JPH04155344A - Photo sensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain high O2-RIE resistance as well as to enable development to be processed by the use of alkali developing solution by letting developing solution be composed of poly(silylenes) inclusing combination which shall be groups while being cleaved so as to be soluble to alkali, and of acid producing material capable of producing acids by means of radioactive ray irradiation. CONSTITUTION:Poly(silylenes) shall be the poly(silylenes) as indicated by a formula (I). In the formula, R<1> represents aryl groups such as, for example, methyl groups, sec(No,2)-butyl groups and the like, R<2> represents a group selected out of alkali groups such as, for example, methyl groups, ethyl groups and the like, and R<6> shall be selected out of t(No.3)-butyl, 2-cyclohexanyl and 1.1-demethyl benzyl. And the molecular weight of the poly(silylenes) shall be the weighted means of 2,000 through 50,000. In addition, some acid producing material is available, which is excellent in compatibility with the poly(silylenes), and is also soluble to solvent used for preparing coating solution at the time of spin coating, in this case, diphenyl(4-t-butylphenyl)sulfoniumP- toluenesulfonate and the like shall be used as a good example. And the content of acid producing material to the poly(silylenes) shall be within the range of 0.01 to 20% by weight. This thereby enables patterning to be processed by the use of alkali developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention can be used as a constituent material of a resist used in the manufacture of semiconductor devices, etc. !
Or, it is used for novel photosensitive resin compositions that respond to radiation such as ion beams.

(Prior Art) As LSIs become more highly integrated, submicron order processing technology is becoming necessary. For this reason, for example, LSI
The etching process during the manufacturing process uses dry etching technology, which allows for high precision and fine processing.

Here, dry etching technology covers the substrate to be processed with resist, patterns this resist using light or electron beams, etc., and uses the resulting pattern as a mask to remove the exposed portion of the substrate from the mask using reactive gas plasma. This is an etching technique. Therefore, the resist used in the dry etching technique is composed of a material that has a resolution on the submicron order and a sufficient reactive gas plasma resistance.

However, as LSIs become more highly integrated, the steps on the substrates to be processed are becoming larger and larger, and patterns with high aspect ratios are being formed on the substrates and boards to be processed. For this reason, there is a tendency for the thickness of the resist layer to be increased in order to flatten the step and to maintain the resist layer as a mask until the end of processing. Therefore, when resist is exposed with light, it is significantly limited by the depth of focus of the exposure optical system, and when exposed with an electron beam, it is significantly affected by the scattering phenomenon of electrons, so the Mg1 force of the resist decreases and the single It is becoming increasingly difficult to process substrates as desired using resist layers.

Therefore, a resist process called a two-layer resist method is being considered as one of the new resist processes. This is a thick polymer layer (hereinafter referred to as a lower layer) for flattening the substrate step.

Usually a layer composed of polyimide or heat-cured odresist) and a ○2-RIE layer formed on this lower layer.
This is a resist process using a thin photoresist layer or electron beam resist layer (hereinafter, these layers are referred to as upper layers) having M properties.

Specifically, the upper layer plays the role of obtaining a high-resolution pattern, and using this upper layer pattern as a mask, the lower layer is patterned by 02-RIE, and the resulting lower layer pattern is used as a mask for dry etching during substrate processing. It is a process of composition that takes on a role.

The upper layer resist has a higher 02-RI than the lower layer resist.
Since it is necessary to have E resistance, it is often composed of a silicone-based photosensitive resin composition. Specifically, silicone-based polymers containing groups sensitive to light or electron beams or added as necessary. A mixture of sensitizers is used.

Conventional examples of such photosensitive resin compositions include, for example, poly(phenylsilsesquioxane) or poly(methylsilsesquioxane) in which 3,3'-diazidodiphenylsulfone or barazidobenzoic acid 2-( Some added azide compounds such as dimethylamino)ethyl.

This was sensitive to cfeep-UV and could be used as a negative resist.

As a type of this type of photosensitive resin composition, for example, the literature
(Journal Vacuum Science and Technology (J, Vac, Sci, Technol
), B4 (1), (1986), p. 414) contains partially methacryloylated poly(phenylsilsesquioxane) and 2,6-his(4″-diazidohenzylidene)-4. - methylcyclohexanone is disclosed, which is said to be useful as an upper layer resist in a two-layer resist method.

(Problems to be Solved by the Invention) However, in conventional photosensitive resin compositions, siloxane has a phenyl group as a substituent, and in order to increase sensitivity, In order to increase the crosslinking density due to silicon, it is necessary to make the methacryloylation ratio 7a close to 70%, and also add about 15% of bisazide to silicon (this can be understood from the explanation related to Figures and 6 of document ■). There was a problem that the content decreased, and as a result, the 02-RIE jt performance decreased.

Also, while the current Ringer's fibrosis process mainly uses alkaline development, this conventional photosensitive resin composition is developed using an organic solvent, making it difficult to incorporate into the current process. there were.

The present invention has been made in view of these points, and therefore, an object of the present invention is to provide a novel photosensitive resin composition that has high 02RIEi1 property and can be developed with an alkaline developer.

(Means for Solving the Problems) In order to achieve this object, the photosensitive resin composition of the present invention includes poly(silylene) containing a bond that is cleaved by the action of an acid and becomes an alkali-soluble group. , and an acid-generating substance that generates acid upon irradiation with radiation.

In carrying out the present invention, it is preferable that the above-mentioned poly(silylene) be a poly(silylene) represented by the following formula 0.

However, R1 in formula 0 is, for example, a methyl group, sec(M2
)-butyl group, an alkyl group such as n(normal)-butyl group, or an aryl group such as phenyl group. Also,
82 to R5 are groups selected from alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, and cyclohexyl group, and even if they are the same, some or all of them are Also, R8 may be t
It is selected from (tertiary)-butyl, 2-cyclohexenyl (formula 1 below) and 1,1-dimethylbenzyl (formula 0 below).

■This poly(silylene) represented by the formula is -C○2R8
1002 which is cleaved by the action of acid and is soluble in alkali
Because there will be eight toads.

Here, in general positive resists with main chain decomposition, it is said that the higher the molecular weight of the base resin is, the better in order to enable strong solvent development, but in the photosensitive resin composition of this invention, Since the poly(silylene) in the exposed area becomes soluble in an alkaline developer due to the action of the acid generated from the acid generating substance in the exposed area, the unexposed area is originally insoluble in the alkaline developer. Therefore, the molecular weight of poly(silylene) (hereinafter sometimes abbreviated as poly(silylene) according to the present invention) containing a bond that is cleaved by the action of an acid and becomes an alkali-soluble group does not need to be very high. ,
The preferred range depends on other factors. Specifically, if the molecular weight of the poly(silylene) according to the present invention is too low, the poly(silylene) becomes liquid or candy-like, making it difficult to obtain a film of the photosensitive resin composition; As the coating temperature increases, it becomes less soluble in solvents, making it difficult to prepare the coating solution for stain coating, and even if the coating solution can be prepared, problems such as residues are likely to occur after development, so these points should be taken into consideration. For example, in the case of poly(silylene) represented by the formula (1), it is preferable to have a weight average molecular weight of 2,000 to so, ooo.

Further, poly(silylene) represented by the formula (2) suitable for use in the present invention can be obtained by the following method.

Conventionally, poly(silylene) was generally synthesized by the Wurtz reaction of disubstituted dichlorosilane, so poly(silylene) modified with a functional group such as poly(silylene) shown by the formula was difficult. but,
For example, literature ■ (Journal of American Chemical Studies (J, Amer, Chem, Soc,
.

1]1. (1989) p. 7641), it has become possible to introduce functional groups such as alkoxycarbonyl groups into poly(silylene) molecules. In this invention, poly(silylene) represented by the formula (2) can be synthesized by this method (details will be described later).

On the other hand, the acid generating substance, which is another essential component of the photosensitive resin composition of the present invention, is one that generates an acid strong enough to cleave the bonds of the poly(silylene) when irradiated with radiation. Various types can be used. However, it is necessary that it has good compatibility with the poly(silylene) according to the present invention and is soluble in the solvent used to adjust the coating properties during spin cording.

Specifically, for example, diphenyl represented by the following formula 0 (
4-t-butylphenyl)sulfonium p-toluenesulfonate, diphenyl(4-1-
Various triarylsulfonium salts such as butylphenyl)sulfonium trifluoromethanesulfonate, bis(4-1-butylphenyl)iodonium p-toluenesulfonate represented by the following formula 0, and dos(4-1- Mention may be made of various diaryliodonium salts such as butylphenyl)iodonium trifluoromethanesulfonate.

In addition, α-sulfonyloxyketones such as hengeyne arylsulfonate and hengeyne alkylsulfonate can also be used as acid generating substances in the present invention, and specifically, for example, hengeyne p-toluenesulfonate represented by the following formula 0, Mention may be made of hendiintrifluoromethanesulfonate represented by the following formula.

In addition, polyhalogen compounds can also be used as acid generators in this invention. Specifically, carbon tetrabromide (CBr, )
, trihaloacetamide such as trichloroacetamide ((13CGONH2), aromatic compound having a trihalomethyl group, etc. Here, as a specific example of an aromatic compound having a trihalomethyl group, the following formula 0 is used. α, α
, α.

α', α', α'-Hexachloro-p-xylene, 2,4-dichlorohencytrichloride represented by the following formula [Y], tribromoquinaldine represented by the following formula 0, the following 0
2,4,8-tris(trichloromethyl) represented by the formula
-8-triazine, 2-phenyl- represented by the following formula 0
4,6-bis(trichloromethyl)-8-triazine,
2-methoxyphenyl-4,6-his(trichloromethyl)-s-triazine represented by the following formula 0, the following [phase]
2-styryl-4,6-bis(trichloromethyl)-s-triazine represented by the formula, 2-( represented by the following formula 0)
4-methoxystyryl)-4,6-bis(trichloromethyl)-8-triazine, 2-(4
-dimethylaminostyryl)-4,6-his(trichloromethyl)-3-triazine, and the like.

0CH3 N(CI(3)2) In this invention, the acid generating substance exhibits the desired catalytic function even in a small amount, and if the amount is too large, the acid generating substance may precipitate in the film when forming the film of the photosensitive resin composition. From these points, the content ratio of the acid generating substance to the poly(silylene) according to the present invention is 0.0.
A preferable range is 1 to 20% by weight.

When using this photosensitive resin composition, the composition is applied onto a substrate by a spin code method to form a film on the substrate. Therefore, a solvent is required for preparing the coating solution. Examples of this solvent include chlorohensen, anisole, xylene, and the like.

(Function) According to the configuration of the present invention, since poly(silylene) has a high silicon content, the photosensitive resin composition contains at least 20% silicon and has a high 02-RI.
E resistance f! shows.

Further, the photosensitive resin composition of this invention may be selectively irradiated*1.
When the poly(silylene) according to the present invention is irradiated with V irradiation, the acid generating substance emits acid in this area, and this acid acts on the poly(silylene) according to the present invention, so that an alkali-soluble group is generated in the exposed area. Therefore, buttering using an alkaline developer becomes possible.

Further, the amount of exposure when irradiating with radiation may be small, as long as it is enough to generate acid from the acid generating substance in the radiation-irradiated portion of the photosensitive resin composition. Therefore, the throughput of the exposure process is improved compared to the conventional method.

(Examples) Examples of the photosensitive resin composition of the present invention will be described below. In addition, the numerical conditions such as the materials used, the amount of materials used, processing time, temperature, film thickness, etc. mentioned in the following explanation are as follows:
This is merely a preferred example within the scope of the invention. Therefore, it should be understood that the present invention is not limited only to these conditions.

In this example, poly(silylene) containing a bond that is cleaved by the action of an acid and becomes an alkali-soluble group,
Each of R1-R4 in the above formula 0 is CH3, and day 5
or n-CaHs, R6 or C(CH3)3,
t-Butoxycarbonylpoly(dimethylsilylene-C○
-methyl n-butylsilylene) is used.

Synthesis of Polysilylene First, poly(silylene) used in the Examples is synthesized as described below according to a method similar to that disclosed in Document ①.

First, 3.129 1-phenyl-7,7,8-trimethyl-8-n-butyl-7,8-disilabicyclo[2,
2,2-year old cata-2,5-diene is dissolved in dry tetrahydrofuran (hereinafter referred to as THF) at 50 mA. Note that the THF used was one distilled from LiAlH4 and roughly distilled from Nahensiphenone.

The solution is then frozen using a cold bath of ether cooled with liquid nitrogen, then degassed, and then dissolved. This process is repeated three times, and finally the inside of the system is replaced with argon gas. Freeze this solution again, and add 0.8 mI of 1.0M methyllithium in ether to it! After addition, remove the cold bath to dissolve the mixture and begin stirring. Stirring is continued for an additional 3 hours after the temperature of the mixture returns to room temperature.

Next, t-butyl chloroformate 1.69VTHF1.6m
After adding the solution of ρ to the above mixture, the mixture is stirred for 1 hour.

Next, add 500ml of the reaction mixture! Add 1 tablespoon of methanol to form a precipitate. Collect this precipitate by filtration and use 50ml of methanol.
After washing several times with l2jE- and drying overnight, 0
．． 639 objects are obtained.

The weight average molecular weight Mw of this product was found to be 17,000 (as measured by GPC Nigel permeation chromatography).

Moreover, this substance was identified by 'HNMR and IR. As a result, in 'HNMR, -Si
C ratio 1.60.8 to -8i ratio LCH2CH2CH3,
Absorption of methyl and t-butyl of butyl group was observed in 61,1. In IR, absorption of the carbonyl group of the carbonate ester was observed at a wave number of 1740 cm-'.

1.09 of the poly(silylene) obtained in the above synthesis and 10 mg of diphenyl(4-t-butylphenyl)sulfonium p-1-luenesulfonate (formula 0 above) as an acid generating substance in 10 mβ dissolved in chlorohensen,
Next, this solution is filtered through a Teflon filter having pores with a diameter of 0.2 um to prepare a coating solution of the photosensitive resin composition of Example.

Next, this coating solution was coated on a silicon substrate by a spin coating method, and then this sample was coated on a hot plate for 8 hours.
A 0.2 um thick film of the photosensitive resin composition of Example 1 was formed on the silicon substrate by baking at a temperature of 0 DEG C. for 1 minute.

Next, a chrome mask having a test pattern is brought into close contact with the sample, followed by Xe-Hq clamp exposure, followed by a 1 minute haze at a temperature of 140° C. using a photo plate. The above exposure was performed using a Canon PLA501 aligner equipped with a CM250 cold mirror.

The sample that has been subjected to heating after exposure is treated with a 0.54N tetramethylammonium hydroxy solution (specifically,
1 with a developer called MF312 manufactured by Shiraplay Co.
Develop for 20 seconds, and then rinse with pure water for 120 seconds to obtain a resist pattern.

A plurality of samples are prepared according to the above procedure except that the exposure amount is changed, and various resist patterns with different exposure amounts are obtained.

When each resist pattern was observed using a SEM (scanning electron microscope), it was found that a 0.5 um line and space pattern was resolved in the sample exposed with an exposure dose of 20 mJ/cm2. .

In the configuration of Example 1, except that the acid generating substance was 50m9 of diphenyl (4-1-butylphenyl)sulfonium trifluoromethanesulfonate shown by the formula 0 instead of the one shown by the formula 0. A coating solution of the photosensitive resin composition of Example 2 is prepared in the same manner as in Example 1.

Next, using this, a patterning experiment is conducted in the same manner as the patterning experiment procedure of Example 1.

As a result, it was found that a 0.5 um line and space pattern was resolved in the sample exposed with an exposure dose of 15 mJ/cm2.

Next, the amount of methyllithium used in the synthesis of poly(silylene) is reduced to about half of that in the above-mentioned synthesis example, and poly(silylene) is synthesized again in the same manner as in the above-mentioned synthesis example.

The weight average molecular weight Mw of the obtained poly(silylene) is 3
It was 4.000.

Next, this poly(silylene) 19 and 10 m9 of the acid generating substance used in Example 1 (of the above formula 0) were added to 10 mf
The photosensitive resin composition of Example 3 is dissolved in chlorohenzene, and then a coating solution of the photosensitive resin composition of Example 3 is prepared in the same manner as in Example 1.

Next, using this, a patterning experiment is performed in the same procedure as the patterning experiment in Example 1.

As a result, it was found that a 0.5 um line and space pattern was resolved in the sample exposed with an exposure dose of 20 mJ/cm2.

Although Examples of the photosensitive resin composition of the present invention have been described above, the present invention is not limited to the above-mentioned Examples.

For example, in the above embodiments, the exposure light source was a Xe-H9 lamp, but the photosensitive resin composition of the present invention is also sensitive to other light sources other than the above, such as electron beams, X-rays, and KrF excimer lasers. It shows the same effect as the example.

Moreover, in the above-mentioned examples, 1-phenyl-7,7,8-trimethyl-8-n-butyl-7,8 as a monomer
-Disilabicyclo[2,2,2]octa-2,5-diene is subjected to living anion polymerization using methyllithium to produce a living anion (poly(silylenyl) anion), which is then combined with chloro! A poly(silylene) having a t-butoxycarbonyl terminal was synthesized by reacting with t-butyl lI acid, and this was used as a haese resin. However, the poly(silylene) that can be used is not limited to this. For example, R2-R5 in the formula 0 is the ti of the monomer used.
The anionic polymerization proceeds smoothly unless the monomer contains a particularly large number of bulky groups. Therefore, 82~R5
Poly(silylene) in which is an alkyl group such as ethyl, n-propyl, n-butyl, cyclohexyl, etc. can also be synthesized and used as the poly(silylene) according to the present invention.

(Effects of the Invention) As is clear from the above description, the photosensitive resin composition of the present invention contains at least 20% by weight of silicon and has high 02 RIE resistance since it contains poly(silylene) or a high silicon content. show sacrifice.

Roughly speaking, when the photosensitive resin composition of the present invention is selectively irradiated with radiation, an acid generating substance or acid is emitted from this part, and this acid is cleaved by the action of the acid to form a bond that becomes an alkali-soluble group. Since it acts on poly(silylene) containing , alkali-soluble groups are generated in the exposed area. For this reason, it becomes possible to perform buttering using an alkaline developer.

Further, the amount of exposure when irradiating the radiation may be small as long as it can generate acid from the acid-generating substance in the radiation-irradiated portion of the photosensitive resin composition. Therefore, the throughput of the exposure process is improved compared to the conventional method.

Patent applicant: Oki Electric Industry Co., Ltd.

Claims (4)

[Claims] (1) A photosensitive resin composition comprising poly(silylene) containing a bond that is cleaved by the action of an acid and becomes an alkali-soluble group, and an acid-generating substance that generates an acid when irradiated with radiation. (2) In the photosensitive resin composition according to claim 1, the poly(silylene) is represented by the following formula (1) and has a weight average molecular weight of 2,000 to 500,000. A photosensitive resin composition characterized by (however,
R^1 in formula (1) is an alkyl group or an aryl group. Further, R^2 to R^5 are alkyl groups, and may be the same or partially or entirely different. Also, R^6
is selected from t-butyl, 2-cyclohexenyl and 1,1-dimethylbenzyl. ). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (3) In the photosensitive resin composition according to claim 1, the acid generating substance is a substance selected from triarylsulfonium salts, diaryliodonium salts, α-sulfonyloxyketones, and polyhalogen compounds. A photosensitive resin composition characterized by: (4) The photosensitive resin composition according to claim 1 or 3, characterized in that the content of the acid generating substance with respect to the poly(silylene) is in the range of 0.01 to 20% by weight. Resin composition.