JP3035536B1 - Semiconductor pattern forming apparatus and semiconductor pattern forming method - Google Patents

Abstract

A fine pattern is accurately formed when a silylation process is used for forming a semiconductor pattern. SOLUTION: After applying a silylated resist 2 on a substrate 1 to be processed, a surface film 3 is applied as a thin film on the silylated resist 2, and a silylating agent is applied to the thin film (surface film 3).
To silylate the silylated resist 2. As described above, the surface film 3 is coated and formed on the silylated resist 2, and the thin film-coated surface film 3 is permeated and silylated to thereby control the atmospheric contamination of the silylated resist surface, Swelling of the silylated layer can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor pattern forming apparatus and method for forming a fine pattern in semiconductor manufacturing.

[0002]

2. Description of the Related Art In general, as a method of forming a fine pattern in the manufacture of semiconductors, a method of forming a resist pattern by applying a photosensitive material as a resist on a substrate to be processed, and performing exposure and wet development processing is common. Was. However, in recent years, with the miniaturization of patterns, Journal
f Photopolymer Science Tec
hnology Volume11, Number4
As disclosed in (1998) 613-618, after exposure, a treatment (silylation treatment) is performed in an organic gas atmosphere containing silicon (Si) as a constituent element, and a Si element is selectively applied only to a desired portion of the resist. A method has been studied in which oxygen plasma resistance is imparted by being introduced, and then a fine pattern is formed by dry (dry) development with oxygen plasma.

A conventional example will be described with reference to the drawings. FIG. 4 shows a schematic diagram of the process. FIG. 5 shows a flowchart of the process. FIG. 4A shows a substrate to be processed, 1 is an Si substrate (silicon substrate), and 9 is a silicon oxide (SiO ₂ ) film. It is assumed that the SiO ₂ film 9 is formed on the Si substrate 1 by S11 in FIG. Next, as shown in FIG.
A resist 8 is spin-coated on the iO ₂ film 9 (S12).
After that, prebaking is performed (S13). Next, as shown in (c), the resist 8 is cross-linked by exposing a desired portion of the resist 8 to form a cross-linked portion 4 of the resist 8 (S14). The exposure method here is a well-known ultraviolet ray,
An exposure method capable of irradiation with high energy such as X-rays and electron beams can be applied. Then, post bake (S1
5). Next, the resist 8 including the cross-linked portion 4 cross-linked by exposure is exposed to an Si gas-containing organic gas atmosphere, for example, a dimethylsilyl dimethylamine (DMSDMA) atmosphere for a desired time (for example, about 60 seconds) to obtain silyl. A conversion process is performed (S16). As shown in (d) by this silylation treatment, the resist 8 in the uncrosslinked portion 5 excluding the crosslinked portion 4 due to the above-mentioned exposure causes the phenolic hydroxyl group contained in the structure to react with DMSDMA by the silylation reaction. Then, the Si element is taken into the resist 8. In FIG. 4, the silylated portion is a portion indicated by oblique lines, and is hereinafter referred to as a silylated layer. Next, (e)
As shown in (2), the entire surface is etched by oxygen plasma to selectively remove the resist 8 only by etching (dry development) only in the cross-linking portions 4 into which Si atoms do not enter.
I do. Further, by etching with a CF-based gas such as CF ₄ or an F-based gas, the SiO ₂ film is removed (S
17). Thus, the fine pattern 6 can be formed. Finally, as shown in (f), the resist 8 is stripped (S18).

A negative silylation process using a chemically amplified positive resist has also been proposed. In this negative silylation process, the t-butyl group of poly (t-butylphenol), which is a polymer of the resist, is deprotected by the generation of an acid from an acid generator in the resist by exposure, and the poly (vinylphenol) is deprotected. ) By selective silylation treatment only on the exposed portion of the resist
Is introduced. The non-exposed portion where Si is not introduced is selectively removed by oxygen plasma etching later to form a negative pattern.

[0005]

However, in a conventional pattern forming method involving a silylation process, a resist is applied on a substrate to be processed to a thickness of about 0.7 μm.
Since the resist was exposed to light and subjected to a silylation treatment, the resist was affected by an exposure atmosphere or an atmosphere left after exposure (for example, ammonia in the air), further affected by a silylation treatment, and a The resolution and dimensional controllability were deteriorated. Particularly, in the case of using a chemically amplified resist as a resist in order to achieve high sensitivity in the silylation pattern forming method, the acid generated by exposure is easily deactivated due to atmospheric contamination, so that the pattern resolution and The dimensional controllability was deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an apparatus and method for accurately forming a fine pattern when a silylation process is used for forming a semiconductor pattern. The purpose is to obtain. In particular, it is an object of the present invention to provide an apparatus and method capable of preventing a change in silylation characteristics due to atmospheric contamination of a silylated resist and improving the resolution and patterning margin of the silylated resist.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention is to apply a silylated resist on a substrate to be processed and then apply a surface film as a thin film on the silylated resist. The silylation resist is passed through the thin film to silylate the silylated resist. As described above, the surface film is formed on the silylated resist by coating, and the silylation is performed by transmitting the thin film-coated surface film, whereby the atmospheric contamination on the surface of the silylated resist can be controlled and the silylated layer can be controlled. Swelling can be suppressed.

Further, by using a surface film whose acidity at the exposed portion changes upon exposure, the amount of transmission of the silylating agent (transmission contrast) can be changed.
The silylation contrast of the silylated resist can be improved. Here, the silylation contrast is a ratio of a silylation ratio between a region to be silylated and a region not to be silylated, and it is well known that the larger the value of the silylation contrast is, the more preferable in forming a fine pattern. is there.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The case of the positive silylation process will be described with reference to the drawings. FIG.
It is a schematic diagram of a process. FIG. 2 is a flowchart of the process. On the left side of FIG. 2, the device names used for each step are shown. Hereinafter, the points different from the related art will be mainly described.

FIG. 1A shows a substrate to be processed produced as a result of S11, 1 is a Si substrate, and 9 is a SiO 2 substrate.
_Two films. First, as shown in FIG. 2B, as a silylated resist 2 on the SiO ₂ film 9, for example, NTS-
4 is spin-coated to a thickness of about 0.7 μm (S21), and 9
Prebaking is performed at a temperature of about 0 ° C. (S22).

Thereafter, as shown in (c), a commercially available TSP-5A manufactured by Tokyo Ohka Kogyo Co., Ltd. is applied as a surface layer 3 for silylation on the baked silylated resist by a spin coating method. It is applied and formed on a thin film of about 0.05 μm (S23). Since the surface film 3 applied here is water-soluble, it is preferably applied without being mixed with the silylated resist 2.

Next, as shown in (d), the silylated resist is exposed through the surface film 3 (S14), and thereafter, post-exposure bake is performed (S15) to crosslink the exposed portions of the silylated resist. , Forming a bridge portion 4. As the exposure method here, a well-known exposure method capable of irradiating high energy such as ultraviolet rays, X-rays, and electron beams can be applied. If the exposure is performed using an argon fluoride (ArF) excimer laser, The irradiation amount is preferably about 10 to ²⁰ mJ / cm ² .

Next, as shown in (e), the silylated resist including the crosslinked portion 4 and the uncrosslinked portion 5 crosslinked by exposure and post-exposure bake is applied to a gas atmosphere containing Si (silylating agent atmosphere), For example, it is exposed to a dimethylsilyldimethylamine (DMSDMA) atmosphere for a desired time to perform a silylation treatment to form a silylated layer region (S24). Here, when the silylation is performed by passing through the surface film 3, Si is used.
Is absorbed by the surface film 3, so that the time of exposure to the atmosphere needs to be slightly longer than in the case where there is no surface film. According to the results of our experiment,
When there is no surface film under the conditions of the silylation treatment at r and 80 ° C., the treatment time is preferably about 60 sec (second), but the silylation is performed by transmitting the TSP-5A surface film having a thickness of 0.05 μm. In this case, about 90 seconds, which is 1.5 times the processing time, was suitable. As a result of this silylation treatment, the silylation agent permeates through the surface film 3 and reaches the silylated resist 2, and as shown in FIG. In 5), the phenolic hydroxyl group reacts with Si by a well-known silylation reaction, and Si atoms are incorporated into the silylated resist. In (e), a hatched portion indicates a portion where a silylation reaction has occurred.

In the present invention, the surface film 3 is applied on the silylated resist 2, and the silylated resist 2 is permeated through the surface film 3 so as to contaminate the atmosphere of the silylated resist. This can prevent the variation of the silylation characteristics due to the above, and can improve the resolution and patterning margin of the silylated resist.

Thereafter, as shown in (f), the surface film is removed with pure water (S25). The surface film also contains some Si due to the silylation treatment, and it is necessary to remove the surface film with pure water in order to improve the efficiency of the subsequent etching. For removal with pure water, washing with running water for about 1 minute (minute) is sufficient.

Next, as shown in (g), the entire surface is etched by oxygen plasma to selectively etch away (dry develop) the silylated resist only at the portions where Si atoms do not enter, thereby obtaining the fine pattern 6. Can be formed.

In the description of the present embodiment, an example in which a surface film as a protective film is applied to the silylation process has been described. It is needless to say that it is possible to function as a surface anti-reflection film by applying as described above. The surface antireflection film refers to a film that prevents reflection of exposure light generated from the surface of the silylated resist 2 or the Si substrate 1.

The required characteristics of the surface film are shown below. (1) The surface film functions as a protective film for the silylated resist. That is, the silylated resist should not be affected in an exposure atmosphere or an atmosphere left after exposure. (2) The surface film should not mix with the silylated resist. That is, the resist function of the silylated resist is not impaired. (3) The surface film transmits the exposure light. In this regard,
It is desirable that the surface film be transparent. (4) The surface film should allow the silylating agent to permeate as much as possible, and contain as little Si atoms as possible by the silylation treatment. (5) The surface film can be easily removed from the silylated resist without affecting the silylated resist. For example, it is preferable to perform cleaning using pure water. However, as long as it can be easily removed from the silylated resist and does not dissolve the silylated resist, it need not be water-soluble. (6) The surface film desirably serves as an antireflection film for exposure light.

Although the etching result is slightly inferior, the etching may be performed without removing the surface film. When it is only necessary to eliminate the influence of the exposure exposure atmosphere or the exposure exposure atmosphere, the surface film may be removed not before the silylation treatment but before the silylation treatment.

Embodiment 2 Embodiment 2 will be described with reference to the drawings. FIG. 3 is a schematic diagram of the process. The flowchart of the process is the same as FIG. 2 and is not particularly shown.

The case of the positive silylation process will be described with reference to the drawings. 1 in FIG. 3A is a Si substrate as a substrate to be processed. 9 is a SiO ₂ film.

First, as shown in FIG. 2B, as a silylated resist 2 on the SiO ₂ film 9, for example, NTS manufactured by Sumitomo Chemical Co., Ltd.
-4 is spin-coated to a thickness of about 0.7 μm and prebaked at a temperature of about 90 ° C.

Thereafter, as shown in (c), polyvinyl alcohol is applied to the baked silylated resist as a surface film 3 for the silylated resist by a spin-coating method.
It is applied and formed on a thin film of about um. Here, a photoacid generator is added to the polyvinyl alcohol in order to change its acidity by exposure. As the photoacid generator,
Any type can be used as long as the acidity can be changed by exposure, for example,
Triphenylsulfoniumtriflat
e, etc., may be added in several percent. Here, since the polyvinyl alcohol applied as the surface film 3 is water-soluble, it is well applied without being mixed with the silylated resist 2.

Next, as shown in (d), the silylated resist is exposed through the surface film 3 and then baked after exposure to cross-link the exposed portions of the silylated resist and cross-link the exposed portions of the silylated resist.
To form The exposure method here is a well-known ultraviolet ray, X
Exposure methods capable of high-energy irradiation such as electron beams and electron beams can be applied.
When exposing with an excimer laser,
It is about 10 to ²⁰ mJ / cm ² . Here, a photoacid generator is added to the surface film, and the acid generation region 10 is formed in the surface film by exposure or by subsequent baking after exposure. The part has a higher acidity than the unexposed part.

Next, as shown in (e), the silylated resist including the cross-linked portion 4 and the non-cross-linked portion 5 cross-linked by exposure and baking is applied to a Si-containing gas atmosphere, for example, dimethylsilyldimethylamine (DMSDMA). ) Expose the atmosphere for the desired time. When the silylation is performed by passing through the surface film, the gas containing Si is absorbed by the surface film as in the first embodiment, so that the time of exposure to the atmosphere is slightly longer than when the surface film is not provided. There is a need to do. here,
In the exposed portion of the surface film, an acid generating region 10 is formed, and particularly, since the acidity is large, alkaline DMSDMA as a silylating agent is easily absorbed by a neutralization reaction. It is difficult for the exposed portion to pass a gas containing Si. Since no acid is generated in the unexposed portion of the surface film and the acid concentration does not change, the amount of transmission of the silylating agent between the exposed portion and the unexposed portion is different. In other words, by using the photoacid generator-containing surface film, the transmission contrast (silylation contrast) of the gas containing Si can be increased. By this silylation treatment, (e)
As shown in the above, in the unexposed portion (uncrosslinked portion 5) except for the crosslinked portion 4 due to the exposure baking described above, the phenolic hydroxyl group and Si react by a well-known silylation reaction, and Si atoms are contained in the resist. Will be captured. In (e), a hatched portion indicates a portion where a silylation reaction has occurred.

In the present invention, a surface film is applied on the silylated resist, and the acidity of the surface film is changed by exposure, and then the silylation is performed, so that the silylation contrast in the silylation treatment is improved. And the resolution of the silylated resist can be improved.

Thereafter, as shown in FIG. 3F, the surface film is removed with pure water, and then, as shown in FIG. By removing the silylated resist by etching, the fine pattern 6 can be formed as shown in FIG.

In the second embodiment, the case where an acid generator is added to the surface film has been described. However, by adding a base generator instead of the acid generator, the acidity of the exposed portion of the surface film can be reduced. Obviously, a method of lowering the amount of the silylating agent permeated only in the exposed area can be applied to the negative silylation process.

As described above, this embodiment relates to a method of forming a silylation pattern in forming a fine pattern.
It is characterized in that a surface film is applied and formed on the silylated resist, and the silylated resist is silylated by passing through the surface film. Further, a surface film containing an additive whose acidity can be changed by exposure is used as a surface film applied and formed on the resist. Further, the silylation layer is formed by changing the acidity of the surface film of the exposed portion to change the transmission contrast of the silylating agent permeating the surface film.

In the present invention, pre-bake and post-bake are optional, and are performed if necessary. Further, the SiO ₂ film is an example, and another film may be used. Further, the Si substrate is an example, and another semiconductor substrate may be used.

[Brief description of the drawings]

FIG. 1 is a process schematic diagram of Embodiment 1 of the present invention.

FIG. 2 is a flowchart of the first embodiment of the present invention.

FIG. 3 is a process schematic diagram of Embodiment 2 of the present invention.

FIG. 4 is a schematic view of a conventional process.

FIG. 5 is a conventional flowchart.

[Explanation of symbols]

1 substrate, 2 silylated resist, 3 surface layer, 4 bridge, 5 uncrosslinked portion, 6 a fine pattern, 8 resist, 9 SiO ₂ film, 10 acid-generating region.

Claims (4)

(57) [Claims] 1. A method for forming a silylated resist on a substrate and using a material containing an additive for changing the acidity by exposure.
Te, and means for applying a surface layer on silyl resists, the surface layer and the silylated resist to partially exposed
The exposed portion of the surface film and the silylated resist
Form unexposed areas and unexposed areas of surface film
Area with acidity different from the acidity of the part
Means for differentiating the silylation contrast between the exposed and unexposed areas.
The silylation agent permeates the silylated resist from the surface of the surface film.
1. A semiconductor pattern forming apparatus, comprising: means for silylating a silylation resist by causing the substrate to undergo silylation; and means for etching a silylation-treated substrate. 2. The semiconductor pattern forming apparatus according to claim 1, further comprising:
2. The semiconductor pattern forming apparatus according to claim 1, further comprising means for removing a surface film from the silylation-treated substrate. 3. The method according to claim 1, wherein the surface film is silylated during the silylation treatment.
2. The semiconductor pattern forming apparatus according to claim 1, wherein swelling of the resist is suppressed . 4. A process for forming a silylated resist on a substrate.
And degree, a material including an additive to change the acidity by exposure using
A step of applying a surface film on the silylated resist and partially exposing the surface film and the silylated resist.
The exposed portion of the surface film and the silylated resist
Form unexposed areas and unexposed areas of surface film
Area with acidity different from the acidity of the part
A step where the silylation contrast differs between the exposed part and a table where the silylation contrast differs between the exposed part and the unexposed part.
The silylation agent permeates the silylated resist from the surface of the surface film.
Process to silylate the silylated resist
And a step of etching the silylated substrate .