JP3031287B2 - Anti-reflective coating material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for an anti-reflection film, and more particularly to a method for exposing a chemically amplified resist formed on a semiconductor substrate through a mask or reticle on which a desired semiconductor integrated circuit pattern is drawn, thereby forming a PEB. The present invention relates to a base anti-reflective coating material used for forming a photoresist pattern by developing using a developing solution after processing.

[0002]

2. Description of the Related Art In conventional photolithography, g-line (436 nm) and i-line (365 nm) are used as exposure light. As a resist, a novolak resin is used as a base resin, and naphthoquinone diazide is used as a photosensitizer. The mainstream was a dissolution-suppressing positive-type resist that used a resist.

However, with recent miniaturization of semiconductor devices, lithography using excimer laser light (248 nm, 193 nm, etc.), which is far ultraviolet light, which is advantageous for further miniaturization, is required. G
In the case of a resist for line and i-line, the light absorption was too large, a good resist pattern could not be obtained, and the sensitivity was greatly increased.

[0004] In order to solve such a problem, a chemically amplified resist utilizing a sensitization reaction of an acid catalyst generated from a photoacid generator has been devised, and a resist for short wavelength lithography and an electron beam requiring high sensitivity have been developed. It is becoming mainstream as a resist for lithography. This chemically amplified resist (chemic
ally amplified resist) contains an acid generator as a photosensitizing agent in the resist, and the acid generated by exposure induces a catalytic reaction in a subsequent heat treatment (post-exposure bake; PEB) to make it insoluble in a developer ( This is a resist that promotes negative (negative) or solubilization (positive).

[0005] A feature of the chemically amplified resist is that a resin having a very high transparency is used, whereby the influence of the reflected light from the underlying substrate is reduced by the conventional g-line and i-line resists. The size of the lithography used,
The need to use anti-reflective coatings (ARCs) has increased.

As an anti-reflection film, an organic anti-reflection film composed of a crosslinking agent and a solvent has been used in conventional g-line and i-line lithography, but this is continuously used in KrF excimer laser lithography. Have been.

The acidity of the organic antireflection film is not controlled, and when used as a base for a chemically amplified resist, the chemically amplified resist is positive and the acidity of the antireflection film is low. When the acidity of the resist is high, constriction occurs in the resist pattern 503 as shown in FIG. 2, and when the acidity of the resist is low, the bottom of the resist pattern 603 is formed as shown in FIG. Pull occurs,
There was a problem.

As a method for solving this problem,
Conventionally, several methods have been proposed, for example, a method of adding an acid or a base to a chemically amplified resist itself is known (for example, see Japanese Patent Application Laid-Open No. 7-72628).

[0009]

However, according to the above-mentioned conventional method of adding an acid or a base to the chemically amplified resist itself, the resist pattern can be prevented from being narrowed or skirted on the antireflection film, but the resist is not developed. The steepness of the steepest part of the exposure characteristic dependence of the dissolution characteristic in the liquid, particularly the dissolution characteristic that most affects the resolution, is reduced.

[0010] This corresponds to the degradation of resolution.
This means that not only the original resist performance cannot be exerted, but also that there is a problem that the dimensional accuracy is deteriorated as the dissolution contrast is lowered.

In particular, for the formation of a fine pattern, the deterioration of the resolution and dimensional accuracy of the photoresist pattern caused by such deterioration of the dissolution rate characteristics is fatal.

As described above, it is necessary to improve the antireflection film material itself.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an anti-reflection method for eliminating constriction and tailing of a resist pattern on an anti-reflection film peculiar to a chemically amplified resist. It is to provide a film material.

Further, the present invention achieves the above object, and can obtain a rectangular resist pattern, improves resolution and dimensional accuracy, and enables high integration of a device pattern. It is intended to provide.

[0015]

In order to achieve the above object, an antireflection coating material of the present invention is provided under a chemically amplified resist.
Used to form an anti-reflective coating on the ground, at least a crosslinking agent,
And anti-reflection film material containing a solvent, said chemical amplification
Acidity at the interface between the resist and the antireflection coating
So that the acidity of the chemically amplified resist is
Depending on the anti-reflective acid compound or basic compound
It is characterized by being added to a film material .

[0016]

Embodiments of the present invention will be described below. In a preferred embodiment, the antireflection coating material of the present invention is obtained by adding an acidic compound or a basic compound, or both to an antireflection coating material containing at least a crosslinking agent and a solvent.

As described above, in the embodiment of the present invention, an acidic compound or a basic compound or both of them are used for an antireflection film material comprising a cross-linking agent and a solvent. By adding the acid according to the acidity, that is, the acidity of the acid generated from the photoacid generator, it is possible to prevent the resist pattern from becoming narrow and having a skirted shape. This is because the acidity becomes almost the same at the interface between the resist film and the antireflection film, and the deprotection reaction of the positive resist does not proceed at the interface between the resist film and the antireflection film.

Further, since the resist composition is not forced to change the composition excessively, as a result, the gradient of the dissolution characteristic which most affects the resolution of the resist can be kept large, and the resolution can be increased.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the drawings in order to explain the present invention more concretely. In one embodiment of the present invention, the anti-reflective coating material comprises a crosslinking agent (hexamethoxymethylmelamine) and a solvent (Propylene) as shown below.
Glycol Monomethyl Ether Acetate, Propylene glycol monomethyl ether acetate; PGME
A).

[0020]

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To this, benzenesulfonic acid represented by the following chemical formula 2 is added.

[0022]

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For example, when a two-component chemically amplified resist composed of a polyhydroxystyrene resin having a t-BOC (t-butoxycarbonyl) group as a protecting group and a photoacid generator is used, benzenesulfonic acid is used as a protective agent. By adding 5% by weight of the crosslinking agent, a rectangular resist pattern 303 can be obtained as shown in FIG.

This is because the acidity becomes almost the same at the interface between the resist film and the antireflection film, and the deprotection reaction of the positive resist does not proceed at the interface between the resist film and the antireflection film. .

The same effect can be obtained with a negative resist, but in this case, the crosslinking reaction of the negative resist does not proceed at the interface between the resist film and the antireflection film.

Examples of the base to be added include N-methylpyrrolidone represented by the following chemical formula 3.

[0027]

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Depending on the type of the resist, the acidity of the antireflection film is high, and the resist pattern is constricted. In such a case, a rectangular resist pattern can be obtained by adding a basic compound.

Regardless of whether an acidic compound or a basic compound is added, the kind and amount of the resist material used on the anti-reflection film, especially the kind and amount of addition, are appropriately adjusted according to the acidity of the acid generated from the photoacid generator. You need to choose. In either case, the amount of addition is desirably about 1 to 10% by weight relative to the crosslinking agent.

As described above, according to the present embodiment, a rectangular resist pattern can be obtained, so that dimensional accuracy can be improved. Specifically, both resolution and dimensional accuracy are 10
% Or more.

In the present invention, the kind of the compound to be added may be acidic or basic in the antireflection film, and is not limited to those shown in the above chemical formulas 2 and 3. Absent.

[0032]

As described above, according to the antireflection coating material of the present invention, the resist pattern of the chemically amplified resist used thereon is prevented from being narrowed and skirted, and the original resolution of the resist is prevented. That can demonstrate
This has the effect.

According to the present invention, the resist pattern shape on the antireflection film can be controlled and the resolution can be improved by appropriately selecting the type and amount of the acid and base to be added. Can be.

Further, according to the present invention, since a rectangular resist pattern is obtained, there is an effect that resolution and dimensional accuracy can be improved. In particular, the effect is great for forming a fine pattern, and a rectangular photoresist pattern can be formed with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a pattern cross-sectional view of one embodiment of a chemically amplified positive resist formed on an antireflection film of the present invention.

FIG. 2 is a pattern sectional view of a chemically amplified positive resist formed on a conventional antireflection film.

FIG. 3 is a pattern sectional view of a chemically amplified positive resist formed on a conventional antireflection film.

[Explanation of symbols]

301, 501, 601 Wafer 302 Anti-reflective coating 502, 602 Conventional anti-reflective coating 303, 503, 603 Chemical amplification type positive resist pattern

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/11 G03F 7/004 G03F 7/039 G03F 7/26 H01L 21/027

Claims (4)

(57) [Claims] 1. The shape of an anti-reflection film underlying a chemically amplified resist
Used in the formation, at least an anti-reflective coating material containing a crosslinking agent and a solvent , at the interface between the chemically amplified resist and the anti-reflective coating.
In order to make the acidity of both the same,
Depending on the acidity of the strike, acidic or basic compounds
An antireflection film material, which is added to the antireflection film material. 2. An anti-reflective coating material according to claim 1, wherein the amount of said acidic compound or basic compound to be added is 1 to 10% by weight relative to a crosslinking agent. 3. The anti-reflective coating material according to claim 1 or 2,
There are, this addition of benzenesulfonic acid as the acidic compound
An anti-reflective coating material characterized by the following . 4. The anti-reflection coating material according to claim 1 or 2
And N-methylpyrrolidone was added as the basic compound.
An anti-reflection film material characterized by the above-mentioned.