JPS6321855A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the difference of the thickness between the electrode wirings out of a contact hole and the film thereby to improve the uniformity of the film thickness of the electrode wirings by increasing the thicknesses of the wirings to become equal on the side and the bottom of the hole. CONSTITUTION:A contact hole 6b is formed in an insulating film 3 on a semiconductor substrate 1, and a first conductive material 4e is buried to cover it. Then, it is so etched as to allow a conductive material 4h to remain in the bottom of the hole 6b. Then, a second conductive material 4c is so buried as to cover the hole 6b, and etched to so form electrode wirings 4d as to increase the thickness of the film in the hole 6b. Thus, the difference of the thickness between electrode wirings 4i and electrode wirings 4c is reduced to improve the uniformity of the thickness of the film of the whole wirings 4d.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device that can improve the thickness of electrode wiring inside a contact hole.

[Prior Art] FIG. 8 is a diagram showing a schematic cross-sectional structure of a contact hole portion of a conventional semiconductor device.

In FIG. 8, a PSG film 3 grown by the CVD method is formed on a silicon substrate 1, and a contact hole 6 is formed by selectively removing the PSG film 3 using a photoresist film.
is formed. A metal aluminum film is grown by the Svanta method so as to cover this contact hole 6,
The electrode wiring 4 is formed by selectively removing the metal aluminum film using a photoresist film. Furthermore, a resist film 5 is formed thereon.

[Problems to be Solved by the Invention] In a conventional semiconductor device, when comparing the thickness of the electrode wiring 4a on the inner wall of the contact hole 6 with the thickness of the electrode wiring 4b outside the contact hole 6, Electrode wiring 4
The film thickness of a is significantly thinner. For this reason, when the current flowing through the electrode wiring 4 increases, electromigration causes wire breakage, resulting in problems such as a decrease in the reliability of the operation of the semiconductor device.

Therefore, a main object of the present invention is to provide a method of manufacturing a semiconductor device that can increase the thickness of electrode wiring inside a contact hole.

[Means for Solving the Problems] The present invention is a method for manufacturing a semiconductor device, in which in a first step, a contact hole is formed in an insulating film on a semiconductor substrate, and a first film is formed so as to cover the contact hole. embed conductive material. In a second step, the first conductive material is etched so as to remain only at the bottom of the contact hole, and in a third step, a second conductive material is buried to cover the contact hole. Then, in a fourth step, the first conductive material is etched to form electrode wiring so as to increase the film thickness inside the contact hole.

[Function] In the method for manufacturing a semiconductor device according to the present invention, the thickness of the electrode wiring on the side surface and the bottom surface of the contact hole is increased so that it is equal in thickness, so that the thickness of the electrode wiring outside the contact hole is equal to the thickness of the electrode wiring on the outside of the contact hole. The difference in thickness can be reduced, and the uniformity of the film thickness of the electrode wiring can be improved.

Embodiment of the Invention FIGS. 1 to 7 are cross-sectional views of a semiconductor device in each manufacturing process according to the invention.

First, as shown in FIG.
A PSG film 3 grown by the VD method is formed. Then, using a photoresist mask, the PSG film 3 is selectively removed to form a contact hole 6b. An aluminum film 4e is grown by sputtering on the PSG film 3 so as to cover this contact hole 6b. Furthermore, a resist film 5 is formed on the aluminum film 4e.

Next, as shown in FIG. 3, the resist film 5 is etched by an etch-back method to form a resist pattern 5a only in the contact hole 6b. Next, as shown in FIG. 4, using the resist pattern 5a as a mask, the aluminum film 4e is anisotropically etched to form an aluminum pattern 4f.
form.

Furthermore, as shown in FIG. 5, the resist pattern 5a is removed, and the protrusions 4g of the aluminum film 4e are removed by isotropic etching, resulting in an aluminum pattern 4h as shown in FIG.
is formed only at the bottom of contact hole 6b. Furthermore, as shown in FIG. 7, an aluminum film 4C is formed on the PSG film 3 and the aluminum pattern 4h by sputtering,
By selectively removing the aluminum film 4c using a photoresist mask, an electrode wiring 4d as shown in FIG. 1 is formed.

As mentioned above, since the aluminum pattern 4h is buried in the bottom of the contact hole 6b in advance, the film thickness of the electrode wiring 41 inside the contact hole 6b becomes thicker in FIG. 1, and the film thickness of the electrode wiring 4c outside the contact hole 6b increases. The difference in film thickness between the electrode wirings 4a and 4b shown in FIG. 8 described above is smaller than that between the electrode wirings 4a and 4b, and the uniformity of the film thickness of the entire electrode wiring is improved.

In addition, in the above-mentioned embodiment, a case was explained in which metal aluminum was used as a conductive material and an electrode wiring material to fill the contact hole 6b. It can also be used as a wiring material, and the same effect can be achieved for increasing the thickness of the electrode wiring inside the contact hole 6b.

[Effects of the Invention] As described above, according to the present invention, since the conductive material is buried in the bottom of the contact hole in advance and the electrode wiring is formed thereon, the film thickness of the electrode wiring inside the contact hole is reduced. This makes it possible to reduce the difference in the film thickness of the electrode wiring inside and outside the contact hole, reducing the number of locally thin areas of the electrode wiring, and reducing the reliability of semiconductor device operation due to disconnection of the electrode wiring due to electromigration, etc. It can prevent sexual deterioration.

[Brief explanation of the drawing]

1 to 7 are cross-sectional views of a semiconductor device in each manufacturing process according to the present invention. FIG. 8 is a sectional view of a conventional semiconductor device. In the figure, 1 is a silicon substrate, 2 is polysilicon, and 3 is a silicon substrate.
4 is a PSG film, 4 is an aluminum wiring, 4d is an electrode wiring, 4e is an aluminum film, 4f and 4h are aluminum patterns, 5 is a resist film, and 6b is a contact hole.

Claims (4)

[Claims] (1) A method for manufacturing a semiconductor device, comprising: forming a contact hole in an insulating film on a semiconductor substrate; and filling the contact hole with a first conductive material so as to cover the contact hole. a second step of etching so that the conductive material remains only at the bottom; a third step of burying a second conductive material so as to cover the contact hole; and a third step of etching the first conductive material. A method of manufacturing a semiconductor device, comprising a fourth step of forming an electrode wiring so as to increase the film thickness inside the contact hole. (2) The first step includes forming a resist film on the first conductive material, and the second step includes etching so that the resist film remains only in the contact hole. After that, using the remaining resist film as a mask, etching is performed so that the first conductive material remains only at the bottom of the contact hole, and removing the resist film left after the etching. A method for manufacturing a semiconductor device according to claim 1. (3) The method for manufacturing a semiconductor device according to claim 1 or 2, wherein the first conductive material is aluminum, aluminum alloy, or metal silicide. (4) The method for manufacturing a semiconductor device according to claim 1, wherein the second conductive material is one of aluminum, aluminum alloy, and metal silicide.