JPH022200A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent shortcircuit of adjacent separate patterns when forming the patterns on a two-layer film pattern through an insulating film by providing a mask material to a side section of an upper layer film and then by etching a lower film using the upper layer film and the mask material as a mask. CONSTITUTION:A lower layer film A is etched using an upper layer film B and a photoresist film 10 as a mask, and then the film 10 is eliminated. In this case, a hydrofluoric acid etchant is used and the film B is prevented from overhanging the film A through this etching. A two-layer film pattern 15 is constituted by the film A and the film B. Then an insulating film C of silicon oxide is formed through heat oxidation. A polysilicon film D is formed all over and a specified area of the film D is removed by etching. As shown in a cross section (a-b), the film B has no overhanging are and, therefore, the film D does not remain below an overhanging section. Adjacent separate patterns 21, 22... do not shortcircuit thus improving product reliability.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for manufacturing a semiconductor device having a structure in which another pattern is formed on a two-layer film pattern via an insulating film, when forming a two-layer film pattern, an upper layer pattern is formed on a lower layer. Form it so that it does not overhang the pattern,
In order to prevent short circuits between adjacent patterns and to form fine patterns, the upper layer film is patterned after forming the lower layer film and the upper layer film on the substrate. and a step of etching the lower FBH'A using the upper 1i911Q and the mask material as an etching mask.

[Industrial application field]

The present invention relates to a manufacturing method for an I'-conductor device having a structure in which another pattern is formed on a two-layer film pattern via an insulating film.

With the recent development of ICs, multilayer wiring having the above structure is often used. In this case, as shown in FIG. 5, another pattern 2 is placed on top of the two-layer film pattern 1 via an insulating film.
It has a membrane structure that intersects +, 22, .

When manufacturing a semiconductor device with such a structure, if the two-layer film pattern is not formed correctly, problems such as sheeting of different patterns may occur in the subsequent patterning process. It is necessary to form the pattern correctly.

[Conventional technology]

FIG. 6 shows a process diagram of an example of a conventional manufacturing method.

Note that the a=b cross section shown in the same figure is the a-b cross section shown in FIG.
A cross-sectional view taken along line c-d is a cross-sectional view taken along line c-d shown in FIG. In FIG. 6(A), the substrate 3
A lower layer film A' of silicon oxide, a soil layer film B' of polysilicon, and a photoresist II on top! I4 is formed in this order, and films A' and B' are successively etched using film 4 as a mask, or Fi14 is etched after film B' is etched.
is removed and film A' is etched using film B' as a mask. As a result, a two-layer film pattern of ' and WAB' is formed on the film. In this case, if hydrofluoric acid-based wet etching or dry etching with side etching is performed, this etching will result in 11.
The side portion of 1JA recedes, and film B' overhangs film A'.

Next, as shown in FIG. 6(B), an insulating film C' of silicon oxide is formed by thermal oxidation or the like. Next, Figure 6 (C
), a polysilicon film D' is formed on the entire surface,
Predetermined portions of the film D' are removed by etching to form other patterns 2+, 22, . . . shown in FIG. In this case, since the film B' has an overhang part, as shown in FIG.
As shown in the cross section a-b of C), a film remains under the overhang portion of the film B', although the film D' is unnecessary in this part.

[Problem to be solved by the invention]

As described above, since the film D' remains under the overhang portion of the film B', the adjacent patterns 2+ and 22.

(FIG. 5) A short circuit occurs between the two through the remaining film D', resulting in a problem that the product lacks reliability.

On the other hand, a method of over-etching so that the film D' does not remain under the overhanging portion of the film B' can be considered, but since this method involves side etching, it is necessary to form the width of the film D' wide in advance. There was a problem that fine patterns could not be formed.

In the present invention, when forming a two-layer film pattern, the upper layer pattern is formed so as not to overhang the lower layer pattern, so that adjacent patterns are separated from each other.
It is an object of the present invention to provide a method for manufacturing a semiconductor device that can prevent defects and form fine patterns.

[Means to solve the problem]

FIG. 1 shows a diagram of the principle of the present invention. The above problem is that the substrate 1
After forming the lower layer A and the upper layer 111B on 1, the upper layer W
A step of buttering AB, a step of forming a mask material 10 on the side portion of the upper layer glB after the buttering, and etching the lower layer giA using the upper layer B and the mask material 10 after the buttering as an etching mask. The problem is solved by a method of manufacturing a semiconductor device characterized by including steps.

[Effect]

When forming a two-layer film pattern consisting of film A and film B, NI
A mask material 10 is provided on the side portion of B and then etched. For this mask material 10, the upper layer Igi! B does not overhang the upper layer Δ, and therefore, when forming another pattern on this two-layer film pattern via a broken film, there is no film between WAB and film A. There will be no residue left behind. Therefore, there is no need for a process such as overetching to avoid leaving a film.

〔Example〕

FIG. 2 shows the steps of one embodiment of the present invention. Note that the -b cross section and the c-d cross section shown in the figure correspond to the cross-sectional view explained in FIG. 6. As a method for forming the photoresist film 10 on the side portion of the film B shown in FIG. 2(A), there are a method shown in FIG. 3 and a method shown in FIG.

In FIG. 3 (A>), a lower layer film A of silicon oxide, an upper layer film B of polysilicon, and a photoresist film 12 are formed in this order on a substrate 11, and only the film B is etched using the film 12 as a mask. 12. Next, in Figure 3 (
In B), membrane A.

A low viscosity photoresist film (positive resist gil>13) is applied on top of 1111B and baked, and then, as shown in FIG. , MA, Ig!B
The resist film remaining on each flat part of
Obtain the structure shown in A).

On the other hand, in the method shown in FIG. 4, the step shown in FIG. 4(A) is the same as the step shown in FIG. 3(A), and then the step shown in FIG.
) in - membrane A, l! A photoresist film (
A body resist 1-111) 14 is applied, and the entire surface is exposed in FIG. 4(C). In this case, the exposure level is set to 4 so that only a thin portion of the film 14 other than the side portions of the film B is exposed. After completing this exposure and developing, the image shown in Fig. 4 (D
), the film 14 remains on the side part of 1lAB, which is the thick part of the film 14, and the structure shown in FIG.
I can do that.

Now, returning to FIG. 2, in FIG. 2(A), the film Δ is etched using the film B and the film 10 as masks, and the film 10 is removed. In this case, a hydrofluoric acid-based T-etch solution is used to etch the film to 1ill utl so that the film B does not overhang the film A due to this etching. In the present invention, since the film 10 is provided on the side portion of the film B, it is easy to control the film B so that it does not overhang the film A. Two-layer film pattern 15 with film A and film B
is configured.

Next, in FIG. 2C, an insulating film C of silicon oxide is formed by thermal oxidation. Subsequently, as shown in FIG. 2(D), a polysilicon film is formed on the entire surface, and another pattern 2+, 22 shown in FIG. 5 is formed.

. . . A predetermined portion of l1iD is removed by etching. In this case, as is clear from the a-b cross section, the film B
Since there is no overhanging part, there is no film left under the overhanging part as in the conventional example.
As a result, adjacent patterns 2+, 22 . ...
(Membrane D) is not short-circuited as in the conventional example, and can improve the reliability of the product.

In addition, the present invention does not require overetching to avoid leaving a film under the overhang portion as in the conventional example, and as a result, unlike the conventional example, the widths of the films A and B can be made wider in advance. It is not necessary to form the pattern in advance, and the pattern can be formed finer than in the conventional example.

〔Effect of the invention〕

As explained above, according to the present invention, after the mask material is provided on the side portion of the upper layer film, the lower layer film is etched using the upper layer film and the mask material as a mask, so that the upper layer film overhangs the lower layer film. This will not result in
When forming another pattern on this 2 HIIA t< turn via an insulating film, the film of the different pattern will not remain between the lower layer film and the upper layer film, and adjacent different patterns will short-circuit. There isn't. In addition, there is a concern about over-etching to avoid leaving another pattern film, and there is no need to form the upper and lower layers wider in advance, so compared to the conventional example. can form fine patterns.

[Brief explanation of the drawing]

FIG. 1 is an original diagram of the present invention, FIG. 2 is a process diagram of an embodiment of the present invention, FIGS. 3 and 4 are process diagrams of each embodiment of forming a photoresist film in the present invention, and FIG. The figure is a plan view of a case in which another pattern is provided across a two-layer film pattern, and FIG. 6 is a conventional process diagram. In the figure, A is the lower layer film of the two-layer film pattern, B is the upper layer film of the two-layer film pattern, C is the insulating film, D is the film of another pattern, 10° 12° 13° 14 is the photoresist film, 1 is the substrate , 5 indicates a two-layer pattern.

Claims (1)

[Claims] A step of forming a lower layer film (A) and an upper layer film (B) on a substrate (11), and then patterning the upper layer film (B); and a step of patterning the upper layer film (B) after the patterning. A step of forming a mask material (10) on the side portion, and an upper layer film (B) after the patterning and the mask material (10).
) as an etching mask to etch the lower layer film (A).