JPH04152655A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable the upper part of an opening to be bridged with a third conductive film close the opening without making the conductive film protrude much out of the opening by a method wherein a second conductive film is made to grow once, then an installing film is deposited, a second opening is provided above a first opening, and the third conductive film is made to grow. CONSTITUTION:A second insulating film 7 is formed on the whole surface, a second opening 8 equal to or smaller than a first opening 3 is provided to the second insulating film 7 through a photomask method and dry etching method so as to enable at least a first tungsten 6 to be partially exposed. A second tungsten 9 serving as a third conductive film 9 is selectively formed on the second opening 8 through a CVD method. A fourth conductive film 10 is formed so as to cover at least the second tungsten 9. By this setup, the second conductive film 6 is prevented from protruding much out of the opening, and the upper part of the second opening 8 is bridged with the third conductive film 9 to block the opening 8.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a method for manufacturing a semiconductor device.Conductor There is a method in which a conductive film is formed only in the small openings formed in the upper insulating film, and then tungsten is selectively formed in the openings using the CVD method. C for forming conductive films
Table For example, to prevent the conductor from being eroded by a reduction reaction when forming tungsten. To use the conductor where tungsten is difficult to grow. To use it as a seed for tungsten growth. During heat treatment after tungsten formation, tungsten and the conductor react. Problems that the invention aims to solve, such as when using a conductive film as a barrier layer to prevent Tungsten uses the conductive film as a seed to grow from the side walls of the opening, overflowing the opening, and growing outside the opening. Therefore, if tungsten is grown until the upper part of the opening is covered by tungsten, the tungsten may protrude from the opening in a large umbrella shape and short circuit with tungsten grown from an adjacent opening. The figure is a cross-sectional view showing a case where tungsten grown from adjacent openings are connected to each other. Tungsten is embedded through 24.

Furthermore, if the growth of tungsten is stopped before the upper part of the opening is filled with tungsten, it may be difficult to make contact with the upper part. An object of the present invention is to provide a method for manufacturing a semiconductor device that can be embedded in an opening without protruding outside. a step of forming an insulating film in the first insulating film, a step of providing a first opening in the first insulating film reaching the conductor by a photomask method and dry etching, and a step of forming a first conductor only in the first opening. a step of selectively forming a second conductive film in the first opening by a CVD method; and a step of forming a second conductive film in the first opening, and forming a second insulating film over the entire surface of the first insulating film, and exposing at least a portion of the second conductive film to the second insulating film over the first opening; a step of providing a second opening not larger than the first opening by a photomask method and dry etching; a step of forming a third conductive film in the second opening by a CVD method; and a step of forming a fourth conductive film so as to cover a part of the conductive film of No.3. A second opening is formed on the first opening to grow a third conductive film.By performing the opening formation and the conductive film growth process in two steps, the conductive film is Although the upper part of the opening can be bridged and closed with a third conductive film without protruding to the outside significantly, FIG. A more detailed explanation will be given below based on FIG. 1. First, in FIG. 1(a), a first insulating film 2 is formed on a conductor 1, and then the first insulating film 2 is formed by a photomask method and dry etching. It is also possible to provide a first opening 3 that reaches the conductor l.
Here, the conductor 1 is a silicon substrate, the first insulating film 2 is a 5iOa film, and in FIGS. After forming on the entire surface including the first conductive film 4, a resist 5 is applied, and then the resist in the area other than the first opening 3 is removed by, for example, dry etching. Po
Next, in FIG. 1(d), the first conductive film 4 in the area other than the first opening 3 is etched by dry etching, and then the first conductive film 4 is etched into the first opening 3. The remaining resist 5 is removed. Next, in FIG. 1(e), LCVD is performed.
The first tungsten 6, which will become the second conductive film, is selectively formed only in the first opening 3 by the method. The first insulating film 7 is formed by photomask method and dry etching.
A second opening 8 not larger than the first opening 3 is formed in the second insulating film 7 over the opening 3 of the second insulating film 7 so that at least a part of the first tungsten 6 is exposed. The insulating film 7 is, for example, a 5i02 film, and then in FIG.
Then, in FIG. 1(i), a fourth conductive film is formed to cover at least the second tungsten 9. At this time,
The fourth conductive film is, for example, WSix. In this embodiment, the second conductive film is WSix. Doped polyester which can be selectively grown by force exchange using tungsten as the third conductive film.
It goes without saying that aluminum or the like may be used (°C) According to the present invention, the first
After forming a conductive film, when forming a second conductive film in the opening using the CVD method, the second conductive film does not protrude significantly from the opening, and the third conductive film is formed on the top of the second opening.
The conductive film bridges and connects to close the opening.A good contact can be formed with the conductive film of the upper wiring without shorting with the adjacent contact, and its practical effect is large (℃

[Brief explanation of drawings]

FIG. 1 is a process sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 2 is a sectional view showing a conventional example. L 3...1st
4... First conductive IL 5... Resist, 6... First tungsten, 7... Second insulating air 8... Second opening 9 River 2nd Tungsten, 1o... Name of the fourth conductive film agent Patent attorney Akira Odori Two people Figure 3 Opening in calculation 1 ＼ Figure Stripe cause

Claims (1)

[Claims] a step of forming a first insulating film on the conductor; a step of providing the first insulating film with a first opening reaching the conductor by a photomask method and dry etching; and a step of forming the first opening. a step of selectively forming a second conductive film in the first opening by a CVD method; and a step of selectively forming a second conductive film in the first opening by a CVD method; forming a second insulating film on the first opening and the entire surface of the first insulating film; forming a second opening not larger than the first opening using a photomask method and dry etching so that a portion of the conductive film is exposed; and forming a third conductive film in the second opening using a CVD method. a fourth conductive film so as to cover a part of this third conductive film.
A method for manufacturing a semiconductor device, comprising: forming a conductive film.