JPH0242441A - Optical thin film body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical thin film body, and more particularly to an optical thin film body having high light transmittance in a short wavelength region.

(Conventional technology) Conventionally, photolithography has been the mainstream semiconductor microfabrication technology, but semiconductor devices have also changed from LSI to VLSI.
Due to high density, the limit of photolithography is 2~3
Ultra-fine processing technology is being developed, and far ultraviolet rays are attracting attention along with electron beams and X-rays. Conventionally, ultraviolet light (350 to 450 nm) has been used as a light source in photolithography for manufacturing LS, but in recent years ultraviolet light (350 to 450 nm) has been used as a light source to manufacture highly integrated wafers and chips. Techniques for exposure to short wavelength ultraviolet light have been developed. However, conventional optical plastics such as polycarbonate and polymethyl methacrylate have a
The light transmittance at 0 nm was as low as 50% or less, and it could not be used as a protective film for photoresists in these short wavelength regions. Furthermore, in the case of conventionally used nitrocellulose membranes, the transmittance decreases rapidly at wavelengths below 300 nm, so that they cannot be used at shorter wavelengths.

(Problems to be Solved by the Invention) As a result of intensive research to solve the above-mentioned problems, the present inventors found that an addition-type compound containing a norbornene compound as a monomer component (
The inventors have discovered that an optical thin film with high light transmittance in a short wavelength region can be obtained by using a co-polymer, and have completed the present invention based on this knowledge.

(Means for Solving the Problems) According to the present invention, there is provided an optical thin film formed from an addition polymer of a norbornene monomer or an addition copolymer of a norbornene monomer and an olefin. The body is provided.

The norbornene monomer used in the present invention has a norbornene skeleton in the molecule, and has the following equation (I
) has the structure shown.

(In the formula, RI and RI2 are hydrogen or hydrocarbon residues, which may be the same or different, and further R9 or R1
1l and Rl 1 or R12 may mutually form a ring. n is O or a positive number of 1 or more, and when R5 to R8 are repeated multiple times, they may be the same or different. ) Specific examples of such norbornene monomers include norbornene, methylnorbornene, ethylnorbornene,
Bicyclics such as dimethylnorbornene, vinylnorbornene, ethylidene norbornene, tricyclics such as dicyclopentadiene, dihydrodicyclopentadiene, methyldicyclopentadiene, 1,4,5,8-dimethano -1,2,3,4,4a,5,8.8a-octahydronaphthalene, 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8.8a - Tetracyclics such as octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2゜3.4.4a, 5,8,8a-octahydronaphthalene, 1,4, 5.8-dimethano-i, 2,3,4.4a, 4b, 5+ 8 +
81 + 98-decahydro-9H-fluorene, 4
,9,5.8-dimethano-2,3,3a,4.4a+5
．． Examples include pentacyclic or even polycyclic norbornene compounds such as 8,8a, 9.9a-decahydro-1■-benzoindene, etc., but usually up to about 6 rings. Polycyclic rings are used, and among them, tetracyclic rings are prized.

These norbornene monomers may be used singly or as a mixture of two or more.

The addition type polymer in the present invention is an addition type polymer of the above-mentioned norbornene monomer or an addition type copolymer of a norbornene type monomer and an olefin. Such copolymerizable olefins include α-olefins and cyclic olefins. α-olefin has 2 to 2 carbon atoms
, preferably 2 to 10 α-olefins, such as ethylene, propylene, 1-butene, 3-methyl-1-
Butene, 1-pentene, 3-methyl-1-pentene, 4
-Methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-
Examples include hexadecene, 1-eicosene, styrene, and α-methylstyrene, with ethylene being particularly preferred from the viewpoint of copolymerizability. Examples of the cyclic olefin include non-crosslinked cycloolefins such as cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, and 2-(2-methylbutyl)-1-cyclohexene.

In order to produce the polymer of the present invention, a norbornene monomer may be used alone, or a norbornene monomer and an olefin may be polymerized using a common Ziegler catalyst.

As titanium compounds, TICQa, T i Bra
, T i C113, TiBr3 or other titanium halides or T l (OR) mX 4-# (however,
R represents a hydrocarbon residue such as methyl, ethyl, propyl, butyl, hexyl, cyclohexyl, phenyl, etc., and X represents a halogen. m is in the range O<m≦4. ) can be mentioned.

Vanadium compounds include V CQ a, VBr4,
Vanadium halides such as V CQ 3, ■Br3, V
Vanadium oxyhalides such as OCl2, VOBr3, VOC'12, VOBr2 or VO(OR)-X
3-- (However, R is the same hydrocarbon residue as above, X
represents halogen. m is in the range O<m≦3. ) can be mentioned.

Alkylaluminum compounds used with titanium or vanadium compounds have the formula - R', kQ
X' 3-- (However, R' represents a hydrocarbon residue such as methyl, ethyl, propyl, butyl, isobutyl, hexyl, etc. X' represents a halogen. m is in the range of O<m≦3 ).

Examples of the alkyl aluminum compound include trialkylaluminum, dialkylaluminum halide, alkyl aluminum civalide, any mixture thereof, or a mixture of these and alkyl aluminum trihalide.

The Ziegler catalyst used in the present invention is a titanium compound, a titanium compound supported on a magnesium compound,
A catalyst consisting of a transition metal such as a vanadium compound and a reducing agent such as an alkyl aluminum compound.

Polymerization takes place in a hydrocarbon solvent. For example, hexane,
Aliphatic hydrocarbons such as heptane, octane, and kerosene, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene, toluene, and xylene can be used alone or in combination as a solvent.

The polymerization temperature is -50 to 300°C, preferably -30 to 20°C.
0℃, polymerization pressure is generally O ~ 50 g/cm2,
Preferably, gIC112 is maintained at θ~20.

Furthermore, a molecular weight regulator such as hydrogen may be present as appropriate to adjust the molecular weight of the polymer.

The composition ratio (mole ratio) of norbornene monomer/olefin in the polymer of the present invention is 10010 to 5195,
Preferably 90/10 to 1 O/90. More preferably, it is 80/20 to 15/85.

The addition type (co)polymer produced in this way is one in which the carbon-carbon double bond of the norbornene skeleton of the norbornene-based monomer is opened and the monomer is polymerized alone or with an olefin. The structural unit of the norbornene monomer during coalescence is disclosed in JP-A-61-2926.
01. It has a structure as disclosed in Japanese Patent No. 61-211215.

The molecular weight of the addition type (co)polymer is 0.1 to 20aQ/g, especially 0, as an intrinsic viscosity [η] measured in decalin at 135°C.
．． It is preferable that the crystallinity is in the range of 3 to 1Oa/g, and the crystallinity (as measured by X-ray diffraction method) is 5% or less, especially oz.

The polymer having the above structure has good transparency because it is substantially non-porous, and has excellent dimensional stability without molding shrinkage. Moreover, it has excellent heat resistance. That is, the glass transition temperature (Tg) is usually 50 to 220°C, often 60 to 21°C.
It is in the range of 0℃, and the heat distortion temperature is usually 40 to 210℃,
Most are in the range of 50-200°C. Also, the refractive index (no
o) is usually 1.47 to 1.58, often 1.50 to 1.
56, which is one of the highest refractive indexes among plastics.

The optical thin film body of the present invention is formed from the addition type (co)polymer. There are various methods for molding optical thin films, but since these polymers are soluble in solvents such as toluene, they can be molded by molding methods such as casting and spin cording. In general, molding methods that require heating such as melt extrusion molding tend to cause coloring during molding. However, if a film is formed without heating by a casting method or a spin cord method, a transparent thin film body without coloring or deterioration can be obtained, and the obtained thin film body has a wavelength of 250~250 μm, for example, when the film thickness is 10 μm. The light transmittance at 500 nn+ is as high as 8 (H or more), which is an advantage that other transparent films do not have.

Examples of solvents that can be used in the cast molding method include aromatic hydrocarbons such as benzene, toluene, and xylene;
-Aliphatic hydrocarbons such as pentane, hexane, and heptane, alicyclic hydrocarbons such as cyclohexane, and halogenated hydrocarbons such as methylene dichloride, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, dichlorobenzene, and trichlorobenzene. etc., and two or more of these may be used in combination. Although the concentration of the resin solution can be determined as appropriate depending on the desired thickness of the thin film, it is usually preferably in the range of 0.1 to 50% by weight.

Solvents that can be used in the spin code method have a boiling point of 160
-250°C, preferably 30-230°C, and is an organic solvent such as aromatic hydrocarbons such as benzene, toluene, and xylene, alicyclic hydrocarbons such as cyclohexane, methylene dichloride, dichloroethane, dichloroethylene, and tetrachloride. Examples include halogenated hydrocarbons such as ethane, chlorobenzene, dichlorobenzene, and trichlorobenzene, and two or more of these may be used in combination.

The concentration of the resin solution is 0.01 to 50% by weight, preferably 0.
．． 5-20 weight ji%, rotation speed is 10-10,00
0 rpm.

Preferably 100-6. OOOrpm. The obtained molded products can be used as surface protective films for optical recording materials such as compact discs, video discs, and computer discs, as well as photoresist protective films and photoresist carriers by taking advantage of their properties such as transparency, moisture resistance, and heat resistance. It can be used for films, etc. In particular, the optical thin film body of the present invention has 25
Since it has a high light transmittance of 80% or more in the wavelength range of 0 to 500 nm, it is useful as a film for protecting a photoresist in ultrafine processing technology of photolithography.

(Example) The present invention will be described in more detail below with reference to Examples and Reference Examples. Note that parts and percentages in Examples, Comparative Examples, and Reference Examples are based on weight unless otherwise specified.

Example 1 Ethylene and 2-methyl-1,4,5,8-dimethano-1 were continuously produced using a 2Q glass polymerization vessel equipped with a stirring blade.
A copolymerization reaction with 2.3,4.4a,5,8.8a-octahydronaphthalene (hereinafter abbreviated as M-DMON) was carried out as follows.

That is, M-0M0811 degrees in the polymerization vessel is 60g/
A toluene solution of M-DMON was added from the upper part of the polymerization vessel at a rate of 0.9 Q/hr so that the concentration of VO (
OC2) 1s) Ch toluene solution at 0.711/hr
, AI(C2■s)+, 6CI1. so that the AIJI degree in the polymerization vessel was 2 mmol/R. A toluene solution of S was continuously fed into each polymerization vessel at a rate of 0.49/hr, and on the other hand, the polymer solution was continuously drawn out from the bottom of the polymerization vessel so that the volume of the polymer solution was always 12%. In addition, 2511/hr of ethylene and 80'J of N2 were supplied from the top of the polymerization vessel.
/hr, N2 is supplied at a rate of 2Sl/hr. The copolymerization reaction was controlled at 10° C. using a refrigerant.

A small amount of methanol is added to the polymer polymerization liquid continuously drawn out from the bottom of the polymerization vessel to stop the polymerization reaction, and then it is poured into a large amount of isopropyl alcohol to precipitate the produced copolymer, and then further poured with isopropyl alcohol. Washed. At this time, the copolymer was obtained at a rate of 30 g/hr. The washed copolymer was dried under reduced pressure at 100° C. all day and night.

In addition, dust countermeasures were taken such as cleaning the equipment and instruments used in this polymerization with dust-free acetone, and using a solvent that had been purified by distillation after filtering.

The copolymer (1) thus obtained is “C-N
According to MR analysis, ethylene is 55 moJL! [η] measured in decalin at 135°C is 0.64 (L
ll/g1 Manufactured by DuPont, manufactured by DMA, 0 loss A modulus of elasticity (E”
) was measured at a heating rate of 5° C./win, and the Tg determined from the peak temperature was 139° C., and the n2 coefficient measured with an Atsube refractometer was 1.537.

Example 2 Copolymers (It) and (III) were obtained according to Example 1, except that the norbornene monomer shown in Table 1 was used instead of M-DMON in the polymerization of Example 1. The ethylene content mole %, [η] and Tg of each copolymer were measured and shown in Table 1.

Table 1 Zero 1: l, 4,5,8-seemethano-1,2,3,4a
, 5,8.8a-octahydronaphthane.

Zero 2: 6-ethylhycyclo[2,2,11 indicates 70 to-2-ene.

Example 3 A 15z chlorobenzene solution of copolymers (I) to (III) was spin-coded on a smooth glass plate using looorpmX for 1 minute, and then dried at 100° C. for 2 hours. after that,
A thin polymer film was obtained by applying ultrasonic vibration to a glass plate in pure water. The film thickness was 4.5 μm. The light transmittance of the obtained thin film body is shown in Table 2.

For comparison, a conventional nitrocellulose membrane (product name B
Table 2 shows the light transmittance of the B-2,85 type film (manufactured by Advanced Semiconductor Products Co., Ltd.).

Table 2

Claims (1)

[Claims] (1) An optical thin film formed from an addition polymer of a norbornene monomer or an addition copolymer of a norbornene monomer and an olefin.