JPH01119028A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To allow patterns of submicron thick to be formed using an exposing technique with an ordinary light by patterning a material remaining in a sidewall of an intermediate layer as a mask. CONSTITUTION:Aluminum 2 is bonded to an oxide film 1 to cause an intermediate layer consisting of an oxide film 3 to grow. Such layer is etched with a photoresist 4 as a mask, the photoresist 4 being removed to cause a plasma nitride film 5 to grow on the entire surface of a wafer. When removing the oxide film 3 and the plasma nitride film by means of a reactive ion etching, the plasma nitride film 5 bonded to the side of the oxide film 3 remains due to anisotropy of the etching. The aluminum is etched with the remained nitride film 5 as a mask, an aluminum wiring of about 0.3mum wide save the mask being formed. A polysilicon wiring is also formed with an aluminum sidewall as a mask.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming a fine pattern.

[Conventional technology]

Conventionally, a common method for patterning a film to be processed is to form a desired pattern using a photoresist and remove the film to be processed using this as a mask.

FIG. 3 shows an example of patterning aluminum using a conventional manufacturing method. First, as shown in FIG. 3(a), aluminum 22 is deposited on an oxide film 21 by, for example, sputtering, and a desired pattern is formed using a photoresist 24. As shown in FIG.

Next, as shown in FIG. 3(b), using the 7-photoresist 24 as a mask, unnecessary parts of the aluminum are etched with reactive ion etchant.

Excluding 9 due to chingu. Finally, as shown in FIG. 3(C), the photoresist used as a mask is removed by oxygen plasma to complete the aluminum patterning.

[Problem that the invention seeks to solve]

In the conventional pattern forming method described above, the workpiece is processed according to the pattern of the photoresist as a mask, so the minimum width of the pattern is determined by the width of the photoresist. In the current photoresist exposure method using light, the minimum width is limited to about 1 μm, and it is difficult to form a submicron photoresist pattern. Therefore, there is a drawback that it is difficult to pattern a workpiece with a submicron width.

[Means for solving problems]

The method for forming a fine pattern of a semiconductor device according to the present invention includes a step of forming an insulating film or a conductive film only on the side wall of an intermediate layer on a film to be processed, and a step of forming an insulating film or a conductive film on the side wall of the intermediate layer.
and a step of removing the film to be processed by reactive ion etching using the remaining insulating film or conductive film as a mask.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing the manufacturing process of the first embodiment of the present invention.

First, as shown in FIG. 1(a), aluminum 2, which is a workpiece, is deposited on a base oxide film 1, and an intermediate oxide film 3 of about 500 OA is grown by, for example, the CVD method. Subsequently, a butter layer is formed using photoresist 4. Next, as shown in FIG. 1(b), using the photoresist 4 as a mask, the oxide film 3 as the intermediate layer is coated with, for example, CF4 + L.
Remove by reactive ion etching using gas. Next, as shown in FIG. 1(C), the photoresist 4 is removed by oxygen plasma and a plasma nitride film 5 is formed over the entire surface of the wafer.
t - for example, about 300 of.・After this, as shown in FIG. 1(d), the plasma nitride film grown on the rR film 3 and the aluminum 2 is removed by reactive ion etching using, for example, CF gas. At this time, due to the anisotropy of etching, the oxide film 3
The plasma nitride film 5 adhering to the side surface remains without being removed. Further, as shown in FIG. 1(e), the oxide film 3, which is the intermediate layer, is removed by, for example, buffered hydrofluoric acid. After that, as shown in FIG. 1(f), using the remaining plasma nitride film 5 as a mask, unnecessary parts of aluminum are coated with, for example, BCfls + CCQ.
, removed by reactive ion etching with gas.

Finally, as shown in FIG. 1(g), the plasma nitride film 5 used as a mask is removed using, for example, CF4+O gas plasma to form an aluminum wiring having a wiring width of about 0.3 μm.

FIG. 2 is a sectional view showing the manufacturing process of a second embodiment of the present invention. First, as shown in FIG. 2(a), a polysilicon 16, which is a workpiece, is deposited on a base oxide film 11, and an oxide film 13, which is an intermediate layer, is deposited to a thickness of about 500 OA by, for example, CVD.
Make it grow. Subsequently, a pattern is formed using photoresist 14. Next, as shown in FIG. 2(b), using the 7-otoresist 14 as a mask, the oxide film that is the intermediate layer is made of, for example, CF.
+H, removed by reactive ion etching with gas. Next, as shown in FIG. 2(C), the 7 photoresist 14 is removed using oxygen plasma, and the aluminum 1
2 is grown to about 200 OA by, for example, the CVD method.

After this, as shown in FIG. 2(d), for example, B Cft s +
Aluminum grown on oxide film 13 and polysilicon 16 is removed by reactive ion etching using CCu4 gas. At this time, the aluminum 12 on the side wall of the oxide film 13 remains. Furthermore, as shown in FIG. 2(e), the intermediate layer, ie, the phlegmatic film, is removed by, for example, buffing. After that, as shown in FIG. 2(f), using the remaining aluminum 12 as a mask, the unnecessary portions of polysilicon are coated with, for example, CCf1.
2F, removed by reactive ion etching with gas. Finally, as shown in Figure 2 (g), the aluminum used for the mask is removed using PHC liquid, and the wiring width is approximately 0.2μ.
m polysilicon interconnections are formed.

〔Effect of the invention〕

As explained above, the present invention performs patterning by using the material remaining on the sidewall of the intermediate layer as a mask.
Even if exposure technology using ordinary light is used, submicron patterns can be formed effectively. Furthermore, the finished width of the workpiece is determined by the thickness of the material grown on the intermediate layer, so dimensional reproducibility is also good.

[Brief explanation of the drawing]

FIGS. 1(a) to (g) are cross-sectional views showing the manufacturing process of the @1 embodiment of the present invention, and FIGS. 2(a) to (g) are sectional views of the second embodiment of the present invention.
3(a) to (C) are cross-sectional views showing the manufacturing process of the example of
) is a sectional view showing a conventional manufacturing method. 1.11,21... Oxide film, 2,12.22.
... Aluminum, 3.13 ... Oxidation M
, 4, 14° 24... Photoresist, 5...
...Plasma nitride film, 16...Polysilicon. Agent Patent Attorney Susumu Uchihara (C) (T) (D) Figure 1 [Q] <e) (
b) (f) IC)
(9) (Figure 2 (bi) (b) Figure 3

Claims (1)

[Claims] A process of forming an insulating film or a conductive film only on the sidewalls of the intermediate layer on the film to be processed, a process of removing the intermediate layer while leaving the insulating film or conductive film on the sidewalls, and a process of using the remaining insulating film or conductive film as a mask. 1. A method for manufacturing a semiconductor device, comprising the step of removing a film to be processed by reactive ion etching.