JP2676981B2 - Photosensitive resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive resin composition used for a radiation sensitive resist used for forming a fine pattern of a semiconductor device such as a VLSI. is there.

[Prior Art] With the demand for high integration of semiconductor devices, development of fine processing technology at the quarter micron level is underway. Several methods have been studied to realize this technology.Among them, an excimer laser is used as an exposure radiation source to shorten the wavelength of the light source used in the photolithography technology, and optical interference is used. Exposure techniques such as the use of electron beams and X-rays as exposure radiation sources, which can ignore problems, are drawing attention.

BACKGROUND ART Conventionally, as a resist for photolithography, a resist composed of a novolac resin and naphthoquinone azide has been known, and these have excellent properties such as high resolution, dry etching resistance, and high sensitivity.

However, as the wavelength of the exposure radiation source becomes shorter, problems such as incompatibility of the photosensitive wavelength and poor transmittance of the resist itself for the shorter wavelength occur.

As resists for electron beams and X-rays, positive resists such as polymethacrylate resins and polyolefin sulfone resins, and negative resists such as chloromethylated polystyrene have been developed. However, the former has the drawback of low dry etching resistance and low sensitivity, and the latter has the drawback of reduced resolution due to swelling by the developer.

Further, JP-A-60-175046 discloses an alkali-soluble phenolic resin and a radiation-sensitive onium salt, which have a dissolution resistance in an alkali solution before exposure and become alkali-soluble in a portion thereof when exposed to radiation. Are disclosed. Further, JP-A-63-59131 discloses a composition of an alkali-soluble polymer compound and an alkali-insoluble organic acid ester which decomposes an ester upon irradiation with high-energy radiation to generate a carboxylic acid. The purpose is to obtain a highly sensitive resist.

On the other hand, a resist process for making up for the defects of the resist is also being studied. A thick flattening organic layer is formed on a semiconductor substrate, and the resist pattern of the upper layer is sequentially transferred to the lower layer by dry etching, and the aspect ratio of Multilayer processes have been developed to form high resist patterns.

[Problems to be Solved by the Invention] However, although the composition disclosed in the above publication has some improvement in various performances, it is difficult to improve it to a practical level, and the composition has a multilayer structure. In the method, the dry etching process must be performed several times in order to transfer the resist pattern, and there is a problem that a very complicated process process and a long process time are required.

The present invention has been made to solve the above problems, and provides a photosensitive resin composition capable of obtaining a positive-type radiation-sensitive resist having high sensitivity to radiation exposure and resolution of quart-micron level. With the goal.

[Means for Solving the Problems] The photosensitive resin composition of the present invention comprises an alkali-soluble polymer compound, a compound that generates an acid upon exposure to radiation, and a compound represented by the following general formulas (I) and (II). It contains at least one of the above.

(Ar in the formula represents a benzene ring or a heterocyclic compound of the m-substituted, Y is -, - O -, - SO 2 -, - CH 2 -, - CO -, - C
Represents one of (CH ₃ ) ₂ − and —C (CF ₃ ) ₂ −,
X represents one of --COO--, --OCOO--, and --SO _3- ,
R ₁ , R ₂ and R ₃ represent an alkyl group, an alkoxy group, an alkenyl group or an alkynyl group having n carbon atoms, R ₁ ,
Either R ₂ or R ₃ has n = 2 or more, and two of them may have a ring structure. However, m is 1 to 4
Indicates an integer. ) [Action] In the present invention, the alkali-soluble polymer compound interacts with at least one of the compounds represented by the general formulas (I) and (II) and is insoluble in an alkaline aqueous solution. Become. However, when exposed to radiation, at least one of the compounds represented by the above general formulas (I) and (II) is generated due to the effect of the acid generated from the coexisting radiation-generating compound. Is decomposed, and the portion irradiated with radiation becomes soluble in alkali. As a result, a positive pattern can be formed. In order for this decomposition reaction to occur, it is essential to generate an acid, but it is often possible to significantly improve the sensitivity by adding a heating step.

[Examples] In the compounds represented by the above general formulas (I) and (II) according to the present invention, when X is -COO-, the corresponding carboxylic acid halide and alcohol are used in a tertiary amine. It can be synthesized by a general method of condensation reaction, and -OCOO-
If it can be synthesized by a method of condensing a method or corresponding hydroxy compound with Jikaboneito to condensation hydroxy compound and the carbonic acid halide with a tertiary amine To each applicable, -SO ₃ - applicable each case a Can be synthesized by a condensation reaction of a sulfonic acid halide alcohol in a tertiary amine or a condensation reaction of a sulfonic acid silver salt and a bromide. Ar in the compounds represented by the general formulas (I) and (II) is, for example, benzene, naphthalene, anthracene, benzophenone, naphthoquinone, anthraquinone, pyridine, pyrazine, pyrimidine, pyridazine, triazine, tetrazine, pyrrole, imidazole, pyrazole, Triazole, phenanthridine, phenanthrene, benzocinnoline, quinoxaline, phenazine,
Azabenzonaphthene, polyazaphenanthrene, oxadiazine, benzooxadiazine, dioxadiazine,
Indole, benzimidazole, carbazole, quinoline, acridine, pyrocholine, furan, benzofuran, chromone, chromene, xanthone, thiophene, benzothiophene, oxazole, isoxazole, thiazole, benzothiazole, oxazoline, oxazolidine, benzooxathine, isatin, indolenine , Piperidone, isoquinoline, acridone, tropinone, flavone, pyrone, pyrrolidone, 4H-pyran-4-
And the like, which may be substituted with an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a halogen atom, or the like.

Examples of the alkali-soluble polymer compound (base polymer) according to the present invention include -OH, -COOH, -NH ₂
A polymer compound (including a copolymer) having an alkali-soluble functional group such as
For example, polyacrylic acid, polymethacrylic acid, poly-α-
Chloroacrylic acid, polyhydroxystyrene, poly-α
-Methyl hydroxystyrene, polystyrene carboxylic acid, polyaminostyrene, homopolymers such as polyallylamine or copolymers of these with polystyrene or polymethylmethacrylate, phenol novolac resins, cresol novolac resins, naphthol novolac resins, and the like, You may use these 2 or more types together.

Examples of the compound (photoacid generator) which generates an acid upon irradiation with radiation according to the present invention include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroarsineate and triphenylsulfonium hexafluoroarsineate. Phenylsulfonium hexafluorophosphate, triphenylsulfonium trifluorosulfonate, 4-thiophenoxydiphenylsulfonium tetrafluoroborate, 4-thiophenoxydiphenylsulfonium hexafluoroantimonate, 4-thiophenoxydiphenylsulfonium hexafluoroarsineate, 4- Thiophenoxydiphenylsulfonium hexafluorophosphate, 4-thiophenoxydiphenylsulfonium trifluorosulphate Nate, 4-tert-butylphenyl diphenyl sulfonium tetrafluoroborate, 4
-Tert-butylphenyldiphenylsulfonium hexafluoroantimonate, 4-tert-butylphenyldiphenylsulfonium hexafluoroarsineate, 4
-Tert-butylphenyldiphenylsulfonium hexafluorophosphate, 4-tert-butylphenyldiphenylsulfonium trifluorosulfonate, tris (4-methylphenyl) sulfonium tetrafluoroborate, tris (4-methylphenyl) sulfonium hexafluoroantimonate , Tris (4-methylphenyl) sulfonium hexafluoroarsineate, tris (4-methylphenyl) sulfonium hexafluorophosphate, tris (4-methylphenyl) sulfonium trifluorosulfonate, tris (4-methoxyphenyl) sulfonium tetrafluoro Borate, tris (4-methoxyphenyl) sulfonium hexafluoroantimonate, tris (4-methoxyphenyl) sulfonium hexaf Oroarushineito, tris (4
Methoxyphenyl) sulfonium hexafluorophosphate, tris (4-methoxyphenyl) sulfonium trifluorosulfonate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsineate, diphenyliodonium hexa Fluorophosphate, diphenyliodonium trifluorosulfonate, 3,3'-dinitrodiphenyliodonium tetrafluoroborate, 3,3'-dinitrodiphenyliodonium hexafluoroantimonate, 3,3'-dinitrodiphenyliodonium hexa Fluorolucinate, 3,3'-dinitrodiphenyliodonium hexafluorophosphate, 3,3'-dinitrodiphenyliodonium tri Le Oro sulfo Nate,
4,4'-dimethyldiphenyliodonium tetrafluoroborate, 4,4'-dimethyldiphenyliodonium hexafluoroantimonate, 4,4'-dimethyldiphenyliodonium hexafluoroarsineate, 4,
4'-dimethyldiphenyliodonium hexafluorophosphate, 4,4'-dimethyldiphenyliodonium trifluorosulfonate, 4,4'-ditert-butyldiphenyliodonium tetrafluoroborate, 4,
4'-ditert-butyldiphenyliodonium hexafluoroantimonate, 4,4'-ditert-butyldiphenyliodonium hexafluoroarsineate, 4,4 '
-Ditert-butyldiphenyliodonium hexafluorophosphate, onium salts such as 4,4'-ditert-butyldiphenyliodonium trifluorosulfonate, 2,4,6, -tris (trichloromethyl) triazine,
2-allyl-4,6-bis (trichloromethyl) triazine, α, α, α, -tribromomethyl-phenyl sulfone, α, α, α, α ′, α ′, α ′,-hexachloroxylylene, 2 , 2-bis (3,5-dibromo-4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane,
Halogen-containing compounds such as 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) ethane, 2-nitrobenzyl tosylate, 2,6-dinitrobenzyl tosylate, and 2,4-dinitrobenzyl tosiate. Examples thereof include sulfonate, methyl sulfonic acid 2-nitrobenzyl ester, acetic acid 2-nitrobenzyl ester, sulfonic acid ester such as p-nitrobenzyl-9,10-dimethoxyanthracene-2-sulfonate, and the like. You may use together.

Generally, the photosensitive resin composition of the embodiment of the present invention,
The compound according to the present invention is used together with a solvent which dissolves and does not react with them.
Methyl cellosolve, ethyl cellosolve, dimethyl glyme, diethyl glyme, cyclopentanone, cyclohexanone, γ-butyrolactone, isoamyl acetate and the like are common. Preferably, the boiling point is in the range of 100 to 220 ° C. If the boiling point is lower than this, unevenness is likely to occur, and if the boiling point is higher than this, it is not easy to dry the solvent.

The content ratio of the photosensitive resin composition of the example of the present invention,
The content of at least one of the compounds represented by the general formulas (I) and (II) is preferably 5 to 80% by weight, more preferably 10 to 40% by weight. The alkali-soluble polymer compound is preferably 20 to 95% by weight, more preferably 60 to 90% by weight. The amount of the compound that generates an acid upon irradiation with radiation is preferably 0.05 to 20% by weight, more preferably 0.5 to 10% by weight.
When at least one of the compounds represented by the general formulas (I) and (II) is less than 5% by weight, patterning tends to be difficult to perform, and when it exceeds 80% by weight, it may be mixed with other components. Since it becomes difficult to obtain uniform compatibility, defects in the formed pattern are likely to occur. Further, when the amount of the compound that generates an acid upon irradiation with radiation is less than 0.05% by weight, it becomes difficult to form a good pattern, and when it exceeds 20% by weight, a uniform phase with other components is formed. Since it becomes difficult to obtain the solubility, defects in the formed pattern are likely to occur.

Next, the case where pattern formation is performed using the photosensitive resin composition of the embodiment of the present invention will be described. The solution of the photosensitive resin composition of the embodiment of the present invention is applied on a substrate such as a silicon wafer, prebaked, UV light, Deep
After irradiation with radiation such as UV light, X-rays, and electron beams, heating at about 80 to 150 ° C. is performed for 30 seconds to 20 minutes, and then development can be performed to form a pattern. As the resist developing solution, an aqueous solution of ammonia, triethylamine, dimethylaminomethanol, tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, choline, or the like can be used.

In addition, the photosensitive resin composition of the embodiment of the present invention, an adhesion improver for improving the adhesion between the substrate and the resist, for example, aminosilazane, aminoalkoxysilazane, alkylalkoxysilazane and the like, other necessary A compound suitable for the purpose may be contained according to the above.

The photosensitive resin composition of the present invention will be described below with reference to specific examples, but the invention is not limited thereto. Table 1 shows the compounds represented by the above general formula (I), and Table 2 shows the compounds represented by the general formula (II).

In the general formula (I), Ar is X is —COO—, R ₁ is —CH ₃ , R ₂ is —CH ₃ , and R ₃ is —CH ₂ —CH _3.
Compound 1 was synthesized by a general method in which a corresponding carboxylic acid halide and an alcohol are subjected to a condensation reaction in a tertiary amine so as to be −.

1.0 g of this compound, 3 g of p-vinylphenol polymer and triphenisulfonium triflate as an acid generator
0.1 g was dissolved in 7 ml of cyclohexanone and filtered with a 0.2 μm filter to prepare a solution of the photosensitive resin composition of one example of the present invention.

This solution was coated on a silicon wafer using a spin coater with a rotation speed of 3000 rpm and precured in an oven at 80 ° C for 15 minutes. Cool this substrate to room temperature,
An exposure of about 8 mJ / cm ² was performed with Deep UV light of 250 nm. After exposure 1
It was heated in an oven at 10 ° C. for 10 minutes and immersed in a 2% tetramethylammonium aqueous solution for 2 minutes.

A good pattern was obtained by this operation. Also, instead of using Deep UV light as the exposure radiation source, an electron beam with an acceleration voltage of 20 kV was
Even when irradiated with μC / cm2, a good pattern was obtained as with Deep UV light.

Examples 2 to 21 Using the compounds shown in Tables 1 and 2 and under the conditions shown in Table 3 in the same manner as in Example 1, solutions of the photosensitive resin compositions of Examples of the present invention were obtained. Next, as in Example 1, the sensitivity and resolution of this solution were examined and the results are shown in Table 3. as a result,
It was shown that all the examples showed a resolution of 0.35 μm or more and a sensitivity of 20 mj / cm ² or less.

[Effects of the Invention] As described above, the present invention contains an alkali-soluble polymer compound, a compound that generates an acid upon exposure to radiation, and at least one of the compounds represented by the following general formulas (I) and (II). It is possible to obtain a photosensitive resin composition capable of obtaining a positive-type radiation-sensitive resist having a high sensitivity to radiation exposure and a resolution of a quart-micron level, by using This photosensitive resin composition can be effectively used for manufacturing a required semiconductor element, and by using this photosensitive resin composition, patterning can be performed with high sensitivity and high resolution.

(Ar in the formula represents a benzene ring or a heterocyclic compound of the m-substituted, Y is -, - O -, - SO 2 -, - CH 2 -, - CO -, - C
Represents one of (CH ₃ ) ₂ − and —C (CF ₃ ) ₂ −,
X represents one of --COO--, --OCOO--, and --SO _3- ,
R ₁ , R ₂ and R ₃ represent an alkyl group, an alkoxy group, an alkenyl group or an alkynyl group having n carbon atoms, R ₁ ,
Either R ₂ or R ₃ has n = 2 or more, and two of them may have a ring structure. However, m is 1 to 4
Indicates an integer. )

Front page continued (72) Inventor Shigeru Kubota 8-1-1 Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Material Research Laboratory (72) Inventor Hiroshi Hizuka 8-1-1 Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture (56) Reference JP-A-1-106040 (JP, A) JP-A-1-300250 (JP, A) JP-A-63-27829 (JP, A) JP-A-3- 198059 (JP, A)

Claims (1)

(57) [Claims] 1. A photosensitive resin composition containing an alkali-soluble polymer compound, a compound which generates an acid upon exposure to radiation, and at least one of compounds represented by the following general formulas (I) and (II). (Ar in the formula represents a benzene ring or a heterocyclic compound of the m-substituted, Y is -, - O -, - SO 2 -, - CH 2 -, - CO -, - C
Represents one of (CH ₃ ) ₂ − and —C (CF ₃ ) ₂ −,
X represents one of --COO--, --OCOO--, and --SO _3- ,
R ₁ , R ₂ and R ₃ represent an alkyl group, an alkoxy group, an alkenyl group or an alkynyl group having n carbon atoms, R ₁ ,
Either R ₂ or R ₃ has n = 2 or more, and two of them may have a ring structure. However, m is 1 to 4
Indicates an integer. )