JPH01292012A - Resist comprising styrene polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer highly sensitive to light, with high resolution, to be used for resists, etc., by treating a p-methylstyrene polymer with an organolithium compound followed by reaction with a chlorosilane and chlorodisilane to effect introduction of Si atom. CONSTITUTION:Firstly, p-methylstyrene is polymerized under cooling in a solvent such as tetrahydrofuran, using a n-butyllithium catalyst to produce poly-p- methylstyrene. Thence, this poly-p-methylstyrene is dissolved in e.g., cyclohexane followed by addition of n-buthyllithium and then reaction with pentamethylchlorodisilane and/or allyl-dimethylchloro silane which heating to 50 deg.C, thus obtaining the objective polymer constituted of recurring units of formula I, II (R<1>-R<5> are each 1-6C alkyl) and III (R<6>-R<8> are each 1-6C alkyl, at least one being 2-4C alkenyl).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resist comprising a styrenic polymer having silicon atoms.

BACKGROUND OF THE INVENTION Conventionally, as a negative photoresist, a mixture of cyclized rubber and bisazide has been used. However, this material has problems such as swelling during development, insufficient resolution, and lack of dry etching resistance.

A resist containing silicon atoms is used as the upper layer of a two-layer resist, and has been used in Japanese Patent Application Laid-open Nos. 59-15419 and 6
Various attempts have been made, as described in Japanese Patent No. 0-205609, but the performance is not sufficient.

It is known that in photosensitive molecules such as resist materials, the more silicon-containing particles there are, the better the oxygen plasma resistance will be.

As a styrene thread polymer with improved silicon content, for example, a monomer in which a disilyl group is introduced into α-methylstyrene is synthesized, and then this 7-mer is polymerized to obtain a 9-styrene polymer. known (Proceedings of the Society of Polymer Science and Technology, 5
5, No. 8, p. 2566), the method for producing this polymer is complicated.

Problems to be Solved by the Invention It is an object of the present invention to provide a resist that is excellent in j9 degree and resistance to reactive ion etching.

Means for Solving the Problems As a result of intensive research, the present inventors found that a polymer obtained by t-lithiation of poly(baramethylstyrene) and then introducing a disilyl group and an alkenylsilyl group was obtained according to the present invention. The present invention was completed after discovering that the object could be achieved.

Summary of the invention That is, the present invention.

Resist containing as a component a styrene polymer consisting of a bond of repeating units (B) and (C)
(B) (CJ [However, R
1.Rh is the same or different alkyl group having 1 to 6 carbon atoms,
R・R7 and R1 are the same or different alkyl groups having 1 to 6 carbon atoms or alkenyl groups having 2 to 6 carbon atoms;
At least one of '#R' and R- is an alkenyl group, A/B/C (mol%) = 1-70/1-60/1-
I'm 40. ] The styrenic polymer according to the present invention is %@ (6).

The repeating units of (B) and (C) are randomly combined, and the proportions are as shown in the previous ruby, but in particular, 1 to 30 molar units, (2) 30 to 60 molar units, (C) 10
~40 mol% is desirable.

This styrenic polymer has a weight average molecular weight of several thousand to several million 0, and has a weight average molecular weight (h)/number average molecular weight (
in) = 2.0 or less, but especially law
= 10,000 to 500,000, preferably My/Mn tO to 1.5.

Method for producing styrenic polymers Styrenic polymers are made of polymethylstyrene (hereinafter referred to as PM
It's called 8. ) polymer (polyPM8) was reacted with an organic lithium compound to partially lithiate the para-methyl groups in the poly2 bar s, and then the formula RIR"R"81R4R'8
1X (However, R1 to R are the same or different carbons a1 to 6
number of alkyl groups.

X represents a halogen atom. ] After reacting with silicon compound l and further reacting with organolithium compound, 2R@R
7shi81x [However, R・~R1 have the same or different carbon number 1
~6 alkyl groups or alkenyl groups having 2 to 6 carbon atoms, and at least one of R.~R8 is an alkenyl group. Alternatively, it is a halogen atom. ] can be produced by reacting with silicon compound ■,
J1 is obtained by simultaneously reacting polyPMS with an organolithium compound, and simultaneously reacting a silicon compound l with a silicon compound...
1! You may leave it behind. Further, this reaction cycle of organolithium compound→silicon compound I→organostechum compound→silicon compound or organic lithium compound→silicon compound 1/silicon compound U can be further carried out one or more times.

In some cases, the reaction order of silicon compound 1 and silicon compound 2 may be reversed.

Each compound used in producing the styrenic polymer will be explained.

■ Poly PM8 Bo! JPMS can be produced by normal radical polymerization or living polymerization of PM8, but
In particular, polyPM8 obtained by living polymerization is desirable because it has a narrow molecular weight distribution.

The living polymerization is carried out in the presence of an initiator, 4flI, or an N-stium compound such as n-butyllithium or moat-butyllithium, which forms a steryl anion. Living polymerization can be carried out in the presence of a solvent, such as hexane, which is inert to the initiator and generated anions.

Examples include hydrocarbons such as heptane, octane, cyclohexane, benzene, toluene, and xylene, and ethers such as diethyl ether, diptyl ether, tetrahydrofuran, and dioxane.

Living polymerization is carried out by reacting PM8 at a temperature of -80° C. to +50° C. (L5 to 50 hours).

By doing this, thousands to millions, preferably 10,000 to
A polyPM8 is obtained with a weight average molecular weight of 500,000 and a MW/Mn of less than 2.0, preferably between tO and t5.

■Organolithium compounds Organolithium compounds are represented by the general formula RLi.Specifically, examples include compounds in which 4R is an alkyl group having 1 to 12 carbon atoms.Representative examples include methyllithium, ethyl lithium.

n-butyl lithium % gas-butyl lithium tert-
butyl lithium, n-pentyl lithium, tert
-Pentyllithium, hexylylithium, octyllithium, todecyllithium, etc., but butyllithium is particularly preferred.

■ Silicon compound l The silicon compound vJ1 is represented by the above formula, and R1,
, = pi is preferably a methyl, ethyl, n-propyl% n-butyl group, and particularly preferably all of R1 to Hm are methyl groups. X is preferably a chlorine atom.

(2) Silicon compound The silicon compound n is represented by the above formula, and when H%, RT, and R1 in the formula are alkyl groups, it is preferably a methyl, ethyl, n-propyl, or n-butyl group. Methyl and ethyl groups are preferable for p, @,
H? , When R1 is an alkenyl group, it is preferably a vinyl, allyl, propenyl, impropenyl or butenyl group, particularly a vinyl or allyl group. X is preferably a chlorine atom.

Reaction polyFMS of BolJPM8 and organolithium compound
The reaction between the organic lithium compound and the organic lithium compound can be carried out in a solvent that is inert to the organic lithium compound. Examples of solvents that can be used include hydrocarbons such as hexane, heptane, octane, cyclohexane, benzene, toluene, and xylene, and ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, and dioxane. In the reaction, polyPMB is dissolved in or swollen with these solvents, and an organic lithium compound is allowed to act on the polyPMB. On this occasion,
Component 1 that increases the reactivity of the organolithium compound, such as amines, can be used. The amine that can be used is preferably %N, N, N: N'-tetramethylethylenediamine.

The reaction temperature can be freely set from -70°C to the boiling point temperature of each solvent, but in order to efficiently achieve a high lithiation rate, a temperature above room temperature is desirable. The usage amount can be set arbitrarily.
The lithiation rate can be arbitrarily adjusted within a range of 50 units molti or less. The amines may be used in the same amount as the organolithium compound, but may be used in excess. The reaction time is the reaction@
It varies depending on the degree, but usually α1 to 100 hours,
By lengthening the reaction time, the lithiation rate can be increased.

Since the thiolated polyPM8 prepared in this way has high reactivity and reacts with all the air and moisture, it is desirable to use it in the subsequent reaction without separating it.

Lithio-bo! The reaction between JPMS and the silicon compound 1 is achieved by directly adding the silicon compound 1 to the first stage reaction system in which the lithiated product IJ PM8 is present and bringing them into contact. The silicon compound l is usually 1 to 100 Wr mol, preferably 1 mol, relative to the organolithium compound used in the previous stage.
~10 times the molar amount is used. The reaction is -50℃ to +150℃
, preferably at 0 to 50° C. (11 to 100 hours, preferably [L5 to 20 hours).

Although disilylated polyPM8 is obtained in this manner, it may be separated from the reaction system before being subjected to the next reaction.

The reaction between the disilylated polyPM8, the organolibram compound, and the subsequent silicon compound may be carried out in the same manner as the reaction between the polyPM8, the organolithium compound, and the subsequent silicon compound 1 described above.

In addition, after reacting BoIJPM8 with an organic lithium compound,
Even when the silicon compound 1 and the silicon compound .

The polymer produced as described above is desirably washed with water, dilute salt, etc., and is desirably purified by reprecipitation or the like.

R''%R' of the repeating unit (J3) of the styrenic polymer obtained as described above is the same as in the case of silicon compound 1. That is, Hl and R1 are C1 to C4 alkyl groups. Preferably, methyl and ethyl groups are preferred when L<%%.

Further, R', R', R'' of the repeating unit (C) are the same as in the case of the silicon compound. That is, %R6 to R1
At least one of 1 is an alkenyl group. R.

When R7 or R1 is an alkyl group, an alkyl group of %01%C is preferable, and a methyl or ethyl group is particularly preferable.

Moreover, in the case of an alkenyl group, C! ~C4 alkenyl groups are desirable, and vinyl and allyl groups are particularly desirable. In the styrenic polymer according to the present invention, the composition of the recycle unit 4s(')% (c) is within the above ratio range, and the organic lithium compound used is It can be set arbitrarily depending on the weight and reaction conditions of the raw material polymer.

Even if an excess of 4A of the organolibram compound is used, the thiolation rate will not exceed 50 units of the raw material polymer in one lithiation reaction. In the reaction between lithiated polyPMB and a silicon compound, The organolithium compound used in the previous lithiation reaction may be reacted with a silicon compound in an amount equal to or more than that of the organic lithium compound. Therefore, in the case of reacting a silicon compound of the group, the number of silyl groups to be reacted depends on the efficiency of lithiation in the previous step. In addition, when two types of silicon compounds are reacted simultaneously, if the composition of the two types of silicon compounds is changed as necessary, Il! The composition of the resulting polymer can be varied within the range of rIR lithiation efficiency.

The resist of the present invention contains the polymer obtained as in the above MQ as a component, but it is also possible to form a composition by using the polymer in combination with a photosensitive crosslinking agent.

Examples of the photosensitive crosslinking agent used include bisazide compounds. For example, 4,4'-diazide chalcone, 2
．． Examples include 6-di(4'-azidobenzal)cyclohexanone, 2,6-di(4''-azidobenzal)4-methylcyclohexanone, 2,6-di(4'-azidocinnamylidene)4-hydroxycyclohexanone, etc. However, among these, 2,6-di(4'-azidobenzal)4-methylcyclohexanone is preferred.

The proportion of the photosensitive crosslinking agent in the composition is 1 to 10]
[1i% is preferred. If the content of the photosensitive crosslinking agent is less than 1 weight, it will not be sufficient to form a crosslinking structure and insolubilize it, while if it exceeds 1 weight, there will be no further effect and it will be uneconomical9. This is undesirable because crosslinking occurs before exposure.

The composition can be prepared by dissolving the styrenic polymer and the photosensitive cross-linking agent in a solvent and then removing the solvent, or by dissolving both in a bath. The lv medium to be used is not limited to, but for example, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene, and monochlorotoluene can be used.

When the styrenic polymer and composition thus obtained are used as a resist in the production of semiconductor devices, a commonly used spinner coating method can be used.

The polymer and the composition according to the present invention are dissolved in the above-mentioned bath medium, and the bath medium is used to obtain a desired consistency.

By performing spin coding on a commonly used substrate, a uniform resist layer can be formed on the substrate.

The resist layer fi is usually formed with a thickness of α2 to μm. This resist layer is usually prebaked, and the conditions are generally 90 to 150°C (L1 to 1 hour).Of course, it may also be prebaked under reduced pressure.

Next, the pattern is baked by irradiation with electron beam-xis far ultraviolet rays, ultraviolet rays, etc. After 9 days, it is developed with a commonly used developer, and if necessary, further post-baking is performed to obtain a sharp negative pattern. .

Effects of the Invention The resist of the present invention has many silicon atoms, is highly sensitive to light, and can provide high resolution.

Real N Liu The present invention will be explained in detail below using two examples.

In addition, the identification of the polymer was performed using the following equipment.

IHNMR: The sample was CDC2,-) 20wt% dissolved a.

Varian a'JI E M 560 A '11
Measured at k (60 MHss) 0 Measurement conditions: 20°C Example 1 Synthesis of poly PM8 1,00011 t of distilled tetrahydrofuran was placed in a nitrogen-substituted flask and cooled in a dry ice-methanol bath. In this flask, add 51 n-butyllithium
Add mmol and PM8100-, and start stirring by stirring. After polymerizing at -78°C for 2 hours, inbanol 5- was added to stop the polymerization. The reaction solution was diluted twice with tetrahydrofuran and poured into heavy methanol to precipitate polyP M 889.7t. According to GPC analysis, nw=545 x 1
0', Mw/Mn=t07.

The polyP obtained above was added to the flask in which the pentamethyldisilyl group had been replaced with tIIt.
Add M81αOf and 200 m'i of cyclohexane, and Bo!
Understand JPM'8 and take an oil bath at 50℃.
It was hot. 60 mmol of n-butyllithium and N,
N, N: N'-nato2methylethylenediamine (T
Float 60 mmol of MEDA).

After reacting at 50°C for 2 hours, it was cooled in a water bath.

124 milliliters of pentamethylchloride was added, and the mixture was allowed to react in a chamber for 2 hours. After washing the reaction solution with water, it was poured into methanol to precipitate white polymer 12.5F.

'HNMR analysis confirmed the presence of 1 pentamethyl□disilyl group, and the integration ratio of the pentamethyl silyl group was 58 units. The chemical shift value is as follows: 0 δ (ppm): 7.05 to 6.15 (aromatic ring),
2.25 (big Σcps).

Into a nitrogen-substituted flask, 10v of the polymer obtained above and containing t-pentamethyldisilyl group and 200m of cyclohexane were placed, and the polymer was heated at 50°C.
60 mmol of n-butyllithium and 60 mmol of TMEDA were added to the bath solution heated to 0.0° C., and the mixture was reacted at 50° C. for 2 hours. Cool in a water bath, add 120 mmol of allyldimethylchlorosilane, and react at room temperature for 2 hours. The reaction solution was treated in the same manner as above to obtain white polymer 150f.

IHNMR analysis confirmed the presence of allyldimethylsilyl groups, and the integration ratio of allyldimethylsilyl groups was 56 units)%. The chemical shift value is determined by the following procedure.

δ (ppm), near, 05~&15 (aromatic ring), a74
(-CH=CH,).

4.87p4.82 (-CH=Cshi), 2.25(
((Precept C and 3).

From the above results, the obtained polymer has the following structure, (b)
, It turned out that the repeating units of (C) were randomly bonded to form a 7'c polymer.
was spin-coded onto silicon ueno (
Film thickness α4 μm) Q Using Mikasa's mask aligner MAIG (using a 500W high-pressure mercury lamp) and using a trapane test chart as a mask, a residual film started to appear after 20 seconds, and the % exposure time was 50 seconds. When developed with a mixed bath solution, α9 μm lines and spaces were resolved.

(2) Polymer 5f% 2.6-di(
4'-azidobenzal)-4-methylcyclohexanone α25t was added to xylene 452 at 8%.

This was spin-coated on a silicon wafer (film thickness α4 μm), exposed and developed in the same manner as above. ) Using a silicon wafer coated with the bath solution of (2) above, an optical interference filter (passing only 457.5 nm light) was placed on a mask and exposed. 45 on the exposure side
The intensity at 6 nm was 2.7 mW/>”@%Il
Remaining film starts at 1 exposure time of 8 seconds, and at 15 seconds of exposure time (1
It resolved 9 μm'y in and space.

Example 2 PolyPM810F obtained in Example f81 was substituted with bentametherdisilyl group and allyldimethyl nitrogen, and then put into a flask.
Add 200 - of cyclohexane and boil IJ PMS.
4n in this bath number heated to 50℃ while dissolving
-Add 60 mmol of butyllithium and 60 mmol of TMRDA.

The reaction was carried out at 50°C for 2 hours. Cooled in a water bath, added a mixture of 62 mmol of pentamethylcooldisilane and 62 mmol of allyldimethylchlorosilane, and allowed to react at room temperature for 2 hours. After washing the reaction solution with water, it was poured into methanol, and white polymer 12-4f was added. It was precipitated.

”As a result of HNMR analysis, the obtained polymer was found to be of Example 1.
It consists of the same repeating units (5), (uniform and (C) bonds) as the nine polymers obtained, and the ratio is (A) 5 (B)
α1B(C)Ill? In addition, the polymer 10f obtained above was again mixed with 20
0sdK,! The tiles were heated to 50°C. To this, 50 mmol of n-butyllithium and 50 mmol of TMgDA were added, and the mixture was allowed to react at 50°C for 2 hours. After cooling in a water bath, 62 mmol of pentamethylchlorzine was added, and the resulting mixture was allowed to react for 2 hours. A white polymer 145f was obtained by treatment in the same manner as ae.

IHNMR analysis result 4 The obtained polymer is Example 1
The same repeating units (5) and (b) as the polymer obtained in
and (C), the ratio of which is (A) (L28
(B) α5B (C) It was found that cL19 was responsible.

Photosensitive bond value 11+ Polymer obtained above 2ft-xylene 1
8? ◎ Sensitivity and performance evaluation of Example 1 (Exposure was performed in the same manner as in 11, and 19 μm lines and spaces were resolved with an exposure time of 45 seconds. 90 (2) ) Polymer 59,2,6-di(4') obtained above
-7zidobenzal)-4-methylcyclohexanone α2
5F was dissolved in 45 tons of xylene.

When this bath was spin-coated on a silicon wafer and exposed in the same manner as in Photosensitivity Evaluation (2) of Example 1,
It was able to resolve 19 μm lines and spaces with a light time of 1 second.

(3) When a silicon wafer coated with the bath solution in (2) above was exposed to light in the same manner as in photosensitivity evaluation (3) in Example 1, [L9 μm lines and spaces were resolved with an exposure time of 20 seconds. was.

Claims (1)

[Scope of Claims] A resist containing as a component a styrenic polymer consisting of bonds of repeating units (A), (B) and (C) shown below. (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (B) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (C) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, R^1 to R^5 are The same or different alkyl groups having 1 to 6 carbon atoms, R^6, R^7 and R^8 are the same or different alkyl groups having 1 to 6 carbon atoms or alkenyl groups having 2 to 6 carbon atoms, At least one of R^6, R^7 and R^8 is an alkenyl group, and A/B/C (mol%)
=1-70/1-60/1-40.