JP2003140338A - Positive photosensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive photosensitive composition and a resist material having an excellent balance in various performances such as heat resistance, sensitivity, resolution. SOLUTION: The positive photosensitive composition containing (A) a hydroxystyrene polymer having the structural unit expressed by formula (1) and (B) a photosensitive agent which is decomposed by light, is characterized in that the hydroxystyrene polymer (A) has a syndiotactic structure having >=30% tacticity of racemipentad of the C1 carbon in the phenyl group by<13> C-NMR.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive type photosensitive material having improved heat resistance, sensitivity, resolution and the like which are sensitive to radiation such as ultraviolet rays, deep ultraviolet rays (including excimer lasers), electron beams, ion beams, X-rays and the like. Composition and resist material.

[0002]

2. Description of the Related Art Nowadays, with the high integration of integrated circuits, submicron pattern formation is required, and positive resists excellent in various properties such as heat resistance, profile, development residue (scum), sensitivity and resolution have been developed. Is requested. Especially 16 ~
In the production of 64M DRAM, it is necessary to resolve a pattern having a line width of 0.5 μm or less with a good profile. For example, to improve the heat resistance of the resist,
There is a method of removing or reducing low molecular weight components in the resin. However, this method usually suffers from reduced sensitivity and reduced throughput in integrated circuit fabrication.

Further, as the integrated circuit is highly integrated, dry etching has become the mainstream instead of the conventional wet etching. In dry etching, the temperature of the substrate is likely to rise, and the dimensional accuracy is lowered due to the thermal deformation of the resist pattern, so good heat resistance is required. From this point of view, JP-A-58-221842
Japanese Patent Laid-Open No. 3-185447, Japanese Patent Laid-Open No. 6-7
Looking at the technology of a photosensitive resin composition composed of an alkali-soluble resin and a quinonediazide compound disclosed in, for example, Japanese Patent No. 5369 and Japanese Patent Publication No. 7-66184, atactic in which the three-dimensional structure of the alkali-soluble resin component is not regular Since it has a structure, the heat resistance of the alkali-soluble resin component is low, so that it cannot be said that the photosensitive resin composition is at a satisfactory level in terms of the balance of various properties such as heat resistance, sensitivity and resolution.

[0004]

An object of the present invention is to provide a positive photosensitive composition and a resist material which are excellent in balance of various properties such as heat resistance, sensitivity and resolution.

[0005]

Means for Solving the Problems That is, as a result of intensive studies by the present inventor, a positive type photosensitive composition comprising a hydroxystyrene polymer having a syndiotactic structure and a photodegradable photosensitizer was found to be heat resistant. The present invention has been accomplished by discovering that a resist pattern having a good balance of various properties such as property, sensitivity and resolution is provided.

That is, the present invention provides (A) the following formula (1)

[Chemical 2] A positive type photosensitive composition comprising a hydroxystyrene polymer having a structural unit represented by: and (B) a photodegradable photosensitizer, wherein (A) the C ₁ carbon of the phenyl group of the hydroxystyrene polymer A positive photosensitive composition, characterized in that it is a hydroxystyrene polymer having a syndiotactic structure having a tacticity of 30% or more in racemic pentad by ¹³ C-NMR. In particular, (B) the photodecomposable photosensitizer is a quinonediazide compound, which is a positive photosensitive composition. The present invention is a resist material using the positive photosensitive composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in more detail below. The polymer used as the component (A) of the present invention is a racemic pen having a C ₁ carbon tacticity of the phenyl group of the hydroxystyrene unit having the structural unit represented by the above general formula (1) by ¹³ C-NMR. It is a polyhydroxystyrene polymer having a syndiotactic structure characterized by having a tod of 30% or more. Here, the syndiotactic hydroxystyrene-based polymer used as the component (A) has a syndiotactic structure, that is, phenyl, which is a side chain with respect to the main chain formed from carbon-carbon bonds. The group has a steric structure in which the groups are alternately located in opposite directions, and the tacticity thereof is quantified by a nuclear magnetic resonance method (NMR method).

Specifically, the C ₁ carbon signal of the aromatic ring, the methine / methylene carbon signal or ¹³ H by the ¹³ C-NMR method (nuclear magnetic resonance spectrum with isotope carbon).
-By analysis of the proton signal of NMR. Tacticity quantified by NMR is the abundance ratio of a plurality of continuous structural units (that is, a relative conformational ratio of continuous structural units), for example, in the case of two diads, in the case of three. Triads can be represented by pentads in the case of 5, but having a syndiotactic structure in the present invention means 30% in racemic pentads.
Say more than that. Preferably 7 in racemic diads
It is 5% or more, more preferably 85% or more. Alternatively, a racemic pentad having a syndiotacticity of 50% or more is preferable. More preferably 75%
It is above, and more preferably 85% or more.

However, the degree of syndiotacticity varies slightly depending on the type of substituent and the content of each repeating unit. In the syndiotactic hydroxystyrene-based polymer of the present invention, the repeating units bonded are:
Each of the hydroxystyrene units has a syndiotactic structure (co-syndiotactic structure). The hydroxystyrene polymer having a syndiotactic structure according to the present invention does not necessarily need to be a polymer having a single stereoregularity. As long as the tacticity is within the above range, a mixture with a styrene-based polymer having an isotactic or atactic structure or a hydroxystyrene-based copolymer having an atactic structure may be incorporated in the polymer chain.

The syndiotactic hydroxystyrene-based polymer of the present invention may be a polymer consisting essentially of hydroxystyrene units, but within the range in which the hydroxystyrene units can exhibit the effects of the present invention. It may be a copolymer having another unit derived from one or more vinyl compounds other than the hydroxystyrene unit. Even in the case of a copolymer, the hydroxystyrene unit is preferably present in an amount of 50 mol% or more based on the whole polymer.
Examples of vinyl compounds for forming units other than hydroxystyrene units include aromatic vinyl compounds and unsaturated acid esters.

The aromatic vinyl compound as used herein is a compound in which a vinyl group is bonded to an aromatic ring, and specific examples thereof include styrene, m- or p-toxystyrene, m- or p-ethoxystyrene, m- or p-propoxystyrene, m- or p-isopropoxystyrene, m- or p-butoxystyrene, m- or p-tert-butoxystyrene,
m- or p- (1-ethoxyethoxy) styrene, m- or p- (1-ethoxypropoxy) styrene, m- or p-
(1-isobutoxyethoxy) styrene, m- or p-
(2-tetrahydropyranyloxy) styrene, m- or p-tert-butoxycarbonyloxystyrene, m- or p-acetoxystyrene, m- or p-propionyloxystyrene, m- or p-pivaloyloxystyrene, m
-Or p-benzoyloxystyrene, m- or p-mesyloxystyrene, m- or p-phenylsulfonyloxystyrene, m- or p-tosyloxystyrene and the like are included.

The unsaturated acid ester is acrylic acid,
Methacrylic acid, maleic acid, fumaric acid, various esters of carboxylic acid having an unsaturated bond such as itaconic acid, specifically, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate,
Tert-butyl acrylate, cyclohexyl acrylate,
Phenyl acrylate, benzyl acrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-acrylate
Adamantyl, 3-hydroxy-1-adamantyl acrylate, 2-oxo-3-tetrahydrofuryl acrylate,
Methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, methacrylic acid te
rt-Butyl, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-methacrylic acid
Methyl-2-adamantyl, 2-ethyl-2-methacrylate
It includes adamantyl, 3-hydroxy-1-adamantyl methacrylate, 2-oxo-3-tetrahydrofuryl methacrylate, diethyl maleate, diethyl fumarate, diethyl itaconate and the like. In addition, various compounds having an unsaturated bond such as maleic anhydride, 1,3-butadiene, acrylonitrile, methacrylonitrile, vinyl chloride and vinyl acetate can be converted into structural units other than those represented by the formulas (1) and (2). It can be a vinyl monomer for guiding.

In the syndiotactic hydroxystyrene polymer of the present invention, its number average molecular weight (Mn) is preferably 1,000 to 10,000,000, more preferably 2,000.
-5,000,000, more preferably 3,000-2,000,000. If the molecular weight is too small, the heat resistance will decrease, and the physical properties of the resist polymer will be inadequate. Conversely, if the molecular weight is too large, molding will be difficult. The preferred range of the molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the syndiotactic hydroxystyrene polymer of the present invention is 15
Hereafter, it is more preferably 10 or less, and even more preferably 3.0 or less. Particularly preferably 2.5 or less,
Most preferably, it is 2.0 or less. If the molecular weight distribution is too wide, problems such as a decrease in heat resistance and a decrease in resolution occur, which is not preferable.

Such a syndiotactic hydroxystyrene polymer uses, for example, a reaction product of a transition metal compound component such as cyclopentadienyl titanium trichloride and a cocatalyst component such as an aluminoxane compound or a boron compound as a catalyst. It is obtained by polymerizing hydroxystyrene whose hydroxyl group is protected by a protecting group such as trialkylsilyl group, and then removing the protecting group.

The photodecomposable photosensitizer of the component (B) is an ultraviolet ray,
It means that it decomposes by being sensitive to radiation such as electron beams, resulting in a change in solubility and solubilization in an alkaline aqueous solution. Known photodegradable photosensitizers can be used.
Of these, quinonediazide compounds are preferred. Further, among the quinonediazide compounds, quinonediazidesulfonic acid ester compounds and quinonediazidesulfonic acid amide compounds can be mentioned as preferable compounds in terms of heat resistance.

A preferred example of the quinonediazide compound synthesized in this manner will be specifically shown. As the quinonediazide sulfonate compound, hydroquinone-1,
2-naphthoquinonediazide- (2) -5-sulfonic acid ester, resorcin-1,2-naphthoquinonediazide- (2)-
5-5-sulfonic acid ester, 2,4-dihydroxybenzophenone-1,2-naphthoquinonediazide- (2) -5-
Sulfonic acid ester, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide- (2) -5-
Sulfonic acid ester, 2,2 ', 4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-
(2) -5-sulfonic acid ester, 4,4′-dihydroxydiphenyl-1,2-naphthoquinonediazide- (2) -5
Sulfonic acid ester, 4,4'-dihydroxydiphenylsulfone-1,2-naphthoquinonediazide- (2) -5-sulfonic acid ester, tris (4-hydroxyphenyl) methane-1,2-naphthoquinonediazide- (2)- 5-sulfonic acid ester,

Hydroquinone-1,2-naphthoquinonediazide- (2) -4-sulfonic acid ester, resorcin-1,
2-naphthoquinonediazide- (2) -4-sulfonic acid ester, phloroglucin-1,2-naphthoquinonediazide-
(2) -4-sulfonic acid ester, 2,4-dihydroxybenzophenone-1,2-naphthoquinonediazide- (2)-
4-sulfonic acid ester, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide- (2)-
4-sulfonic acid ester, 2,2 ', 4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide
-(2) -4-sulfonic acid ester, 4,4'-dihydroxydiphenyl-1,2-naphthoquinonediazide- (2) -4
-Sulfonic acid ester, 4,4'-dihydroxydiphenyl sulfone-1,2-naphthoquinonediazide- (2) -4-
Sulfonic acid ester, tris (4-hydroxyphenyl) methane-1,2-naphthoquinonediazide- (2) -4-
Examples thereof include sulfonic acid ester.

Examples of the quinonediazide sulfonic acid amide compound include 1,4 phenylenediamine-1,2-naphthoquinonediazide- (2) -5-sulfonic acid amide and 4,4'-diaminogephenylsulfone-1,2-naphthoquinonediazide. -(2) -5-Sulfonamide, 4,4'-diaminogephenylmethane-1,2-naphthoquinonediazide-
(2) -5-Sulfonamide, 3,3′-diaminogephenylsulfone-1,2-naphthoquinonediazide-
(2) -5-Sulfonamide, 3,3'-diaminogephenylmethane-1,2-naphthoquinonediazide- (2)-
5-sulfonic acid amide, 1,4-phenylenediamine-
1,2-naphthoquinonediazide- (2) -4-sulfonic acid amide, 4,4′-diaminogephenylsulfone-1,2
-Naphthoquinonediazide- (2) -4-sulfonic acid amide,
4,4'-diaminogephenylmethane-1,2-naphthoquinonediazide- (2) -4-sulfonic acid amide, 3,
3'-diaminogephenylsulfone-1,2-naphthoquinonediazide- (2) -4-sulfonic acid amide, 3,3'-
Mention may be made of diaminogephenylmethane-1,2-naphthoquinonediazide- (2) -4-sulfonic acid amide.

The amount of the quinonediazide compound used is usually preferably 5 to 100 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the syndiotactic hydroxystyrene polymer of the photosensitive composition. If the amount is less than 5 parts by weight, the insolubilizing effect of the quinonediazide compound on the syndiotactic hydroxystyrene polymer is insufficient, and the alkali solubility between the light-irradiated portion and the non-irradiated portion cannot be differentiated and patterning becomes difficult. There is.
On the other hand, if it exceeds 100 parts by weight, all of the added quinonediazide compound cannot be decomposed by light irradiation for a short time, and it may be difficult to develop with a developing solution containing an alkaline aqueous solution.

The photosensitive composition of the present invention is prepared by dissolving a syndiotactic hydroxystyrene polymer and a photodegradable photosensitizer in a solvent. The solvent used at this time is preferably one which has an appropriate drying rate and gives a uniform and smooth coating film. Such solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, methyl cellosolve acetate, ethyl. Glycol ether esters such as cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol propyl ether acetate,

Methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl oxyacetate, methyl 2-hydroxy-3-methylbutanoate,
3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, butyl acetate, methyl acetoacetate, aceto Examples thereof include esters such as ethyl acetate, ethyl pyruvate, n-amyl acetate and ethyl lactate, and ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone and γ-butyrolactone. These solvents may be used alone or in admixture of two or more. The amount of solvent is not particularly limited as long as it is possible to apply a coating film that is uniform on the substrate and has no pinholes or uneven coating.
The photosensitive composition solution is prepared so as to be 50% by weight.

A sensitizer may be added to the composition of the present invention in order to improve the sensitivity as a resist. As the sensitizer, 2H-pyrido [3,2-b] -1,4-oxazin-3 [4H] ones, 10H-pyrido [3,2-b] [1,4]
-Benzothiazines, urazoles, hydantoins,
Examples thereof include barbituric acids, glycine anhydrides, 1-hydroxybenzotriazoles, alloxans, maleimides and the like. The compounding amount of the sensitizer is 1,2-
1 to 100 parts by weight of the quinonediazide compound is usually used.
100 parts by weight, preferably 4 to 60 parts by weight.

Further, the composition of the present invention may contain a surfactant or the like for improving the coating property, for example, the developability of the irradiation product after striation or dry film formation. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate and the like. Nonionic surfactant, Fluorine surfactant,
Examples thereof include organosiloxane polymers and acrylic acid-based or methacrylic acid-based (co) polymers. The content of these surfactants is usually 2 parts by weight or less, preferably 1 part by weight or less, based on the solid content of the composition.

Dyes and pigments may be added to visualize the latent image on the radiation-irradiated portion and to reduce the effect of halation during radiation irradiation, and an adhesion aid may be added to improve the adhesiveness. A storage stabilizer, a defoaming agent, etc. can also be added. Examples of the storage stabilizer include butylamine, monoethanolamine, triethylamine, aniline, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, tetraethylthiuram monosulfide, tetrabutylthiuram monosulfide, dipenta. Examples thereof include methylene thiuram tetrasulfide. The amount of these storage stabilizers used is usually 10 parts by weight or less, preferably 0.001 to 5 parts by weight, based on 100 parts by weight of the alkali-soluble resin. Furthermore, if necessary, filtration or the like is performed to prepare a composition.

[0025]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these. In the examples, “part” represents “part by weight”.

Example 1 and Comparative Example 1 Syndiotactic poly (p-hydroxystyrene)
[Weight average molecular weight: 4,200, dispersity: 1.45, syndiotacticity: 95% (racemic pentad,
¹³ C-NMR)] (abbreviated as polymer-1 in the table), atactic poly (p-hydroxystyrene) [weight average molecular weight: 4,400, dispersity: 1.51, syndiotacticity: 2% (racemic pentad, ¹³ C-N
MR)] (abbreviated as polymer-R1 in the table), 2,3,4-trihydroxybenzophenone-1,2-
Naphthoquinonediazide- (2) -5-sulfonic acid ester (abbreviated as quinonediazide-1 in the table) was dissolved in 50 parts by weight of ethylene glycol monomethyl ether in a compounding amount shown in Table 1 below.

The resulting solution was filtered through a 0.2 μm Teflon (registered trademark) filter to prepare a solution of the photosensitive composition. This solution was applied onto a washed silicon wafer with a spin coater to a thickness of 1.10 μm, and baked on a hot plate at 90 ° C. for 60 seconds. The film thickness after baking was 1.08 μm. Next, a reduction projection exposure machine (manufactured by Nikon, NSR 17) having an exposure wavelength of 365 nm (i-line).
55i7A NA = 0.5) and the exposure amount was changed stepwise for exposure. This was developed with Sumitomo Chemical developer SOPD for 1 minute to obtain a positive pattern. The resolution was the exposure amount (effective sensitivity) at which the 0.4 μm line-and-space pattern became 1: 1 and the dimension of the line-and-space pattern that was separated without film reduction was evaluated by SEM (scanning electron microscope). The heat resistance was measured by measuring the temperature (° C.) at which a 3 μm line-and-space pattern begins to thermally deform when a silicon wafer is post-baked on a hot plate for 3 minutes.
The results are shown in Table 1 below.

[0028]

[Table 1]

[0029]

The positive-working composition of the present invention has excellent balance of various properties such as heat resistance, sensitivity and resolution.
Therefore, the above-mentioned photosensitive composition is particularly useful as a photoresist material used in the production of highly integrated circuits, but in addition to this, a photosensitive printing plate, an organic antireflection film, a photosensitive adhesive, a photosensitive material It is also useful as a photosensitive material such as a photosensitive coating material, a photosensitive sealant, a photosensitive coating material and a photosensitive film.

Claims (3)

[Claims] (A) The following formula (1): A positive type photosensitive composition comprising a hydroxystyrene polymer having a structural unit represented by: and (B) a photodegradable photosensitizer, wherein (A) the C ₁ carbon of the phenyl group of the hydroxystyrene polymer A positive photosensitive composition, which is a hydroxystyrene polymer having a syndiotactic structure and having a tacticity of 30% or more in terms of racemic pentad by ¹³ C-NMR. 2. The positive photosensitive composition according to claim 1, wherein the photodegradable photosensitizer (B) is a quinonediazide compound. 3. A resist material using the positive photosensitive composition according to claim 1.