JPH0621053A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a reduction in a thickness of a high melting point metal film in a contact hole by etching back. CONSTITUTION:A tungsten film 7 provided on a surface including a contact hole is etched back with an adhesive film 6 as an etching stopper, buried in the hole, then an aluminum film 8 is deposited, and the films 8 and 6 are sequentially etched to form wirings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device.

[0002]

2. Description of the Related Art A conventional semiconductor device manufacturing method is as follows.
As shown in FIG. 2A, the N-type diffusion layer is aligned with the gate electrode 3 provided on the element formation region partitioned by the field oxide film 2 selectively provided on one main surface of the P-type silicon substrate 1. 4 is formed, and an interlayer insulating film 5 is formed on the surface including the gate electrode 3.
And a contact hole is formed. Next, an adhesion film 6 made of a titanium film and a titanium nitride film and a tungsten film 7 are sequentially deposited on the surface including the contact hole, and the tungsten film 7 is etched back by dry etching with SF ₆ gas to be embedded in the contact hole. After that, the adhesive film 6 is removed by dry etching with Cl ₂ gas using the tungsten film 7 as a mask.

Next, as shown in FIG. 2B, an adhesive film 10 made of a titanium film and a titanium nitride film is deposited by sputtering, and then an aluminum film 8 and a titanium nitride film 9 are deposited and patterned to form wiring. Was.

[0004]

In this conventional method of manufacturing a semiconductor device, when the adhesive film and the tungsten film provided on the surface including the contact holes are etched back, first the SF film is formed.
_Since the tungsten film was etched back using a gas such as ₆ to leave the tungsten film only in the contact holes, and then the adhesive film was etched back using Cl ₂ gas, the tungsten film was contacted by etching the adhesive film. There is a problem that the tungsten film that should be left in the hole is further etched, resulting in contact failure and poor flatness.

[0005]

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming a contact hole in an interlayer insulating film provided on a semiconductor substrate, and an adhesion for improving adhesion on a surface including the contact hole. A step of sequentially depositing a film and a refractory metal film, a step of etching back the refractory metal film by using the adhesive film as an etching stopper and filling the contact hole, and a metal film on the surface including the refractory metal film. Is deposited and patterned to form a wiring electrically connected to the refractory metal film.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

1A to 1C are cross-sectional views of a semiconductor chip showing the order of steps for explaining a manufacturing method according to an embodiment of the present invention.

First, as shown in FIG. 1A, an element formation region is partitioned by a field oxide film 2 selectively formed on one main surface of a P-type silicon substrate 1, and the element formation region is provided on this element formation region. The N-type diffusion layer 4 is formed in alignment with the gate electrode 3. Next, an interlayer insulating film 5 is deposited on the surface including the gate electrode 3 and selectively anisotropically etched to form a contact hole to expose the surface of the N-type diffusion layer 4. Next, a thickness of 1 is formed on the surface of the interlayer insulating film 5 including the contact holes by the sputtering method.
A titanium film having a thickness of 0 to 200 nm and a titanium nitride film having a thickness of 10 to 200 nm are sequentially deposited to form an adhesive film 6, and a tungsten film 7 is formed on the surface of the adhesive film 6 by a CVD method in an amount of 0.1 to 1 μm.
Deposit to a thickness of m.

Next, as shown in FIG. 1B, the tungsten film 7 is etched back by anisotropic dry etching using SF ₆ gas until the surface of the adhesive film 6 is just exposed. The tungsten film 7 is buried in the. Here, the etching rate of the tungsten film 7 is 30
The etching rate of the adhesive film 6 is less than 0.1 nm / min for 0 to 800 nm / min, and the adhesive film 6 is hardly etched.

Next, as shown in FIG. 1C, an aluminum film 8 is deposited on the surface including the buried tungsten film 6 by a sputtering method, and a titanium nitride film 9 is formed as an antireflection film for alignment exposure. 50 to 200 nm by sputtering method
And the titanium nitride film 9, the aluminum film 8 and the adhesive film 6 are selectively and sequentially etched to form an electrode wiring electrically connected to the N-type diffusion layer 4 through the tungsten film 6.

A TiW film having a thickness of about 150 nm may be used as the adhesive film 6, which has an advantage that an abnormal reaction with the tungsten film 7 is unlikely to occur.

[0012]

As described above, according to the present invention, in the etching back for forming the tungsten film to be buried in the contact hole, only the tungsten film is etched back without etching the adhesive film. There is an effect that the reduction of the tungsten film inside the contact hole can be suppressed, contact failure with the aluminum film can be prevented, and the flatness of the wiring can be improved.

[Brief description of drawings]

1A to 1C are cross-sectional views of a semiconductor chip, which are shown in the order of steps for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a semiconductor chip showing the order of steps for explaining a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 1 P-type silicon substrate 2 Field oxide film 3 Gate electrode 4 N-type diffusion layer 5 Interlayer insulating film 6, 10 Adhesive film 7 Tungsten film 8 Aluminum film 9 Titanium nitride film

Claims (1)

[Claims] 1. A step of forming a contact hole in an interlayer insulating film provided on a semiconductor substrate, a step of sequentially depositing an adhesive film and a refractory metal film for improving adhesion on a surface including the contact hole, A step of etching back the refractory metal film by using the adhesive film as an etching stopper and burying it in the contact hole, and depositing and patterning a metal film on the surface including the refractory metal film to electrically connect the refractory metal film And a step of forming a wiring connected to the semiconductor device.