JP2002093682A - Pattern-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the shape of a resist pattern by increasing the thickness of a sylilation layer formed at the exposed part of a resist film. SOLUTION: After pattern exposure is carried out, by irradiating the resist film 11 made of positive chemical amplification type resist with an energy beam via a photomask, the resist film 11 is heated. Then the resist film 11 is developed with an alkaline developer, to form a thin film part 11c at the exposed part 11a of the resist film 11 and then a sylilation process 14 is carried out for the resist film 11 to form a sylilation layer 15 at the thin film part 11c of the resist film 11. The resist film 11 is dry-etched through the sylilation layer 15 as a mask, to form a resist pattern 11A of the thin film part 11c of the resist film 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pattern forming method used in a semiconductor process.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor process, a resist pattern is formed by photolithography using ultraviolet rays. With the miniaturization of semiconductor elements, use of a short-wavelength light source as exposure light has been studied.

When a short wavelength light source is used as exposure light,
In recent years, in order to increase the depth of focus or improve the resolution, development of a surface resolution process using dry development has been advanced.

[0004] As a surface resolution process, Proc. SPIE, V
As shown in olume 3333, p. 188 (1998), a negative silylation process using a positive chemically amplified resist has been proposed. This surface resolving process is to remove the protecting group from the polymer of the chemically amplified resist by the catalytic action of the acid generated from the acid generator in the exposed part of the resist film, and then to silylate the resist film. Then, a silylated layer is formed on the surface of the exposed portion, and then the resist film is dry-etched using the silylated layer as a mask to form a resist pattern formed of the exposed portion of the resist film.

Hereinafter, a conventional surface resolution process will be described.
This will be described with reference to FIGS.

First, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxystyrene) [base polymer] 10 g diphenyl disulfone [acid generator] 0.3 g diglyme [ Solvent] 40g 40g

[0008] Next, as shown in FIG.
After the above-mentioned chemically amplified resist was applied thereon, a pre-bake was performed at a temperature of 90 ° C. for 60 seconds to obtain a 0.4 μm
Is formed.

Next, as shown in FIG. 10B, pattern exposure was performed by irradiating the resist film 2 with an ArF excimer laser beam 4 through a photomask 3 on which a desired pattern was drawn. Thereafter, as shown in FIG.
A heat treatment is performed at a temperature of 0 ° C. for 90 seconds to cause a catalytic reaction of the acid generated from the acid generator in the exposed portion 2 a of the resist film 2, so that the protecting group (t) is removed from the base polymer.
-Butyl group). In this case, since the acid is not generated from the acid generator in the unexposed portion 2b of the resist film 2, the protecting group is not eliminated from the base polymer.

[0010] Next, as shown in FIG. 10 (d), the resist film 2 is subjected to a gas-phase silylation treatment 6 using dimethylsilyldimethylamine, and silicon is introduced into the exposed portion 2 a of the resist film 2 so as to be silyl. An oxide layer 6 is formed.

Next, as shown in FIG. 10 (e), the O ₂ and S
An ICP plasma etching 7 using O ₂ as a main gas is performed to form a resist pattern 2A including an exposed portion 2a of the resist film 2.

[0012]

However, FIG.
As shown in (e), the resist pattern 2A becomes a defective pattern whose shape has been lost.

The reason for the formation of the defective pattern is that the protective group was not sufficiently removed at the exposed portion 2a of the resist film 2 and thus the silylation process was performed to form the silylated layer 6. It is probable that the silylation layer 6 did not withstand plasma etching because the silylation reaction did not proceed sufficiently, the thickness of the silylation layer 6 was small, and the silicon content in the silylation layer 6 was small.

The occurrence of such a defective pattern is a very serious problem that leads to a cause of a defect in a later process and, consequently, to a reduction in the yield of semiconductor device production.

In view of the foregoing, it is an object of the present invention to increase the thickness of a silylated layer formed on an exposed portion of a resist film to improve the shape of a resist pattern.

[0016]

A first pattern forming method according to the present invention comprises a step of forming a resist film made of a positive type chemically amplified resist and a step of forming a resist film through a mask having a desired pattern shape. Performing a pattern exposure by irradiating an energy beam, and then heating the resist film, and developing the resist film with an alkaline developer to form a thin film portion on the exposed portion of the resist film, Performing a silylation process on the resist film to form a silylated layer on the thin film portion of the resist film; and performing dry etching on the resist film using the silylated layer as a mask to form a resist comprising the thin film portion of the resist film. Forming a pattern.

According to the first pattern forming method, the resist film is developed with an alkaline developing solution,
Since a thin film portion is formed on the exposed portion of the resist film, the polar component increases on the surface of the thin film portion, so that the silylation reaction proceeds sufficiently. For this reason, in the thin film portion of the resist film, a thick silicide layer having a large silicon content is formed, so that in the step of performing dry etching on the resist film using the silyl layer as a mask, The silylation layer is less likely to be damaged, whereby a resist pattern having a good cross-sectional shape can be obtained.

A second pattern forming method according to the present invention comprises:
After forming a resist film made of a positive chemically amplified resist containing an acid and irradiating the resist film with an energy beam through a mask having a desired pattern shape, pattern exposure is performed, and then the resist film is heated. The process of
Performing a silylation process on the resist film to form a silylated layer on the exposed portion of the resist film; and performing dry etching on the resist film using the silylated layer as a mask to form a resist comprising the exposed portion of the resist film. Forming a pattern.

According to the second pattern forming method, since the resist film contains an acid, the polar component increases on the surface of the resist film, so that the silylation reaction proceeds sufficiently.
For this reason, in the exposed portion of the resist film, a silylated layer having a large thickness and a large silicon content is formed,
In the step of performing dry etching on the resist film using the silylated layer as a mask, the silylated layer is less likely to be damaged, whereby a resist pattern having a good cross-sectional shape can be obtained.

A third pattern forming method according to the present invention comprises:
Positive-type chemistry comprising a first acid generator that generates a first acid that removes a protecting group of the base polymer and a second acid generator that generates a second acid that does not remove a protecting group. Forming a resist film composed of an amplification type resist, irradiating the resist film with an energy beam through a mask having a desired pattern shape, performing pattern exposure, and then heating the resist film; Performing a silylation process to form a silylated layer on the exposed portion of the resist film, and performing dry etching on the resist film using the silylated layer as a mask to form a resist pattern including the exposed portion of the resist film And a step of performing

According to the third pattern forming method, since the resist film contains the second acid generator for generating the second acid which does not remove the protecting group, the resist film is formed by the second acid. Since the polar component is increased in the exposed area, the silylation reaction proceeds sufficiently. Therefore, in the exposed portion of the resist film, a silylated layer having a large thickness and a large silicon content is formed in the exposed portion of the resist film. In the step of performing dry etching on the resist film using the silylated layer as a mask,
The silylation layer is less likely to be damaged, whereby a resist pattern having a good cross-sectional shape can be obtained.

According to a fourth pattern forming method of the present invention,
After forming a resist film made of a positive chemically amplified resist containing a compound having an OH group, and performing pattern exposure by irradiating the resist film with an energy beam through a mask having a desired pattern shape, Heating the resist film, performing a silylation process on the resist film, forming a silylated layer on the exposed portion of the resist film, and performing dry etching on the resist film using the silylated layer as a mask, Forming a resist pattern composed of exposed portions of the resist film.

According to the fourth pattern formation method, since the resist film contains a compound containing an OH group, the polar component increases on the surface of the resist film, so that the silylation reaction proceeds sufficiently. For this reason, since a silylated layer having a large thickness and a large silicon content is formed on the surface of the exposed portion of the resist film, a dry etching is performed on the resist film using the silylated layer as a mask. In this case, the silylated layer is less likely to be damaged, whereby a resist pattern having a good cross-sectional shape can be obtained.

According to a fifth pattern forming method of the present invention,
After forming a resist film made of a positive chemically amplified resist containing a polymer having an OH group, and performing pattern exposure by irradiating the resist film with an energy beam through a mask having a desired pattern shape, Heating the resist film, performing a silylation process on the resist film, forming a silylated layer on the exposed portion of the resist film, and performing dry etching on the resist film using the silylated layer as a mask, Forming a resist pattern composed of exposed portions of the resist film.

According to the fifth pattern forming method, the resist film contains a polymer containing an OH group, and the polar component increases on the surface of the resist film, so that the silylation reaction proceeds sufficiently. For this reason, since a silylated layer having a large thickness and a large silicon content is formed on the surface of the exposed portion of the resist film, a dry etching is performed on the resist film using the silylated layer as a mask. In this case, the silylated layer is less likely to be damaged, whereby a resist pattern having a good cross-sectional shape can be obtained.

According to a sixth pattern forming method of the present invention,
Forming a resist film made of a positive chemically amplified resist on the organic film, and irradiating the resist film with an energy beam through a mask having a desired pattern shape to perform pattern exposure; Heating the film, developing the resist film with an alkaline developer to form a thin film portion on the exposed portion of the resist film, and performing a silylation treatment on the resist film to form a thin film portion on the resist film. Forming a silylated layer on the resist film and an organic film by dry-etching the resist film and the organic film using the silylated layer as a mask, and a resist pattern comprising a thin film portion of the resist film and an organic film pattern comprising an organic film. Forming a two-layered mask pattern.

According to the sixth pattern forming method, as in the first pattern forming method, a thick silylated layer having a large silicon content is formed in the thin film portion of the resist film. Further, in the step of performing plasma etching on the organic film using the silylated layer as a mask, the silylated layer is less likely to be damaged, so that a two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern consisting of a resist pattern composed of a thin film portion of the resist film and an organic film pattern is formed, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved. .

A seventh pattern forming method according to the present invention comprises:
A step of forming a resist film made of a positive chemically amplified resist containing an acid on the organic film, and pattern exposure was performed by irradiating the resist film with an energy beam through a mask having a desired pattern shape. Thereafter, a step of heating the resist film, and a silylation process is performed on the resist film,
A step of forming a silylated layer on the exposed portion of the resist film, and performing dry etching on the resist film and the organic film using the silylated layer as a mask, and forming a resist pattern comprising the exposed portion of the resist film and an organic film comprising Forming a two-layer mask pattern composed of a film pattern.

According to the seventh pattern forming method, as in the second pattern forming method, a silylated layer having a large thickness and a large silicon content is formed in the exposed portion of the resist film. In the step of performing plasma etching on the film and the organic film using the silylated layer as a mask, the silylated layer is less likely to be damaged, so that a two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern consisting of a resist pattern composed of exposed portions of the resist film and an organic film pattern is formed, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved. .

An eighth pattern forming method according to the present invention comprises:
A first acid generator that generates a first acid that releases a protective group of the base polymer, and a second acid generator that generates a second acid that does not release a protective group on the organic film. Forming a resist film made of a positive chemically amplified resist including: and performing pattern exposure by irradiating the resist film with an energy beam through a mask having a desired pattern shape, and then heating the resist film. Performing a silylation process on the resist film, forming a silylated layer on the exposed portion of the resist film, and performing dry etching on the resist film and the organic film using the silylated layer as a mask,
Forming a two-layer mask pattern including a resist pattern composed of an exposed portion of the resist film and an organic film pattern composed of an organic film.

According to the eighth pattern forming method, as in the third pattern forming method, a silylated layer having a large thickness and a high silicon content is formed in the exposed portion of the resist film. In the step of performing plasma etching on the film and the organic film using the silylated layer as a mask, the silylated layer is less likely to be damaged, so that a two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern consisting of a resist pattern composed of exposed portions of the resist film and an organic film pattern is formed, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved. .

According to a ninth pattern forming method of the present invention,
Forming a resist film made of a positive chemically amplified resist containing a compound having an OH group on the organic film, and irradiating the resist film with an energy beam through a mask having a desired pattern shape; After exposure, heating the resist film, performing a silylation treatment on the resist film to form a silylated layer on the exposed portion of the resist film, and a silylation layer on the resist film and the organic film. Forming a two-layer mask pattern composed of a resist pattern composed of exposed portions of the resist film and an organic film pattern composed of an organic film by performing dry etching with the mask as a mask.

According to the ninth pattern forming method, as in the fourth pattern forming method, a silylated layer having a large thickness and a high silicon content is formed in the exposed portion of the resist film. In the step of performing plasma etching on the film and the organic film using the silylated layer as a mask, the silylated layer is less likely to be damaged, so that a two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern composed of a resist pattern composed of exposed portions of the resist film and an organic film pattern is formed, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved. .

In a tenth pattern forming method according to the present invention, a step of forming a resist film made of a positive type chemically amplified resist containing a polymer having an OH group on an organic film; After performing pattern exposure by irradiating an energy beam through a mask having a pattern shape, a step of heating the resist film and performing a silylation process on the resist film to form a silylated layer on the exposed portion of the resist film Performing a dry etching process on the resist film and the organic film using the silylation layer as a mask to form a two-layer mask composed of a resist pattern composed of exposed portions of the resist film and an organic film pattern composed of the organic film. Forming a pattern.

According to the tenth pattern forming method, the fifth
Similarly to the pattern forming method of the above, in the exposed portion of the resist film,
Since the silylated layer having a large thickness and a large silicon content is formed, the silylated layer is less likely to be damaged in the step of performing plasma etching on the resist film and the organic film using the silylated layer as a mask. Therefore, a two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern consisting of a resist pattern composed of exposed portions of the resist film and an organic film pattern is formed, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved. .

In the first or sixth pattern formation method, the alkaline developer is preferably an aqueous solution of tetramethylammonium hydroxide.

In this manner, the polar component can be reliably bonded to the surface of the thin film portion of the resist film, and the silylation reaction can proceed sufficiently.

In the second or seventh pattern forming method, the acid is preferably acetic acid or formic acid.

In this manner, the polar component can be reliably present on the surface of the resist film, and the silylation reaction can proceed sufficiently.

In the third or eighth pattern forming method, the second acid generator preferably generates a carboxylic acid.

In this manner, the polar component can be reliably present on the surface of the exposed portion of the resist film, and the silylation reaction can proceed sufficiently.

In the third or eighth pattern forming method, the second acid generator is preferably a naphthoquinonediazidosulfonic acid ester.

By doing so, the polar component can be reliably present on the surface of the exposed portion of the resist film, and the silylation reaction can proceed sufficiently.

In the third or eighth pattern formation method, the chemically amplified resist preferably further contains an acid.

In this manner, the amount of the polar component present in the exposed portion of the resist film increases, so that the silylation reaction in the exposed portion of the resist film further proceeds.

In the fourth or ninth pattern forming method, the compound having an OH group is preferably bisphenol A or pyrogallol.

By doing so, the polar component can be reliably present on the surface of the resist film, and the silylation reaction can proceed sufficiently.

In the fifth or tenth pattern forming method, the polymer having an OH group is preferably polyvinyl phenol, novolak resin, polyacrylic acid or polymethacrylic acid.

In this manner, the polar component can be reliably present on the surface of the resist film, and the silylation reaction can proceed sufficiently.

In the sixth to tenth pattern forming methods, the thickness of the resist film is preferably smaller than the thickness of the organic film.

By doing so, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is reliably improved.

In the sixth to tenth pattern forming methods, the thickness of the resist film is preferably 0.1 μm or less.

In this way, a silylated layer can be formed in almost the entire exposed portion of the resist film.
The resolution of the mask pattern is reliably improved.

In the first to tenth pattern formation methods, it is preferable that the base polymer of the chemically amplified resist is completely substituted with a protecting group which is eliminated by an acid.

In this case, since the polar component does not exist on the surface of the resist film, the contrast between the exposed portion having the polar component and the unexposed portion having no polar component is improved.

In the first to tenth pattern forming methods, the protecting group released by an acid in the base polymer of the chemically amplified resist is t-butyl, t-butyloxycarbonyl, t-butyloxycarbonylmethyl or the like. , A 1-ethoxyethyl group or a tetrahydropyranyl group.

In the first to tenth pattern forming methods, the energy beam is KrF, ArF, F ₂ , Xe
₂ , Kr ₂ , ArKr, Ar ₂ , soft X-ray, EB or X-ray.

In the first to tenth pattern forming methods, the silylation treatment is preferably performed in a gas phase or a liquid phase.

In the first to tenth pattern forming methods, the silylating agent used in the silylation treatment is preferably dimethylsilyldimethylamine, dimethylsilyldiethylamine or dimethylaminodimethyldisilane.

[0065]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a pattern forming method according to a first embodiment will be described with reference to FIG.
2 (a) to 2 (c) and FIGS. 2 (a) to 2 (c).

First, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxystyrene) [base polymer] 10 g diphenyldisulfone [acid generator] 0.3 g diglyme [ Solvent] 40g 40g

Next, as shown in FIG.
After applying the above chemically amplified resist on top of
Prebake for 60 seconds at a temperature of 0.4 μm
A resist film 11 having a thickness of m is formed.

Next, as shown in FIG. 1B, pattern exposure was performed by irradiating the resist film 11 with an ArF excimer laser beam 13 through a photomask 12 on which a desired pattern was drawn. Later, as shown in FIG.
A heat treatment is performed at a temperature of 90 ° C. for 90 seconds to cause a catalytic reaction of an acid generated from an acid generator in an exposed portion 11 a of the resist film 11 to remove a protecting group (t-butyl group) from the base polymer. Let go. In this case, since no acid is generated from the acid generator in the unexposed portion 11b of the resist film 11, the protecting group is not eliminated from the base polymer.

Next, after developing the resist film 11 with an aqueous solution of tetramethylammonium hydroxide (alkaline developer), rinsing with pure water is performed, as shown in FIG. The exposed portion 11a of the resist film 11 is partially removed, so that the exposed portion 11a of the resist film 11 has a thin film portion 11c having a thickness of 0.2 μm.
To form

Next, as shown in FIG. 2B, the resist film 11 is subjected to a gas-phase silylation treatment 14 using dimethylsilyldimethylamine, and the thin film portion 11c of the resist film 11 is subjected to the silylation layer 15c. To form

Then, as shown in FIG. 2C, the resist film 11 is subjected to ICP plasma etching 16 using O ₂ and SO ₂ as main gases using the silylated layer 15 as a mask. Then, a resist pattern 11A having a pattern width of 0.12 μm, which is composed of the thin film portion 11c of the resist film 11, is formed.

According to the first embodiment, the resist film 11
Is subjected to development with an alkaline developer to form a thin film portion 11c on the exposed portion 11a of the resist film 11, so that an OH group (polar component) is bonded to the surface of the thin film portion 11c. Proceed well. For this reason,
Since the silylated layer 15 having a large thickness and a large silicon content is formed in the thin film portion 11c of the resist film 11, the resist film 11 is subjected to plasma etching using the silylated layer 15 as a mask. In this case, the silylation layer 15 is less likely to be damaged, whereby a resist pattern 11A having a good cross-sectional shape can be obtained.

(Second Embodiment) Hereinafter, a pattern forming method according to a second embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxystyrene) [base polymer] ····································································· ............ 1 g diphenyl disulfone [acid generator] ... 0.3 g diglyme [solvent] ... ……………… 40g

Next, as shown in FIG.
After applying the above chemically amplified resist on top of
Prebake for 60 seconds at a temperature of 0.4 μm
A resist film 21 having a thickness of m is formed.

Next, as shown in FIG. 3B, pattern exposure was performed by irradiating the resist film 21 with ArF excimer laser light 23 through a photomask 22 on which a desired pattern was drawn. Later, as shown in FIG.
A heat treatment is performed at a temperature of 90 ° C. for 90 seconds to cause a catalytic reaction of the acid generated from the acid generator in the exposed portion 21 a of the resist film 21 to remove the protective group (t-butyl group) from the base polymer. Let go. In this case, since the acid is not generated from the acid generator in the unexposed portion 21b of the resist film 21, the protecting group is not eliminated from the base polymer.

Next, as shown in FIG. 3D, the resist film 21 is subjected to a gas-phase silylation process 24 using dimethylsilyldimethylamine, so that the surface of the exposed portion 21a of the resist film 21 is silylated. A layer 25 is formed.

Next, as shown in FIG. 3E, the resist film 21 is subjected to ICP plasma etching 26 using O ₂ and SO ₂ as main gases using the silylated layer 25 as a mask. Thus, a resist pattern 21A composed of the exposed portions 21a of the resist film 21 and having a pattern width of 0.12 μm is formed.

According to the second embodiment, the resist film 21
Contains acetic acid, and the surface of the resist film 21 has COO
Since the H group (polar component) is present, the silylation reaction proceeds sufficiently. Therefore, the exposed portion 21a of the resist film 21
Is formed on the surface of the silicon film 25. The silylated layer 25 having a large thickness and a large silicon content is formed on the surface of the resist film 21. In the step of performing plasma etching on the resist film 21 using the silylated layer 25 as a mask, 25 is less likely to be damaged, whereby a resist pattern 21A having a good sectional shape can be obtained.

In the second embodiment, acetic acid is used as the acid contained in the chemically amplified resist, but formic acid may be used instead.

(Third Embodiment) Hereinafter, a pattern forming method according to a third embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxycarbonyloxystyrene) [base polymer]................ 0.3 g of 1,2,3-hydroxybenzophenonenaphthoquinonediazidosulfonic acid ester [second acid generator] diphenyl disulfone [first acid generator] ………………………………………………………………… 0.2 g diglyme [solvent] …………………………………………… 40 g

The first acid generator generates an acid capable of removing a protecting group by irradiation with an energy beam,
The second acid generator generates an acid that does not remove a protecting group by irradiation with an energy beam.

Next, as shown in FIG.
After applying the above chemically amplified resist on top of
Pre-bake for 60 seconds at a temperature of 0.2 μm
A resist film 31 having a thickness of m is formed.

Next, as shown in FIG. 4B, pattern exposure is performed by irradiating the resist film 31 with an F ₂ excimer laser beam 33 through a photomask 32 on which a desired pattern is drawn. After that, as shown in FIG.
A heat treatment is performed at a temperature of 0 ° C. for 90 seconds to cause a catalytic reaction of the acid generated from the first acid generator in the exposed portion 31 a of the resist film 31, thereby causing the protecting group (t-butyl) to be removed from the base polymer. Group) is eliminated. In this case, since no acid is generated from the first acid generator in the unexposed portion 31b of the resist film 31, the protecting group is not eliminated from the base polymer.

Next, as shown in FIG. 4D, the resist film 31 is subjected to a gas-phase silylation process 34 using dimethylsilyldimethylamine, so that the surface of the exposed portion 31a of the resist film 31 is silylated. The layer 35 is formed.

Next, as shown in FIG. 4E, the resist film 31 is subjected to ICP plasma etching 36 using O ₂ and SO ₂ as main gases using the silylated layer 35 as a mask. Thus, a resist pattern 31A having an exposed portion 31a of the resist film 31 and having a pattern width of 0.08 μm is formed.

According to the third embodiment, the resist film 31
Contains a second acid generator that generates an acid (carboxylic acid) that does not substantially remove a protective group by irradiation with an energy beam, so that the exposed portion 31a of the resist film 31
Has a COOH group (polar component), so that the silylation reaction proceeds sufficiently. For this reason, on the surface of the exposed part 31a of the resist film 31, the silylated layer 25 having a large thickness and a large silicon content is formed on the surface of the exposed part 31a. In the step of performing the plasma etching, the silylated layer 35 is less likely to be damaged, whereby the resist pattern 31A having a good cross-sectional shape can be obtained.

The chemically amplified resist according to the third embodiment may further contain an acid such as acetic acid or formic acid.

In this way, the amount of COOH groups (polar components) present in the exposed portions 31a of the resist film 31 increases, so that the silylation reaction in the exposed portions 31a of the resist film 31 further proceeds.

(Fourth Embodiment) Hereinafter, a pattern forming method according to a fourth embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, a chemically amplified resist having the following composition is prepared.

Poly (1-ethoxyethyloxystyrene) [base polymer] 10 g bisphenol A [compound containing OH group] 1 g di (phenylsulfonyl) diazomethane [Acid generator] 0.3 g diglyme [solvent] ... 40 g

Next, as shown in FIG.
After applying the above chemically amplified resist on top of
Prebake for 60 seconds at a temperature of 0.4 μm
A resist film 41 having a thickness of m is formed.

Next, as shown in FIG. 5B, pattern exposure is performed by irradiating the resist film 41 with an F ₂ excimer laser beam 43 through a photomask 42 on which a desired pattern is drawn. After that, as shown in FIG.
A heat treatment is performed at a temperature of 0 ° C. for 90 seconds to cause a catalytic reaction of the acid generated from the acid generator in the exposed portion 41 a of the resist film 41, thereby removing the protecting group from the base polymer. In this case, the unexposed portion 4 of the resist film 41
In 1b, since no acid is generated from the acid generator, the protecting group is not eliminated from the base polymer.

Next, as shown in FIG. 5D, the resist film 41 is subjected to a gas-phase silylation treatment 44 using dimethylsilyldimethylamine, so that the surface of the exposed portion 41a of the resist film 41 is silylated. The layer 45 is formed.

Next, as shown in FIG. 5E, the resist film 41 is subjected to ICP plasma etching 46 using O ₂ and SO ₂ as main gases using the silylated layer 45 as a mask. Thus, a resist pattern 41A composed of the exposed portions 41a of the resist film 41 and having a pattern width of 0.08 μm is formed.

According to the fourth embodiment, the resist film 41
Contains a compound containing an OH group, and since the OH group (polar component) is present on the surface of the resist film 41, the silylation reaction proceeds sufficiently. Therefore, the resist film 41
Since the silylated layer 45 having a large thickness and a large silicon content is formed on the surface of the exposed portion 41a, the resist film 41 is subjected to plasma etching using the silylated layer 45 as a mask. , Silylation layer 45
Is less likely to be damaged, whereby a resist pattern 41A having a good cross-sectional shape can be obtained.

In the fourth embodiment, bisphenol A is used as the compound having an OH group, but pyrogallol may be used instead.

(Fifth Embodiment) Hereinafter, a pattern forming method according to a fifth embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxycarbonyloxystyrene) [base polymer]............... Polyhydroxystyrene [polymer containing OH group] 0.5 g diphenyl disulfone [acid generator] 0.3 g diglyme [solvent] ………………………………………… 40g

Next, as shown in FIG.
After applying the above chemically amplified resist on top of
Pre-bake for 60 seconds at a temperature of 0.2 μm
A resist film 51 having a thickness of m is formed.

Next, as shown in FIG. 6B, pattern exposure was performed by irradiating the resist film 51 with an ArF excimer laser beam 53 through a photomask 52 on which a desired pattern was drawn. Later, as shown in FIG.
A heat treatment is performed at a temperature of 90 ° C. for 90 seconds to cause a catalytic reaction of the acid generated from the acid generator in the exposed portion 51 a of the resist film 51 to remove a protecting group (t-butyl group) from the base polymer. Let go. In this case, since the acid is not generated from the acid generator in the unexposed portion 51b of the resist film 51, the protecting group is not eliminated from the base polymer.

Next, as shown in FIG. 6D, the resist film 51 is subjected to a gas-phase silylation treatment 54 using dimethylsilyldimethylamine, so that the surface of the exposed portion 51a of the resist film 51 is silylated. The layer 55 is formed.

Next, as shown in FIG. 6E, the resist film 51 is subjected to ICP plasma etching 56 using O ₂ and SO ₂ as main gases using the silylated layer 55 as a mask. Then, a resist pattern 51A composed of the exposed portions 51a of the resist film 51 and having a pattern width of 0.12 μm is formed.

According to the fifth embodiment, the resist film 51
Contains a polymer containing an OH group, and since the OH group (polar component) is present on the surface of the resist film 51, the silylation reaction proceeds sufficiently. Therefore, the resist film 5
Since the silylated layer 55 having a large thickness and a large silicon content is formed on the surface of the first exposed portion 51a, the resist film 51 is subjected to plasma etching using the silylated layer 55 as a mask. In the silylation layer 5
5 is less likely to be damaged, whereby a resist pattern 51A having a good cross-sectional shape can be obtained.

In the fifth embodiment, polyhydroxystyrene is used as the polymer having an OH group. However, the present invention is not limited to this, and polyvinyl phenol, novolak resin, polyacrylic acid or polymethacrylic acid is widely used. be able to.

(Sixth Embodiment) Hereinafter, a pattern forming method according to a sixth embodiment will be described with reference to FIGS.
This will be described with reference to FIGS.

First, similarly to the first embodiment, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxystyrene) [base polymer] 10 g diphenyldisulfone [acid generator]... 0.3 g diglyme [ Solvent] 40g 40g

Next, as shown in FIG.
An organic film having a thickness of 0.3 μm is formed by applying a resist film for, for example, an i-line thereon, and then heating the resist film at a temperature of 250 ° C. for 90 seconds to cure the resist film. 61 is formed. Next, after applying the above-described chemically amplified resist on the organic film 61, pre-baking is performed at a temperature of 90 ° C. for 60 seconds to form a resist film 62 having a thickness of 0.2 μm.

Next, as shown in FIG. 7B, pattern exposure was performed by irradiating the resist film 62 with an ArF excimer laser beam 64 via a photomask 63 on which a desired pattern was drawn. Later, as shown in FIG.
A heat treatment is performed at a temperature of 90 ° C. for 90 seconds to cause a catalytic reaction of an acid generated from the acid generator in the exposed portion 62 a of the resist film 62 to remove a protective group (t-butyl group) from the base polymer. Let go.

Next, after developing the resist film 62 with an aqueous solution of tetramethylammonium hydroxide (alkaline developer), rinsing with pure water is performed, as shown in FIG. The exposed portion 62a of the resist film 62 is partially removed, and a thin film portion 62c having a thickness of 0.1 μm is formed on the exposed portion 62a of the resist film 62.
To form

Next, as shown in FIG. 8B, the resist film 62 is subjected to a gas-phase silylation process 65 using dimethylsilyldimethylamine, and the thin film portion 62c of the resist film 62 is subjected to the silylation layer 66. To form

Next, as shown in FIG. 8C, the resist film 62 and the organic film 61 are subjected to ICP plasma using O ₂ and SO ₂ as main gases using the silylated layer 66 as a mask. Etching 67 is performed to form a two-layer mask pattern having a pattern width of 0.11 μm and including a resist pattern 62A including the thin film portion 62c of the resist film 62 and the organic film pattern 61A.

According to the sixth embodiment, similarly to the first embodiment, since the silylated layer 66 having a large thickness and a large silicon content is formed in the thin film portion 62c of the resist film 62, In the step of performing plasma etching on the film 62 and the organic film 61 using the silylated layer 66 as a mask, the silylated layer 66 is less likely to be damaged.
A two-layer mask pattern having a good cross-sectional shape can be obtained.

Further, since a two-layer mask pattern composed of the resist pattern 62A composed of the thin film portion 62c of the resist film 62 and the organic film pattern 61A is formed, the thickness of the resist film 62 can be reduced. The image quality is improved.

(Seventh Embodiment) Hereinafter, a pattern forming method according to a seventh embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, similarly to the second embodiment, a chemically amplified resist having the following composition is prepared.

Poly (t-butyloxystyrene) [base polymer] 10 g acetic acid [acid] …………………………………………………… ............ 1 g diphenyl disulfone [acid generator] ... 0.3 g diglyme [solvent] ... ……………… 40g

Next, as shown in FIG.
An organic film having a thickness of 0.3 μm is formed by applying a resist film for, for example, an i-line thereon, and then heating the resist film at a temperature of 250 ° C. for 90 seconds to cure the resist film. 71 is formed. Next, after applying the above-described chemically amplified resist on the organic film 71, a pre-bake is performed at a temperature of 90 ° C. for 60 seconds to form a resist film 72 having a thickness of 0.1 μm.

Next, as shown in FIG. 9B, pattern exposure was performed by irradiating the resist film 72 with an ArF excimer laser beam 74 through a photomask 73 on which a desired pattern was drawn. Later, as shown in FIG.
A heat treatment is performed for 90 seconds at a temperature of 90 ° C. to cause a catalytic reaction of the acid generated from the acid generator in the exposed portion 72 a of the resist film 72 to remove the protective group (t-butyl group) from the base polymer. Let go.

Next, as shown in FIG. 9D, the resist film 72 is subjected to a gas-phase silylation process 75 using dimethylsilyldimethylamine, and the exposed portion 72a of the resist film 72 is exposed to the silylated layer 76. To form

[0128] Next, as shown in FIG. 9 (e), the resist film 72 and the organic film 71, the ICP method for the O ₂ and SO ₂ by the silylated layer 76 as a mask the main gas plasma Etching 26 is performed to form a two-layered mask pattern having a pattern width of 0.11 μm, which includes a resist pattern 72A formed of exposed portions 72a of the resist film 72 and an organic film pattern 71A.

According to the seventh embodiment, as in the second embodiment, the silylated layer 76 having a large thickness and a large silicon content is formed in the exposed portion 72a of the resist film 72. In the step of performing plasma etching on the resist film 72 and the organic film 71 using the silylated layer 76 as a mask, the silylated layer 76 is less likely to be damaged. Can be.

Further, since a two-layer mask pattern composed of the resist pattern 72A composed of the exposed portion 72a of the resist film 72 and the organic film pattern 71A is formed, the thickness of the resist film 72 can be reduced. The image quality is improved.

In the seventh embodiment, a two-layer mask pattern composed of a resist pattern 72A and an organic film pattern 71A is formed using the same chemically amplified resist as that of the second embodiment. Instead, a two-layer mask pattern composed of a resist pattern and an organic film pattern may be formed using the same chemically amplified resist as in the third to fifth embodiments. By doing so, the thickness of the resist film can be reduced, so that the resolution of the mask pattern is improved.

In the first to seventh embodiments, it is preferable that the base polymer of the chemically amplified resist is completely substituted with a protecting group which is eliminated by an acid.

In this case, since no polar component is present on the surface of the resist film, the contrast between the exposed portion having the polar component and the unexposed portion having no polar component is improved.

The protecting group of the base polymer of the chemically amplified resist in the first to seventh embodiments is not particularly limited, and a protecting group which is eliminated by an acid, for example, t-butyl group, t-butyloxycarbonyl Group, t-butyloxycarbonylmethyl group, 1-ethoxyethyl group, tetrahydropyranyl group or the like can be used as appropriate.

In the first to seventh embodiments, an ArF excimer laser is used as an energy beam for pattern exposure, but instead of a KrF excimer laser,
F ₂ laser, Xe ₂ laser, Kr ₂ laser, ArKr laser, Ar ₂ laser, soft X-ray, EB or X-ray can be used.

In the first to seventh embodiments,
Although the gas-phase silylation treatment was performed, a liquid-phase silylation treatment may be performed instead.

Further, as the silylating agent used in the silylation treatment, dimethylsilyldiethylamine or dimethylaminodimethyldisilane can be used instead of dimethylsilyldimethylamine.

[0138]

According to the first to fifth pattern forming methods, a thick silylated layer containing a large amount of silicon is formed in an exposed portion of the resist film. In the step of performing dry etching using the oxide layer as a mask, the silylated layer is less likely to be damaged, so that a resist pattern having a good cross-sectional shape can be obtained.

According to the sixth to tenth pattern forming methods, since the silylated layer having a large thickness and a large silicon content is formed in the exposed portions of the resist film, the resist film and the organic film can be formed. In the step of performing dry etching using the silylated layer as a mask, the silylated layer is less likely to be damaged, so that a two-layer mask pattern having a good cross-sectional shape can be obtained. Further, since the thickness of the resist film can be reduced, the resolution of the mask pattern is improved.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views showing respective steps of a pattern forming method according to a first embodiment.

FIGS. 2A to 2C are cross-sectional views illustrating respective steps of a pattern forming method according to the first embodiment.

FIGS. 3A to 3E are cross-sectional views illustrating respective steps of a pattern forming method according to a second embodiment.

FIGS. 4A to 4E are cross-sectional views illustrating respective steps of a pattern forming method according to a third embodiment.

FIGS. 5A to 5E are cross-sectional views illustrating respective steps of a pattern forming method according to a fourth embodiment.

FIGS. 6A to 6E are cross-sectional views illustrating respective steps of a pattern forming method according to a fifth embodiment.

FIGS. 7A to 7C are cross-sectional views illustrating respective steps of a pattern forming method according to a sixth embodiment.

FIGS. 8A to 8C are cross-sectional views illustrating respective steps of a pattern forming method according to a sixth embodiment.

FIGS. 9A to 9E are cross-sectional views illustrating respective steps of a pattern forming method according to a seventh embodiment.

FIGS. 10A to 10E are cross-sectional views showing steps of a conventional pattern forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 11 Resist film 11A Resist pattern 11a Exposed part 11b Unexposed part 11c Thin film part 12 Photomask 13 ArF excimer laser beam 14 Silylation processing 15 Silylation layer 20 Substrate 21 Resist film 21A Resist pattern 21a Exposed part 21b Unexposed part 22 Photomask 23 ArF excimer laser beam 24 Silylation treatment 25 Silylation layer 30 Substrate 31 Resist film 31A Resist pattern 31a Exposed portion 31b Unexposed portion 32 Photomask 33 ArF excimer laser beam 34 Silylation process 35 Silylation layer 40 Substrate 41 Resist Film 41A Resist pattern 41a Exposed portion 41b Unexposed portion 42 Photomask 43 ArF excimer laser beam 44 Silylation treatment 45 Silylation layer 50 Substrate 51 Resist film 51A Resist Pattern 51a exposed portion 51b unexposed portion 52 photomask 53 ArF excimer laser beam 54 silylation treatment 55 silylated layer 60 substrate 61 organic film 61A organic film pattern 62 resist film 62A resist pattern 62a exposed portion 62b unexposed portion 62c thin film portion 63 Photomask 64 ArF excimer laser 65 Silylation treatment 66 Silylation layer 70 Substrate 71 Organic film 71A Organic film pattern 72 Resist film 72A Resist pattern 72a Exposed portion 72b Unexposed portion 73 Photomask 74 ArF excimer laser 75 Silylation process 76 Cyril Layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/36 G03F 7/38 512 7/38 512 7/40 7/40 H01L 21/30 568 H01L 21 / 3065 21/302 HF term (reference) 2H025 AA00 AA02 AA03 AB16 AC05 AC06 AC08 AD03 BE00 BE01 BG00 CC20 DA40 FA03 FA12 FA17 FA20 FA28 FA41 2H096 AA25 BA09 BA11 BA20 CA05 EA04 EA05 EA06 EA07 FA01 FA04 FA05 FA10 GA08 JA03 5F004 DB26 EA04 5F046 LA17 LA18 LB01

Claims (24)

[Claims] A step of forming a resist film made of a positive chemically amplified resist; and performing a pattern exposure by irradiating the resist film with an energy beam through a mask having a desired pattern shape. Heating the resist film, developing the resist film with an alkaline developer to form a thin film portion on the exposed portion of the resist film, and performing a silylation process on the resist film; Forming a silylated layer on the thin film portion of the resist film, and performing a dry etching on the resist film using the silylated layer as a mask to form a resist pattern comprising the thin film portion of the resist film. A pattern forming method, comprising: 2. A step of forming a resist film made of a positive chemically amplified resist containing an acid, and irradiating the resist film with an energy beam through a mask having a desired pattern shape to perform pattern exposure. Thereafter, a step of heating the resist film; a step of performing a silylation treatment on the resist film to form a silylated layer on an exposed portion of the resist film; and a step of masking the silylated layer with respect to the resist film. Forming a resist pattern comprising exposed portions of the resist film by dry etching. 3. A first acid generator for generating a first acid capable of removing a protecting group of a base polymer, and a second acid generator generating a second acid capable of not removing the protecting group. Forming a resist film made of a positive type chemically amplified resist including, and performing a pattern exposure by irradiating the resist film with an energy beam through a mask having a desired pattern shape. Heating, performing a silylation treatment on the resist film to form a silylated layer on an exposed portion of the resist film, and performing dry etching on the resist film using the silylated layer as a mask. Forming a resist pattern comprising an exposed portion of the resist film. 4. A step of forming a resist film made of a positive type chemically amplified resist containing a compound having an OH group, and irradiating the resist film with an energy beam through a mask having a desired pattern shape. After exposure, heating the resist film; performing a silylation treatment on the resist film to form a silylated layer on the exposed portion of the resist film; Forming a resist pattern comprising exposed portions of the resist film by performing dry etching using the patterned layer as a mask. 5. A step of forming a resist film made of a positive type chemically amplified resist containing a polymer having an OH group, and irradiating the resist film with an energy beam through a mask having a desired pattern shape. After exposure, heating the resist film; performing a silylation treatment on the resist film to form a silylated layer on the exposed portion of the resist film; Forming a resist pattern comprising exposed portions of the resist film by performing dry etching using the patterned layer as a mask. 6. A step of forming a resist film made of a positive-type chemically amplified resist on an organic film, and irradiating the resist film with an energy beam through a mask having a desired pattern shape. Performing a step of heating the resist film, developing the resist film with an alkaline developer to form a thin film portion on an exposed portion of the resist film, Performing a process to form a silylated layer on the thin film portion of the resist film; and performing dry etching on the resist film and the organic film using the silylated layer as a mask to form a thin film portion of the resist film. Forming a two-layer mask pattern composed of a resist pattern composed of an organic film and an organic film pattern composed of the organic film. Pattern forming method comprising and. 7. A step of forming a resist film made of a positive-type chemically amplified resist containing an acid on an organic film, and irradiating the resist film with an energy beam through a mask having a desired pattern shape. Heating the resist film after performing pattern exposure by performing a patterning process, performing a silylation process on the resist film to form a silylated layer on an exposed portion of the resist film, and the resist film and the organic film. Dry etching the film using the silylation layer as a mask to form a two-layer mask pattern composed of a resist pattern composed of exposed portions of the resist film and an organic film pattern composed of the organic film And a pattern forming method comprising: 8. A first acid generator for generating a first acid for removing a protecting group of a base polymer, and a second acid for generating a second acid which does not remove the protecting group, on an organic film. Forming a resist film made of a positive chemically amplified resist containing an acid generator of No. 2, and irradiating the resist film with an energy beam through a mask having a desired pattern shape to perform pattern exposure. Thereafter, a step of heating the resist film, a step of performing a silylation treatment on the resist film to form a silylated layer on an exposed portion of the resist film, and a step of forming the silyl layer on the resist film and the organic film. Dry etching is performed using the patterned layer as a mask to form a two-layer mask pattern composed of a resist pattern composed of exposed portions of the resist film and an organic film pattern composed of the organic film. A pattern forming method. 9. A step of forming a resist film made of a positive type chemically amplified resist containing a compound having an OH group on an organic film, and energy is applied to the resist film through a mask having a desired pattern shape. A step of heating the resist film after performing pattern exposure by irradiating a beam; a step of performing a silylation treatment on the resist film to form a silylated layer on an exposed portion of the resist film; Dry etching is performed on the film and the organic film using the silylation layer as a mask, and a two-layer mask pattern including a resist pattern including an exposed portion of the resist film and an organic film pattern including the organic film Forming a pattern. 10. A step of forming a resist film made of a positive type chemically amplified resist containing a polymer having an OH group on an organic film, and forming an energy on the resist film through a mask having a desired pattern shape. A step of heating the resist film after performing pattern exposure by irradiating a beam; a step of performing a silylation treatment on the resist film to form a silylated layer on an exposed portion of the resist film; Dry etching is performed on the film and the organic film using the silylation layer as a mask, and a two-layer mask pattern including a resist pattern including an exposed portion of the resist film and an organic film pattern including the organic film Forming a pattern. 11. The pattern forming method according to claim 1, wherein the alkaline developer is an aqueous solution of tetramethylammonium hydroxide. 12. The pattern forming method according to claim 2, wherein the acid is acetic acid or formic acid. 13. The pattern forming method according to claim 3, wherein the second acid generator generates a carboxylic acid. 14. The pattern forming method according to claim 3, wherein the second acid generator is naphthoquinonediazidosulfonic acid ester. 15. The pattern forming method according to claim 3, wherein the chemically amplified resist further contains an acid. 16. The pattern forming method according to claim 4, wherein the compound having an OH group is bisphenol A or pyrogallol. 17. The method according to claim 5, wherein the polymer having an OH group is polyvinylphenol, novolak resin, polyacrylic acid or polymethacrylic acid.
Or the pattern forming method according to 10. 18. The pattern forming method according to claim 6, wherein the thickness of the resist film is smaller than the thickness of the organic film. 19. The method according to claim 6, wherein said resist film has a thickness of 0.1 μm or less.
The pattern forming method according to the above item. 20. The pattern forming method according to claim 1, wherein the base polymer of the chemically amplified resist is completely substituted with a protecting group which is eliminated by an acid. . 21. The protecting group released by an acid in the base polymer of the chemically amplified resist is t-butyl group, t-butyloxycarbonyl group, t-butyloxycarbonylmethyl group, 1-ethoxyethyl group or tetrahydroethyl group. 2. A pyranyl group.
0. The pattern forming method according to any one of 0. 22. The energy beam, wherein the energy beam is KrF, A
rF, F ₂ , Xe ₂ , Kr ₂ , ArKr, Ar ₂ , soft X
2. An electron beam, an EB or an X-ray.
0. The pattern forming method according to any one of 0. 23. The pattern forming method according to claim 1, wherein the silylation treatment is performed in a gas phase or a liquid phase. 24. The pattern according to claim 1, wherein the silylating agent used in the silylation treatment is dimethylsilyldimethylamine, dimethylsilyldiethylamine or dimethylaminodimethyldisilane. Forming method.