JP2768139B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device used in a process for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In recent years, miniaturization has been increasingly required as semiconductor devices become more highly integrated. A lithography process is one of the main processes for miniaturization of semiconductor devices. In the conventional lithography process, light having a wavelength such as g-line or i-line has been used. A chemically amplified resist is used as a resist material. A chemically amplified resist generally comprises two or three components, and a positive resist comprises a polymer which is insoluble in a developer and an acid generator which generates an acid by a photoreaction. When the positive resist is irradiated with light, an acid is generated from the acid generator. This acid reacts with the functional group of the side chain of the polymer, which makes the polymer insoluble in the developer, and changes into a soluble functional group, and the polymer, that is, the resist becomes soluble.

Hereinafter, an example of a method for manufacturing the above-described conventional semiconductor device will be described with reference to the drawings.

FIG. 2 shows a process chart of a conventional method for manufacturing a semiconductor device. In FIG. 2, reference numeral 1 denotes a semiconductor substrate. Reference numeral 2 denotes a chemically amplified positive resist. Reference numeral 3 denotes a mask, and reference numeral 4 denotes ultraviolet light for exposure.

[0005] A method of manufacturing the semiconductor device configured as described above will be described. First, in FIG.
Then, a chemically amplified positive resist 2 is applied. Then Figure 2
2B, exposure is performed using the mask 3. FIG. In FIG. 2 (c), 5 is an exposed portion where the resist becomes soluble in a developing solution, and a pattern can be formed by performing development in FIG. 2 (d).

[0006]

However, in the above configuration, the resolution of the minimum dimension that can be exposed in the lithography process is represented by R = kλ / NA. Here, k is a constant of about 0.4, λ is an exposure wavelength, and NA is a lens numerical aperture of about 0.4. Therefore, since the wavelength is 248 nm when a KrF excimer laser is used, the minimum dimension is limited to about 0.25 μm. In the case of exposing a dimension equivalent to the exposure wavelength, there is a problem that pattern dependence is remarkably exhibited due to a standing wave effect, and it is difficult to obtain a desired dimension.

The present invention has been made in view of the above problems, and provides a method of manufacturing a semiconductor device in which a pattern is formed using an excimer laser and a chemically amplified resist.

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a semiconductor device according to the present invention comprises a step of coating a semiconductor substrate with a chemically amplified positive resist, a step of exposing, and subsequently, in an acidic atmosphere. It has a processing step and a developing step thereafter.

[0009]

According to the present invention, an acid is selectively dissolved in a portion which has been made soluble by exposure by performing a treatment for a predetermined time in an acidic atmosphere after exposure according to the above structure, and the acid reacts with an unexposed portion, The soluble portion is widened and the resist pattern dimension can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor device according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a process chart of a method of manufacturing a semiconductor device according to an embodiment of the present invention. In FIG.
Reference numeral 1 denotes a silicon substrate, 2 denotes a chemically amplified positive resist, 3 denotes a mask, 4 denotes light having a wavelength of 248 nm, 5 denotes a portion rendered soluble by exposure, and 6 denotes an acidic atmosphere.

A method for manufacturing the semiconductor device configured as described above will be described below with reference to FIG.

First, in FIG. 1A, a chemically amplified positive resist of 1.0 μm is applied on a silicon substrate by spin coating. FIG. 1B shows the wavelength of a KrF excimer laser using a mask 3.
Exposure at 248 nm. FIG. 1 (c) shows a state where the resist is exposed to form a soluble portion 5 according to FIG. 1 (b). FIG.
(D) is maintained in a closed container in an acidic atmosphere 6 after exposure. This treatment shows that the acid selectively dissolves in the portion rendered soluble by exposure, and further reacts with the unexposed portion to change the soluble portion 5. FIG.
(E) is a view after heat treatment after exposure and development with a TMAH aqueous solution. As described above, according to the present embodiment, after exposure, by performing treatment in an acidic atmosphere for a predetermined time, the acid is selectively dissolved in the portion that became soluble by the exposure, and the acid reacts with the unexposed portion. However, the soluble portion is widened and the resist pattern dimension can be reduced.

The acid concentration in the acidic atmosphere is 1 ng / l to 100
The reaction is preferably controlled to about 0 ng / l depending on the retention time and concentration.

If the atmosphere after the exposure contains 1 ng / l or more of an acidic or alkaline gas as an impurity, a desired shape may not be obtained. In order to reduce the amount of impurities to 1 ng / l or less, it can be kept in a high-purity gas or air from which impurities have been removed.

In the embodiment, 1 is a chemically amplified positive resist, but 1 may be a chemically amplified negative resist by treating in an alkaline atmosphere.

[0017]

As described above, according to the present invention, the step of exposing using a chemically amplified positive resist and the subsequent processing in an acidic or alkaline atmosphere make it possible to obtain a resist having a limit of 0.25 μm or less in the conventional excimer laser exposure. A pattern can be formed.

[Brief description of the drawings]

FIG. 1 is a process chart in a first embodiment of the present invention.

FIG. 2 is a process chart of a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 chemically amplified positive resist 3 mask 4 light 5 soluble part 6 acidic atmosphere

Claims (1)

(57) [Claims] 1. A method of manufacturing a semiconductor device, comprising: a step of coating a semiconductor substrate with a chemically amplified positive resist, a step of exposing, a step of subsequently treating in an acidic atmosphere, and a step of subsequent development.