacturing equipment is used, causing problems such as disconnection of the aluminum wiring and abnormal pattern shapes.

[Purpose of the invention]

The present invention has been made in consideration of the above situation, and an object of the present invention is to provide a method for manufacturing a semiconductor device that can form an interlayer insulating film having a uniform thickness and fewer defects.

[Summary of the invention]

In order to achieve this object, the method for manufacturing a semiconductor device according to the present invention deposits a polycrystalline silicon film on a conductive layer by LP CVD method, and then thermally oxidizes the polycrystalline silicon film to insulate the conductive layers. It is characterized by forming an interlayer insulating film. In addition, in this manufacturing method, 4.
', It is desirable to add impurities before thermally oxidizing the polycrystalline silicon film.

[Embodiments of the invention]

A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to FIG. Impurity diffusion layer 2.3 on semiconductor substrate 1
, gate oxide film 4, and polycrystalline silicon electrode 5 are formed (
Figure 3(a)). Next, LPCVD method (Lovr Pre
ssure Chemical Vapor Depo
polycrystalline silicon layer 6 by approximately 50%
0X~aoooo! (Fig. 3(b)). The reason why the LPCVD method is used instead of the CVD method is that a uniform deposited film can be obtained. Further, the reason why polycrystalline silicon is deposited instead of silicon oxide is that there is a problem in electrical insulation if silicon oxide is directly deposited.

This polycrystalline silicon layer 6 may be immediately oxidized to form the interlayer insulating film 6, but before that, an impurity such as phosphorus (P) is diffused or ion-implanted to add an impurity to the polycrystalline silicon layer 6 (third step Figure (C)). After that, when thermal oxidation is carried out, the thermal oxidation rate becomes faster and lower waves (approximately 700'C, -900°C
) thermal oxidation is possible. Thermal oxidation without the addition of impurities is carried out at approximately 900°C to 1100°C. By thermal oxidation, the polycrystalline silicon layer 6 becomes a silicon oxide layer, that is, an interlayer insulating film 6 (FIG. 3(d)), and then an aluminum wiring layer 7 is formed to complete the manufacturing of the semiconductor device (FIG. 3(e)). ).

The manufacturing method according to the present invention can be applied not only to the embodiments but also to all semiconductor devices having an interlayer insulating film, and can be applied to most semiconductor devices such as memory microprocessors.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to form an interlayer insulating film having a uniform thickness and fewer defects, thereby improving the yield of manufacturing semiconductor devices and improving the reliability of the manufactured semiconductor devices.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a specific example of a semiconductor device having an interlayer insulating film, FIG. 2 is a cross-sectional view of a specific example of a semiconductor device formed by a conventional manufacturing method, and FIGS. ), (e
), (d), and (e) are process diagrams of a method for manufacturing a semiconductor device according to an embodiment of the present invention. 1... Semiconductor substrate, 2.3... Impurity diffusion layer, 4.
...Gate oxide film, 5...Polycrystalline silicon electrode, 6.
...Interlayer insulating film, 7... Aluminum wiring layer. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] 1. A polycrystalline silicon film is deposited on a conductive layer by the LP CVD method, and then this polycrystalline silicon film is thermally oxidized to form a glabella insulating film that insulates between the conductive layers. A method for manufacturing a featured semiconductor device. 2. A method for manufacturing a semiconductor device according to claim 1, characterized in that impurities are added to the polycrystalline silicon film before thermally oxidizing it.