JPH04215658A - Radioactive ray sensitive negative type resist composition material - Google Patents

Abstract

PURPOSE:To obtain a negative type resist composition material which is sensitive to radioactive rays, has good balance of sensitivity, residual film ratio and resolution, has excellent heat resistance and dry etching resistance, and can be developed with fine processing alkali by containing a polymer containing vinyl phenol monomer unit, a triazine compound, and a sulfone compound generating acid via the radiation of radioactive rays. CONSTITUTION:This radioactive ray sensitive negative type resist composition material contains binder resin containing vinyl phenol monomer unit expressed by the formula 1, a triazine compound expressed by the formula 2, and a sulfone compound expressed by the formula 3. The resin of the formula 1 is obtained by ion-polymerizing or radical-polymerizing hydroxystyrene or alpha-alkyl hydroxystyrene. The compound of the formula 2 is easily bridge-reacted with binder resin via a small quantity of acid, and the molecular weight can be increased.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an alkali-developable negative-tone radiation-sensitive resist composition, and more specifically to a resist composition used in the manufacture of semiconductor integrated circuits such as ICs and LSIs, and masks. A negative-tone radiation-sensitive resist that is sensitive to radiation such as ultraviolet rays, electron beams, and X-rays, has a good balance of sensitivity, residual film rate, and resolution, and has excellent heat resistance and dry etching resistance and can be developed with alkali for microfabrication. The present invention relates to a composition.

0002

[Prior Art] Conventionally, in the production of semiconductor integrated circuits, etc., resist is applied onto a substrate such as a silicon wafer, radiation is irradiated through a mask, and development is performed to form a fine pattern. Etching is being carried out on the substrate portion. In recent years, in order to improve the performance and reliability of integrated circuits, there has been an increasing demand for higher density elements. As current resists, positive resists and negative resists are known.

Polymethyl methacrylate and polyolefin sulfone are known as positive resist compositions that are sensitive to radiation such as far ultraviolet rays, electron beams, and X-rays, but although the former has excellent resolution, it has very low sensitivity. Although the latter has high sensitivity, it has the disadvantage that dry etching cannot be performed. Also, U.S. Patent No. 4,339,522 and Ch.
emische Berichte 92,130 (
Attempts have also been made to utilize oxydiazo compounds such as Meldrum's acid and dimedone as disclosed in 1959) as positive resist compositions. These compositions are alkaline-developable, have good resolution, and have no problem with dry etching resistance, but they are unstable under thermal loads and sublimate during prebaking, resulting in a considerable amount of loss. There are drawbacks.

[0004] As negative resist compositions, resin compositions containing chloromethylated polystyrene or chlorinated polymethylstyrene in which polystyrene is used as a backbone polymer are known. Development processing using an alkaline aqueous solution is generally advantageous in order to increase resolution, but these compositions have high sensitivity and excellent dry etching resistance, but because development processing is performed using an organic solvent, the transferred pattern may be affected by swelling. It has the disadvantage of poor resolution due to distortion and peeling of the film. JP-A-63-191142 has an example of a composition using an alkali-soluble resin and a bisazide compound. These compositions can be developed with an alkaline aqueous solution, do not swell, and have improved resolution. However, since azide compounds produce reaction products such as azo compounds when irradiated with ultraviolet rays, the absorption near the irradiated light increases, and the problem is that the light does not reach the bottom of the resist layer sufficiently, resulting in an inverted trapezoidal pattern. be. Furthermore, this compound has the disadvantage that it does not have sufficient sensitivity to radiation such as electron beams and X-rays.

On the other hand, a resist composition comprising a thermosetting resin and a halogen compound as a photoacid generator (JP-A-6
No. 2-164045) is known. This resist composition can be developed with alkali and has high sensitivity, but the transferred pattern obtained by irradiation with an electron beam has low image contrast, and the cross-sectional shape is prone to streaks and has a high resolution pattern, such as adjacent patterns joining together. The disadvantage is that it is difficult to obtain.

On the other hand, a resist composition comprising a novolac resin as an alkali-soluble resin, an alkoxymethylated melamine resin polymerized by acid, a halogenated triazine compound as an acid generator, and a benzophenone ester compound of naphthoquinonediazide as an additive (JP-A-2003-100000) -2
17855) is known. However, this resist composition requires a long development time in order to obtain a high-resolution pattern, and is not practical.

[0007]

[Problem to be solved by the invention] Microfabrication that is sensitive to radiation such as deep ultraviolet rays, electron beams, and X-rays, has a good balance of sensitivity, residual film rate, and resolution, and has excellent heat resistance and dry etching resistance. There is a need for the development of negative-tone radiation-sensitive resist compositions that can be developed with alkali.

[0008]

[Means for Solving the Problems] The present inventors have conducted intensive research to solve the above-mentioned problems, and as a result, they have arrived at the present invention. That is, the present invention provides formula (1)

0
009]

(In formula (1), R1 represents a hydrogen atom or a methyl group.) A binder resin having a group represented by formula (2)

[0011]

(In formula (2), R2, R3, R4,
R5 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R6 represents an alkyl group having 1 to 3 carbon atoms or a formula

(wherein R7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms) and a compound represented by formula (3)

[
0015

(In formula (3), R8 and R9 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X1, X2, and X3 each independently represent a hydrogen atom,
Indicates a chlorine atom, a bromine atom, or an iodine atom. ) It is an object of the present invention to provide a negative radiation-sensitive resist composition characterized by containing a compound represented by the following.

The negative radiation-sensitive resist composition of the present invention will be explained in detail below.

The binder resin used in the negative radiation-sensitive resist composition of the present invention is a polymer or copolymer having a structural unit represented by the above formula (1), such as hydroxystyrene or α-alkylhydroxystyrene. It can be obtained by ionic polymerization or radical polymerization. The position of the -OH group in each polymer is
It may be located at any of the o-position, m-position, and p-position. As the other vinyl monomer used in the copolymer, any monomer that can be copolymerized with hydroxystyrene or α-alkylhydroxystyrene can be used. Specific examples include acrylic acid monomers such as (meth)acrylic acid and (meth)acrylic esters, and styrene monomers such as styrene, α-alkylstyrene, and vinyltoluene.

In addition, in order to increase the solubility difference in an alkaline developer between the radiation irradiated area and the unirradiated area and improve the image contrast, as well as to improve the adhesion to the silicon substrate or the chromium substrate, the above-mentioned (1) Among the polymers represented by the formula, weight average molecular weight (Mw) is 2,0
00 to 20,000, preferably 4,000 to 15
,000 is given as a preferable example.

The compound represented by the above formula (2) as a component of the negative radiation-sensitive resist composition of the present invention easily undergoes a crosslinking reaction with the binder resin with a small amount of acid to increase the molecular weight, and as a result, the irradiated area and A difference in solubility in the alkaline developer occurs in the unirradiated area.

Specific examples of the compound represented by formula (2) are as follows: (2-1) 2,4-bis(bismethoxymethyl)amino-6-phenyl-
1,3,5-s-triazine (2-2)
2-(N-ethoxymethyl-N'-methoxymethyl)amino-4-bismethoxymethylamino-6-phenyl-1,3,5-s
-triazine (2-3)
2,4-bis(bisbutoxymethyl)amino-
6-methyl-1,3,5
-s-triazine (2-4) 2,4-bis(bismethoxymethyl)amino-6-ethyl-1
,3,5-s-triazine(2
-5) 2,4-bis(bisethoxymethyl)amino-6-ethyl-1
,3,5-s-triazine (2-6) 2
,4-bis(bisbutoxymethyl)amino-6-ethyl-1 ,3,5-s-triazine(2-7) 2,4-bis(bismethoxymethyl)amino-6-butyl-1
,3,5-s-triazine (2-8)
2,4-bis(bisethoxymethyl)amino-
6-butyl-1,3,5
-s-triazine (2-9) 2,4-bis(bisbutoxymethyl)amino-6-butyl-1
,3,5-s-triazine(2
-10) 2,4-bis(bismethoxymethyl)
Amino-6-methyl-1
,3,5-s-triazine (2-11)
2,4-bis(bisethoxymethyl)amino-6
-Phenyl- 1,3,5
-s-triazine(2-12) 2,4-bis(
bisbutoxymethyl)amino-6-phenyl-
1,3,5-s-triazine (2
-13) 2,4-bis(bismethoxymethyl)
Amino-6-tolyl-1
,3,5-s-triazine (2-14) 2,4
-bis(bisethoxymethyl)amino-6-tolyl-1
,3,5-s-triazine(2-15) 2,4-bis(bisbutoxymethyl)amino-6-tolyl-1
,3,5-s-triazine (2-16)
2,4-bis(bismethoxymethyl)amino-6-cumyl-1,3,5-s-triazine(2-17) 2,4-bis(bisethoxymethyl)amino-6-cumyl-1
,3,5-s-triazine (2-18)
2,4-bis(bisbutoxymethyl)amino-6
-cumyl-1,3,5-
s-triazine (2-19) 2-(N-ethoxymethyl-N'-methoxymethyl)amino-
4-bismethoxymethylamino-6
-methyl-1,3,5-s-
Triazine (2-20) 2,4-bis(bisethoxymethyl)amino-6-methyl-1
,3,5-s-triazine
(2-21) 2-(N-butoxymethyl-
N'-ethoxymethyl)amino-
4-bismethoxymethylamino-6-methyl-
1,3,5-s- triazine (2-22) 2-(N-butoxymethyl-
N'-ethoxymethyl)amino-
Examples include 4-bismethoxymethylamino-6-phenyl-1,3,5-s-triazine, but the present invention is not limited thereto. Further, these compounds can be used alone or in combination of two or more.

The compound represented by the formula (3) as a component of the negative radiation-sensitive resist composition of the present invention generates an acid when irradiated with radiation, particularly high-energy actinic light such as deep ultraviolet rays, electron beams, and X-rays. It is a compound.

Specific examples of the compound represented by formula (3) are as follows: (3-1) Tribromomethylphenylsulfone (3-2) Dichloromethylphenylsulfone (3-3) Trichloromethylphenylsulfone (3- 4) Monobromomethylphenylsulfone (3-5) Dibromomethylphenylsulfone (3-6) Monochloromethylphenylsulfone (3-7) Monoiodomethylphenylsulfone (3-8) Diiodomethylphenylsulfone (3-9) ) Triiodomethylphenyl sulfone (3-10)
Monochloromethyltolylsulfone (3-11)
Dichloromethyltolylsulfone (3-12) Trichloromethyltolylsulfone (3-13) Monobromomethyltolylsulfone (3-14) Dibromomethyltolylsulfone (3-15) Tribromomethyltolylsulfone (3-16) Mono Iodomethyltolylsulfone (3-17) Diiodomethyltolylsulfone (3-18) Triiodomethyltolylsulfone (3-19) Monochloromethylcumylsulfone (3-20) Dichloromethylcumylsulfone (3-21) Trichloromethylcumylsulfone (3-22) Monobromomethylcumylsulfone (3-23) Dibromomethylcumylsulfone (3-24) Tribromomethylcumylsulfone (3-25) Monoiodomethylcumylsulfone ( 3-26) Diiodomethylcumyl sulfone (3-27) Triiodomethyl cumyl sulfone (3-28) Trichloromethyl-2,4-dimethylphenyl-sulfone (3-29) Tribromomethyl-2,4- Examples include dimethylphenyl-sulfone, but the present invention is not limited thereto. Moreover, these compounds can be used alone or in combination of two or more.

In the present invention, each component has a total solid content of 10
When 0 parts by weight, the binder resin containing the compound of formula (1) is 60 to 95 parts by weight, preferably 65 to 90 parts by weight, and the compound of formula (2) is 5 to 40 parts by weight, preferably 9 parts by weight. to 32 parts by weight, and the compound of formula (3) is preferably contained in an amount of 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight. If you deviate from the above range,
This is not preferred because it has an adverse effect on sensitivity, pattern shape, resolution, alkali solubility, and dry etching resistance.

The negative radiation-sensitive resist composition of the present invention is obtained by mixing the above-mentioned components, and is usually used in the form of a photosensitive solution by dissolving the above-mentioned components in an organic solvent. The organic solvents used in this case include ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol methyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, methyl cellosolve, ethyl cellosolve,
Examples include butyl acetate, amyl acetate, methyl ethyl ketone, methyl isobutyl ketone cyclohexanone, methyl lactate, ethyl lactate, butyl lactate, and the like. These may be used alone or in combination of two or more.

The negative radiation-sensitive resist composition of the present invention may further contain additives such as a plasticizer, a photochromic agent, a dye, an adhesion improver, and a surfactant, depending on the intended use.

Next, a method for forming a fine pattern using the composition thus obtained will be explained.

The total solid content of the prepared composition is added to the above-mentioned solvent at a concentration of 5 to 60%, preferably 10 to 4%.
After dissolving the solution to a concentration of 0%, adding the above-mentioned additives as necessary, and filtering as necessary to remove insoluble materials, a photosensitive solution is obtained. First, this photosensitive liquid is applied onto a substrate such as a silicon wafer or a chromium-deposited plate using a spinner to obtain a uniform film, and then this is baked at a temperature of 70 to 160°C, preferably 80 to 140°C. After drying the coating film, it is selectively irradiated with radiation such as far ultraviolet rays, electron beams, and X-rays, and further heated to 90 to 160°C, preferably 1
A fine pattern can be transferred onto a substrate by heating at a temperature of 00 to 150° C., subjecting it to a sensitization reaction treatment, and then developing it with an alkaline aqueous solution of an appropriate concentration.

The heat treatment after radiation irradiation is a treatment for increasing the sensitivity of the negative radiation-sensitive resist composition,
This is essential to achieving the purpose of the present invention. If the processing temperature is less than 90°C, it will be difficult to obtain practical sensitivity.
Furthermore, if the temperature exceeds 160° C., the transferred patterns tend to bond together, making it difficult to obtain a good pattern.

Examples of alkaline developers that can be applied to the negative radiation-sensitive resist composition of the present invention include aqueous organic alkali solutions such as tetramethylammonium hydroxide, triethylamine, and triethanolamine, sodium hydroxide, potassium hydroxide, sodium carbonate, Although inorganic alkaline aqueous solutions such as potassium carbonate can be used, it is preferable to use organic alkaline aqueous solutions in integrated circuit manufacturing processes.

The negative radiation-sensitive resist composition of the present invention has high sensitivity to radiation, and the transferred pattern has
It has no swelling and excellent resolution, and also has excellent dry etching resistance and heat resistance.

[0032]

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Polyhydroxystyrene (weight average molecular weight 5,200)
Product name: Linker M-S2P (manufactured by Maruzen Petrochemical Co., Ltd.) 73.9 parts by weight, 22.4 parts by weight of the compound (2-1) above, and 3.7 parts by weight of the compound (3-1) above at a concentration of was dissolved in ethyl lactate to a concentration of 18%, and the resulting solution was filtered under pressure using a membrane filter with a pore size of 0.2 μm to obtain a photosensitive solution.

Next, the photosensitive liquid thus obtained was applied to a chromium vapor-deposited substrate whose surface had been treated by a known method.
A resist layer having a thickness of 0.6 μm was obtained by spin coating at 00 rpm for 20 seconds and drying on a hot plate with a surface temperature of 120° C. for 90 seconds. Next, this resist layer was coated with 1.2 μC/cm2 at an accelerating voltage of 20 kV using an ELS-3300 electron beam lithography system manufactured by Elionix Co., Ltd.
After being irradiated with an electron beam with an energy of
A heat sensitization reaction was carried out for 600 seconds on a hot plate at ℃, and a tetramethylammonium hydroxide aqueous solution with a concentration of 2.35% by weight (trade name: TOKUSO SD-1) was prepared.
By immersing it in Tokuyama Soda Co., Ltd. (manufactured by Tokuyama Soda Co., Ltd.) for 60 seconds, the areas not irradiated with the electron beam were dissolved and removed to obtain a pattern. This transfer pattern had a residual film rate of 90% or more and had a rectangular cross-sectional shape. Further, it was confirmed that the minimum line width had a resolution of 0.15 μm, and no bonding between adjacent patterns was observed.

Examples 2 to 12 The type of binder resin, the type of compound represented by the above formula (2), the type of compound represented by the above formula (3) and their blending amounts, and the type of substrate are as shown in the table. The same operation as in Example 1 was performed except that the resist composition was changed to evaluate the characteristics of each resist composition. As a result, all the transfer patterns in Examples 2 to 12 had a residual film rate of 90% or more and a rectangular cross-sectional shape. The minimum line width is 0.2μ
It was confirmed that the film had a resolution capable of transferring m patterns, and no joining of adjacent patterns was observed.

[0036]

[0037]

(Note) In the above table, chromium-deposited substrates were used in Examples 2 to 6, and silicon wafers were used in Examples 7 to 12. Also, Examples 2 to 10
In Examples 11 to 12, far ultraviolet rays with a wavelength of 248 nm were used as radiation.

[0039]

[Effects of the Invention] The negative radiation-sensitive resist composition of the present invention has high sensitivity to radiation, and the pattern transferred to the substrate does not swell and has extremely high resolution. Furthermore, it has extremely excellent dry etching resistance and heat resistance. Therefore, it is extremely useful for manufacturing semiconductor integrated circuits.

Claims (1)

[Claims] Claim 1: A binder resin having a group represented by formula (1) (in formula (1), R1 represents a hydrogen atom or a methyl group), and a binder resin having a group represented by formula (2) (in formula (2), R2, R3, R4, R5 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R6 is an alkyl group having 1 to 3 carbon atoms or a formula (wherein R7 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). represents an alkyl group) and a compound represented by formula (3) (
In formula (3), R8 and R9 each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X1 and X2
, X3 each independently represents a hydrogen atom, a chlorine atom, a bromine atom or an iodine atom. ) A negative radiation-sensitive resist composition comprising a compound represented by: