JPS63177539A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To prevent occurrence of electrical faults related with wirings on throughhole parts, by forming through hole opening parts between lower and upper wirings and next making a thin insulating film grow uniformly and performing anisotropic etching over the whole surface so that the thin insulating film remains only on sides of the throughhole opening parts. CONSTITUTION:A coverage repair film 4 is formed by piling a lower wiring 2 on a surface of a Si substrate 1 and covering the lower wiring 2 with a lower part insulating film 3 and coating the film 3 with a solution of silicon dioxide and next sintering this substrate 1. Three insulating layers serving as upper insulating films 5 are formed on the film 4. Next, through holes are formed similarly by a conventional method. Next, a thin insulating film 9 of a plasma nitriding film is formed uniformly on the surface inclusive of the through holes. Next, when anisotropic etching is performed uniformly to etch only the thickness of the thin insulating film 9, the thin insulating film 9 remains only on through hole internal sides so as to form a throughhole side insulating film 7. Next, when an upper wiring is formed, a semiconductor device is obtained to have wirings in no direct contact with the coverage repair film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor device and a method for manufacturing the same, and in particular to a semiconductor device and a method for manufacturing the same. The present invention relates to a semiconductor device and a manufacturing method thereof.

[Conventional technology]

Conventionally, through-holes in this type of three-layer insulating layer were patterned with a resist, and the three-layer insulating layer was etched using the resist pattern as a mask to open the hole.Then, the resist was peeled off and the wiring was directly connected to the next layer. The material was growing.

[Problem that the invention seeks to solve]

The problems with the conventional through-hole shape described above will be explained with reference to the drawings. FIG. 4 is a sectional view of a main part of a semiconductor device formed by a conventional semiconductor device manufacturing method. As shown in FIG. 4, a conventional semiconductor device has a lower wiring film 2 on a substrate 1. Lower insulating film 3° Coverage improvement film 4. Upper insulating film 5. It consists of upper layer wiring 6. Reference numeral 8 denotes a contact portion between the coverage improvement film 4 and the upper layer wiring 6. The material of the coverage improvement film 4 is usually an organic substance or a substance containing an organic medium, and it easily reacts with the wiring material. This has the disadvantage that electrical faults in the wiring are likely to occur in the hole portions, reducing reliability.

An object of the present invention is to directly contact the coverage improving film material and the upper wiring material on the side surface of the through-hole part of the insulating layer having a three-layer structure including the coverage improving film for improving the step coverage as an insulating layer between the eyebrows. Without a doubt,
Therefore, it is an object of the present invention to provide a semiconductor device and a method for manufacturing the same, in which there is no reaction between the two, and electrical defects in the wiring do not occur in the through-hole portion.

[Means for solving problems]

In the semiconductor device of the first aspect of the present invention, the insulating layer that insulates between the upper layer interconnect and the lower layer interconnect is a three-layer insulating layer consisting of an upper insulating film, an upper insulating film, a lower insulating film, and a coverage improvement film sandwiched between the two insulating films. In the semiconductor device having a through hole in the insulating layer, at least the side surface of the coverage improvement film on the inner side surface of the through hole provided in the insulating layer is covered with another thin insulating film. Constructed as a feature.

Further, the method for manufacturing a semiconductor device according to the second invention of the present invention includes:
forming an insulating layer with a three-layer structure consisting of an upper insulating film, a lower insulating film, and a coverage improvement film sandwiched between the two insulating films as an insulating layer for insulating between the upper layer wiring and the lower layer wiring; forming a through hole in an insulating layer having a layered structure; The method is characterized by comprising the steps of uniformly forming a thin insulating film on the surface, and then performing anisotropic etching in the vertical direction to etch by the thickness of the thin insulating film.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment of a semiconductor device according to a first aspect of the present invention.

As shown in FIG. 1, this embodiment has a three-layer structure consisting of a lower insulating film 3 formed to cover a lower wiring 2 formed on a silicon substrate 1, a coverage improvement film 4, and an upper insulating film 5. The insulating layer has a through hole for connecting the lower layer wiring 2 and the upper layer wiring 6, and the side surface of the insulating layer of the through hole is covered with a thin through hole side insulating film. 7, and has a structure in which contact between the upper layer wiring and the coverage improvement film is prevented by this thin through-hole side insulating film.

FIGS. 2(a) and 2(b) are cross-sectional views of an element in some manufacturing steps shown in the order of steps for explaining an embodiment of the second invention of the present invention, and are similar to those shown in FIG. 1. The manufacturing method of the example will be explained.

First, as shown in FIG. 2(a), a lower insulating film 3 (for example, a plasma nitride film) is applied to cover the lower wiring 2 formed on the surface of the silicon substrate 1, and a silicon dioxide solution is applied thereon, followed by baking. Coverage improvement film formed by bonding 4. Thereon, an insulating layer consisting of three layers of an upper insulating film 5 (for example, a plasma nitride film) is formed. Next, through holes are formed in the same manner as in the conventional method. Next, a thin insulating film 9 of plasma nitride film having a thickness of 0.1 to 0.5 μm is uniformly formed on the surface including the through holes.

Next, as shown in FIG. 2(b), when etching is performed uniformly by the thickness of the thin insulating film 9, the thin insulating film 9 remains only on the inner side surface of the through hole. An insulating film 7 can be formed.

Next, by forming upper layer wiring, a semiconductor device having wiring that does not come into direct contact with the coverage improving film of the embodiment of the present invention shown in FIG. 1 is obtained.

FIG. 3 is a sectional view of an element for explaining the structure and manufacturing method of another embodiment of the present invention.

This embodiment will be explained with emphasis on the points that are different from the first embodiment.

As shown in FIG. 3, in order to improve the coverage of the upper layer wiring 6 in the through-hole portion, when opening the insulating layers 3 and 4.5, as an etching method after patterning the resist, first isotropic etching is performed. Next, anisotropic etching is performed to form holes. If the depth of the isotropic etching at this time is stopped before reaching the coverage improvement film 4, the thin insulating film can be uniformly grown after the through-hole is opened, as in the first embodiment of the present invention, and the If anisotropic etching is performed, a thin insulating film can be left only in the anisotropically etched area around the through hole. As a result, a structure is obtained in which the coverage improvement film on at least the side surface of the through hole is covered with a thin insulating film, and as a result, a semiconductor device is obtained in which the coverage improvement film and the wiring material do not come into direct contact.

〔Effect of the invention〕

As explained above, in the present invention, when a coverage improving material is used as an inter-wiring insulating layer, a thin insulating film is uniformly grown after opening a through-hole between the lower and upper interconnects,
A semiconductor device is obtained by anisotropically etching the entire surface, leaving a thin insulating film only on the side surfaces of the through-hole openings.As a result, in the completed semiconductor device, the coverage improvement material and the wiring material are in direct contact. Therefore, there is no reaction with the coverage improving material, and there is an effect that electrical defects in the wiring do not occur in the through-hole portion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the first invention of the present invention, and FIG.
Figures (a) and (b) are cross-sectional views of an element partially in the middle of the process shown in the order of steps to explain an embodiment of the second invention of the present invention, and Fig. 3 is another embodiment of the present invention. FIG. 4 is a sectional view of an element having a through-hole structure to explain a conventional example. DESCRIPTION OF SYMBOLS 1... Silicon substrate, 2... Lower layer wiring, 3... Lower insulating film, 4... Coverage improvement film, 5... Upper insulating film, 6... Upper layer wiring, 7... Through-hole side insulating layer, 8... contact portion between 4 and 6, 9... thin insulating material.

Claims (2)

[Claims] (1) The insulating layer that insulates between the upper layer wiring and the lower layer wiring has a three-layer structure consisting of an upper insulating film, a lower insulating film, and a coverage improvement film sandwiched between these two insulating films, and the insulating layer 1. A semiconductor device having a through hole, wherein at least a side surface of a coverage improvement film on an inner side surface of the through hole provided in the insulating layer is covered with another thin insulating film. (2) A step of forming an insulating layer with a three-layer structure consisting of an upper insulating film, a lower insulating film, and a coverage improvement film sandwiched between the two insulating films as an insulating layer that insulates between the upper layer wiring and the lower layer wiring. forming a through hole in the insulating layer having the three-layer structure; Manufacturing a semiconductor device comprising the steps of uniformly forming a thin insulating film on a surface including holes, and then performing anisotropic etching in the vertical direction to etch by the thickness of the thin insulating film. Method.