JPS5885529A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide manufacturing method of semiconductor devices with less influence of disconnection of aluminum conductors, by a method wherein an electrode window of two steps structure is provided between the lower conductive layer and the opening of a contact for connection of the upper electrode. CONSTITUTION:A silicon dioxide film 2 is formed on a P type single cyrstalline silicon substrate 1, and impurities are introduced to the main surface of the silicon substrate through the film 2 to form a diffusion layer region 3 having the reverse conductive type to the silicon substrate 1. Simultaneously, an insulating film 4 between layers 4 is formed on the silicon dioxide layer 2. A plasma nitride film 7 is formed on the insulating film 4 betwen layers. The film 4 is selectively side-etched utilizing a photo-resist 8 as a mask to form the second hole, and the insulating film 4 between layers is wet- etched utilizing the plasma nitride film 7 as a mask up to one third of the original thickness to form a hollow surrounded by a remained film 4'. Then the remained film 4' and the silicon dioxide layer 2 directly below the film 4' are etched utilizing the photo-resist 8 as a mask to form an opening, and thereby form the two steps structure having an essentially flat bottom. The photo-resist 8 and plasma nitride film 7 are removed. After that, the insulating film between layers with the opening is thermal- treated to sag the film in high temperature atmosphere, and a conductive wiring layer is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor integrated circuit device in which a two-stage electrode window is formed between a lower conductive layer and a contact hole for connecting an upper electrode. .

FIGS. 1(a) to 1(e) are cross-sectional views sequentially illustrating a conventional method for forming contact holes in a semiconductor substrate.

As shown in FIG. 1(a), this manufacturing method involves forming a silicon oxide film 2 by a thermal oxidation method on one main surface of a silicon substrate 1 having a P-type conductivity, and then An impurity having a conductivity type opposite to that of the silicon substrate 1 is introduced into the main surface of the silicon substrate through the film 2 by ion implantation to form a diffusion layer region 3. Next, silicon dioxide film 2-
First, an interlayer insulating film 4 is formed by vapor phase epitaxy. Next, as shown in FIG. 1(b), a predetermined pattern is formed using a photoresist film 5 on this interlayer insulating film 4, and then wet etching is performed to form the interlayer insulating film 4 as shown in FIG. ), perform side etching until a predetermined remaining film is reached. Next, using the photoresist film 5 as a mask, the remaining interlayer insulating film 4 is etched using an anisotropic plasma etching device, as shown in FIG.
The structure shown in the cross-sectional view d) is obtained.

Next, after removing the photoresist film 5, heat treatment is performed in a high temperature atmosphere to make the interlayer insulating film 4 evenly smooth after the opening), and then an aluminum electrode is formed thereon. 1st
In the structure of the aluminum disconnection window formed as shown in Figure (el), since the slope of the interlayer insulating film 4 at the opening is steep, disconnection between the aluminum electrodes 6 and 61 is likely to occur at that part. , the function as an integrated circuit device may be lost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device in which the influence of aluminum wire breakage as described above is particularly reduced.

In the present invention, first and second
forming an insulating film on the second insulating film; and forming a first insulating film on the second insulating film.
forming a second hole having a diameter larger than the first hole in the second insulating film using the photoresist film as a mask; forming four portions of a predetermined depth in the first insulating film using the second insulating film as a mask; and partially forming an opening in the recess of the first insulating film using the photoresist film as a mask. The method of manufacturing a semiconductor device includes a step of forming an electrode, and a step of forming at least an electrode within the opening.

According to the manufacturing method of the present invention, by forming the interlayer insulating film of the electrode window into a two-stage structure, the inclination of the contact portion is made gentler, and the effect of disconnection of the aluminum electrode can be reduced.

Next, the present invention will be explained in detail using the drawings. Figure 2 (a
) to FIG. 2(e) are cross-sectional views of a semiconductor substrate to which an embodiment of the present invention is applied.

1. First, as shown in FIG. 2(a), a silicon dioxide film 2 is formed on the surface of a P-type nested crystalline silicon substrate 1 by thermal oxidation. Next, an impurity that gives a conductivity type opposite to that of the silicon substrate 1 is introduced into the surface of the silicon substrate by ion implantation through the entire VC1 silicon dioxide film 2 to form a diffusion layer region 3)1ν,
do. Next, an interlayer insulating film 4 is formed on the silicon dioxide layer 2 by vapor phase growth. Next, using the photoresist film 8 having the first hole as a mask, the interlayer insulating film 4 is selectively side-etched so that the diameter becomes wider than the first hole in the photoresist (see FIG. 2(b). )) A second insulating film 7 (here, a plasma nitride film formed by plasma vapor deposition method is used) is formed on the interlayer insulating film 4. This plasma nitride film 7 is selectively side-etched using an isotropic plasma etching apparatus using the photoresist 8 as a mask, as shown in FIG. 2(b), to form second holes.

Next, using the side-etched plasma nitride film 7 as a mask, the interlayer insulating film 4 is wet-etched to 1/3 or less of the original film thickness, and the remaining film 4' is etched as shown in FIG. 2(C).
form. That is, there are four parts. Next, using the photoresist 8 as a mask, the remaining film 4' portion shown in FIG. 2(C) and the silicon dioxide layer 2 immediately below it are etched using an anisotropic plasma etching apparatus, and the remaining film 4' shown in FIG. 2(d) is etched using an anisotropic plasma etching apparatus. Form a cross-sectional structure like this. In this way, an opening is provided. In this way, a so-called two-stage structure is formed in which a substantially flat bottom surface of the recessed portion of the remaining film 4I of the interlayer insulating film remains. next,
The photoresist 5 as the mask 8 and the plasma nitride film 7 are removed. Next, as shown in FIG. 2(e), the interlayer insulating film after opening is smoothed (smoothed) by heat treatment in a high-temperature atmosphere, and then a conductive wiring layer is provided by a conventional method.

That is, the present embodiment includes a step of depositing a first insulating film on the entire surface of a semiconductor substrate having a -conductivity type, and an impurity that provides a conductivity type opposite to the -conductivity type through the first insulating film. a step of rupturing a second insulating film on the first insulating film, and a step of rupturing a third insulating film on the second insulating film (see FIG. 2(a)). ), a step of depositing a photoresist pattern having holes for forming holes in the third insulating film, and selectively forming the third insulating film using the photoresist pattern as a mask. forming the opening by side-etching the hole to be wider than the hole (corresponding to FIG. 2(b)); and selectively forming the second insulating layer using the third insulating film as a mask. 1/ of the film thickness of
Etching process with 3 or less blades (corresponding to Figure 2 (C))
and selectively forming the second insulating film using the photoresist pattern as a mask.

The process of etching the thin part left behind (see Figure 2 (d)
)) and a step of removing the third insulating film etc. to provide an electrode (corresponding to FIG. 2(e)).

In particular, it is preferable that the third insulating film is formed of a silicon nitride film.

As described above, according to the present invention, a two-stage electrode window is formed between the lower layer 4- and the opening of the connection contact of the upper electrode, thereby reducing aluminum disconnection at the contact portion. be able to.

In one embodiment of the present invention, a plasma nitride film is used as the side-etched insulating film, but the same effect can be obtained by using a polycrystalline silicon film instead.

Further, although the embodiment of the N-channel MO8 integrated circuit device according to the present invention has been described, the present invention can be applied to various semiconductor integrated circuit devices.

[Brief explanation of drawings]

FIGS. 1(a) to 1(e) are cross-sectional views sequentially showing a conventional method of manufacturing a semiconductor substrate, and FIGS. 2(a) to 2(e)
) are cross-sectional views sequentially illustrating a method of manufacturing an N-chain non-circular silicon MO8 integrated circuit device according to an embodiment of the present invention; In the plan view, 1... P-type nest crystal silicon substrate, 2... Silicon dioxide film, 3... Impurity diffusion region, 4... Interlayer insulating film. ,41・
... Remaining film of interlayer insulating film, 5.8 ... Photoresist film, 6.6', 9 ... Aluminum electrode, 7 ... Plasma nitride film . -I Zbu

Claims (1)

[Claims] a step of sequentially forming a box 1 and a second insulating film on a semiconductor region of one conductivity type; a step of forming a photoresist film having a first hole on the second insulating film; and a step of forming a photoresist film having a first hole on the second insulating film. forming a second hole having a larger diameter than the first hole in the second insulating film using the mask as a mask; and forming a second hole in the first insulating film to a predetermined depth using the second insulating film as a mask. a step of forming an opening in the recess of the first insulating film using the photoresist film as a mask; and a step of forming an electrode in at least the opening. A method for manufacturing a semiconductor device including: