JPH021125A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make a contact window between aluminum wiring parts unnecessary by a method wherein a protrusion is formed under a first aluminum wiring part and the first aluminum wiring part upheaved by this protrusion is brought into contact with a second aluminum wiring part. CONSTITUTION:A silicon nitride film is dry-etched; a protrusion 13' is formed; a first aluminum film is evaporated; a first aluminum wiring part pattern 15, is formed; a silicon oxide film 16 is grown; a photoresist 19 is coated. Then, the photoresist 19 and the silicon oxide film 16 are dry-etched; the first aluminum wiring part 15' on the protrusion 13' is exposed; a second aluminum film 17 is evaporated; a photoresist mask 18 for a second aluminum wiring part pattern is formed. Then, the second aluminum film 17 is dry-etched; the second aluminum wiring part pattern is formed. Thereby, a first aluminum wiring part can be connected to a second aluminum wiring part without forming a contact window.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention lifts the first aluminum wiring using a protrusion and makes contact with the second aluminum wiring, thereby eliminating the need for a contact window between the aluminum wirings and at the same time reducing the level difference in the contact portion. The present invention relates to a method for manufacturing a semiconductor device that provides a flat two-layer wiring structure with no flat wiring structure.

BACKGROUND OF THE INVENTION In recent years, many MO8 type integrated circuits have two-layer aluminum wiring due to demands for improved performance.

Conventionally, a contact window is opened in the insulating film on the first aluminum wiring, and then a second aluminum wiring is formed.
A layered aluminum wiring structure was obtained.

FIGS. 2(a) to 2(d) are process flow charts showing a conventional example.

First, as shown in FIG. 2(a), a first aluminum wiring pattern 3 is formed on an insulating film 2 grown on a semiconductor substrate 1. After this, as shown in FIG. 2(b), an insulating film 4 is deposited, a contact window is opened by dry etching using the photoresist 5 as a mask, and then the photoresist 5 is removed. As shown in Figure 2 (C),
A second aluminum film 6 is deposited. Next, the second aluminum film 6 is etched using the photoresist 7 as a mask to form a second aluminum wiring pattern as shown in FIG. 2(d).

Problems to be Solved by the Invention In the above-mentioned two-layer aluminum wiring technology, there is a possibility that the second aluminum wiring may break at the step of the contact window, and furthermore, the step of the contact window requires consideration of three or more layers of aluminum wiring. It becomes a problem if

The present invention solves such problems by providing a protrusion under the first aluminum wiring and bringing the first aluminum wiring lifted up by the protrusion into contact with the second aluminum wiring, thereby making it possible to connect the aluminum wiring. The present invention provides a method for manufacturing a semiconductor device that eliminates the need for a contact window and at the same time achieves a flat two-layer aluminum wiring structure.

Means for Solving the Problems A method for manufacturing a semiconductor device according to the present invention to solve the above problems includes the steps of forming a first insulating film on a semiconductor substrate, and then growing a second insulating film or a conductive film. , etching the second insulating film or the conductive film using a photoresist as a mask to provide insulating protrusions at predetermined locations;
depositing a first aluminum film on the entire surface, then using a photoresist as a mask to form a first aluminum wiring pattern having the protrusions on the wiring; growing a third insulating film to be thicker than at least the height of the protrusions; Next, a step of applying a photoresist, dry etching the photoresist and a third insulating film at the same speed to expose at least the first aluminum film on the protrusion, and depositing a second aluminum film, This process consists of a step of forming a second aluminum wiring pattern to be connected to the first aluminum film on the protrusion using a photoresist as a mask.

According to this method of manufacturing a semiconductor device, since the first aluminum wiring lifted by the protrusion contacts the second aluminum wiring in the inter-wiring contact in the two-layer aluminum wiring, there is no need to form an inter-wiring contact window. A flat two-layer aluminum wiring structure without a step in the contact window portion can be achieved.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIGS. 1(a) to 1(f) are process flow charts showing one embodiment of the present invention.

First, as shown in FIG. 1(a), silicon oxide 11112 is formed on a semiconductor substrate 11, a silicon nitride film 13 is grown to a thickness of about 800 mm, and then a photoresist 14 is formed at a predetermined location.

Next, as shown in FIG. 1(b), the silicon nitride film 13
A protrusion 13° is formed by dry etching, and then a first aluminum film 15 is deposited at a power of about 500W. At this time, it is desirable that the protrusion 13' has a tapered shape.

Next, as shown in FIG. 1(C), a first aluminum wiring pattern 15' is formed using a photoresist mask and dry etching, and a silicon oxide film 16 is further deposited at 9.
00 nm, and then photoresist 19 is applied.

Next, as shown in FIG. 1(d), photoresist 1
9 and the silicon oxide film 16 are dry-etched under conditions such that the etching rate is the same.
The aluminum wiring 15' is exposed.

Next, as shown in FIG. 1(e), a second aluminum film 17 of about 700+ nm is deposited to form a photoresist mask 18 of a second aluminum wiring pattern.

Next, the second aluminum film 17 is dry etched to form a second aluminum wiring pattern 17'.

In the above embodiment, the protrusion 13'' is formed of an insulating silicon nitride film, but it may be formed of conductive polysilicon or aluminum.

Effects of the Invention As described above, according to the method of manufacturing a semiconductor device of the present invention,
To achieve a flat two-layer aluminum wiring structure in which a first aluminum wiring and a second aluminum wiring can be connected without forming a contact window between the two-layer aluminum wiring, and which does not have a step in a contact part. I can do it.

[Brief explanation of the drawing]

FIGS. 1(a) to (f) are process flowcharts showing an embodiment of the present invention, and FIGS. 2(a) to (d) are process flowcharts showing a conventional example. 1.11... Semiconductor substrate, 2... First
Insulating film, 3.15.15'...First aluminum film, 4...Second insulating film, 5.7, 14, 18
, 19... Photoresist, 6, 17.17'
...Second fulminium membrane, 12.16...
...Silicon oxide film, 13.13'...Silicon nitride film. Name of agent Patent attorney Toshio Nakao One idiot Figure 1 Figure 1

Claims (1)

[Claims] A step of forming a first insulating film on a semiconductor substrate and then growing a second insulating film or a conductive film, and etching the second insulating film or conductive film using a photoresist as a mask to form an insulating layer at predetermined locations. a step of depositing a first aluminum film over the entire surface, and then using a photoresist as a mask to form a first aluminum wiring pattern having the projections on the wiring; and a step of depositing a third insulating film on at least the projections. , and then applying a photoresist, and dry etching the photoresist and the third insulating film at the same etching rate to expose at least the first aluminum film on the protrusion. and depositing a second aluminum film,
A method for manufacturing a semiconductor device, comprising the step of forming a second aluminum wiring pattern in contact with the first aluminum film on the protrusion using a photoresist as a mask.