JPH04158363A - Pattern forming resist material - Google Patents

Abstract

PURPOSE:To obtain an extremely fine pattern by providing an alkali-soluble polymer compound protected by a protective group decomposed with the specific ratio of an alkali-soluble functional group by acid or base and compound generating acid or base via the radiation of radioactive rays. CONSTITUTION:In an alkali-soluble polymer compound (a) protected by a protective group decomposed with an alkali-soluble functional group 5-50% by acid or base, the relative action between the functional group and a substrate is generated by the existence of the functional group with high polarity, and the adhesion to the substrate is improved. Acid or base is generated at an exposure section, part of the protective group of the functional group offering the alkali- solubility of the compound (a) is decomposed, and the solubility of the compound (a) is decomposed, and the solubility of the exposure section of a composition material is improved. Part of the alkali-soluble section of the compound (a) is protected at a nonexposure section, and the solubility is made extremely lower than that of the well-known unprotected alkali compound. The solubility of the exposure section is sharply improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resist material for forming fine patterns with high precision.

[Prior Art] Patterning for microfabrication of semiconductor elements and the like is mainly performed by photolithography.

In this case, resists that are sensitive to actinic rays such as radiation are widely used, and conventionally, materials that decompose when irradiated with radiation or compounds that harden when irradiated with radiation have been used as resist materials.

However, these compounds undergo only a sequential reaction and react with irradiation energy, so the efficiency is extremely low and it is often impossible to expect a significant increase in anger level.

In recent years, in order to solve these problems, resists based on the idea of a so-called chemical reaction amplification mechanism have been studied.

This is a method of thermally promoting a chemical reaction by using an acid generated by light irradiation as a catalyst. In this method, the amount of light irradiation is sufficient to generate a catalytic amount of acid, and extremely high sensitivity can be achieved.

For example, in the method disclosed in JP-A No. 59-45439, a polymer having acid-labile groups on the side cap is used, and the acid generated by light irradiation generates alkali-soluble functional groups. We use a method that allows

On the other hand, the properties required of resist materials have become significantly more sophisticated in recent years, and it is impossible to satisfy all the properties by constructing a resist with a single polymer compound.Therefore, various properties are shared among several types. Many proposals have also been made regarding multi-component resists that use several materials in combination.

For example, Polymer Engineering 5c
a resist consisting of a novolac resin, a melamine resin, and an acid generator described in J.I.ence, Vol. 26, p. etc. have been proposed.

[Problem to be solved by the invention]

However, the above-mentioned former resist material has hydrophobic properties because the functional groups in its side chains are insoluble in alkali, resulting in poor adhesion to the substrate and resist peeling during development, resulting in poor patterning. I don't want sex.

These materials have negative photosensitivity, and swell with the developer, making it difficult to expect an improvement in resolution.

In the latter case, since it is a positive type, swelling can be avoided, but unexposed areas are melted to some extent, so film peeling is likely to occur during development, and problems such as a decrease in resolution and pattern accuracy are unavoidable.

The present invention was made to solve the problems of the prior art as described above, and it has high sensitivity to radiation, only the exposed area is faithfully dissolved in the developer, and moreover, it improves the adhesion mentioned above. Another object of the present invention is to provide a positive pattern forming resist material in which unexposed areas are hardly dissolved in a developer.

[Means for Solving the Problems] As a result of extensive research, the present inventors have found that 5 to 50% of the functional groups that confer alkali solubility are protected with protecting groups that are decomposed by acids or bases. A composition consisting of a polymer compound (a) and a compound (b) that generates an acid or base upon irradiation with radiation, and 5 to 50% of the functional groups that provide alkali solubility are decomposed by the acid or base. An alkali-soluble polymer compound (a) protected with a protective group, a compound (c) that generates an acid or base upon irradiation with radiation, and a compound (c) that becomes alkali-soluble when decomposed by an acid or base. It has been found that a composition is useful as a material for pattern formation in solving the above problems.

[For production]

In the present invention, an alkali-soluble polymer compound (a) in which 5 to 50% of the functional groups imparting alkali solubility is protected with a protecting group that can be decomposed by an acid or a base.
In this case, the presence of a highly polar functional group (a functional group that provides alkali solubility) causes interaction between the functional group and the substrate, thereby improving the adhesion with the substrate.

Then, an acid or base is generated in the exposed area, and this acid causes
Some of the protective groups of the functional groups that confer alkaline solubility in the alkali-soluble polymer compound (al) are decomposed, and the solubility of the exposed areas of the composition is improved.On the other hand, in the unexposed areas, the alkali-soluble polymer compound (a) Since a part of its alkali-soluble portion is protected, its solubility is extremely lower than that of commonly known unprotected alkali-soluble polymer compounds.

Therefore, the difference in solubility between the exposed and unexposed areas can be significantly improved, making it possible to form a pattern with high resolution.

Further, the compound (c) which becomes alkali-soluble by being decomposed by the acid or base described above becomes alkali-soluble by the acid or base, and at the same time, the compound (c) becomes alkali-soluble by the acid or base, and at the same time, the alkali-soluble polymer compound (a) has a functional group that provides alkali solubility. Some of the protecting groups are also decomposed, which greatly improves the solubility of the exposed portion of the composition and eliminates the above-mentioned problems.

〔Example〕

The alkali-soluble polymer compound (a) used in the present invention preferably has a structure with excellent dry etching resistance, and materials suitable for this purpose include:
Examples include phenol-formaldehyde resins such as phenol novolak resin, talesol novolak resin, and naphthol novolak resin, polyvinylphenol resin, or copolymers of vinylphenol and acrylic or styrene monomers.

The average molecular weight of these is from 2000 to 5o from a practical point of view.
ooo is desirable; if it is less than 2000, it will not be possible to obtain uniform coating properties and the dry etching resistance will decrease.
Further, if it is more than 50,000, the solubility of the exposed area during development may decrease and development residue may be generated, which is not preferable.

Next, the protective substituents for the functional groups that provide these alkali solubility include t-butoxycarbonyl group, t-amyloxycarbonyl group, 1-()ethyl)methoxycarbonyl group, t-butyl group, t-amine group, Examples include t-hexyl group, allyl group, and 2-cyclohexyl group.

The protection by these substituents is preferably within the range of 5 to 50% of the functional groups that confer alkali solubility to the alkali-soluble polymer compound. Below the lower limit of 5%, the difference in solubility between foggy light and unexposed light cannot be compensated for, causing film loss during development; when above 50%, the difference in solubility is sufficient, but the functional groups are reduced. This is not appropriate because the adhesion to the substrate decreases due to this, and the minute patterns tend to flow during development.

Next, as the compound (b) which generates an acid upon radiation irradiation in the present invention, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroalshite, triphenylsulfonium hexafluoroalshite, triphenylsulfonium Hexafluorophosphate, triphenylsulfonium trifluorosulfonate, 4-thiophynoxydiphenylsulfonium tetrafluoroborate, 4-thiophenoxydiphenylsulfonium hexafluoroarsinate, 4-thiophenoxydiphenylsulfonium hexafluoroarsinate, 4-thio Phenoxydiphenylsulfonium hexafluorophosphate, 4-thiophenoxydiphenylsulfonium trifluorosulfonate, 4-tert-butylphenyldiphenylsulfonium tetrafluoroborate, 4-tert-butylphenyldiphenylsulfonium trifluorosulfonate, tris(4 -Methoxyphenyl)sulfonium hexafluoroarshite, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsinate, diphenyliodonium hexafluorophosphate, diphenyliodonium trifluorosulfonate nate, 3.3'-dinitrodiphenyliodonium trifluorosulfonate, 4.4'-
Dimethyldiphenyliodonium tetrafluoroborate, 4,4'-dimethyldiphenyliodonium hexafluoroantimonate, 4,4'-dimethyldiphenyliodonium trifluorosulfonate, 4,4'-
Di-tert-butyldiphenyliodonium hexafluoroantimonate, 4.4'-di-tert-butyldiphenyliodonium hexafluorophosphate, 4
．． Onium salts such as 4'-di-tert-butyldiphenyliodonium trifluorosulfoite, 2,4.
6-) Lis(trichloromethyl)triazine, 2-allyl-4,6-bis(trichloromethyl)triazine,
α,α,α,-tribromomethyl-phenylsulfone,
α, α, α, α′, α′.

α', -hexachloroxylylene, 2,2-bis(3゜5-dibromo-4-hydroxyphenyl) -1,1゜1.3,3.3-hexafluoropropane, 1.1.1
-) halogen-containing compounds such as lis(3,5-dibromo-4-hydroxyphenyl)ethane; Examples include sulfonic acid esters such as leitate, methylsulfonic acid 2-nitrobenzyl ester, acetic acid 2-nitrobenzyl ester, and P-nitrobenzyl-9,10-dimethoxyanthracene-2-sulfonium.

In addition, as the compound (b) that generates a base upon radiation irradiation, 1. L 1-triphenylmethanol, 1.
1.1-)su(methoxyphenyl)methanol, 1,
L 1-tri(methylphenyl)methanol, l.

1.! -) Nitrophenyl) methanol, 1. l
.

1-triphenylcyanomethane, 1,1. l-)
IJ (methoxyphenyl)cyanomethane, 1,1.1-
Examples include tri(methylphenyl)cyanomethane.

In the first invention of the present invention, compound 99 of the above (a)
．． 95-80%, preferably 99-90%, and (b)
It is appropriate to select the compound within a composition range of 0.05 to 20%, preferably 1 to 10%.

If the above component is less than 0.05%, a good pattern cannot be formed, and if it exceeds 20%, residue may be generated during development or it may be difficult to obtain component compatibility, which is preferable. do not have.

Next, in the second invention of the present invention, the above-mentioned compound (a) and compound (b) are generally exceptional (similar ones are used. A compound that decomposes and becomes alkali-soluble (c
1 includes the following:

That is, - an ester compound represented by formula (1), (R,
H-X Rz (1) (wherein, R,
represents an n-valent alkyl group or aryl group, R2 is a t-butyl group, L-amyl group, 1.1.1-(triethyl)methyl group, phenyl group, Hensyl group, α-methylhensyl group, α, α′ It represents a dimethylhensyl group, etc., n represents an integer of 1 to 4, and X represents any one of -C00-1-803-. ) Also, a carbonate compound represented by the following general formula (n), (R3--OCOO-R4(I[) (wherein, R3 represents an n-valent aryol group, and R4 represents a t-butyl group) , t-amyl group, 1,1.1- (triethyl)
It represents a methyl group, a phenyl group, a benzyl group, an α-methylbenzyl group, an α, α' dimethylbenzyl group, and n represents an integer of 1 to 4. ) Furthermore, an oxime ester compound represented by the formula (I[l), (R5hr--C00N=R6(I[[) (wherein R1
represents an n-valent alkyl group or an aryl group, R6 represents an alkylene group, and n represents an integer of 1 to 4. ) The ester compound represented by formula CI) above can be easily synthesized by reacting an acid chloride with a corresponding alcohol. Examples of the acid chloride include isophthalic acid dichloride, terephthalic acid dichloride, benzenetricarboxylic acid chloride,
Benzophenone dicarboxylic acid chloride, diphenyl ether dicarboxylic acid chloride, polyphenylmethane dicarboxylic acid chloride, naphthalene dicarboxylic acid chloride, benzene disulfonic acid chloride, benzene trisulfonic acid chloride, diphenyl ether disulfonic acid chloride, polyphenylmethane disulfonic acid chloride, hexamethylene dicarboxylic acid chloride , cyclohexyldicarboxylic acid chloride, butanetetracarboxylic acid chloride, and the like.

Further, the carbonate compound represented by formula (If) is bisphenol A or bisphenol S.

It can be easily synthesized by reacting a phenol compound such as biphenol, catechol, phloroglycitur, or pyrogallol with di-t-butyl dicarponate.

Furthermore, the oxime ester compound represented by formula (III) can be synthesized by reacting the above-mentioned acid chloride with oximes such as acetoxime, cyclohexane oxime, acetophenone oxime, and benzophenone oxime.

In the second aspect of the present invention, the three types of components, namely (
90-40% of compound a), 10-60% of compound (b)
%, the compound (c) is suitably selected within a composition range of 0.05 to 20%. When the content of the compound (a) is 90% or more, patterning by exposure becomes difficult because the component (c) is small, and when it is below 40%, the content of alkali-soluble polymer compounds is low, resulting in poor dry etching resistance. Also, if component (c) is 0.0
If it is less than 5%, it will not be possible to form a good pattern, and if it exceeds 20%, a residue will be generated during development or it will be difficult to obtain compatibility of the three components, both of which are preferable. do not have.

In the present invention, the compositions of the first and second inventions are prepared as solutions and applied using a spin coater or the like, and the solvent used at that time is the two components,
Alternatively, it can be used almost without exception as long as it does not react with the three components. For example, cellosolve acetate, dimethyl glyme, dimethyl diglyme, cyclohexanone, cyclopentanone, methyl isobutyl ketone, isoacetate, amyl, dioxane, etc. are common.

A method of carrying out the present invention is to apply a solution containing the above-mentioned pattern-forming resist material to a substrate such as a silicone wafer, heat it to remove the solvent, and then irradiate it with radiation through a mask having a predetermined pattern. (in the case of a sagittal line), heating is performed at 60 to 150°C, and then development is performed.

As the developer at this time, an aqueous solution of ammonia, triethylamine, dimethylethanol, tetramethylammonium hydroxide, sodium hydroxide, sodium carbonate, etc. can be used.

The pattern-forming resist material of the present invention is composed of two or three components as described above, and an adhesion improver (for example, aminosilazane, (aminoalkoxysilane, alkyl alkoxysilane, metal chelate, etc.) and other compounds for other purposes can be added as necessary.

The pattern forming material of the present invention can be used as a resist for microfabrication of semiconductor devices, printed wiring boards, etc. that requires micropatterning.

The present invention will be explained below using specific examples, but is not limited to these.

Example 1 (Protection reaction of alkali-soluble functional groups) 0.2 mol of poly p-vinylphenol (Mn = 8000) was dissolved in 300 m of tetrahydrofuran,
Stir under nitrogen flow. Then 0.04 mol of sodium tert-butylade is added and after 10 minutes 0.04 mol of di-t-butyl dicarbonate is added dropwise. After stirring at room temperature for 4 hours, the reaction product was poured into a saturated aqueous sodium chloride solution and thoroughly washed with water to recover the reaction product (PVP-tB-20).

(Preparation of resist solution) Partially protected polyp-vinylphenol 9 synthesized above
．． 3 g and 0.3 g of diphenyliodonium tetrafluoroporate were dissolved in 30 g of cyclohexanone,
A resist solution was prepared by filtration using a 0.2 micron filter.

This resist solution was applied onto a silicon wafer and
Breculated in the open for °CIO minutes.

The wafer was cooled to room temperature and passed through a mask at 250nm.
It was irradiated with DeeplJV light of m. After irradiation, 110°C
The film was heated on a hot plate for 2 minutes, returned to room temperature, and then developed by immersing it in a 2% aqueous solution of tetramethylammonium hydroxide for 2 minutes.

Through this series of operations, a good pattern with lines and spaces of 0.35 microns was obtained.

Examples 2 to 17 The compounds shown in Table 1 below were synthesized in the same manner as in Example 1,
A resist solution was prepared in the same manner as in Example 1.

A pattern was formed by the same operation as in Example 1.

Both have high sensitivity as shown in Table 2 below, with 0.3
A good pattern with a 5 micron shape is shown in Table 1 2 PVP-tB-109,8g TPSFA 0
．． 2g3 PVP-1B-259,8g 〃0.
2 g4 PVP-tB-309
,8g Kino 0.2g
5 PVP-tB-359.8g /70.2g
6 PVP-tB-209,8g PTNMT 0
．． 3g7 PVP-tA-109,7g DITF
B 0.3g8 PVP-tA-259,7g
〃0.3 g9 PVP-tA-309,7g
N 0.3g10 CNR-tB-209,7g
/IO, 3gl 1 〃9.7g TPSFB
0.3g12 〃9.7g PTNMT 0.
3g13 PVP-AR-209, 7g DITF
B 0.3g14 PVP-BO-209,9g
NO, 1g15 PVP-BO-209, 8g
n 0.2gte: t-butquine carnenyl '74,
tA: t-amyloxyca(&kinyl AR: 7lyl group, BO: t-butoquino group TP
SFA: 2-phenyl-4,6-bis(tric[IOmethyl)trianone DI]
TFB: diphenyliodonium tetra 711
Table 2 Example Sensitivity Resolution 2 5mJ / cill 0.35u
m3 7mJ / Ci 0.35um
4 9mJ/c4 0.35um5
10mJ/cllIo, 35um6
1 uC/c+a O', 25um7
3vaJ/ci (1,35um8
4mJ/cJ 0.35um9
6+IIJ/CTI O, 30um1
0 13mJ / cJ 0.35um
11 13mJ/cdl 0.35
um12 3uC/ci 0.28u
m13 6mJ/cII! 0.35um14
16mJ/e11! 0.35um
15 12+IIJ/all 0.
35us16 10mJ/cell
0.40um17 6+wJ/ca
0.40 um Example 6.12 was subjected to electron beam exposure.

Example 18 (Protection reaction of alkali-soluble functional group) The same procedure as in Example 1 was carried out.

(Synthesis of ester compound) 1 mole of t-amyl alcohol and 0.2 mole of pyridine are mixed and stirred. Then, terephthalic acid chloride 0
．． Add 1 mol and stir for 4 hours. After the reaction, the reactant is poured into water to precipitate it and recrystallized from ethanol to obtain the desired ester compound.

(Preparation of resist solution) 7 g of partially protected poly p-vinylphenol synthesized above
and 3 g of di-t-butyl terephthalate and 0.3 g of diphenyl iodonium tetrafluoroborate to 25 g of cyclohexanone? 8, and filtered using a 0.2 micron filter to prepare a resist solution.

This resist solution was applied onto a silicon wafer and
Brecured in the oven for °CIO minutes.

The wafer was cooled to room temperature and passed through a mask at 250nm.
Deep UV light of m was irradiated. After irradiation, the film was heated on a hot plate at 110°C for 2 minutes, returned to room temperature, and then developed by immersing it in a 2% aqueous solution of tetramethylammonium hydroxide for 2 minutes.

Through this series of operations, a good pattern with lines and spaces of 0.35 microns was obtained.

Examples 19 to 32 The compounds shown in Table 3 below were synthesized in the same manner as in Example 18, and resist solutions were prepared in the same manner.

Patterns were formed using the same operations as in Example 18, and as shown in Table 4 below, all patterns were highly sensitive and had a good pattern of 0.35 microns. Jt-f
35 siphthalate 5g TPSFA 0.
2g20//6g
4g Horn 0.2g21 〃7
g 3g 〃0.2g22〃8g2g〃0.
2g 23 n 7g 3g PTNMT(1,3
g24 PVP-107g 3g DITF
B 0.3g25 PVP-257g 3g
n 0.2g26 PVP-307g
3g 40.3g27 PVP-357g
3g 40.3g28 CNR-207g
3g n 0.3gpvp: Polyvinylphenol TPSFA:) Riphenylsulfonium hexatrifluoroantimonate PTN-T: 2-phenyl-4,
6-bis(trichloromethyl)triazine D) Ding FB
: Sifenil 3-tonium tetra71011! Rate table 4 19 3mJ / ctA 0
．． 35um20 5mJ/c 0.35um 21 5mJ/ctl 0.30um22 7mJ/
cf 0.35um 23 1uC/ct 0.20um 24 17mJ/Ci 0.40um25 12mJ
/c+fl 0.30um26 12n+J/ci
0.30um27 13mJ/all 0.35u
m2Fi 13a+J/ci! 0.35um29
7mJ/ci O, 35um 30 6mJ/ct O, 35um 31 8mJ/ctB 0.35um32 5+J/
at 0.35 um In Example 23, electron beam exposure was performed.

According to the results of the above examples, it is clear that the pattern forming materials of the examples, that is, of the present invention, have extremely high sensitivity to radiation and are useful materials for forming ultrafine patterns. .

〔Effect of the invention〕

As is clear from the above description and the results of Examples, the pattern forming material according to the present invention provides a resist material for forming ultrafine patterns having excellent properties such as extremely high sensitivity to radiation. The industrial effect is very large.

Claims (2)

[Claims] (1) 5 to 50% of the functional groups that confer alkali solubility are
A pattern-forming material comprising: an alkali-soluble polymer compound (a) protected with a protecting group that is decomposed by an acid or a base; and a compound (2) that generates an acid or base upon irradiation with radiation. (2) 5 to 50% of the functional groups that confer alkali solubility are
An alkali-soluble polymer compound (a) protected with a protecting group that can be decomposed by an acid or a base; a compound (b) that generates an acid or a base when irradiated with radiation; and a compound (b) that can be decomposed by an acid or a base to become alkali-soluble. A pattern forming material consisting of a compound (c) consisting of: