JP3350097B2 - Photosensitive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition capable of forming a polysilane film pattern.

[0002]

2. Description of the Related Art Polysilane has a Si-Si main chain,
It is an organic polymer having semiconductor properties. In addition, polysilane is known as a material that alone undergoes a decomposition or crosslinking reaction upon exposure to light, for example, irradiation with EB, X-ray, or the like, and changes in solubility in a solvent. For this reason, polysilane is attracting attention as a semiconductor organic material capable of forming a pattern alone by exposure and development based on the above characteristics. However, when a pattern was formed using polysilane alone as described above, the cross-sectional shape and resolution of the obtained pattern were insufficient.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-mentioned problems, and is intended to provide a photosensitive film having a good cross-sectional shape and capable of forming a polysilane film pattern having excellent resolution. It is intended to provide a composition.

[0004]

An object of the present invention is to provide a photosensitive composition comprising a polysilane having a repeating unit represented by the following general formula (1) and a compound capable of generating an acid upon exposure. Achieved by

[0005]

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In the formula, R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms,
Or a substituted or unsubstituted aralkyl group having 7 to 22 carbon atoms. Provided that at least one of R ¹ and R ² have an alkoxyl group or an aromatic ring substituted with siloxyl group, when at least one of R ¹ and R ² is an aryl group or an aralkyl group, the Two or more adjacent sites on the aromatic ring may be substituted with an alkoxyl group, and the two or more alkoxyl groups may be linked to each other to form a ring.

The photosensitive composition of the present invention comprises a polysilane having a repeating unit represented by the above general formula (1) as a main component and a compound capable of generating an acid upon exposure as a photosensitive component (hereinafter referred to as photoacid generator). Agent).

The polysilane having the repeating unit (1) has a Si—Si bond as a main chain and a side chain R ^1. And R
^Two Is each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. The average molecular weight of the polysilane used in the present invention is preferably about 1,000 to 5
00,000. When the average molecular weight is less than 1,000, the dissolution rate of the photosensitive composition in the developing solution used in the pattern forming process may be excessively high. On the other hand, when it exceeds 500,000, it takes a long time to synthesize the polysilane, and the sensitivity of the photosensitive composition may be further reduced. Hereinafter, specific examples of the polysilane generally used in the present invention will be listed.

[0009]

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In the present invention, as the polysilane having the repeating unit (1), at least one side chain, that is, at least one of R ¹ and R ² is preferably substituted with at least one alkoxyl group or siloxyl group . Those having a modified aromatic ring can be used. Specifically, the polysilane having the repeating unit (1), wherein at least one of R ¹ and R ² is a substituted or unsubstituted alkoxyl group or an aryl group substituted with a substituted or unsubstituted siloxyl group. Polysilane, R
^A polysilane in which at least one of ¹ and R ² is an aralkyl group having an aromatic ring substituted by a substituted or unsubstituted alkoxyl group or a substituted or unsubstituted siloxyl group can be preferably used. In addition, R
Wherein at least one of ¹ and R ² is an aryl group or an aralkyl group, wherein two or more adjacent sites on the aromatic ring are substituted with an alkoxyl group, and these two or more alkoxyl groups are linked to each other; Alternatively, a polysilane forming a ring may be used. Further, among the repeating units as described above, a polysilane copolymer composed of two or more different repeating units may be used.

Further, in the present invention, as the polysilane having the repeating unit (1), R ¹ And R ² A polysilane having an aromatic ring substituted by a hydroxyl group on at least ^{one of} And R ² May be used as at least one of them, such as a mixture with a polysilane having an aromatic ring substituted by a substituted or unsubstituted alkoxyl group or a substituted or unsubstituted siloxyl group.

Specific examples of the polysilane having an aromatic ring substituted on at least one side chain by an alkoxyl group and the polysilane having an aromatic ring substituted on at least one side chain by a siloxyl group, which can be used in the present invention. Specific examples are listed below. These polysilanes are
In the composition of the present invention, a hydroxyl group is generated only at the time of exposure and development processing, which is preferable in that alkali developability is exhibited. In particular, a polysilane having an aromatic ring substituted by a siloxyl group in a side chain is preferable because its synthesis is easy.

[0013]

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[0014]

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On the other hand, in the photosensitive composition of the present invention, the photoacid generator, which is a photosensitive component, is not particularly limited as long as it is a compound capable of decomposing upon exposure to generate an acid, and examples thereof include a sulfonium salt and an iodonium salt. , Nitrobenzyl compound,
Naphthoquinonediazide compounds and the like can be used. Specific examples of these photoacid generators are shown below. In addition, among these photoacid generators, sulfonium salts are particularly preferred for practical use.

[0016]

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[0017]

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The photosensitive composition of the present invention can be prepared by dissolving a polysilane having a repeating unit (1) and a photoacid generator as described above in a suitable solvent. As the solvent, for example, toluene, xylene, dimethylformamide, dimethylacetamide, a cellosolve solvent, or the like can be used. In this case, about 0.01 to 30 parts by weight, more preferably 0.5 to 5 parts by weight of the photoacid generator may be blended with respect to 100 parts by weight of the polysilane having the repeating unit (1). The reason for this is that if the photoacid generator is less than 0.01 parts by weight, the reaction between the acid generated at the time of exposure and the polysilane may be insufficient, and
If the amount is more than 10 parts by weight, the storage stability of the photosensitive composition and the semiconductor characteristics of the finally obtained polysilane film (pattern) may be adversely affected.

[0019]

The operation of the photosensitive composition of the present invention will be described below along the pattern forming process using the composition.

First, the photosensitive composition prepared as described above is applied on a substrate such as a silicon wafer by a spinner. Further, by pre-baking this coating film at about 70 to 120 ° C., the solvent is evaporated to some extent to form a photosensitive composition layer. Next, this layer is exposed to Deep UV light, KrF excimer laser light, electron beam, X-ray, or the like via a desired mask pattern, and then hard-baked at about 90 to 130 ° C. as necessary.

At the time of the above-mentioned exposure, in the exposed portion of the photosensitive composition layer, the photoacid generator is decomposed to generate an acid , and this acid serves as a catalyst, and the polysilane having the repeating unit (1) is converted to Si-
The Si main chain is cut to reduce the molecular weight. Further, by performing the hard baking, the reduction of the molecular weight of the polysilane is further accelerated.

Subsequently, the photosensitive composition layer after hard baking is subjected to a developing treatment using an organic solvent such as an alcohol solvent as a developing solution, and further washed (rinsed).
At this time, in the exposed portion of the photosensitive composition layer, the polysilane has a low molecular weight as described above, and thus has high solubility in a developing solution. Therefore, only the exposed portion is removed by this developing process, and the unexposed portion remains. That is, the photosensitive composition of the present invention exhibits positive photosensitive performance,
A polysilane (film) having a desired pattern is obtained.

According to the photosensitive composition of the present invention, a pattern can be easily formed by following the above-described process. In particular, the action of the photoacid generator accelerates the lowering of the molecular weight of the polysilane in the exposed portion and increases the solubility in the developing solution, as compared with the conventional polysilane alone. For this reason, the cross-sectional shape of the finally obtained pattern is improved, and the resolution is improved. In other words, it is possible to form a polysilane film pattern having a cross-sectional shape close to a rectangle and having submicron level lines and spaces and having excellent resolution.

Further, in the photosensitive composition of the present invention, one of the side chains of the polysilane having the repeating unit (1) may be used.
That is, since a compound having an aromatic ring substituted by an alkoxyl group or a siloxyl group is used for at least one of R ¹ and R ² , the resolution of a formed pattern can be further improved.

Since the polysilane having the repeating unit (1) contains an aromatic ring substituted by an alkoxyl group or a siloxyl group in the side chain, the polysilane having the same structure as that of Si-
Breakage of the Si main chain is further promoted, lowering the molecular weight of the polysilane is further accelerated, and a finer pattern can be obtained. Furthermore, since this polysilane exhibits alkali solubility due to a hydroxyl group (for example, a phenolic hydroxyl group) directly bonded to an aromatic ring, it becomes possible to use an aqueous alkali solution during the development process, and the swelling of the formed pattern, etc. Is prevented, and the resolution is further improved.

The polysilane having a repeating unit (1) is, since an aromatic ring substituted by alkoxyl groups or siloxyl group in the side chain, after exposure, further reaction in addition to the low molecular weight occurs. That is, in the presence of an acid generated by exposure, for example, by performing a hard bake after exposure, an alkoxyl group or siloxyl group bonded to an aromatic ring in a side chain of polysilane is changed to a hydroxyl group. In this case, a hydroxyl group (for example, a phenolic hydroxyl group) directly bonded to an aromatic ring is generated on the side chain of the polysilane only in the exposed portion of the photosensitive composition.
Therefore, in addition to being able to adopt the development processing using an alkaline aqueous solution, the difference in solubility in an alkaline aqueous solution between an exposed portion and an unexposed portion of the photosensitive composition is extremely large, and thus the photosensitive composition is formed. The resolution of the pattern can be significantly improved.

As a photosensitive composition for forming a fine pattern such as a photoresist, a composition containing a carbon-based polymer such as an alkali-soluble polymer and a photoacid generator usable in the present invention. It has been known. Also in this composition, the photoacid generator is decomposed by exposure to light to generate an acid, and this acid acts on the carbon-based polymer, so that the solubility in the developer varies. However, in such a composition, the carbon-based polymer exhibits a large absorption based on the CC bond of the main chain to ultraviolet rays having a wavelength of about 200 nm or less, particularly to exposure by an ArF excimer laser (193 nm). Light transmittance in the wavelength region is low. Therefore, in this composition, when UV exposure at a wavelength of about 200 nm is applied, the decomposition of the photoacid generator does not sufficiently proceed, and the sensitivity is low.

On the other hand, in the photosensitive composition of the present invention,
The UV absorption of the polysilane is based on the Si-Si bond of the main chain, and the absorption region of the C-C bond, that is, about 150 to 200 n
The wavelength is shifted to a longer wavelength region than m. Therefore,
When the composition of the present invention is subjected to UV exposure at a wavelength of about 200 nm, the composition has excellent light transmittance, sufficiently decomposes the photoacid generator, and improves the acid generation efficiency. As described above, the photosensitive composition of the present invention has a very high sensitivity due to the combination of the polysilane and the photoacid generator, when short-wavelength ultraviolet rays having a wavelength of about 250 nm or less, particularly when exposure with an ArF excimer laser is applied. It is.

[0029]

The present invention will be described in more detail with reference to the following examples. These examples are provided for the purpose of facilitating the understanding of the present invention, and do not limit the present invention. Reference Example 1, Examples 2 to 5 According to the formulation shown in Table 1 below, polysilane and a photoacid generator were mixed in an appropriate solvent to prepare a photosensitive composition. Comparative Examples 1 and 2 As comparative examples, polysilanes shown in Table 1 below were prepared. In these comparative examples, no photoacid generator was added to the polysilane.

Using each of the photosensitive compositions of Reference Example 1, Examples 2 to 5, and the polysilanes of Comparative Examples 1 and 2, coating and exposure (KrF excimer laser: wavelength 248 nm, A pattern was formed according to conditions such as electron beam), hard baking, and development. Table 1 also shows the exposure amount (sensitivity) of each sample, the resolution of the obtained pattern, and the cross-sectional shape. The structural formulas of the compounds described as abbreviations in Table 1 are shown in Chemical Formulas 8 and 9.

[0031]

[Table 1]

[0032]

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[0033]

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As is clear from the results shown in Table 1, the photosensitive composition of the present invention containing the polysilane having the repeating unit (1) and the photoacid generator is different from the polysilane of the comparative example alone. And high sensitivity. Further, a pattern formed by subjecting this composition to exposure and development shows very excellent performance in both resolution and cross-sectional shape. Reference Examples 2 to 4 and Examples 6 and 8 According to the formulations shown in Table 2 below, polysilane and a photoacid generator were mixed in an appropriate solvent to prepare a photosensitive composition. Comparative Example 3

As a comparative example, a photosensitive composition was prepared by mixing polyvinyl phenol and a photoacid generator in a suitable solvent according to the formulation shown in Table 2 below. This comparative example is a system containing a carbon-based polymer.

Using each of the photosensitive compositions of Reference Examples 2 to 4, Examples 6, 8 and Comparative Example 3, coating and exposure (ArF excimer laser: wavelength 192 nm) shown in Table 2 were carried out.
A pattern was formed according to conditions such as hard baking and development. Table 2 also shows the exposure amount (sensitivity) of each sample, the resolution of the obtained pattern, and the cross-sectional shape. In addition, the structural formulas of the compounds described as abbreviations in Table 2 are shown in Chemical Formula 10.

[0037]

[Table 2]

[0038]

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As is clear from the results shown in Table 2, the photosensitive composition of the present invention containing the polysilane having the repeating unit (1) and the photoacid generator used the carbon-based polymer of the comparative example. Compared with the photosensitive composition, the sensitivity is particularly high with respect to exposure with an ArF excimer laser. Further, a pattern formed by subjecting the composition of the present invention to exposure and development shows excellent resolution.

[0040]

As described in detail above, according to the present invention,
A photosensitive composition capable of forming a polysilane film pattern having high sensitivity and excellent cross-sectional shape and resolution by applying a pattern forming process including exposure and development processing under appropriate conditions. Can be provided.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G03F 7/075 511 G03F 7/075 511 (56) References JP-A-62-153852 (JP, A) JP-A-2-296801 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 83/00-83/16 C08G 77/00-77/62

Claims (1)

(57) [Claims] 1. A polysilane having a repeating unit represented by the following general formula (1), and a compound which is mixed with 0.01 to 30 parts by weight based on 100 parts by weight of the polysilane and generates an acid upon exposure to light. Photosensitive composition. Embedded image In the formula, R ¹ and R ² each independently represent a hydrogen atom, a carbon atom
To 18 substituted or unsubstituted alkyl groups, having 6 to 6 carbon atoms
18 substituted or unsubstituted aryl groups, or 7 carbon atoms
To 22 substituted or unsubstituted aralkyl groups. Provided that at least one of R ¹ and R ² is an alkoxy
Or an aromatic ring substituted with a siloxyl group ,
When at least one of R ¹ and R ² is an aryl group or an aralkyl group, two or more adjacent sites on the aromatic ring are substituted with an alkoxyl group, and these two or more alkoxyl groups are linked to each other. It may form a ring.