TWI579354B - Mask mask - Google Patents

Description

Photomask

In the case of manufacturing a semiconductor device such as an LSI (large scale integrated circuit) or a super LSI, or a liquid crystal display panel, the present invention relates to a photomask protective film used for preventing foreign matter from adhering to a photomask. In particular, it relates to a lithographic mask for a lithography using a pseudo-molecular laser used for exposure requiring high resolution. Optima is a lithographic mask for lithography used for exposure to ultraviolet light below 200 nm.

In the photolithography step of semiconductor manufacturing, in order to form a photoresist pattern corresponding to an integrated circuit on a wafer, a semiconductor manufacturing apparatus such as a stepper (reduced projection exposure apparatus) is currently used. The mask film is provided with a transparent film on one end surface of the mask film frame having a frame shape, and it is possible to prevent foreign matter from directly adhering to the mask due to the formation of the circuit pattern. Therefore, even if foreign matter adheres to the mask film in the photolithography step, since the foreign matter is not imaged on the wafer coated with the photoresist, the semiconductor integrated circuit caused by the image of the foreign matter can be prevented. Short circuit or disconnection, etc., can improve the manufacturing yield of the photolithography step.

In recent years, with the high integration of semiconductor devices, the exposure light used in the photolithography step tends to be short-wavelength. That is, it is required to draw a fine circuit pattern in a narrower line width when an integrated circuit pattern is drawn on a wafer. In order to cope with this requirement, for example, exposure light as a stepper for photolithography has been developed from the previous g-ray (wavelength 436 nm), i-ray (wavelength 365 nm) to the use of KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm) and then F2 excimer laser (wavelength 157 nm) and other shorter wavelengths of light.

As a method of fixing the reticle film to the reticle, a method of detachably fixing with an adhesive is generally employed. As the adhesive for fixing, an acrylic, rubber, or polybutene system is known. An adhesive such as a polyurethane or a polyoxygen (see Patent Document 1). The adhesive layer is formed on the other end surface of the reticle film frame on which the reticle film is disposed on one end surface. Therefore, when the reticle film or the reticle is contaminated, the reticle film must be temporarily peeled off from the reticle. Remove the dirt and reattach the reticle to the reticle. Further, in order to eliminate the problem that the mask film is peeled off from the mask during the exposure step, the above-mentioned adhesive is also required to have no load-bearing resistance even if a certain load is applied.

On the other hand, as the exposure light is shortened in wavelength and energy is increased, the frequency of fouling (referred to as "atomization") of the photomask film or the mask due to exposure increases.

It is considered that the organic gas component generated by the self-adhesive during exposure causes one of the causes of fogging due to the short-wavelength and high energy of the exposure light. Polyoxynoxy adhesives or rubber-based adhesives which have hitherto used generate more gas components during exposure. As a method of reducing the gas component generated by the self-adhesive agent, the techniques disclosed in Patent Documents 2 to 4 are known, but the problem has not been completely solved.

Further, as the exposure light is shortened in wavelength and energy is increased, the frequency at which the mask film or the mask is stained by exposure increases, and the frequency of replacement of the mask film or the mask is also increased. Under the above circumstances, it is desirable to stabilize the adhesive for the reticle film which has an appropriate adhesive force and which does not generate residual glue on the reticle. In particular, in the photolithography step using light having a wavelength shorter than 200 nm, the above-mentioned atomization is more likely to occur. Therefore, it is more desirable to leave the photoresist film on the photomask without leaving adhesive residue. On the other hand, in the current photolithography step using a KrF excimer laser (wavelength 248 nm), the polyoxygen-based adhesive used as an adhesive for the mask film has a residual adhesive residue on the mask. And the problem of insufficient bearing capacity.

As a method of improving the residual residual glue after peeling off the mask film, Patent Document 5 discloses a mask film having an adhesive layer having a cohesive breaking strength of 20 g/mm ² or more. However, the problem of the adhesive residue and the load-bearing property of the adhesive is usually a trade-off relationship, and the adhesive having less residual adhesive is poor in load-bearing property, and the adhesive may be peeled off during the exposure.

In addition, with the short-wavelength and high energy of the exposure light in recent years, the pattern tends to be finer. Therefore, it is considered that if the flatness of the photomask is poor, there is a problem in that a focus shift occurs during exposure and is baked. The accuracy of the pattern deteriorates. Therefore, the flatness requirements for the reticle are more stringent than before.

It is considered that one of the factors for changing the flatness of the reticle by the reticle film, in particular, a method of changing the flatness by using the reticle adhesive material, is disclosed in Patent Documents 6 and 7.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 05-281711

[Patent Document 2] Japanese Patent Laid-Open No. Hei 10-171103

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2001-147518

[Patent Document 4] International Publication No. 2004-046827

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-146085

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2009-276504

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2009-025560

The inventors of the present invention have found that the organic solvent component represented by toluene or ethyl acetate is the main cause of atomization generated on the mask by the organic gas component produced by the adhesive.

The organic solvent is mainly used in solution polymerization, and in particular, toluene and ethyl acetate have high solubility to an adhesive and have a moderate boiling point, and thus are industrially very easy to use solvents. However, a certain amount of the organic solvent component remains in the adhesive produced by using the above organic solvent, which is released as a gas during the exposure. In order to reduce the gas generated from the adhesive layer, a method of drying the low-boiling component such as a solvent to be used at a high temperature for a long period of time to minimize the solvent remaining in the adhesive layer is usually employed. However, long-term drying impairs productivity, and even if a method of removing the organic solvent component in the adhesive is carried out, a certain amount of the organic solvent component is always left, and the organic solvent component volatilizes to cause atomization.

Therefore, the inventors of the present invention have conducted diligent research and found that the organic gas adsorbing property of the reticle coating itself can prevent the atomized organic gas from being adsorbed on the reticle, thereby completing Invention of the present application.

An object of the present invention is to provide a photomask film having an adhesive having excellent organic gas adsorption performance.

As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by the following invention.

That is, the present invention is as follows:

A reticle protective film comprising a reticle protective film frame, having a reticle film on one end face of the reticle cover film and having an adhesive on the other end face, and the adhesive is toluene The weight swelling degree is more than 5 times.

2. The photomask film according to the above 1, wherein the adhesive contains a reaction product of an alkyl (meth) acrylate copolymer and a hardening material, and the alkyl (meth) acrylate copolymer has a carbon number A copolymer of an alkyl (meth) acrylate having 4 to 14 alkyl groups and a monomer having a functional group reactive with a hardening material.

3. Support the photomask film 1 or 2, wherein the adhesive by a stretching speed of 300% modulus value at 23 ℃ 30 mm / min of tensile test of the obtained 50 ~ 350 mN / mm ² .

4. The photomask film according to the above 1 or 2, wherein the hardening material is at least one selected from the group consisting of a polyfunctional epoxy compound and an isocyanate compound.

5. The photomask film according to the above 1 or 2, wherein the adhesive comprises an adhesive composition comprising a polymer having a polymerization starting end and a polymerization initiator, and a polymerization initiator in the adhesive The total weight is 8 ppm or less relative to the total weight of the adhesive.

6. The photomask film according to the above 1 or 2, wherein the adhesive contains 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a hardening material.

7. The photomask film according to the above 4, wherein the polyfunctional epoxy compound is a nitrogen-containing epoxy compound having 2 to 4 epoxy groups.

8. The photomask film according to the above 3, which comprises acrylic acid as a monomer having a functional group reactive with the hardening material, the amount of the acrylic acid being relative to all of the alkyl (meth)acrylate copolymer The monomer is 0.1 to 5% by weight.

9. The photomask film of the above 3, wherein the (meth)acrylic acid alkyl ester copolymer has a weight average molecular weight of 700,000 to 2.5 million.

10. A reticle film having a reticle film frame, having a reticle film on one end surface of the reticle film frame and having an adhesive on the other end surface, and the adhesive agent comprises In the adhesive composition having the polymer of the polymerization starting end and the polymerization initiator, the total weight of the polymerization initiator in the adhesive is 8 ppm or less based on the total weight of the adhesive.

11. The photomask film according to the above 10, wherein the polymerization initiator is a peroxide polymerization initiator or an azo polymerization initiator, or an alkylphenone polymerization initiator or fluorenylphosphine oxide. It is a polymerization initiator.

12. The photomask film according to the above 10 or 11, wherein the adhesive contains a reaction product of an alkyl (meth) acrylate copolymer and a hardening material, and the alkyl (meth) acrylate copolymer has carbon A copolymer of an alkyl (meth) acrylate having 4 to 14 alkyl groups and a monomer having a functional group reactive with a hardening material.

The photomask 13 of the protective film 10 or 11, wherein the adhesive by a stretching speed of 300% modulus value at 23 ℃ 30 mm / min of tensile test of the obtained 50 ~ 350 mN / mm ² .

14. The photomask film according to the above 10 or 11, wherein the hardening material is at least one selected from the group consisting of a polyfunctional epoxy compound and an isocyanate compound.

15. The photomask cover according to the above 10 or 11, wherein the adhesive has a degree of swelling of toluene of 5 times or more.

16. The photomask film according to the above 12, wherein the adhesive contains 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a hardening material.

17. The photomask cover according to the above 14, wherein the polyfunctional epoxy compound is a nitrogen-containing epoxy compound having 2 to 4 epoxy groups.

18. The photomask film according to the above 12, which comprises acrylic acid as a monomer having a functional group reactive with the hardening material, the amount of the acrylic acid being relative to all of the alkyl (meth)acrylate copolymer The monomer is 0.1 to 5% by weight.

19. The photomask film of the above 12, wherein the (meth)acrylic acid alkyl ester copolymer has a weight average molecular weight of 700,000 to 2.5 million.

An adhesive comprising a reaction product of 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a polyfunctional epoxy compound, which is copolymerized with an alkyl (meth) acrylate. The system has a copolymer of an alkyl (meth) acrylate having a carbon number of 4 to 14 and a monomer having a functional group reactive with an epoxy group, and the viscosity of the adhesive to toluene is More than 5 times.

The photomask film of the present invention is a photomask film having excellent organic gas adsorption performance, so that atomization generated on the photomask can be effectively suppressed.

Hereinafter, the form for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. The following examples are merely illustrative of the invention and are not intended to limit the invention to the following. The present invention can be suitably modified within the scope of the gist of the invention.

The adhesive used for the photomask film of the present invention has a degree of swelling of toluene of 5 times or more. The term "swelling" as used herein refers to a phenomenon in which an elastic gel absorbs a liquid (solvent) to increase the volume and weight, and a weight swelling degree indicates an increase ratio when the elastic gel absorbs a liquid (solvent) and increases the weight.

If the weight of the adhesive is large, the adhesive can adsorb the organic gas represented by toluene and ethyl acetate present in the enclosed space surrounded by the reticle film and the reticle, which can greatly reduce the organic The frequency at which the gas contacts the reticle. As a result, the generation of atomization can be greatly suppressed.

Further, by increasing the degree of swelling, it is possible to adsorb not only the organic gas but also the amount of gas generated. Specifically, it has been found that by controlling the weight of the solvent used in the production of the adhesive and the polymer as a solute, even if the solvent remains in the polymer, the solvent is not released from the polymer as a gas, but remains. In the polymer. The reason for reducing the gas generation by controlling the weight swelling degree is not clear, and it is presumed that the residual solvent is infiltrated into the polymer by increasing the affinity of the polymer to the solvent and controlling the crosslinked network structure of the polymer.

Further, if the degree of swelling of the toluene is 5 times or more, it is presumed that the size of the crosslinked network structure of the polymer is most suitable for the adsorption of toluene and acetic acid in the closed space surrounded by the reticle film and the reticle. The size of the organic gas represented by the ester greatly inhibits the generation of atomization.

For the above reasons, it is preferred that the adhesive used for the mask film has a degree of swelling of toluene of 5 times or more, preferably 7 times or more, more preferably 9 times or more, and particularly preferably 10 times or more.

The adhesive used in the photomask coating of the present invention has a weight swelling degree of not less than 5 times, and is particularly preferably in terms of sufficient adhesion to the photomask and less residual adhesive after peeling. An adhesive comprising a composition comprising a reaction product of an alkyl (meth) acrylate copolymer and a hardening material, and the alkyl (meth) acrylate copolymer is obtained by having a carbon number of 4~ At least two of an alkyl (meth)acrylate (hereinafter referred to as "component A") having 14 alkyl groups and a monomer having a functional group reactive with a hardener (hereinafter referred to as "component B") A copolymer obtained by copolymerizing a monomer component.

When the alkyl ester copolymer is a copolymer of a monomer mixture of 99 to 80% by weight of the A component and 1 to 20% by weight of the component B, it is more preferable because it exhibits an appropriate adhesion to the mask.

Here, the monomer of the component A is divided into a linear one having a carbon number of 4 to 14 (hereinafter referred to as "A1 component") and an alkyl group having 4 to 14 carbon atoms as a chain (hereinafter referred to as In the case of the "A2 component", the copolymer of the monomer mixture of 9 to 59% of the (meth)acrylic acid alkyl ester copolymer A2 component is more excellent in adhesion. When the copolymer of the monomer mixture of 40 to 90% by weight of the A1 component, 9 to 59% by weight of the A2 component, and 1 to 20% by weight of the component B is used, the residual rubber after the peeling is reduced, which is more preferable.

The acrylate-based single-system A1 component has an alkyl (meth) acrylate having 4 to 14 carbon atoms, and specific examples thereof include butyl (meth)acrylate, hexyl (meth)acrylate, and (methyl). A (meth) acrylate of a linear aliphatic alcohol such as octyl acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate or lauryl (meth) acrylate. These may be used alone or in combination of two or more. Among them, an alkyl (meth)acrylate having an alkyl group having 4 to 8 carbon atoms such as butyl (meth)acrylate or octyl (meth)acrylate exhibits a moderate adhesion to the mask, and thus can be compared. Good to use.

The acrylate monomer of the component A2 is a branched alkyl chain, and specific examples thereof include isobutyl (meth)acrylate, isoamyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Ester, isooctyl (meth)acrylate, isodecyl (meth)acrylate. These may be used alone or in combination of two or more. Among them, in terms of copolymerizability, it is preferred to use isobutyl (meth)acrylate (for example, isobutyl acrylate) or 2-ethylhexyl (meth)acrylate (for example, 2-ethylhexyl acrylate). .

The monomer of the component B can be a monomer copolymerizable with the monomer of the above component A, and is a monomer reactive with an epoxy group. For example, a carboxyl group-containing monomer such as (meth)acrylic acid, itaconic acid, maleic acid or crotonic acid, or 2-hydroxyethyl (meth)acrylate or 3-hydroxypropyl (meth)acrylate, A hydroxyl group-containing monomer such as 2-hydroxypropyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. These may be used alone or in combination of two or more. Among them, in terms of copolymerizability, versatility, and the like, it is preferred to use a hydroxyalkyl group having 2 to 4 carbon atoms such as 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. A carboxyl group-containing monomer such as a hydroxyl group (meth) acrylate or (meth) acrylate. Particularly, in terms of residual adhesive, it is preferably (meth)acrylic acid, and the content of (meth)acrylic acid is 0.1 to 5% by weight, more preferably, based on all monomers constituting the alkyl (meth)acrylate copolymer. It is 0.5 to 4% by weight, more preferably 0.8 to 3% by weight.

In the alkyl (meth)acrylate copolymer, the amount of the acrylate monomer of the A1 component is 40 to 90% by weight, preferably 45 to 80% by weight based on the monomer mixture. Further, the component A2 is preferably 9 to 59% by weight, preferably 15 to 50% by weight, and the component B is preferably 1 to 20% by weight, preferably 2 to 10% by weight.

When the weight average molecular weight of the (meth)acrylic acid alkyl ester copolymer is 700,000 or more and 2.5 million or less, the cohesive force and the adhesion force of the adhesive layer are appropriately increased, and it is difficult to leave residual glue and have sufficient adhesion. A load-resistant adhesive is preferred. The weight average molecular weight is preferably 900,000 or more and 2.3 million or less, more preferably 1,000,000 or more and 2,000,000 or less. The method for controlling the weight average molecular weight can be controlled by a well-known method. Specifically, there is usually a tendency that the higher the monomer concentration at the time of polymerization, the larger the weight average molecular weight, the smaller the amount of the polymerization starting dose, and the lower the polymerization temperature, the larger the weight average molecular weight.

As the above-mentioned (meth)acrylic acid alkyl ester copolymer, a well-known production method such as solution polymerization, bulk polymerization, emulsion polymerization, or various radical polymerization can be suitably used. Further, the obtained alkyl (meth)acrylate copolymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like. Further, in the solution polymerization, for example, ethyl acetate, toluene or the like can be used as the polymerization solvent.

As a specific solution polymerization example, 0.01 to 2.0 parts by weight of azobisisobutyronitrile is added as a polymerization initiator, for example, at 50 to 70 ° C under an inert gas flow such as nitrogen, for example, 100 parts by weight based on 100 parts by weight of the total amount of monomers. The next reaction is about 8 to 30 hours. The polymerization initiator, the chain transfer agent, the emulsifier, and the like used in the radical polymerization are not particularly limited, and can be appropriately selected and used.

Preferred examples of the polymerization initiator include azo-type 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 2,2'-couple. Nitrogen bis(2-methylpropionate), 4,4'-azobis-4-cyanoshikimate, or the like, or peroxide-based benzamidine peroxide.

The adhesive used for the photomask film of the present invention is particularly preferably an adhesive comprising a composition containing a reaction product of an alkyl (meth)acrylate copolymer and a hardening material.

Examples of the hardening material include a metal salt, a metal alkoxide, an aldehyde compound, a non-amino resin-based amine compound, a urea compound, an isocyanate compound, a metal chelate compound, a melamine compound, and a nitrogen-based compound. The hardening material used for a usual adhesive such as a pyridine compound is preferably selected from an isocyanate-based compound and polyfunctionality in terms of reactivity with a functional group component of an alkyl (meth)acrylate copolymer. At least one hardening material in the group consisting of epoxy compounds is more preferably a polyfunctional epoxy compound.

Specific examples of the isocyanate-based compound include toluene diisocyanate, and examples of the polyfunctional epoxy compound include neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and bisphenol A diglycidylglycerol. Ether, bisphenol F diglycidyl ether, diglycidyl terephthalate, dimer acid diglycidyl ester, triglycidyl isocyanurate, diglyceryl triglycidyl ether, sorbitol tetraglycidyl ether , N,N,N',N'-tetraglycidyl meta-xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N' , N'-tetraglycidyldiaminodiphenylmethane, and the like.

Among these, a nitrogen-containing epoxy compound having 2 to 4 epoxy groups is preferred, and in terms of reactivity, a nitrogen-containing epoxy compound having 4 epoxy groups is preferably used. When the reactivity is good, the crosslinking reaction is quickly completed after the application of the pressure-sensitive adhesive, and therefore the characteristics are stabilized in a short period of time and are excellent in productivity.

Further, by adjusting the content of the hardened material, the degree of weight swelling can be controlled. The term "swelling" refers to a state in which a solvent molecule enters between polymer molecules to balance the force of expanding the molecular spacing with the elasticity of the cross-linked network structure. The size of the swelling is affected by the affinity of the solvent to the polymer and the degree of crosslinking of the polymer, and the weight swelling degree of toluene can be controlled by controlling these. Those with higher affinity for the solvent and the polymer generally have an increased degree of weight swelling. As a standard of affinity, a SP value (solubility parameter) is generally used, and various SP values are available in "POLYMERHANDBOOK (4th edition) WILEY-INTER SCIENCE P689-711" in which the SP values are relatively close to each other. It is described that toluene is 18.2 (MPa ^1/2 ), and ethyl acetate is 18.6 (MPa ^1/2 ), which is approximately the same value. Therefore, the SP value of the monomer component constituting the polymer is close to that of toluene or ethyl acetate to increase the degree of weight swelling. For example, butyl acrylate as a monomer component of an acrylic adhesive is 18.0 (MPa ^1/2 ), isobutyl acrylate is 17.4 (MPa ^1/2 ), and butadiene as a monomer component of a rubber-based adhesive is used. It is 14.5 (MPa ^1/2 ), isobutylene is 15.0 (MPa ^1/2 ), ethylene is 15.76 (MPa ^1/2 ), butene is 13.7 (MPa ^1/2 ), and it is used as a monomer component of polyoxyxide adhesive. The dimethyloxane is 10.0 to 12.1 (MPa ^1/2 ). Therefore, from the viewpoint of affinity between the polymer and the solvent, an acrylic adhesive is preferred.

Also, the degree of weight swelling depends on the degree of crosslinking of the polymer. If the degree of crosslinking is too low, the solvent molecules do not penetrate into the polymer network structure, and the weight swelling degree is lowered. Further, if the degree of crosslinking is too high, the polymer cross-linking structure does not enter, and the degree of weight swelling is reduced. Therefore, the degree of weight swelling can be controlled by appropriately controlling the degree of crosslinking of the polymer.

When the content of the hardening material is 0.05 to 3 parts by weight based on 100 parts by weight of the alkyl (meth)acrylate copolymer, the degree of swelling of toluene or ethyl acetate is 5 times or more, which is a preferable mask protection. Adhesive for film. In the case where the content of the hardening material is from 0.05 part by weight to 0.20 part by weight, the degree of swelling of the toluene or ethyl acetate is further increased, and the adhesive for the mask film is further prevented from being generated, which makes it difficult to produce fogging. Residual residue. Further, since a moderate crosslinking density is achieved, it becomes a mask adhesive which does not easily affect the flatness of the mask (especially, the deformation of the mask can be suppressed). The reason for this is considered to be that if the content of the hardening material is 0.20 parts by weight or less, the crosslinking density does not become excessively large, and therefore the adhesive absorbs the stress applied to the mask to alleviate the influence on the flatness of the mask. On the other hand, when it is 0.05 part by weight or more, the crosslinking density does not become too small, so that the workability in the production step is maintained, and there is no problem that residual glue remains when the mask is peeled off from the mask.

In the case of the composition containing the above (meth)acrylic acid alkyl ester copolymer and the polyfunctional epoxy compound, the weight swelling degree can be adjusted up to 15 by controlling the degree of crosslinking of the polymer to be moderate. Times around. In particular, if the degree of swelling of the toluene is about 8 to 14 times, the organic gas such as toluene or ethyl acetate adsorbed in the adhesive has a large effect, and therefore it is preferable. The reason for this is considered to be that if the degree of swelling of the toluene is about 8 to 14 times, the interlaced structure spacing between the polymers is such that it is suitable for capturing toluene and ethyl acetate.

The reaction for obtaining a reaction product of an alkyl (meth) acrylate copolymer and a polyfunctional epoxy compound is carried out by weighing a (meth)acrylic acid alkyl ester copolymer solution and polyfunctionality. The epoxy compound solution is mixed and stirred to achieve uniform mixing, and the solvent is heated and dried to remove it, followed by heating.

If the average molecular weight of the alkyl (meth) acrylate copolymer and the content of the hardened material are adjusted so that the adhesive can obtain a 300% modulus value at 23 ° C by a tensile test at a tensile speed of 30 mm/min. When the temperature is 50 to 350 mN/mm ² , the adhesive is excellent in load resistance and is an adhesive which does not easily leave residual glue, and therefore is preferable. Here, the so-called 300% modulus value refers to an adhesive sample with an adhesive layer thickness of 0.2 mm and a width of 1.5 mm at 23 ° C, 65% RH gas atmosphere using an autostereograph. The stress per unit sectional area of 300% strain at 10 mm and a tensile speed of 30 mm/min. The 300% modulus value is mainly controlled by the weight average molecular weight of the (meth)acrylic acid alkyl ester copolymer and the content of the hardening material. The larger the weight average molecular weight of the (meth)acrylic acid alkyl ester copolymer, the larger the 300% modulus value, and the more the polyfunctional epoxy compound content, the larger the 300% modulus value.

The weight average molecular weight of the (meth)acrylic acid alkyl ester copolymer may be such that the 300% modulus value is in the range of 50 to 350 mN/mm ² , especially when the weight average molecular weight is 700,000 or more and 2.5 million or less. The cohesive force and the adhesive force of the adhesive layer are moderately sized, and it is preferable because it is an adhesive which does not easily retain residual glue and has sufficient adhesive force and load resistance. The weight average molecular weight is preferably 900,000 or more and 2.3 million or less, more preferably 1,000,000 or more and 2,000,000 or less.

The method for controlling the weight average molecular weight can be controlled by a well-known method. Specifically, there is usually a tendency that the higher the monomer concentration at the time of polymerization, the larger the weight average molecular weight, the smaller the amount of the polymerization starting dose, and the lower the polymerization temperature, the larger the weight average molecular weight.

The content of the hardening material may be in the range of 300% modulus value of 50 to 350 mN/mm ² , especially 0.05 to 3 parts by weight relative to the above alkyl (meth) acrylate copolymer, preferably 0.05 to 3 The parts by weight are more preferably 0.1 to 2.5 parts by weight. More preferably, it is 0.15 to 2.0 parts by weight. When the content of the hardening material is within the above range, the crosslinking density reaches an appropriate density, and the adhesive is less likely to remain in the residual rubber and has sufficient adhesion and load resistance.

In the range of the weight average molecular weight of the (meth)acrylic acid alkyl ester copolymer and the content of the hardening material, it is particularly preferable that the adhesive is obtained at 23 ° C by a tensile test at a tensile speed of 30 mm/min. The 300% modulus value is in the range of 50 to 350 mN/mm ² , more preferably 80 to 300 mN/mm ² , and even more preferably 100 to 280 mN/mm ² . When the 300% modulus is 50 to 350 mN/mm ² , it has sufficient adhesion and load-bearing property, and the residual rubber at the time of peeling is also reduced, which is preferable.

The polymerization initiator remaining in the adhesive is preferably 8 ppm or less based on the weight of the adhesive. If the polymerization initiator remaining in the adhesive is 8 ppm or less based on the total weight of the adhesive, the generation of atomization can be greatly suppressed. It is not clear why the atomization of the photomask is improved by reducing the amount of the polymerization initiator remaining in the adhesive layer, and it is considered as follows.

There are many reasons for the atomization. It is believed that the main reason is that the organic gas component existing in the exposed gas environment causes a chemical reaction by the energy of the exposure light, and the reaction product adheres to the reticle to cause atomization. . It is presumed that if a certain amount of the polymerization initiator is present in the adhesive layer, the polymerization initiator will be cracked by the energy of the exposure light, causing a chemical reaction of the organic gas, resulting in the formation of the atomized reaction product. increased badly.

For the above reasons, the amount of the polymerization initiator remaining in the adhesive used for the reticle film is preferably 8 ppm or less, more preferably 7 ppm or less, still more preferably 6 ppm or less, based on the weight of the adhesive.

The method for lowering and controlling the polymerization initiator remaining in the adhesive layer has the following methods, such as: reducing the polymerization initiation amount in the polymerization of the adhesive polymer, or using a polymerization initiator which is easily thermally decomposed; The coating and drying steps of the adhesive, high temperature application for a long period of time, and the polymerization initiator is decomposed by a drying step.

An index indicating the rate of thermal decomposition of the polymerization initiator has a 10-hour half-life temperature. The term "half-life" refers to the time during which the polymerization initiator decomposes to one-half of the original amount, and the 10-hour half-life temperature represents a temperature at which the half-life is 10 hours. The polymerization initiator having a low 10-hour half-life temperature is easily decomposed and thus does not easily remain on the adhesive layer. It is especially preferred to use a polymerization initiator having a 10-hour half-life temperature of 80 ° C or lower, preferably 75 ° C or lower.

When the polymerization initiator is an azo polymerization initiator, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (10-hour half-life temperature 30) °C), 2,2'-azobisisobutyronitrile (10-hour half-life temperature 60 °C), 2,2'-azobis(2,4-dimethylvaleronitrile) (10-hour half-life temperature 51 °C) , 2,2'-azobis(methyl 2-methylpropionate) (10-hour half-life temperature 66 ° C), 2,2'-azobis(2-methylbutyronitrile) (10-hour half-life temperature 67 °C), in the case of a peroxide-based polymerization initiator, examples include: benzoic acid peroxide (10-hour half-life temperature: 74° C.), and dilaurin peroxide (10-hour half-life temperature: 62° C.), but Not limited to this.

Also, the photopolymerization initiator also causes fogging. As a method for lowering and controlling the photopolymerization initiator remaining in the adhesive layer, a method of decomposing the photopolymerization initiator by thermal decomposition or drying, evaporation, or irradiation with ultraviolet rays may be considered. A method of using a photopolymerization initiator which is easily decomposed by the above method, and the like. The photopolymerization initiator which is easily decomposed by the above method may, for example, be an alkylphenone-based polymerization initiator or a mercaptophosphine oxide-based polymerization initiator. Specific examples of the alkylphenone-based polymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl-phenyl ketone, and 2- Hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, 2- Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propenyl)-benzyl]phenyl}-2-methylpropan-1-one, 2-methyl-1-( 4-methylthiophenyl)-2-morpholinylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone, 2 -(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone. Examples of the fluorenylphosphine oxide-based polymerization initiator include 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzylidene). Phenylphosphine oxide and the like.

In order to make the total weight of the polymerization initiator remaining in the adhesive 8 ppm or less based on the total weight of the adhesive, it is preferred to use a reaction product containing a copolymer of an alkyl (meth)acrylate and a hardened material. The adhesive of the composition, the alkyl (meth)acrylate copolymer is obtained by reacting an alkyl (meth)acrylate having an alkyl group having 4 to 14 carbons with a compound having reactivity with a hardening material. A copolymer obtained by copolymerizing at least two monomer components of a monomer.

Further, the adhesive composition may contain a previously known additive such as a filler, a pigment, a diluent, an anti-aging agent, or a UV stabilizer, in addition to the above reaction product. These additives may be used alone or in combination of two or more. However, it is preferred to set the addition amount at a proper time to obtain desired physical properties.

The photomask film of the present invention can be suitably produced, for example, by the following method.

First, the above (meth)acrylic acid alkyl ester copolymer solution and a polyfunctional epoxy compound solution are mixed to obtain an adhesive precursor composition. In this case, in order to apply a mask adhesive layer of a specific thickness and width, the adhesive precursor composition is diluted with a solvent to adjust the solution concentration (viscosity). The solvent to be diluted is selected from the viewpoints of solubility, evaporation rate, and the like. Preferable specific examples of the solvent include acetone, ethyl acetate, and toluene, but are not limited thereto.

Next, the adhesive precursor composition is applied to the other end surface of the reticle film frame having the reticle film on one end. The coating method is not particularly limited, and it is preferably applied by using a dispenser. The viscosity of the acrylic copolymer solution (referred to as a solution containing a solvent and a (meth)acrylic acid alkyl ester copolymer) in the above adhesive precursor composition is not particularly limited, but is preferably 50 P or less, more preferably 10 ~40 P, more preferably about 20~30 P (B type viscometer, 25 ° C). When coating by a dispenser, it is diluted with a solvent, and at this time, the coating liquid has few adhesive filaments, and it is easy to adjust to a stable width and thickness.

Again, the solvent and/or residual monomer can be removed by heating and drying the applied adhesive layer. Further, when the functional group of the (meth)acrylic acid alkyl ester copolymer is heated and reacted with the hardening material to form a crosslinked structure, the photomask cover film adhesive composition is integrated, and is adhered to the photomask The surface of the membrane frame.

The drying temperature is preferably from 50 to 200 ° C, preferably from 60 to 190 ° C, in consideration of the boiling point of the solvent and the residual monomer and the decomposition temperature of the alkyl (meth)acrylate copolymer. Further, it is preferred that the adhesive is applied to the mask film in a sufficiently dried state so that the solvent contained in the adhesive reaches 50 ppb or less in the following outgassing test.

After drying and cross-linking, the release sheet for protecting the adhesive surface may be attached. As the release sheet, a film having a thickness of about 30 to 200 μm such as polyester is usually used. Further, if the peeling force is large when the release sheet is peeled off from the adhesive, the adhesive is deformed when peeled off, so that the release of the polysiloxane or fluorine can be performed on the surface of the film which is in contact with the adhesive. Treatment to form a suitable peel force.

After attaching the release sheet for protecting the adhesive surface, a load is applied to form the surface of the adhesive into a substantially flat surface.

[Examples]

Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited thereto.

<Example 1> (Preparation of Adhesive Precursor Composition)

The alkyl (meth)acrylate copolymer 1 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and is added in a weight ratio of 30/66/1.5/2.5/1.0. a mixture of isobutyl acrylate/butyl acrylate/acrylic acid/2-hydroxyethyl acrylate/2,2'-azobisisobutyronitrile (32 parts by weight), the reaction solution was allowed to stand at 60 ° C under a nitrogen atmosphere Reaction for 8 hours. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.3 million) having a nonvolatile content of 32% by weight. 0.3 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition.

(production of photomask film with adhesive)

Thereafter, the prepared adhesive precursor composition is applied to an end face of the aluminum alloy reticle cover film with a mask film (with an outer diameter of 113 mm × 149 mm, inner diameter) by means of a dispenser. On the other end of 109 mm × 145 mm, height 4.8 mm). The film was heated and dried in two stages (first stage: 100 ° C, 8 minutes; second stage: 180 ° C, 8 minutes) to obtain an adhesive layer (thickness) formed with the above-mentioned adhesive precursor composition. 0.2 mm) of the reticle film of Example 1. Then, a polyester protective film having a thickness of 100 μm which was subjected to polysilicon deoxidation treatment was attached and aged at room temperature (20±3° C.) for 3 days to stabilize the adhesion, and a photomask with an adhesive was prepared. Protective film. The obtained visor film with an adhesive was evaluated by the following method.

(Out of gas test)

The outgas generated from the mask film can be captured by the adsorbent material for analysis. The reticle film obtained in the example was heat-treated at 50 ° C for 30 minutes under a helium flow of 50 mL/min, and was captured by an adsorbent. As the adsorbent, TENAX TA (manufactured by GL Science) was used. The sample was introduced into the GC device using a headspace sampler, and the adsorption tube was treated at 250 ° C for 10 minutes and thermally desorbed by GC/MS (gas chromatography/mass spectroscope). ) Analyze the generated outgas. The GC/MS analysis conditions are as follows.

GC unit: Agilent Technologies 7890A GC System

Column: Agilent Technologies 19091J-413 HP-5 (30 m × 0.320 mm × 0.25 μm)

Temperature condition: 30 ° C ~ 280 ° C (10 ° C / min)

MS device: JEOL Jms-Q1000GC K9

Ionization: 70 eV

Scanning range: m/z=10~500

The amount of toluene was calculated by dividing the weight obtained from the absolute calibration curve by the weight of one sheet of the mask film, and evaluated according to the following criteria.

10 ppb or less... ◎

50 ppb or less...○

51 ppb or more...×

(Atomization test)

The protective film with the adhesive agent obtained in the examples was peeled off from the protective film, and attached to the 6025 quartz blank substrate under a load (30 Kgf, 60 seconds) using a simple type of mounter. On the top, a substrate to which a mask film is attached is obtained.

The obtained substrate was irradiated with an ArF excimer laser at an irradiation dose of 8 m, 5000 J/cm 2 at a frequency of 0.7 mJ/cm 2 /pulse at a frequency of 250 Hz. The substrate and the mask film after the irradiation were visually observed for the occurrence of fogging, and evaluated according to the following criteria.

○...The substrate and the mask film are not fogged.

×...The substrate and the mask film are fogged

(peelability evaluation)

The protective film with the adhesive agent obtained in the examples was peeled off from the protective film, and attached to a 6025 chrome-plated blank substrate under a load (30 Kgf, 60 sec) by a simple type laminating machine. A substrate to which a reticle film is attached is obtained. The substrate to which the photomask film is attached is placed at room temperature (20±3° C.) for 2 hours, and then the substrate is horizontally fixed, and a corner of the mask film is applied along the tensile tester. The mask surface is perpendicular to the direction of stretching at a speed of 5 mm/min, and the mask film is peeled off. The peeling property was observed on the surface of each of the adherends, and evaluated according to the following criteria.

◎: Residual rubber area is 0~5% of the total attached area

○: Residual rubber area is 6~20% of the total attached area

×: Residual rubber area is 21~100% of the total attached area

(with load-bearing test)

The protective film with the adhesive agent obtained in the examples was peeled off from the protective film, and attached to a 6025 quartz blank substrate and 6025 by a simple type bonding machine under a load (30 Kgf, 60 sec). On the blank substrate of chrome, a substrate to which a mask film is attached is obtained. A weight of 1 Kg was placed on the substrate to which the reticle film was attached, and placed at room temperature. The time until the mask film was peeled off from the substrate was evaluated according to the following criteria.

◎: There is no airway after 3 days.

○: After one day, the mask film is peeled off from the substrate.

×: After 3 hours, the mask film peeled off from the substrate.

(molecular weight determination)

The adhesive sample was vacuum dried to remove the solvent. The solution was added to the sample and adjusted to 1.0 mg/mL. Filtration was carried out using a 0.5 micron filter, and the filtrate was used as a GPC sample. The measurement conditions of GPC are as follows.

GPC Data Processing: Tosoh GPC-8020

Device: Tosoh HLC-8220GPC

Column: TSKgel SuperHZN-M (4.6 mmI.D. × 15 cm) 1 + TSKgel SuperHZ2000 (4.6 mmI.D. × 15 cm) 1

Oven: 40 ° C

Dissolved solution: 0.35 mL/min CHCl ₃

Sample volume: 50 μl (1.0 mg/mL)

Detector: RI

Calibration curve: polystyrene

(Measured by the degree of swelling of toluene or ethyl acetate)

Approximately 100 mg (weight A) of the adhesive was scraped from the adhesive layer obtained in the examples using a doctor blade, and wrapped in a nylon mesh (mesh 200 μm) at 20 ° C in toluene solution or acetic acid The ester solution was immersed for 1 week. Thereafter, the inclusions were taken out from the solution, and the weight (weight B) of the undissolved portion of the adhesive immediately after being taken out from the solution was measured. At this time, the value calculated by B/A was taken as the weight swelling degree of toluene or ethyl acetate.

<Example 2>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) is 0.2 parts by weight, A sample of the mask film was prepared and evaluated in the same manner as in Example 1.

<Example 3>

The (meth)acrylic acid alkyl ester copolymer 2 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) was placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate was added in a weight ratio of 98/2/1. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 60 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.7 million) having a nonvolatile content of 32% by weight. 0.2 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 1.

<Example 4>

By using a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane to be 0.45 parts of a trimethylolpropane adduct of toluene diisocyanate A sample of the mask film was prepared and evaluated in the same manner as in Example 1.

<Example 5>

The (meth)acrylic acid alkyl ester copolymer 3 is prepared by a well-known method. Specifically, ethyl acetate (50 parts by weight) was placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate was added in a weight ratio of 98/2/1. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 65 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (18 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 600,000) having a nonvolatile content of 32% by weight. 0.3 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 1.

<Example 6>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) is changed to 2.0 parts. A mask film sample was prepared and evaluated in the same manner as in Example 1.

<Example 7>

The alkyl (meth)acrylate copolymer 4 is prepared by a well-known method. Specifically, ethyl acetate (50 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and is added in a weight ratio of 30/66/1.5/2.5/1.0. a mixture of isobutyl acrylate/butyl acrylate/acrylic acid/2-hydroxyethyl acrylate/2,2'-azobisisobutyronitrile (50 parts by weight), and the reaction solution was allowed to stand at 55 ° C under a nitrogen atmosphere. Reaction for 8 hours. After completion of the reaction, toluene (20 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 2.8 million). 0.3 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition.

<Comparative Example 1>

A mask film was produced in the same manner as in Example 1 except that the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane was changed to 0.02 parts. And evaluate.

<Comparative Example 2>

0.9 parts by weight of a hardener (manufactured by Dow Corning, SRX212) was added to 100 parts by weight of a polyoxyxylene adhesive (manufactured by Dow Corning, SD4580 (trade name) with a nonvolatile content of 40%, toluene/xylene solution). ), an adhesive precursor composition is obtained. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 1.

<Comparative Example 3>

A rubber-based hot-melt adhesive of styrene-ethylene/butylene-styrene is applied to a mask frame of an aluminum alloy film having an outer surface and a mask film (outer diameter: 113 mm × 149 mm, The other end of the diameter is 109 mm × 145 mm and the height is 4.8 mm. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 1.

<Example 8> (Preparation of Adhesive Precursor Composition)

The alkyl (meth)acrylate copolymer 5 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and is added in a weight ratio of 48/48/1.5/2.5/1.0. a mixture of isobutyl acrylate/butyl acrylate/acrylic acid/2-hydroxyethyl acrylate/2,2'-azobisisobutyronitrile (32 parts by weight), the reaction solution was allowed to stand at 60 ° C under a nitrogen atmosphere Reaction for 8 hours. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.2 million) having a nonvolatile content of 32% by weight. 0.25 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition.

(production of photomask film with adhesive)

Thereafter, the adhesive composition prepared by applying the above-mentioned adhesive composition to a single end face and then a mask film of an aluminum alloy film having a mask film (outer diameter 113 mm × 149 mm, inner diameter 109) The other end of mm × 145 mm, height 4.8 mm). It was heat-dried and solidified in two stages (first stage: 100 ° C, 8 minutes; second stage: 180 ° C, 8 minutes) to obtain an adhesive layer (thickness 0.2) formed with the above-mentioned adhesive precursor composition. Mm) The reticle film of Example 8. Then, a polyester protective film having a thickness of 100 μm which was subjected to polysilicon deoxidation treatment was attached and aged at room temperature (20±3° C.) for 3 days to stabilize the adhesion, and a photomask with an adhesive was prepared. Protective film. The following evaluation was performed on the obtained photomask film with an adhesive attached thereto, and the following evaluation was performed.

(modulus measurement)

The adhesive sample having a thickness of 0.2 mm and a width of 1.5 mm of the adhesive layer was stretched by 10 mm between the chucks, a tensile speed of 30 mm/min, and 23 ° C using an autostereograph, and the force at this time was measured.

The force at 300% stretching was divided by the cross-sectional area of the sample, and the obtained value was set to a 300% modulus value.

<Example 9>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) is 0.15 parts by weight. A sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Example 10>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) is 1.8 parts by weight, A sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Example 11>

The alkyl (meth)acrylate copolymer 6 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) was placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate was added in a weight ratio of 99/1/1.0. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 60 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.8 million) having a nonvolatile content of 32% by weight. To 100 parts by weight of the obtained acrylic copolymer solution, 0.15 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, a concentration of a nonvolatile component is added It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Example 12>

The alkyl (meth)acrylate copolymer 7 is prepared by a well-known method. Specifically, ethyl acetate (50 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate is added in a weight ratio of 99/1/1.0. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 65 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (18 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 600,000) having a nonvolatile content of 32% by weight. 0.25 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Comparative Example 4>

A mask film was produced in the same manner as in Example 8 except that the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane was changed to 3.2 parts. Samples were evaluated.

<Comparative Example 5>

A mask film was produced in the same manner as in Example 8 except that the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane was changed to 0.03 parts. And evaluate.

<Comparative Example 6>

0.9 parts by weight of a hardener (manufactured by Dow Corning, SRX212) was added to 100 parts by weight of a polyoxyxylene adhesive (manufactured by Dow Corning, SD4580 (trade name) with a nonvolatile content of 40%, toluene/xylene solution). ), an adhesive precursor composition is obtained. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Comparative Example 7>

A rubber-based hot-melt adhesive of styrene-ethylene/butylene-styrene is applied to a mask frame of an aluminum alloy film having an outer surface and a mask film (outer diameter: 113 mm × 149 mm, The other end of the diameter is 109 mm × 145 mm and the height is 4.8 mm. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 8.

<Example 13> (Preparation of Adhesive Precursor Composition)

The alkyl (meth)acrylate copolymer 8 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and is added in a weight ratio of 48/48/1.5/2.5/1.0. Mixture of isobutyl acrylate/butyl acrylate/acrylic acid/2-hydroxyethyl acrylate/2,2'-azobisisobutyronitrile (AIBN) (10 hour half-life temperature 60 ° C) (32 parts by weight) in nitrogen The reaction solution was allowed to react at 60 ° C for 8 hours under the environment. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.2 million) having a nonvolatile content of 32% by weight. 0.25 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition.

(production of photomask film with adhesive)

Thereafter, the prepared adhesive precursor composition is applied to a reticle cover film of an aluminum alloy having a mask film and a film having an outer diameter of 113 mm × 149 mm by means of a dispenser. The other end of the diameter is 109 mm × 145 mm and the height is 4.8 mm. It was heat-dried and solidified in two stages (first stage: 100 ° C, 8 minutes; second stage: 180 ° C, 8 minutes) to obtain an adhesive formed with the adhesive precursor composition containing the above-mentioned photomask film. Mask layer (0.2 mm thick). Thereafter, the mask film was heat-treated at 130 ° C for 60 minutes to adjust the amount of 2,2'-azobisisobutyronitrile (polymerization initiator) remaining in the adhesive layer. Then, a polyester protective film having a thickness of 100 μm which was subjected to polysilicon deoxidation treatment was attached and aged at room temperature (20±3° C.) for 3 days to stabilize the adhesion, and a photomask with an adhesive was prepared. Protective film. The above evaluation was carried out on the obtained photomask film with an adhesive attached thereto, and the following evaluation was carried out.

(Measurement of residual amount of polymerization initiator)

The residual amount of the polymerization initiator remaining in the adhesive was analyzed by high performance liquid chromatography (HPLC). 0.2 g of the adhesive was placed in a 20 mL spiral tube, and 10 mL of acetonitrile was added. The components were extracted by a penetrator at 120 r.p.m. for 8 hours at 25 °C. The analysis device and extraction conditions were set as follows.

Analytical device: manufactured by Tosoh, HPL CCPM

Column: NuCLEOSLL 7C18 (4.8 mm Φ × 250 mm)

Column pressure: 41 Kg/cm ²

Column temperature: 40 ° C

Injection volume: 10 μL

The basis weight of the polymerization initiator was calculated by dividing the weight determined from the absolute calibration curve by the weight of the adhesive of one sheet of the mask film.

<Example 14>

The alkyl (meth)acrylate copolymer 9 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) was placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate was added in a weight ratio of 99/1/1.0. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 60 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.8 million) having a nonvolatile content of 32% by weight. To 100 parts by weight of the obtained acrylic copolymer solution, 0.15 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, a concentration of a nonvolatile component is added It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 13.

<Example 15>

The alkyl (meth)acrylate copolymer 10 is prepared by a well-known method. Specifically, ethyl acetate (50 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and butyl acrylate is added in a weight ratio of 99/1/2.0. A mixture of acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight) was reacted at 65 ° C for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (18 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 600,000) having a nonvolatile content of 32% by weight. 0.25 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was added to 100 parts by weight of the obtained acrylic copolymer solution, and the concentration of nonvolatile components was added. It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive precursor composition. Thereafter, a sample of the photomask film was produced and evaluated in the same manner as in Example 10.

<Example 16>

A mask film was produced in the same manner as in Example 13 except that the heat treatment conditions of the mask film with the adhesive material layer obtained in Example 13 were changed from 60 minutes at 130 ° C to 60 ° C for 60 minutes. Samples were evaluated.

<Comparative Example 8>

The evaluation was carried out in the same manner as in Example 13 except that the mask film with the adhesive material layer obtained in Example 13 was heat-treated at 130 ° C for 60 minutes without producing a film of the mask film.

<Comparative Example 9>

0.9 parts by weight of a hardener (manufactured by Dow Corning, SRX212) was added to 100 parts by weight of a polyoxyxylene adhesive (manufactured by Dow Corning, SD4580 (trade name) with a nonvolatile content of 40%, toluene/xylene solution). ), an adhesive precursor composition is obtained. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 13.

<Comparative Example 10>

A rubber-based hot-melt adhesive of styrene-ethylene/butylene-styrene is applied to a mask frame of an aluminum alloy film having an outer surface and a mask film (outer diameter: 113 mm × 149 mm, The other end of the diameter is 109 mm × 145 mm and the height is 4.8 mm. Thereafter, a sample of the photomask film was prepared and evaluated in the same manner as in Example 13.

<Example 17> (Preparation of adhesive material composition)

The alkyl (meth)acrylate copolymer 11 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and is added in a weight ratio of 48/48/1.5/2.5/0.5. a mixture of isobutyl acrylate/butyl acrylate/acrylic acid/2-hydroxyethyl acrylate/2,2′-azobisisobutyronitrile (32 parts by weight), under a nitrogen atmosphere, the reaction solution was refluxed Reaction for 8 hours. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.2 million) having a nonvolatile content of 32% by weight. To 100 parts by weight of the obtained acrylic copolymer solution, 0.05 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, a concentration of a nonvolatile component is added It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive material composition.

(production of photomask film with adhesive material)

Thereafter, the adhesive material composition prepared by applying the above-mentioned adhesive material composition to the one end surface and then the reticle film film of the reticle film is used (outer diameter 113 mm × 149 mm, inner diameter 109) The other end of mm × 145 mm, height 4.8 mm). This was heat-dried and solidified in two stages (first stage: 100 ° C, 8 minutes; second stage: 180 ° C, 8 minutes) to obtain an adhesive material composition containing the photomask cover film of Example 17. The reticle film of Example 17 of the adhesive material layer (thickness 0.2 mm). Then, a polyester protective film having a thickness of 100 μm which was subjected to polysilicon deoxidation treatment was attached and aged at room temperature (20±3° C.) for 3 days to stabilize the adhesive force, and a photomask with an adhesive material was prepared. Protective film. The above evaluation was performed on the obtained photomask film with an adhesive material, and the following evaluation was performed.

(evaluation of mask deformation)

The evaluation of the mask deformation was carried out using a FlatMaster 200 manufactured by Tropel. The flatness of the reticle (6025 quartz) was measured before attaching the reticle film, and then the reticle film was attached, and the flatness after attaching the reticle film was measured (measurement range: 135 mm × 110 mm). The flatness before and after the attachment was subtracted, and the degree of deformation of the 6025 quartz due to the attachment of the mask film was calculated.

Attach the mask to the quartz (load: 30 Kgf, 60 sec) using a simple laminator.

◎: The deformation of the mask caused by attaching the mask film is 100 nm or less.

○: The amount of deformation of the mask caused by attaching the mask film is 200 nm or less

×: The deformation amount of the reticle caused by attaching the reticle film is 200 nm or more

<Example 18>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, the toluene solution) is changed to 0.1 part by A sample of the mask film was prepared in the same manner as in Example 17 and evaluated.

<Example 19>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) becomes 0.2 part, A sample of the mask film was prepared in the same manner as in Example 17 and evaluated.

<Comparative Example 11>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the concentration of the nonvolatile component is 5%, and the toluene solution) is 0.24 parts, A sample of the mask film was prepared in the same manner as in Example 17 and evaluated.

<Comparative Example 12>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the nonvolatile content of 5%, the toluene solution) was changed to 0.01 part by A sample of the mask film was prepared in the same manner as in Example 17 and evaluated.

<Example 20>

In addition to the polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the nonvolatile content of 5%, the toluene solution) becomes the toluene diisocyanate trihydroxyl A sample of the photomask film was prepared and evaluated in the same manner as in Example 17 except that 0.15 parts of the methyl propane adduct was used.

<Example 21> (Preparation of adhesive material composition)

The alkyl (meth)acrylate copolymer 12 is prepared by a well-known method. Specifically, ethyl acetate (30 parts by weight) is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and acrylic acid 2 is added in a weight ratio of 69/30/1/0.5. a mixture of ethyl hexyl acrylate/butyl acrylate/acrylic acid/2,2'-azobisisobutyronitrile (32 parts by weight), and the reaction solution was reacted at reflux temperature for 8 hours under a nitrogen atmosphere. After completion of the reaction, toluene (38 parts by weight) was added to obtain an acrylic copolymer solution (weight average molecular weight: 1.5 million) having a nonvolatile content of 32% by weight. To 100 parts by weight of the obtained acrylic copolymer solution, 0.15 parts by weight of a polyfunctional epoxy compound (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, a concentration of a nonvolatile component is added It was 5%, a toluene solution), and stirred and mixed to obtain an adhesive material composition. Thereafter, a sample of the mask film was prepared and evaluated in the same manner as in Example 17.

[Industrial availability]

The photomask film of the present invention is a photomask film having a small amount of outgas generation and excellent organic gas adsorption performance, and thus can be suitably used for an IC (integrated circuit) or an LSI (large-scale integrated circuit). A lithography step such as a TFT-type LCD (thin-film transistor liquid crystal display).

Claims (14)

A reticle protective film, which is characterized in that a reticle protective film frame has a reticle film on one end face of the reticle cover film and an adhesive on the other end face, and the adhesive swells the weight of the toluene The adhesive is more than 5 times, and the adhesive contains a reaction product of a (meth)acrylic acid alkyl ester copolymer and a hardening material, and the alkyl (meth)acrylate copolymer has an alkyl group having 4 to 14 carbon atoms. A copolymer of an alkyl (meth) acrylate and a monomer having a functional group reactive with a hardening material. The reticle film of claim 1, wherein the adhesive has a 300% modulus value of 23 to 350 mN/mm ² at 23 ° C obtained by a tensile test at a tensile speed of 30 mm/min. The reticle film of claim 1, wherein the hardening material is at least one selected from the group consisting of a polyfunctional epoxy compound and an isocyanate compound. The reticle film of claim 2, wherein the hardening material is at least one selected from the group consisting of a polyfunctional epoxy compound and an isocyanate compound. The photomask cover according to any one of claims 1 to 4, wherein the adhesive further comprises a polymerization initiator, and the total weight of the polymerization initiator remaining in the adhesive is 8 ppm or less based on the total weight of the adhesive. . The reticle film of claim 1, wherein the adhesive contains 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a reaction product of the hardened material. The reticle film of claim 5, wherein the adhesive contains 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a reaction product of the hardened material. The photomask film of claim 3, wherein the polyfunctional epoxy compound is a nitrogen-containing epoxy compound having 2 to 4 epoxy groups. The photomask film of claim 1, which contains acrylic acid as the monomer having a functional group reactive with the hardening material, and the amount of the acrylic acid is relative to all of the alkyl (meth)acrylate copolymer The monomer is 0.1 to 5% by weight. The photomask film of claim 5, which contains acrylic acid as the monomer having a functional group reactive with the hardening material, and the amount of the acrylic acid is relative to all of the alkyl (meth)acrylate copolymer The monomer is 0.1 to 5% by weight. The photomask film of claim 1, wherein the (meth)acrylic acid alkyl ester copolymer has a weight average molecular weight of 700,000 to 2.5 million. The photomask film of claim 5, wherein the (meth)acrylic acid alkyl ester copolymer has a weight average molecular weight of 700,000 to 2.5 million. The photomask film of claim 5, wherein the polymerization initiator is a peroxide polymerization initiator or an azo polymerization initiator, or an alkylphenone polymerization initiator or a fluorenylphosphine oxide system. Polymerization initiator. An adhesive characterized by comprising 100 parts by weight of an alkyl (meth) acrylate copolymer and 0.05 to 3 parts by weight of a polyfunctional epoxy compound, the alkyl (meth) acrylate The copolymer is an alkyl (meth)acrylate having an alkyl group having 4 to 14 carbon atoms and having an epoxy group A copolymer of a reactive functional group monomer, and the viscosity of the adhesive to toluene is 5 times or more.