JPH0626203B2 - Micro processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a fine processing method for forming a fine pattern on a material to be processed by using an organic material film mask, and is used in, for example, a semiconductor device manufacturing technical field. it can.

[Conventional technology]

In manufacturing a semiconductor device, a resist (hereinafter, photoresist, electron beam resist or X-ray resist is generically referred to as resist) is used to process a material (material) on a substrate by a so-called photoengraving technique. Fine etching processing is performed on the film.

However, with this simple method, when there is a step on the underlying substrate, there is a difference in the film thickness of the resist above and below the step, and it is difficult to perform fine processing with similar accuracy above and below the step.

2A to 2F are cross-sectional views showing the states at the main stages of the conventional three-layer resist process in which the above-mentioned points are improved. First, as shown in FIG. 2A, an organic material film (3) such as a photoresist is formed on the film (2) to be processed on the substrate (1).
After coating and baking to flatten the surface with steps, an intermediate film (4) such as silicon oxide (SiO ₂ ) is formed,
Further, a resist film (5) such as a photoresist is applied and formed thereon, and after baking, as shown in FIG. 2B,
A fine resist pattern (5a) is formed by exposing and developing the resist film (5). Next, the second
As shown in FIG. C, the intermediate film (4a) is etched by using the resist pattern (5a) as a mask to etch the intermediate film (4a).
After forming the pattern, as shown in FIG.
The organic material film (3) is anisotropically etched by oxygen (O ₂ ) plasma using (5a) and (4a) as a mask to form an organic material film pattern (3a). Next, as shown in FIG. 2E, using the fine pattern composed of the three-layer patterns (5a), (4a), and (3a) formed as described above as a mask, the film to be processed (2) is etched. After obtaining the desired fine pattern (2a), the resist pattern (5a), the intermediate film pattern (4a) and the organic material film pattern (3a) are removed as shown in FIG. 2F.
The process is completed by removing (3a).

[Problems to be solved by the invention]

In addition to the large number of steps, the conventional method has a difficulty in removing the intermediate film pattern (4a) at the stage of FIG. 2F. That is, the above-mentioned SiO ₂ film or aluminum (Al) was used as the intermediate film (4).
In the case of O ₂ film, hydrofluoric acid (HF), in the case of Al film, phosphoric acid (H ₃ P
O ₃ ) Aqueous solution is used, but these solutions attack the target fine pattern (2a) consisting of the film material to be processed and deteriorate the pattern accuracy or damage the substrate (1). There was a point.

The present invention has been made to solve such a problem, and an object thereof is to provide a microfabrication method in which the number of steps is small and an accurate micropattern can be obtained without damaging a base substrate. There is.

[Means for solving problems]

The microfabrication method according to the present invention includes (a) a step of forming an organic material film on a film to be processed provided on a substrate, and (b) forming an inorganic material film having a required pattern on the organic material film. Process,
(c) A first etching step of partially removing the organic material film by a gas plasma containing oxygen as a main component using the inorganic material film as a mask, and (d) subsequent to the step (c), oxygen is added. A second etching step of simultaneously removing the rest of the partially etched portion of the organic material film and the inorganic material film by a mixed gas plasma with a halogen compound, and (e) remaining in the step (d) And a third etching step of removing the film to be processed using the organic material film as a mask.

[Action]

According to the present invention, in forming the organic material film pattern that serves as a mask for etching the film to be processed, the first etching of the organic material film is performed by the second etching by the mixed gas plasma of oxygen and a halogen compound. Since the remaining part of the part etched by the etching and the inorganic material film are removed at the same time, it is possible to eliminate the special step of removing the inorganic material film pattern and the troubles associated therewith.

〔Example〕

1A to 1D are sectional views showing a state in a main stage of an embodiment of the present invention. First, as shown in FIG. 1A, an organic material film (3) such as photoresist or polyimide resin is formed on the film (2) to be processed on the substrate (1) to a thickness of about 1 to 3 μm by using a spinner or the like. The coating is formed to a thickness and baked to flatten the surface having steps. Next, as shown in FIG. 1B, an inorganic material film having a required pattern such as an amorphous silicon film is formed by a chemical vapor deposition reaction using light.
(6) is locally formed at a required site to a thickness of about 500 to 2000Å. After that, as shown in FIG. 1C, the inorganic material film (6)
Etching is applied to the organic material film (3) by using oxygen (O ₂ ) gas plasma as a mask under the conditions of gas pressure: 5 Pa and high frequency power: 500 W, and then about 3/4 of the film thickness is etched. O ₂
By etching the remaining organic material film (3) under the conditions of gas thickness: 3 Pa and high frequency power: 300 W with a mixed gas of 5 mol% of carbon tetrafluoride (CF ₄ ), The non-material film (6) can also be removed at the same time. In this way, the organic material film pattern (3a) is obtained, and then the film to be processed (2) is etched using the organic material film pattern (3a) as a mask, and then the organic material film is formed by oxygen plasma. Pattern (3
By removing a), a desired fine pattern (2a) is obtained as shown in FIG. 1D.

In the above example, the chemical vapor deposition reaction using light was used to locally form the inorganic material film, but in addition to this, the ion beam or the electron beam is selectively irradiated. Alternatively, a method of locally causing a chemical reaction may be used.

〔The invention's effect〕

As described above, in the method of the present invention, not only the number of steps is small, but the inorganic material film pattern is formed on the organic material film for the surface flattening of the film to be processed, and the inorganic material film is used as a mask. The first etching step of removing the organic material film halfway by the gas plasma containing oxygen as a main component, and subsequently, the organic material film is partially etched by the mixed gas plasma of oxygen and a halogen compound. Since the second etching step for simultaneously removing the remaining portion and the inorganic material film is performed, the inorganic material film pattern mask remains, and the formation pattern expected to occur when removing this is removed. Problems such as deterioration of accuracy and damage to the underlying substrate can be avoided, and accurate fine processing is possible.

[Brief description of drawings]

FIG. 1 is a sectional view showing a state at a main stage of an embodiment of the present invention, and FIG. 2 is a sectional view showing a state at a main stage of a conventional fine processing method. In the figure, (1) is a substrate, (2) is a film to be processed, (3) is an organic material film, (3a) is an organic material film pattern, and (6) is an inorganic material film. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A process of forming an organic material film on a film to be processed provided on a substrate, and a process of forming an inorganic material film having a required pattern on the organic material film. c) a first etching step of partially removing the organic material film by gas plasma containing oxygen as a main component using the inorganic material film as a mask; and (d) subsequent to the step (c), oxygen and halogen. A second etching step of simultaneously removing the remaining part of the organic material film that has been partially etched and the inorganic material film by a mixed gas plasma with a compound, and (e) the above-mentioned remaining step (d) And a third etching step of removing the film to be processed using the organic material film as a mask. 2. The microfabrication method according to claim 1, wherein a chemical vapor deposition method utilizing light is used to form the inorganic material film in the step (b).