JPH0247852A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the reliability by forming a conductive film projection and an interlayer insulating film made of a material different from a first wiring at the part, where a concrete hole is formed, of said wiring, flattening the surface and exposing the projection at the same time, forming a second wiring thereon, and conductively connecting the second wiring with the first wiring. CONSTITUTION:A tungsten film 104 is formed on a silicon oxide film 102 including a first wiring composed of an aluminum-silicon alloy film 103 on a semiconductor substrate 101, and then photoetching is performed except for only the part which becomes a contact hole. A silicon oxide film 105 as an interlayer insulating film is formed. A photoresistor 106 is applied by rotation and the surface is flattened. Etching is performed until the silicon oxide film 105 on the tungsten film 104 is completely eliminated to expose the tungsten film 104. And then second wiring composed of an aluminum-silicon alloy 107 is formed and connected with the first wiring. This improves the yield and the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for interconnecting wiring layers in a semiconductor device having multilayer wiring.

[Prior Art] In a conventional method for manufacturing a semiconductor device, as shown in FIG. Figure 2 (
As shown in b), the insulating film 2 between the eyebrows is formed by photo-etching.
04, and finally, as shown in Fig. 2 (C
)like.

Forming the second metal wiring 205 and forming the first metal wiring 203
and the second metal interconnect, 111205, were to be electrically connected to each other. At this time, contact holes are generally etched by dry etching, and wiring metal is formed by sputtering.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, as the pattern becomes finer, the coverage of the wiring metal in the contact hole portion becomes poor, and in the worst case, the second There were cases where the metal wiring was disconnected. Furthermore, the difference in level caused by the unevenness of the surface of the glabellar insulating film also becomes steep, and the second wiring metal may be disconnected at this portion, or conversely, a short circuit may occur between adjacent wirings.

The present invention is intended to solve these problems, and its purpose is to fill the contact hole with a conductor to prevent the wiring from breaking in this area, and to flatten the surface of the insulating film between the eyebrows. An object of the present invention is to provide a method for manufacturing a semiconductor device that prevents disconnections and short circuits in wiring caused by unevenness on the surface of an insulating film between the eyebrows.

[Means for Solving the Problems] The present invention provides a conductive wire made of a material different from the material constituting the first wire, on a first wire formed on a first insulating film above a semiconductor substrate. The process of forming a film.

A step of forming a protrusion made of the conductive film in a portion designed to become a contact hole by photo-etching.

forming a second insulating film over the entire surface of the first insulating film including the first wiring and the protrusion made of the conductive film;

A step of forming a film on the second insulating film so that its surface is flat, thicker in the convex portions and thinner in the concave portions.

Etching the coating film and the second insulating film at the same etching rate to expose protrusions made of the conductive film.

forming a second wiring so as to be electrically connected to the first wiring via the protrusion made of the conductive film;

It is characterized by being more.

[Example] Process cross-sectional views in Examples of the present invention are shown in Figures 1(a) to 1(a).
It is shown in (f) and will be explained in detail below in order of steps.

First, as shown in FIG. 1(a), a semiconductor substrate 101
Aluminum-silicon alloy film 103 formed above
A tungsten film 104 is formed entirely on the silicon oxide film 102 including the first wiring. At this time, the thickness of the aluminum-silicon alloy film is 8000 mm, and the thickness of the tungsten film is 8000 mm.

Next, as shown in FIG. 1(b), by photo-etching, the tungsten film 104 is left only in the part that conducts with the second wiring, that is, in the part that will become the contact hole, and the other tungsten film 104 is Remove. At this time, etching was performed by dry etching, and the conditions were as follows: CF4 = 50 sec, 6P
a. At 500W.

Under these conditions, tungsten is easily etched, but the underlying aluminum-silicon alloy j'1103
And the silicon oxide film 102 is not etched.

Next, as shown in FIG. 1C, a silicon oxide film 105 is formed by 7000 layers as an interlayer insulating film by chemical vapor deposition.

Next, as shown in FIG. 1(d), a photoresist 106 is spin-coated on the silicon oxide film 1.5. At this time, the photoresist is formed thinly on the convex portions and thickly on the concave portions, so that the surface thereof is flat.

Next, as shown in FIG. 1(e), the photoresist 106 and the silicon oxide film 11105 are continuously etched under etching conditions such that the etching rates of the photoresist 106 and the silicon oxide film 105 are equal, and the tungsten film 104 is etched continuously. Etching is performed until the upper silicon oxide film 105 is completely removed and the tungsten film 104 is exposed. The etching conditions at this time are CF4=30SCCm, 0
2:20 sec m, 6 P a, 80
It was 0W.

Finally, as shown in FIG. 1(f), a second wiring made of aluminum-silicon alloy 106 is formed, and the first wiring and second wiring are electrically connected.

[Effects of the Invention] As described above, according to the present invention, a protrusion of a conductive film made of a material different from that of the first wiring is formed in a portion of the first wiring designed to be a contact hole. After this, an insulating film between the eyebrows is formed.

After flattening the surface using an etch-back method and exposing the protrusion, a second wiring is formed on this, and the first wiring and the second wiring are electrically connected through this protrusion. By letting them.

Disconnection at the connection between the first wiring and the second wiring.

It also has the effect of preventing disconnections and short circuits in the second wiring caused by steep irregularities on the surface of the interlayer insulating film, and as a result, it has become possible to manufacture highly reliable semiconductor devices with high yield.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(f) are process cross-sectional views showing two methods of manufacturing a semiconductor device according to the present invention. FIGS. 2(a) to 2(c) are process cross-sectional views showing a conventional method for manufacturing a semiconductor device. 101.201 102, 202 103, 203 104°105, 204 106°107, 205 Semiconductor substrate silicon oxide film (insulating film) Aluminum-silicon alloy (first wiring) Tungsten silicon oxide film (interlayer insulating film) Photoresist aluminum・Silicon alloy (second wiring) o3 10oy

Claims (1)

[Claims] A step of forming a conductive film made of a material different from a material constituting the first wiring on a first wiring formed on a first insulating film above a semiconductor substrate; - forming a protrusion made of the conductive film in a portion designed to become a contact hole by etching; a step of forming a second insulating film on the second insulating film, a step of forming a film thickly on the convex parts and thinly on the concave parts so that the surface thereof is flat; etching the insulating films at the same etching rate to expose the protrusions made of the conductive film; forming a second wiring so as to be electrically connected to the first wiring via the protrusions made of the conductive film; A method for manufacturing a semiconductor device, comprising: a step of forming it.