JPS58116736A - Preparation of semiconductor device - Google Patents

Abstract

PURPOSE:To accurately form a micro-miniature pattern by forming a spacer film and gas shielding film on a semiconductor substrate, forming a film by patterning and by removing said film from the substrate through generation of gas from the spacer film. CONSTITUTION:A spacer film 2 which decomposes when gas is exhausted is formed on a semiconductor substrate 1 by a low temperature annealing. Then, a gas shielding film 3 which prevents transmission of gas is formed thereon. Next, the gas shielding film and spacer film 2 are patterned with a photo resist film 4 used as the mask and thereby a film 5 is formed on the entire part thereof. Thereafter, gas is generated from the spacer film 2 by the low temperature annealing and thereby the spacer film 2, gas shielding film formed thereon and the film 5 formed thereon are removed from the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a semiconductor device that includes a step of patterning a film by a lift-off method.

Traditionally, the material used to perform the lift-off method is photo-fluorescence.
A resist film is often used. That is, a patterned photoresist film is formed on a semiconductor substrate, a film is formed on it, the photoresist film is removed together with the film above it by dissolving it, and the film is patterned. That's what I do.

Incidentally, the vapor deposition method is often applied to form the film, but this requires heating, which has the disadvantage that the photoresist film is deformed by the heat, making it impossible to obtain a fine pattern.

The present invention provides a lift-off method that can reliably form fine patterns, although the number of steps is slightly increased compared to the case where a photoresist film is used, and makes it possible to easily manufacture high-density semiconductor devices. 69, which will be explained in detail below.

1 to 41 are cross-sectional views of a folding portion of a semiconductor device at key points in the process for explaining one embodiment of the present invention, and the following description will be made with reference to these figures.

Refer to Fig. 1 (1) The thickness is, for example, 1 to 2 [μm] on the semiconductor substrate 1.
A spacer film 2 made of a polyimide resin of about 30% is formed. A spin coating method can be applied to apply the polyimide resin.

Note that the spacer film 2 is not only made of polyimide resin, but also has a temperature of 4.
Any material can be used as long as it emits gas when heated to about 0 G (C) or higher and does not have a negative effect on the semiconductor device itself or the manufacturing process.

(2) A gas barrier film 3 made of recycled silicon is formed to a thickness of, for example, about 3,000 mm by, for example, chemical vapor deposition.

The gas barrier film 3 is not limited to silicon nitride, but may be replaced with a material that is dense and can block the permeation of the gas generated from the spacer film 2, and that does not adversely affect the semiconductor device itself or the manufacturing process. I can do it.

(3) Form a photoresist film 4 for performing photolithography.

Refer to FIG. 2 (4) Using the photoresist film 4 as a mask, the gas barrier film 3 and the spacer film 2 are patterned.

In this case, a dry etching method may be used to obtain a sharp pattern.

See Figure 3. (5) A coating 5 made of silicon dioxide, for example, by vapor deposition.
is formed to a thickness of, for example, about 5,000 to aooo [b].

At this time, the photo regimen 11 may be left as shown in the figure, or may be removed. Further, as the film 5, other than silicon dioxide, metals such as aluminum and various other materials can be used.

Refer to Figure 4 (6) Heat treatment is applied at a temperature of about 410 (C). Due to this, gas is generated from the spacer film 2 (made of polyimide wood). However, since this gas is suppressed by the gas barrier membrane 3, only a small amount of the gas emanates outward.

Therefore, a high gas pressure is applied to the spacer film 2, which eventually lifts itself up and peels off from the substrate 1. At this time, the gas barrier film 3, photoresist film 4, and film 5 thereon are also removed at the same time, and patterning is performed by the so-called lift-off method.

In the above embodiment, the temperature at which the silicon dioxide film 5 was formed by vapor deposition (or sputtering) was about 200 [C], and the polyimide resin spacer film 2 did not deform at a temperature below 410C (C'1). Lift-off patterning of a predetermined pattern is possible.Etching is not limited to dry etching, but can also rely on wet etching.In that case, side etching is unavoidable, but in practice This will hardly cause any inconvenience.This will be explained with reference to FIGS. 5 and 6.

Refer to the ms diagram (1) When wet etching is performed in the state shown in Figure 1 and the photoresist 4 used as a mask is removed, the spacer film 2 is patterned in a side-etched structure as seen in Figure 5. Ru.

Here, dry etching using CFa gas can be used as an etching method for the silicon nitride gas barrier film 3, and hydrazine can be used as an etching solution for the polyimide resin spacer film 2.

See FIG. 6 (2) The coating 5 is formed in the same manner as the process explained with reference to FIG.

(3) After this, patterning of the coating 5 is performed in the same manner as in the process explained with reference to FIG.

As can be seen from the above explanation, according to the present invention, a spacer film that degass and decomposes by low-temperature annealing at about 400 (C) or higher is formed on a semiconductor substrate, and a gas barrier film that prevents the permeation of the gas is formed on the spacer film. Since it is used as a material for the film to be lifted off, it can withstand the temperature required to form the film to be lifted off, and the photoresist is This method is effective in manufacturing high-density semiconductor devices because pattern deformation does not occur when the group is used as a chip-off material.

[Brief explanation of the drawing]

1 to 4 are cross-sectional views of main parts of a semiconductor device at key points in the process for explaining one embodiment of the present invention, and FIGS.
The figure is a sectional view of a main part of a semiconductor device at key points in the process for explaining another embodiment. In the figure, 1 is a substrate, 2 is a spacer film, 3 is a gas barrier film, 4 is a photoresist film, and 5 is a coating film. Patent Applicant: Fujitsu Ltd. Representative Patent Attorney Hisa Gobe Tamamushi (3 others) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A spacer film that is degassed and decomposed by low-temperature annealing is formed on the semiconductor substrate, and a gas barrier film that prevents the permeation of the gas is formed thereon, and then the gas barrier film and the spacer film are patterned. A step of forming a film on the entire surface and then performing the low temperature annealing to generate gas from the spacer film and removing the spacer film, the gas barrier film thereon, and the film thereon from the semiconductor substrate. A method of manufacturing a semiconductor device, comprising: