JPS60152040A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form flatly an interlayer insulating film with no step difference by a method wherein three layers consisting of a second insulating film, a silicon compound applied forming coated film and a third insulating film are formed on a first insulating film formed on the surface of a substrate, an aperture in common to these three layers is provided and an aluminum film is evaporated on the whole surface. CONSTITUTION:A silicon dioxide film 2 is formed on the surface of a silicon substrate 1, and three layers of a silicon nitriding film 6, a silicon compound applied forming coated film 7 and a silicon dioxide film 8 are formed thereon. Apertures are provided in order on the three layers 8, 7 and 6. An aluminum film 3 is formed by evaporation on the whole surface. When the films 7 and 8 are removed by dissolution, the aluminum film 3 in the aperture of the silicon nitriding film 6 is left in a nearly non-step difference condition to the surrounding silicon nitriding films 6. A silicon nitriding film 4, which is used as an interlayer insulating film, is formed, covering the aluminum film 3 and the silicon nitriding films 6. Then, an aluminum film 3, which is used as a second wiring layer, is formed by evaporation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a semiconductor device having multilayer wiring layers;
Specifically, the present invention relates to a manufacturing method for forming a flat insulating film between multilayer wiring layers.

Conventional configurations and their problems In highly integrated semiconductor devices such as ICs and LSIs, wiring layers often have a multilayer structure. However.

When forming wiring layers in a multilayer structure, it is necessary to reduce the level difference between the interlayer wiring layers.

FIG. 1 is a sectional view of a conventional semiconductor device having a two-layer wiring structure, in which an insulating film 2 is in close contact with a semiconductor substrate 1, and a first wiring layer 3. Glabella insulating film 4 and second
A wiring layer 5 is formed thereon. The glabella insulating film 4 is usually a silicon nitride vapor-grown film with little anisotropic growth, but in many cases there is a large step at the side end of the first wiring layer 3, and the film is formed on top of this. The second wiring layer 6 has a constricted portion at the stepped portion, and there is a problem in that the wire is easily broken at this constricted portion.

OBJECTS OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device in which an interlayer insulating film is formed flat without any steps.

Structure of the Invention The present invention can be summarized as follows: a first insulating film in close contact with a semiconductor surface; second, a step of sequentially forming a second insulating film, a silicon compound coating and a third insulating film; and a step of sequentially forming the third insulating film. forming a photoresin film mask pattern thereon, and sequentially etching openings in each of the third insulating film, the silicon compound coating film, and the second insulating film along the shape of the mask pattern; and a step of depositing and forming a first wiring layer material covering the third insulating film, and removing the third insulating film and the silicon compound coating to form the first wiring layer material in the opening of the second insulating film. The method of manufacturing a semiconductor device includes a step of leaving a wiring layer and a step of forming an interlayer insulating film covering the first wiring layer material and the second insulating film. Thereby, by making the thickness of the first wiring layer material embedded in the opening of the second insulating film the same as the thickness of the second insulating film, an interlayer insulating film is formed covering the upper surface of these. No step is formed between the two layers, and the surface of the interlayer insulating film becomes flat.

DESCRIPTION OF THE EMBODIMENTS FIGS. 2(a) to 2(d) are sectional views of the embodiment of the present invention in the order of steps. Hereinafter, the present invention will be described in detail with reference to these figures.

First, as shown in FIG. 2 (IL), a silicon dioxide film 2 is formed on the surface of a semiconductor substrate, for example, a silicon substrate 1, and a silicon nitride film 6, a silicon compound coating 7 and a top layer are formed on this. A silicon dioxide film 8 is formed, and a photoresin film mask pattern is used to form a silicon dioxide film 8. Openings are sequentially formed in the silicon compound coating film 7 and the silicon nitride film 6. Silicon substrate 1
The silicon dioxide film 2 as the upper first insulating film is a surface stabilizing film, and may be a phosphorus-containing film, for example. The silicon nitride film 6 as the second insulating film has a thickness of about 1
Formed in μm. The silicon compound coating 7 is usually obtained by preparing silanol with a diluent, forming a coating by spin coating, drying and baking, and is formed to a thickness of about 0.4 μm. The silicon dioxide film 8 as the third insulating film is a film (Si02) formed by vapor phase growth, and has a suitable thickness of about 0.6 μm.

By the way, a photoresist unmasking pattern (not shown) is formed on the uppermost silicon dioxide film 8, and using this as a mask, the silicon dioxide film 8 and the silicon compound D-forming film 7 immediately below it are exposed to the same etching pattern. When etched with an etching liquid, the etching rate of the lower silicon compound coating 7 is about twice that of the upper silicon dioxide film 8, so the upper silicon dioxide film 8 protrudes around the opening. It is etched in a so-called overhang shape. Subsequently, when etching the silicon nitride film 6, the silicon compound coated corrugated film 7 serves as a mask, and openings corresponding to this mask pattern are formed.

Next, as shown in FIG. 2(b), as a first wiring layer, an aluminum film 3 is deposited to a thickness of about 1-μm inside the opening.
It is formed by vapor deposition so that it becomes . At this time, the aluminum film 3 is formed separately on the silicon dioxide film B and its opening.

Therefore, when the silicon compound coating 7 and the silicon dioxide film 8 are dissolved and removed using, for example, a hydrofluoric acid solution, the aluminum film thereon also becomes so-called.
The aluminum film 3 is peeled off by lift-off, and the aluminum film 3 in the opening of the silicon nitride film 6 remains in a substantially stepless state with respect to the surrounding silicon nitride film 6, as shown in FIG. 2(C).

Then, as shown in FIG. 2 (tl), a silicon nitride film 4 is formed as an interlayer insulating film, covering the aluminum film 3 and the silicon nitride film 6. This silicon nitride film 4 is
It is formed to a thickness of about 1 μm by a normal vapor phase growth method. Although not shown in the drawings, this silicon nitride film 4 is selectively formed with a through hole for obtaining electrical contact with the aluminum film 3 of the first wiring layer, if necessary, and then a second wiring layer is formed on the silicon nitride film 4. An aluminum film 3 is formed by vapor deposition. In this case, since the silicon nitride film 4 of the interlayer insulating film is almost flat reflecting the stepless valley between the lower aluminum film 3 and the silicon nitride film 67, the second wiring layer Similarly, the aluminum film 3 can also have a flat shape.

In the above-mentioned example, a film formed by coating a silanol-containing solution was exemplified as a film formed by coating a silicon compound.
Similar effects can be achieved with coatings formed using other silicon oxy derivatives as raw materials. In addition, even if the silicon nitride film and the silicon dioxide film are replaced with each other in their respective positions, an overhang shape is realized in the opening, and there is no step difference between the first wiring layer and the second insulating film. It is quite possible to realize the state.

Effects of the Invention According to the present invention, after forming three layers consisting of a second insulating film, a silicon compound coating, and a third insulating film on a first insulating film on a semiconductor surface, these three layers are formed into a photoresin film manuk pattern. When the opening for forming the first wiring layer is formed using the silicon compound, the opening in the third insulating film becomes overhanging due to the high etching speed of the silicon compound coating.
The first wiring layer deposited in this opening can be formed without any difference in level from the opening in the second insulating film, so that the interlayer insulating film and the second wiring layer formed thereon have good flatness. realizable.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional multilayer wiring structure, Figure 2 (IL)
-(+1) are sectional views in the order of steps of the embodiments of the present invention. 1...Silicon substrate, 2...Silicon dioxide film, 3.-aluminum film (first wiring layer), 4...
Silicon nitride film, 6...aluminum film (second layer 4
91 layers), 6... silicon nitride film, 7...
Silicon compound coating formed film, 8...Silicon dioxide film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 (a-) Figure 2 (b) (d-2

Claims (1)

[Claims] a step of sequentially forming a second insulating film, a silicon compound coating, and a third insulating film on the first insulating film in close contact with the semiconductor surface; forming a photoresist film pattern on the third insulating film; Along the mask pattern shape,
Step of sequentially etching and opening each of the third insulating film, the silicon compound coating film, and the second insulating film, and covering the opening and the third insulating film with a first wiring layer material. a step of leaving the first wiring layer material in the opening of the second insulating film by removing the third insulating film and the silicon compound coating, and a step of leaving the first wiring layer material in the opening of the second insulating film; 2. A method for manufacturing a semiconductor device comprising the step of forming a glabella insulating film covering the second insulating film.