JPH11295879A - Pellicle thin film and pellicle - Google Patents

Abstract

(57) [Problem] To provide a pellicle with improved adhesiveness between a pellicle film and a pellicle frame, excellent light transmittance in a short wavelength range, and high reliability in actual use. A thin film comprising a polymer obtained by ring-opening polymerization of a monomer comprising a specific norbornene derivative or another copolymerizable monomer copolymerizable with the monomer or a hydrogenated product thereof is provided. Pellicle used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellicle thin film for protecting a mask used in a photolithography step in the manufacture of a semiconductor integrated circuit and the like, and a pellicle using the same.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device or a liquid crystal display panel, when irradiating a semiconductor wafer or a liquid crystal master with light to form a pattern, if dust adheres to the exposure master used, the dust generates light. Absorbing or bending light causes the transferred pattern to be deformed, the edges to be rough, and the white background to be stained black, impairing the dimensions, quality, appearance, etc. There has been a problem that the performance and yield of the board are reduced. For this reason, a technique for attaching a pellicle that allows light for exposure to pass through the surface of the original exposure plate well to prevent dust is widely used. Such a pellicle has conventionally been known to have a structure in which a transparent film made of nitrocellulose, cellulose acetate, or the like that allows light to pass well is adhered to an upper part of a pellicle frame made of aluminum, stainless steel, polyethylene, or the like. By adhering the pellicle to the exposure master, dust adheres to the pellicle without adhering directly to the surface of the exposure master.By focusing on the pattern of the exposure master during lithography, the dust on the pellicle is reduced. Be independent of transcription. In recent years, as the pattern integration has progressed, the wavelength of the exposure light source has been shortened, and a pellicle with high transparency in the short wavelength region has been required. It has become. However, this amorphous fluorine-based polymer is more expensive than the cellulosic polymer, and furthermore, the film is stretched by air blow used for removing dust, foreign matter, etc. attached during use of the pellicle,
There was a disadvantage that peeling occurred. In order to improve such disadvantages, a technique using a polymer polymerized from a monomer containing a norbornene derivative as a film material is disclosed in JP-A-8-1.
No. 01497.

[0003]

However, some polymer thin films polymerized from monomers containing these norbornene derivatives have poor adhesion to the pellicle frame, and easily peel off from the frame during repeated air blows. Therefore, a specific adhesive must be used for bonding to the pellicle frame, which is inconvenient. An object of the present invention is to provide a pellicle having improved adhesiveness, which is the problem described above, and also having excellent light transmittance in a short wavelength region.

[0004]

That is, the present invention provides a monomer comprising at least one norbornene derivative represented by the following general formula (1) or a copolymerizable monomer copolymerizable with this monomer: To provide a pellicle thin film comprising a hydrogenated product of a polymer (specific polymer) obtained by ring-opening polymerization of pellicle and a pellicle using the same.

Embedded image (Where A and B are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X and Y are a hydrogen atom or a monovalent organic group, and at least one of X and Y is a hydrogen atom and A group having a polarity other than a hydrocarbon group is shown, and m is 0 or 1.)

In the general formula (1), examples of a group having a polarity other than a hydrocarbon group include-(CH ₂ ) _n COO
_{^{R 1, - (CH 2)}} n OCOR 1, - (CH 2) n CN, -
(CH ₂ ) _n CONR ² R ³ ,-(CH ₂ ) _n COOZ,-
(CH ₂ ) _n OCOZ, — (CH ₂ ) _n OZ, — (CH ₂ ) _n
CW, or -CO-O-OC- composed of X and Y
Or ^{-CO-NR 4 -OC- (R 1} , R 2, R 3, R 4
The hydrocarbon group having 1 to 20 carbon atoms, Z is a hydrocarbon group substituted with a halogen atom, W represents ^{_{SiR 5 p F 3-p (}} R 5 is a hydrocarbon group having 1 to 10 carbon atoms, F is -OCOR ⁶ or -OR ⁶
(R ⁶ represents a hydrocarbon group having 1 to 10 carbon atoms), p is 0
And n represents an integer of 0-10. ). Of these, the polar group is-
(CH ₂ ) _n COOR ¹ (where R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, and n is an integer of 0 to 10), and the resulting hydrogenated polymer is Is preferable because it has a high glass transition temperature. In particular, this-(C
It is preferable that one group represented by H ₂ ) _n COOR ¹ is contained per molecule of the tetracyclododecene derivative of the general formula (1). In the above general formula (1), R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, and it is preferable that as the number of carbon atoms increases, the hygroscopicity of the obtained hydrogenated polymer decreases. Since the glass transition temperature of the polymer decreases, the number of carbon atoms is 1 to 4 from the viewpoint of the balance.
Is preferably a chain alkyl group or a (poly) cyclic alkyl group having 5 or more carbon atoms, and particularly preferably a methyl group, an ethyl group, or a cyclohexyl group.

Further, n is 0 to 10, preferably 0 to 6,
The value is more preferably 0 to 4, but the smaller the value of n, the higher the glass transition temperature of the obtained norbornene-based polymer. In particular, the case where n is 0 is preferable in that the synthesis is easy and the obtained polymer has a high glass transition temperature. The general formula (1)
Is preferable in that m is 1 in that a polymer having a high glass transition temperature can be obtained. In the general formula (1), A
And B are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and at least one of A and B has 1 to 1 carbon atoms.
It is preferably 0 hydrocarbon group. Examples of the hydrocarbon group include an aliphatic group such as an alkyl group and an aromatic group, and are preferably an alkyl group, and particularly preferably have 1 to 4 carbon atoms.
Are preferred, and specific examples include a methyl group, an ethyl group, and a propyl group.

Further,-(CH_Two)_nCOOR¹Represented by
At the same time, the carbon atom having 1 to 10 carbon atoms
In the general formula (1) in which a hydride group is bonded as a substituent,
Tetracyclododecene derivatives are preferred because of their low hygroscopicity.
New In particular, this substituent is a methyl group or an ethyl group.
The tetracyclododecene derivative of the general formula (1)
It is preferred because it has excellent performance as a vehicle and is easy to synthesize.
No. As a specific example of the general formula (1),
Bonylbicyclo [2,2,1] hept-2-ene, 5-
Methyl-5-methoxycarbonylbicyclo [2,2,
1,] hept-2-ene, 5-cyanobicyclo [2,
2,1] hept-2-ene, 8-methoxycarbonyl
Toracyclo [4.4.0.1^2,51^7,10] Dodeca-3-
Ene, 8-ethoxycarbonyltetracyclo [4.4.
0.1^2,51^7,10] Dodeca-3-ene, 8-n-propo
Xycarbonyltetracyclo [4.4.0.1^2,51
^7,10] Dodeca-3-ene, 8-isopropoxycarboni
Letetracyclo [4.4.0.1^2,51^7,10] Dodeca
3-ene, 8-n-butoxycarbonyltetracyclo
[4.4.0.1^2,51^7,10] Dodeca-3-ene, 8-
(1-methylpropyloxycarbonyl) tetracyclo
[4.4.0.1^{2, Five}1^7,10] Dodeca-3-ene, 8-
(2-methylpropyloxycarbonyl) tetracyclo
[4.4.0.1^{2, Five}1^7,10] Dodeca-3-ene, 8-
(2,2-dimethylethyloxycarbonyl) tetracy
Black [4.4.0.1^2,51^7,10] Dodeca-3-ene,
8-cyclohexyloxytetracyclo [4.4.0.
1^2,51^7,10] Dodeca-3-ene, 8-methyl-8-me
Toxicarbonyltetracyclo [4.4.0.1^2,51
^{7,1 0}] Dodeca-3-ene, 8-methyl-8-ethoxyca
Rubonyltetracyclo [4.4.0.1^2,51^{7,1 0}]
Deca-3-ene, 8-methyl-8-n-propoxycal
Bonyl tetracyclo [4.4.0.1^2,5 1^7,10] Dode
Car-3-ene, 8-methyl-8-isopropoxycarbo
Nyltetracyclo [4.4.0.1^2,5 1^7,10] Dodeca
-3-ene, 8-methyl-8-n-butoxycarbonyl
Tetracyclo [4.4.0.1^2,5 1^7,10] Dodeca-3
-Ene, 8-methyl-8-cyclohexyloxycarbo
Nyltetracyclo [4.4.0.1^2,51^7,10] Dodeca
-3-ene. Among these, 8-methyl-
8-methoxycarbonyltetracyclo [4.4.0.1
^2,51^7,10Dodeca-8-ene is preferred. Simplex above
May be used singly or as a ring-opening
A polymerization reaction can also be performed.

The specific polymer used in the present invention may be a polymer obtained by ring-opening polymerization of the above-mentioned specific monomer alone, but the specific monomer and another copolymerizable monomer may be used. It may be one obtained by ring-opening copolymerization with a body. Specific examples of other copolymerizable monomers that can be used in this case include cyclobutene, cyclopentene, cycloheptene,
Examples include cycloolefins such as cyclooctene, bicyclo [2.2.1] hept-ene, tricyclo [5.2.1.02,6] -3-decene, 5-ethylidene-2-norbornene, and dicyclopentadiene. Can be. In addition, a specific monomer may be used in the presence of an unsaturated hydrocarbon polymer containing a carbon-carbon double bond in the main chain, such as polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-nonconjugated diene polymer, and polynorbornene. The monomer may be subjected to ring-opening polymerization and hydrogenated.

The above-mentioned polymer is prepared by combining the above-mentioned monomer or the above-mentioned other copolymerizable monomer with, for example, JP-A-7-28.
It can be obtained by polymerizing using a ring-opening polymerization catalyst, a ring-opening polymerization reaction solvent, a hydrogenation catalyst and the like described in JP-A-7123, and hydrogenating (hydrogenating) this. Such a hydrogenated polymer (hydrogenated polymer) is preferable in that it has excellent heat resistance, weather resistance stability and optical properties as compared with the polymer before hydrogenation.

In the present invention, the above hydrogenated polymer has an intrinsic viscosity ([η] in) measured at 30 ° C. in chloroform.
When h) is in the range of 0.3 to 1.5 dl / g, the resulting resin has a good balance of moldability, heat resistance, and mechanical properties. In particular, from the balance between the strength of the thin film obtained from such a polymer and the moldability of the thin film, 0.6 to 1.3 dl /
It is preferably in the range of g. Further, the glass transition temperature (Tg) of the hydrogenated polymer is preferably in the range of 100 ° C to 250 ° C, particularly preferably in the range of 120 to 200 ° C. If the temperature is lower than 100 ° C., the heat resistance of a molded article made of the resin is inferior. On the other hand, when the Tg exceeds 250 ° C., the molding temperature becomes high, and it becomes difficult to obtain a high-quality molded product such that the resin is burnt and colored.

The hydrogenation rate of the hydrogenated polymer is 60 M
The value measured by Hz and ¹ H-NMR is usually at least 50%, preferably at least 90%, more preferably at least 98%, particularly preferably at least 99%. The higher the hydrogenation rate, the better the stability to heat and light. In the present invention, the hydrogenated polymer used as the thermoplastic resin having a norbornane skeleton preferably has a gel content of 5% by weight or less in the hydrogenated polymer.
% By weight.

In the present invention, if necessary, a known antioxidant can be added to the above hydrogenated polymer as long as the effects of the present invention are not impaired. Specific examples of such antioxidants include, for example, 2,6-di-t-butyl-
4-methylphenol, 2,2'-dioxy-3,3 '
-Di-t-butyl-5,5'-dimethylphenylmethane, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris ( 2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl-benzene, stearyl −β
-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-dioxy-3,3'-
Di-t-butyl-5,5′-diethylphenylmethane,
3,9-bis [1,1-dimethyl-2- [β- (3-t
-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl], 2,4,8,10-tetraoxyspiro [5,5] undecane, tris (2,4-di-t-butylphenyl) phospho Phyte, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-t-butyl-4-methylphenyl) phosphite, 2,2-methylenebis (4,6
-Di-t-butylphenyl) octyl phosphite; These antioxidants are added in a range where the light transmittance of the pellicle in the present invention does not decrease.

In addition to the above-mentioned antioxidants, stabilizers, antistatic agents, flame retardants, elastomers for improving impact resistance, and the like can be added to the hydrogenated polymer.
Further, additives such as a plasticizer and a softener can be added for the purpose of improving moldability and workability. These additives are added in a range where the light transmittance of the pellicle in the present invention does not decrease as in the case of the antioxidant.

In the present invention, the thin film used for the pellicle may be prepared by dissolving or dispersing the above-mentioned hydrogenated polymer and, if necessary, the above-mentioned additive in a solvent to form a solution or dispersion having an appropriate concentration, and then pouring the solution onto a carrier. Or apply,
After drying, a film can be produced by a cast molding method in which the film is peeled off from the carrier. Here, the proportion of the hydrogenated polymer in the solution depends on the thickness of the thin film, but is usually 0.01 to 30% by weight, preferably 0.1 to 30% by weight.
20% by weight. Examples of the solvent include aromatic compounds such as benzene, toluene and xylene, butyl acetate, tetrahydrofuran, dimethoxyethane, chloroform, methylene dichloride, and methyl ethyl ketone, which are generally used as solvents. Further, a mixed solvent thereof may be used. Further, a mixture of a solvent that dissolves the hydrogenated polymer and a solvent that does not dissolve the hydrogenated polymer may be used. In addition, a dispersion may be used by using water and fats and oils as those which do not dissolve the hydrogenated polymer. When dissolving the hydrogenated polymer in a solvent,
Room temperature or high temperature may be used. Thorough stirring provides a uniform solution.

As another method for producing a thin film having a uniform thickness, the above solution is extruded from a die having a fixed width onto a substrate such as a metal drum, a steel vent, a polyester film, a Teflon belt, and the temperature and time are increased. It can be manufactured by drying. Also, spray, brush,
A thin film having a uniform thickness can be produced by applying the solution to the above-mentioned substrate by means of roll, spin coating, dipping, or the like and arbitrarily applying temperature and time. When a desired film thickness cannot be obtained by one application, the film thickness can be increased by repeatedly applying. In the present invention, the thickness of the film is not particularly limited as long as it has a function as a thin film used for a pellicle, but is preferably from 0.2 to 10 μm, more preferably from 0.3 to 8 μm.
μm.

The pellicle of the present invention is obtained by bonding the thin film obtained by the above method to a predetermined pellicle frame. Here, the material of the pellicle frame is not particularly limited, and aluminum, stainless steel, polyethylene, or the like can be used. For bonding the thin film to the pellicle frame, a known adhesive or pressure-sensitive adhesive can be used. As such adhesives / adhesives, those excellent in transparency are preferable, and specific examples thereof include natural rubber, synthetic rubber, and vinyl acetate.
Vinyl chloride copolymers, polyvinyl ethers, acrylics, modified polyolefins, and curable pressure-sensitive adhesives with a curing agent such as isocyanate added thereto, and adhesives for dry lamination that mix a polyurethane resin solution and a polyisocyanate resin solution , Synthetic rubber adhesives, epoxy adhesives and the like.

[0017]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. In the examples, parts and% are by weight unless otherwise specified.

Reference Example 1 Under a nitrogen atmosphere, 8-methyl-8-methoxycarbonyltetracyclo [4.4.
0.1 ^2,5 . 1 ^7,10 ] -3-dodecene (100 parts), toluene (300 parts) and 1-hexene (4 parts) were added, and the mixture was stirred for 8 ^hours .
Heated to 0 ° C. 0.1 mol of paraaldehyde
0.9 part / toluene solution, 1.5 parts 0.5 mol / l toluene solution of diethylaluminum chloride, W
One part of a 0.05 mol / l chlorobenzene solution of Cl5 was added, and reacted at 80 ° C. for 3 hours. After the polymerization reaction,
The polymerization solution was added to a large amount of methanol to precipitate a polymer, and the polymer was separated by filtration and vacuum dried to obtain 95 parts of a polymer. 100 parts of this polymer was added to tetrahydrofuran 200
In 0 parts, a polymer solution was prepared. To this polymer solution, 10 parts of a palladium catalyst (activated carbon supported catalyst; palladium concentration = 5% by weight) was added as a hydrogenation catalyst, and heated in an autoclave at a hydrogen gas pressure of 150 kg / cm 2 and a reaction temperature of 150 ° C. for 4 hours, A hydrogenation reaction was performed. After completion of the reaction, the reaction system was cooled and the pressure of hydrogen gas was released. Further, the hydrogenation catalyst was separated by filtration, and methanol was added to the filtrate to coagulate the hydrogenated polymer to obtain a hydrogenation rate of 9%.
9.5%, glass transition temperature 168 ° C, intrinsic viscosity (ηinh) of polymer 0.75, saturated water absorption at 23 ° C
4% of a thermoplastic norbornene resin A was obtained.

Reference Example 2 A polymer was synthesized under the same conditions as in Reference Example 1 except that the amount of 1-hexene was changed to 6 parts, and the degree of hydrogenation was 99.5%, the glass transition temperature was 168 ° C., and the intrinsic property of the polymer was A thermoplastic norbornene resin B having a viscosity (ηinh) of 0.65 and a saturated water absorption of 0.4% at 23 ° C. was obtained.

Reference Example 3 A polymer was synthesized under the same conditions as in Reference Example 1 except that the amount of 1-hexene was changed to 1.5 parts, and the hydrogenation rate was 99.5.
%, Glass transition temperature 168 ° C, intrinsic viscosity of polymer (ηin
h) was 1.2, and a thermoplastic norbornene resin C having a saturated water absorption of 0.4% at 23 ° C. was obtained.

Reference Example 4 6-methyl-1,4,5,8-dimetano-1,4,4
A polymer was synthesized under the same conditions as in Reference Example 1 except that a, 5,6,7,8,8a-octahydronaphthalene was used, and a hydrogenation rate of 99.9% or more and a glass transition temperature of 14 were obtained.
A thermoplastic norbornene-based resin D having an intrinsic viscosity (ηinh) of 0.5 at 2 ° C. and a saturated water absorption of 0.01% at 23 ° C. was obtained.

Examples 1-3 The thermoplastic norbornene resins A-C obtained in Reference Example 1
Was made into a 3% by weight solution using toluene, and a 0.5 μm thin film was formed by spin coating. This thin film and an aluminum frame were adhered with an ultraviolet curable adhesive, and the light transmittance and adhesiveness were evaluated. Table 1 shows the evaluation results.

Each measurement was performed as follows. Light transmittance Using a spectrophotometer, wavelength 436 nm, 365 nm, 24
The light transmittance of the thin film at 8 nm and 193 nm was measured. Adhesion 10 minutes from the surface of the thin film inside the frame where the thin film is bonded.
Air with a pressure of 3.0 kg / cm 2 was blown for 30 seconds from a distance of mm to evaluate the adhesion between the thin film and the frame.

Comparative Example 1 A toluene solution was prepared in the same manner as in Example 1 except that the thermoplastic norbornene resin D obtained in Reference Example 2 was used, and a 0.5 μm thin film was formed by spin coating. This thin film was adhered to an aluminum frame in the same manner as in Example 1, and the light transmittance and adhesiveness were evaluated. Table 1 shows the evaluation results.

Comparative Example 2 A fluororesin "Teflon (trademark) AF-1600" (manufactured by DuPont) was mixed with a solvent "Fluorinert (trademark) FC-4".
0 "(manufactured by 3M) to make a 3% by weight solution, and a 0.5 μm thin film was formed by spin coating. This thin film was adhered to an aluminum frame in the same manner as in Example 1, and the light transmittance and adhesiveness were evaluated. Table 1 shows the evaluation results.

[0026]

[Table 1]

From Table 1, it can be seen that Examples 1 to 3 have no peeling between the thin film and the frame and are optically excellent.

[0028]

The thin film for a pellicle of the present invention has improved adhesiveness between the thin film and the pellicle frame and has excellent light transmittance in a short wavelength range, and the pellicle using the same has high reliability in actual use. Things.

Claims (2)

[Claims] 1. A polymer obtained by ring-opening polymerization of a monomer composed of at least one norbornene derivative represented by the following general formula (1) or a copolymerizable monomer copolymerizable with this monomer. Pellicle thin film made of united hydrogenated product. Embedded image (Where A and B are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, X and Y are a hydrogen atom or a monovalent organic group, and at least one of X and Y is a hydrogen atom and A group having a polarity other than a hydrocarbon group is shown, and m is 0 or 1.) 2. A pellicle comprising the pellicle thin film according to claim 1.