JPS63122125A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an opening part having an ideal shape and to improve the step coverage of an insulating film by etching it with a resist as a mask to form an opening of predetermined depth in the film, then removing the resist, and etching the film on the whole surface. CONSTITUTION:When a second insulating film 103 is formed on first wirings 102 on a first insulating film 101, the film 103 is formed to be thicker than the necessary thickness of the film to be necessary after the processing thereby to alleviate 'a constriction' of the stepped part 106. Then, with a photoresist 104 as a mask the film 103 is partly etched. Thereafter, after the photoresist 104 is removed, the whole surface of the film 103 is etched, the opening of the film 103 is penetrated to the first wirings 102, and the thickness of the second insulating film is reduced. At this time, if dry etching is executed under suitable condition, the upper end 105 of the hole is formed in a round shape, while the shape of the part 106 can be transferred as the shape before etching as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming an opening in an insulating film.

[Summary of the invention]

In the present invention, when forming an opening in an insulating film, first,
After etching using the resist as a mask to form a hole of a certain depth in the insulating film, the resist is removed and the insulating film is etched over the entire surface to obtain an opening having an ideal shape. This is an attempt to improve the step coverage of the insulating film.

[Conventional technology]

According to the conventional technology, for example, when attempting to form the U8 hole portion in the second insulating film formed on the first wiring on the first RK, the process is as follows. That is,
As shown in FIG. 2-(b), a second insulating film 203 is formed on the first interconnect 202 on the first insulating film 201 shown in FIG. 2-(a). At this time, the film thickness of the second insulating film '203 is the film thickness necessary to insulate the first wiring @ 202 and the second wiring, usually o, 4 to 1.0 μm.
It's a corner. Next, as shown in FIG. 2-<c>, after forming an opening pattern with photoresist 204,
As shown in d), etching is performed using the 7 photoresist 204 as a mask to form an opening in the second insulating film 203. Then, by removing the photoresist 204, the structure shown in FIG. 2-(g) was obtained.

[Problem that the invention seeks to solve]

However, in the above-mentioned prior art, as shown in FIG. 2-(C), the shape of the upper end 205 of the opening portion becomes almost a right angle, and the step portion 206 also has a “constriction”, so that after the above process, When a second wiring is to be formed, there is a problem that the second wiring is disconnected or short-circuited at the upper end 205 of the opening portion and the stepped portion 206.

Therefore, the present invention attempts to solve such problems, and its purpose is to fix the upper end 20 of the aperture portion.
5 and the shape of the stepped portion 206, the second
It is an object of the present invention to provide a manufacturing method for a process C that prevents disconnection and short circuits during wiring formation, has a high yield, and is highly reliable.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes a step of forming an insulating film on a layer in which transistors, diodes, wiring, etc. are formed, a step of forming an opening pattern with a photoresist on the insulating film, and a step of forming an opening pattern with a photoresist on the insulating film. forming a hole with a predetermined depth in a portion of the insulating film by etching the insulating film using a resist as a mask;
The method is characterized by comprising the steps of removing the photoresist, etching the entire surface of the insulating film to make the insulating film thinner, and forming a complete opening in a portion of the insulating film. [Example] FIGS. 1(α) to (1) are process cross-sectional views in an example of the present invention, in which a second insulating film formed on a first wiring on a first insulating film This example shows a case where an opening is formed in the hole. The following explanation will be based on FIG. 1 (α')-(1).

First, as shown in FIG. 1 (α), a first insulating film 10 is formed.
A second insulating film 103 is formed on the first wiring 102 on the first wiring 102 as shown in FIG. 1-(b). At this time, the thickness of the second insulating film 103 is made thicker by 5 μm to 1.0 μm (L5 μm to 1.0 μm) than the film thickness required after the process is completed, so that the “1 constriction” of the stepped portion 106 is relaxed.Next After forming an opening pattern with the photoresist 104 as shown in FIG. 1-<c>, the second insulating film 103 is formed using the photoresist 104 as a mask as shown in FIG. 2-(d). A portion is etched.At this time, the depth of the etching is adjusted so that a hole with a predetermined depth is formed.

Next, as shown in FIG. 1-(,a), after removing the photoresist 104, the entire surface of the second insulating film 103 is etched, and the opening portion of the second insulating film 103 is etched into the first insulating film 103. The film is penetrated to the wiring 102, and the thickness of the second insulating film is measured as shown in FIG. 1-(f). If the etching at this time is performed by dry etching under appropriate conditions, the etching speed of the edge portion of the upper end 105 of the opening portion can be increased, and as a result, the shape that was almost a right angle can be changed to
As shown in FIG. 1-(1), the upper end 105' of the opening has a rounded shape, while the shape of the stepped portion 106 is as follows.
The shape before etching can be transferred as is.

〔Effect of the invention〕

As described above, according to the present invention, the shape of the opening formed in the insulating film can be made into a shape having an ideal taper angle, and the "1 constriction" in the stepped part of the insulating film can be eliminated. This has the effect of preventing disconnection and short-circuiting of the wiring when forming the wiring on the insulating film, and making it possible to manufacture a high-yield, highly reliable process C.

[Brief explanation of the drawing]

FIGS. 1-(α) to (1) are cross-sectional views of the process of forming a complete hole portion in an insulating film according to the present invention. FIGS. 2-(α) to ('g) are sectional views illustrating the process of forming an opening in an insulating film according to the prior art. 101.201...First insulating film 102.20
2...First wiring 103.203...
Second insulating film 104, 204...Photoresist 105...... Upper end of opening portion 105', 205... immediately after resist removal・Upper end 10 of the opening after the process is completed
6.206...Step entrance

Claims (1)

[Claims] A step of forming an insulating film on a layer in which transistors, diodes, wiring, etc. are formed, a step of forming an opening pattern with a photoresist on the insulating film, and etching the insulating film using the photoresist as a mask. forming a hole with a predetermined depth in a portion of the insulating film; removing the photoresist;
A method for manufacturing a semiconductor device, comprising the steps of etching the entire surface of the insulating film to make the insulating film thinner and forming a complete opening in a portion of the insulating film.