JPS61216341A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of disconnection and a reduction in the resolving degree by a method wherein an etching is performed on the silica applied film and the first insulating film at nearly an equal etching ratio. CONSTITUTION:An oxidation treatment is performed on a semiconductor substrate 1, and after an insulating film 2 is formed on the semiconductor substrate 1, a patterning of plycrystalline Si films 3 is performed, and moreover, an insulating film 4 is formed. An applying liquid containing a silica series as its main component is applied on the insulating film 4 to a degree that the surface of the semiconductor substrate 1 is smoothed, a high- temperature treatment is performed in such a way as to set an etching ratio nearly equal to that of the etching to be performed on the insulating film 4, whereby the organic substance being contained in the applying liquid is removed, the applying liquid is made to change and a silica applied film 5 is formed. Then, an etching treatment is performed on the silica applied film 5 at an etching ratio nearly equal to that of the etching to be performed on the insulating film 4 and the surfaces of the films 4 and 5 are nearly smoothed uniformly. Then, in the meaning of solving troubles, such as a trouble that the insulating film 4 on the polycrystalline Si films 3 becomes thinner due to the above-mentioned etching treatment and when a metal wiring (aluminum wiring) 7 is formed on the insulating film 4 in the later process, the capacities between the polycrystalline Si films 3 and the metal wiring 7 become larger; a trouble that the insulation withstand voltage becomes smaller; and troubles of a contamination from the outside and so forth; an insulating film 6 is formed after the surfaces of the films 4 and 5 are smoothed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field] The present invention improves the technique for smoothing the surface of a semiconductor substrate. The present invention relates to a method for manufacturing a semiconductor device.

[Conventional technology]

Conventionally, in a method for manufacturing a semiconductor device, after forming two or more insulating films on a patterned polycrystalline silicon film, aluminum wiring is entirely formed on this insulating film in order to obtain a transistor circuit W11t-. may form.

FIG. 2 is a sectional view showing an example of such a conventional semiconductor device. A polycrystalline silicon film 3 is formed and patterned on a semiconductor substrate l via an insulating film 2, an insulating film 4 is further formed on the polycrystalline silicon film 3, and an aluminum wiring 7 is formed on the surface thereof.

[Problem that the invention seeks to solve]

According to such a conventional manufacturing method, as shown in FIG. 2, when an aluminum wiring crosses a steep step part on a polycrystalline silicon film pattern, 1fTs of the aluminum wiring occurs due to the 5-step difference, and the semiconductor This resulted in a decrease in yield and quality of the equipment.

Furthermore, as the number of patterns decreases year by year.

The dimensions and spacing of wiring have become stricter, and the resolution of photosensitive resin in areas with steps has almost reached its limit. The resolution in the photoresist process is such that K has not yet reached the resolution limit region in flat areas, and steps on the surface of the semiconductor substrate are eliminated.

So-called smoothing technology is becoming more important. In order to smooth this, a method of coating a silica-based coating liquid thickly to eliminate the level difference on the surface of the semiconductor substrate is being considered, but if it is thick, it will not cause cracks on the surface of the silica-based brittle film. This led to problems that reduced reliability.

Therefore, an object of the present invention is to provide a method for manufacturing a semiconductor device that solves all of these problems and improves the technique for smoothing the surface of a semiconductor substrate without reducing the yield or quality of the semiconductor device. .

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes the steps of forming a first insulating film on a patterned polycrystalline silicon film on a semiconductor substrate; A step of forming a silica-based coating film having an etching rate equivalent to that of the first insulating film by applying a coating solution T and heat-treating the same; and etching the silica-based coating film and the first insulating film to the same extent. Etch those surfaces with a speed ratio of t! The method includes a step of uniformly smoothing the film, and a step of forming a second insulating film on the smoothed silica-based coating film and the surface f of the insulating film @1.

[Effect]

In the present invention, the silica-based coating film on the semiconductor substrate is etched by etching the silica-based coating film and the first insulating film, which have been subjected to high temperature treatment so that the etching rate ratio is the same as that of the first insulating film. and the first insulating film is smoothed.

As a result, it is possible to prevent breakage *'i at the step part of the aluminum wiring in the post-process, which conventionally occurred.
It can contribute to improving the yield and quality of semiconductor devices.6 It can also respond to the reduction in wiring that is expected to progress in the future.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor device in main steps for explaining an embodiment of the present invention.

First IC! As shown in FIG. 1 (al), the semiconductor substrate 1 is oxidized to form an insulating film 2t, and then the polycrystalline silicon film 3 is completely patterned, and an insulating film 4 is formed.

Next, as shown in FIG. 1 [b) K, this insulation [4 upper K].

A coating liquid containing silica as a main component is applied to the surface of the semiconductor substrate 1 to the extent that it is smoothed, and organic matter is removed and the silica is transformed by applying high temperature treatment so that the etching rate ratio is almost the same as that of the insulating film 4. A coating film 5 is formed.

Next, as shown in FIG. 1fc)K, this silica-based coating film 5
The etching process m'i is performed at substantially the same etching speed ratio as that of the insulating film 4, so that their surfaces are substantially uniformly smoothed.

Next, as shown in FIG. An insulating film 6 is then formed to solve problems such as an increase in capacitance between metal wirings, a decrease in dielectric strength voltage, and contamination from the outside.

Next, as shown in FIG. 1 f61, an aluminum interconnect 417t- is formed on this insulating film 6.

According to this embodiment, as explained above, the resolution of the photosensitive resin in the photoresist process on the smoothed semiconductor substrate (FIG. 1(d)) is better than the resolution at the stepped portion. This makes it possible to cope with future shrinking patterns, and prevents disconnection of the aluminum wiring 7 in the step part of the polycrystalline silicon film 3, improving the yield of semiconductor devices.
Can contribute to quality improvement. In addition, in the conventional smoothing technology, the problem of surface cracks that occur in the subsequent high temperature treatment process due to the thick application of the silica coating liquid can be solved by etching the surface of the silica coating film 5 in the subsequent etching treatment process. By making the silica-based coating film thinner, it can be reduced, contributing to improving the reliability of semiconductor devices.

〔Effect of the invention〕

As described above in detail, according to the present invention, a silica coating film having the same etching rate ratio as the first insulating film on a buttered polycrystalline silicon film is coated with cedar bark, and this silica coating film and The first insulation [- is etched at approximately the same etching rate ratio and their surfaces are approximately uniform: 5IF
Since the method includes a step of converting the aluminum into aluminum, it is possible to prevent breakage at the stepped portion of the aluminum wiring and to prevent a decrease in the resolution of the photoresist, thereby improving the yield and quality of the semiconductor device. Furthermore, since a thick silica coating film is not used as in the conventional method, surface cracks can be prevented and a semiconductor device with improved reliability can be obtained.

[Brief explanation of the drawing]

FIGS. 1A1 to 1A6 are sectional views of main steps of a semiconductor device for fully explaining an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional semiconductor device. 1... Semiconductor substrate, 2... Insulating film, 3
...Polycrystalline/recon film, 4...Insulating film, 5...Silica-based coating film, 6...Insulating film, 7...・Aluminum wiring. Agent: Susumu Uchihara, Patent Attorney, Group 1, Group 2

Claims (1)

[Claims] The step of forming a first insulating film on a patterned polycrystalline silicon film on a semiconductor substrate, and applying a coating liquid mainly composed of silica on the first insulating film and heat-treating the first insulating film, forming a silica-based coating film having an etching rate equivalent to that of the first insulating film, and etching the silica-based coating film and the first insulating film at an equivalent etching rate ratio to make their surfaces substantially uniform; a smoothing process,
A method for manufacturing a semiconductor device, comprising the step of forming a second insulating film on the smoothed surface of the silica-based coating film and the first insulating film.