JPH02296332A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To flatten the surface of an interlayer insulating film, and flatten also an multilayer wiring layer formed on the interlayer insulating film, by selectively eliminating protruding parts of the interlayer insulating film of the parts where a lower layer wiring and an upper layer wiring intersect each other, and depositing and forming thereon an interlayer insulating film. CONSTITUTION:On the whole surface of an insulating film 2 formed on a semiconductor substrate, e.g. silicon substrate 1, a lower layer wiring film is formed and machined to an arbitrary shape. A lower layer wiring 3 is arranged, and a first interlayer insulating film 4a is formed on the whole surface. By etching, protruding parts of the first interlayer insulating film 4a are selectively eliminated from the intersecting parts of the lower layer wiring 3 and the upper layer wiring 5, e.g. the lower layer wiring 3; a second interlayer insulating film 4b is deposited and formed; thereon an upper layer wiring 5 is formed, thereby forming an interlayer insulating film between the lower layer wiring 3 and the upper layer wiring 5. Hence the surface of the interlayer insulating film can be flattened, processing of the upper layer wiring is facilitated, and a highly reliable semiconductor device wherein disconnection, short, etc., of the upper layer wiring are not present can be obtained.

Description

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

(Prior Art) FIG. 3 is a cross-sectional view of a semiconductor device using a conventional method for forming a glabellar insulating film. In this figure, 1 is a silicon substrate, 2 is an insulating film formed on this silicon substrate 1, 3 is a lower layer wiring formed on this insulating film 2, 4 is an interlayer insulating film formed on the entire surface, and 5 is an insulating film formed on the entire surface. This is an upper layer wiring formed on the interlayer insulating film 4.

Next, a method for forming the same will be explained with reference to FIGS. 4(a) to 4(d).

A lower wiring film 3 is formed on the entire surface of the insulating film 2 formed on the silicon substrate 1 (FIG. 4(a)), and this is processed into an arbitrary shape to arrange the lower wiring 3 (FIG. 4(b)). )).

Next, a glabellar insulating film 4 is formed over the entire surface including the lower wiring 3. At this time, the surface of the interlayer insulating film 4 shows the level difference of the lower wiring 3 as it is and becomes a highly uneven surface (FIG. 4(C)).

Furthermore, upper layer wiring 5 is formed on this glabellar insulating film 4 (
Figure 4(d)).

[Problems to be Solved by the Invention] Since the conventional interlayer insulating film 4 is formed as described above, the surface of the glabella insulating film 40 has large irregularities, so it is necessary to process the upper layer wiring 5 formed thereon. However, processing is difficult and complicated, and there are problems in that short circuits or disconnections between the upper and lower wirings 5 and 3 are likely to occur at the uneven portions of the interlayer insulating film 4.

This invention was made to solve the above-mentioned problems, and aims to flatten the surface of the insulating film between the eyebrows and to provide a method for manufacturing a semiconductor device that does not cause disconnection or short circuit between upper layer wirings. shall be.

[Means to solve the problem]

A method for manufacturing a semiconductor device according to the present invention includes forming an interlayer insulating film on a lower layer wiring arranged on a semiconductor substrate, and selectively removing a convex portion of the interlayer insulating film at a portion intersecting with the lower layer wiring. After that, a multilayer wiring structure is formed by depositing a glabellar insulating film thereon to flatten the surface of the interlayer insulating film, and then forming an upper layer wiring thereon.

[Effect]

In this invention, the convex portion of the interlayer insulating film at the intersection of the lower layer wiring and the upper layer wiring is selectively removed, and the interlayer insulating film is deposited thereon, so that the surface of the insulating film between the eyebrows is flattened. Furthermore, the multilayer wiring layer formed thereon is also planarized.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view of a semiconductor device according to an embodiment of the present invention. In this figure, the same reference numerals as in FIG. 3 indicate the same things, and 4a indicates the removal of the interlayer insulating film at the stepped portion that occurs in the lower layer wiring 3, that is, the convex portion of the interlayer insulating film formed on the lower layer wiring 3. After forming the first interlayer insulating film 4a, the first interlayer insulating film 4b is formed by etching the first interlayer insulating film 4b for the purpose of reducing the level difference.
This is a second interlayer insulating film formed thereon, and the upper layer wiring 5 is formed thereon.

Next, the formation and removal will be explained with reference to FIGS. 2(a) to 2(f).

A lower wiring film 3'' is formed on the entire surface of an insulating film 2 formed on a semiconductor substrate, for example, a silicon substrate 1 (FIG. 2(a)).
, it is processed into an arbitrary shape, and the lower layer wiring 3 is arranged (FIG. 2(b)). Next, a first interlayer insulating film 4a is formed over the entire surface. Since the main purpose of this first interlayer insulating film 4a is to flatten the surface, the thickness of the film to be deposited is limited to the thickness of the lower wiring 3.
The thickness must be the same as or greater than the thickness of the second
Figure (C)).

Next, by etching, the portion where the lower layer wiring 3 and the upper layer wiring 5 intersect, that is, the convex portion of the first interlayer insulating film 4a by the lower layer wiring 3 is selectively removed (FIG. 2(d)).
. Next, a second interlayer insulating film 4b is deposited (FIG. 2(e)), and an upper layer wiring 5 is formed thereon (FIG. 2(e)).
In FIG. 2(f)), an interlayer insulating film between the lower layer wiring 3 and the upper layer wiring 5 is formed.

In addition, although the above embodiment describes the case between two wirings, it may also be applied to an interlayer insulating film between each wiring layer in a multilayer wiring having two or more wiring layers, and the same method as in the above embodiment may be applied. It has the effect of

〔Effect of the invention〕

As explained above, the present invention forms an interlayer insulating film on a lower layer wiring arranged on a semiconductor substrate, selectively removes the convex portion of the interlayer insulating film at a portion intersecting with the lower layer wiring, and then After flattening the surface of the interlayer insulating film by depositing the glabellar insulating film thereon, a multilayer wiring structure is formed by forming the upper layer wiring on top of the planarized surface of the interlayer insulating film. This has the effect that it can be flattened, the upper layer wiring can be easily processed, and a highly reliable semiconductor device with less cross-sectional short circuits of the upper layer wiring can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a process cross-sectional view for explaining the manufacturing method of the present invention, FIG. 3 is a cross-sectional view of a conventional semiconductor device, and FIG. FIG. 2 is a process cross-sectional view for explaining a conventional manufacturing method. In the figure, 1 is a silicon substrate, 2 is an insulating film, 3 is a lower layer wiring, 4a is a first interlayer insulation film, 4b is a second interlayer insulation film, and 5 is an upper layer wiring. Note that the same symbols in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] An interlayer insulating film is formed on a lower layer wiring arranged on a semiconductor substrate, and after selectively removing a convex portion of the interlayer insulating film at a portion intersecting with the lower layer wiring, an interlayer insulating film is deposited thereon. 1. A method for manufacturing a semiconductor device, comprising: flattening the surface of an interlayer insulating film by forming a multilayer wiring structure, and then forming an upper wiring layer thereon to form a multilayer wiring structure.