JPH02106972A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a wiring material (such as aluminum) easily onto polycrystalline silicon, and to lower resistance value by growing a nitride film onto polycrystalline silicon and selectively oxidizing the whole. CONSTITUTION:An oxide film 2 is grown onto a silicon substrate 1, polycrystalline silicon 3 is grown onto the oxide film 2, and a nitride film 4 is grown. The polycrystalline silicon 3 and the nitride film 4 are patterned simultaneously and oxidized selectively. The nitride film 4 is removed, and aluminum 6 grown and patterned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming gate electrodes and wiring using polycrystalline silicon.

[Conventional technology]

Conventionally, when forming gate electrodes and wiring using polycrystalline silicon in a semiconductor device, after growing the polycrystalline silicon, doping the polycrystalline silicon with impurities to lower the resistance value, and then patterning. A method of forming gate electrodes and wiring was used.

FIGS. 3A to 3C are cross-sectional views showing a conventional polycrystalline silicon wiring formation method in order of steps.

First, as shown in FIG. 3(a), an oxide film 2 is formed on a silicon substrate 1, and then polycrystalline silicon 3 is grown.
Doping with impurities. After that, a resist mask 8 is applied.

Next, as shown in FIG. 3(b), the resist mask 8 is patterned, and the polycrystalline silicon 3 is etched using the resist mask 8 as a mask material.

Next, as shown in FIG. 3(C), the patterned resist mask 8 is removed and wiring of polycrystalline silicon 3 is formed.

[Problem to be solved by the invention]

The conventional polycrystalline silicon gate electrode and wiring forming method described above has the disadvantage that the resistance of polycrystalline silicon is high and the switching of the device is slow.

As a countermeasure to this problem, multilayering of wiring can be considered, but this has the disadvantage that the number of PRs increases by two and the process becomes complicated.

[Means to solve the problem]

The method for forming polycrystalline silicon gate electrodes and wiring according to the present invention includes a step of growing polycrystalline silicon, a step of growing a nitride film thereon, a step of simultaneously patterning the polycrystalline silicon and the nitride film, and a subsequent step. , after performing selective oxidation, there is a step of removing the nitride film, and then a step of growing and patterning a wiring material (aluminum, etc.).

In the present invention, a nitride film is formed on polycrystalline silicon, and the polycrystalline silicon and nitride film are simultaneously patterned. after that,
By selectively oxidizing and removing the nitride film, growing a wiring material (aluminum, etc.), and patterning it, a low-resistance gate electrode and wiring can be formed by increasing the number of PRs by one time.

〔Example〕

The present invention will be explained with reference to the drawings. Figure 1 (a
) to (d) are sectional views shown in the order of steps to explain one embodiment of the present invention.

First, as shown in FIG. 1(a), on a silicon substrate 1,
An oxide film 2 is grown, a polycrystalline silicon 3 is grown thereon, and a nitride film 4 is grown thereon. Next, as shown in Figure 1(b),
Patterning polycrystalline silicon 3 and nitride film 4 simultaneously,
After that, selective oxidation is performed.

Next, as shown in FIG. 1(c), after removing the nitride film 4, aluminum 6 is grown. Next, as shown in FIG. 1(d), the aluminum 6 is patterned.

FIGS. 2(a) to 2(e) are sectional views of other embodiments of the present invention. This example relates to a method for forming a polycrystalline silicon gate electrode in an MO8 structure, and includes the same steps as in FIG. 1.

In this embodiment, first, as shown in FIG. 2(a), an oxide film 2. Polycrystalline silicon 3. Nitride films 4 are sequentially formed. Next, as shown in Figure 2(b),
Nitride film 4. Polycrystalline silicon 3 is formed into a predetermined shape, and diffusion layers 7 that will become source/drain regions are formed on both sides of polycrystalline silicon 3. Next, as shown in FIG. 2(c), a selective oxide film 5 is formed on the diffusion layer γ. Then the second
As shown in FIG. 2(d), aluminum 6 is formed, and as shown in FIG. 2(e), aluminum 6 is formed into a predetermined shape.

According to this embodiment, there is an advantage that the resistance value of the gate electrode can be lowered.

〔Effect of the invention〕

As explained above, in the present invention, by growing a nitride film on polycrystalline silicon and performing selective oxidation, a wiring material (aluminum, etc.) can be easily formed on polycrystalline silicon, and the resistance value can be lowered. be able to.

[Brief explanation of drawings]

Figures 1 (a:) to (d) and Figures 2 (a) to (e) are cross-sectional views shown in the order of steps for explaining one embodiment and another embodiment of the present invention, respectively. Figures 3 (a) to (c) are
FIG. 3 is a cross-sectional view showing the steps in order to explain a conventional method. 1... Silicon substrate, 2... Oxide film,
3... Polycrystalline silicon, 4... Nitride film, 5... Selective oxide film, 6... Aluminum,
7... Diffusion layer, 8... Resist. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] forming a polycrystalline silicon layer on a semiconductor substrate; forming a silicon nitride film on the polycrystalline silicon layer;
a step of forming the silicon nitride film in a predetermined shape; a step of selectively removing the polycrystalline silicon layer using the silicon nitride film formed in the predetermined shape as a mask; and a step of forming the silicon nitride film in the predetermined shape. a step of performing selective oxidation using the silicon nitride film formed in the predetermined shape as a mask; and a step of selectively forming a metal film on the polycrystalline silicon layer after removing the silicon nitride film formed in the predetermined shape. A method for manufacturing a semiconductor device characterized by