JP2003320606A - Protective film transfer sheet for photomask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective film transfer sheet for a photomask capable of transferring a protective film to the photomask so that a part of the transferred protective film can be easily removed along with foreign matter. <P>SOLUTION: The protective film transfer sheet is constituted by providing the protective film to a peelable support. The protective film has a property such that, when a part not bonded to the image surface of the photomask is generated when the protective film is transferred to the image surface of the photomask, the non-bonded part of the protective film can be partially removed from the protective film after transfer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film transfer sheet for a photomask capable of transferring a protective film suitable for protecting a photomask such as an original for photoengraving or an original for a printed wiring board whose surface is easily scratched. In particular, the present invention relates to a protective film transfer sheet for a photomask, which can provide a protective film that can remove a part of the protective film after transfer.

[0002]

2. Description of the Related Art Conventionally, in order to protect a photomask whose surface is easily damaged, a thin plastic film such as polyethylene terephthalate is used as a support, and an adhesive or an adhesive is laminated on the plastic film, and the adhesive or the adhesive is adhered. A surface protection film obtained by laminating a release film on the agent is used. By the way, recently, photomasks, which are originals used for photoengraving and printed wiring boards,
The patterns to be created have become complicated, and high resolution has been required. Therefore, a thinner protective film is required. However, in the surface protective film having the above-mentioned structure, if the plastic film is made thinner, the workability in laminating it on the photomask is deteriorated, and wrinkles, bubbles and the like are likely to occur.

As an improvement of such a structure, for example, Japanese Utility Model Publication No. 6-20601 discloses a protective film formation in which a protective film is formed by sequentially laminating a protective layer and an adhesive layer from the side of a peelable support. A multi-layer sheet for use is described.

[0004]

When attaching such a surface protective film or a multilayer film for forming a protective film to the image surface of a photomask, a clean environment is provided so that foreign matter such as dust is not caught. I try to do it below,
It is not possible to prevent foreign matter from being completely caught. If a foreign matter is thus sandwiched between the photomask and the surface protective film or the transferred protective film, the foreign matter causes an exposure failure, and the photomask itself becomes a defective product.

When a surface protective film is used here, when such a foreign substance is sandwiched, the adhered surface protective film can be peeled off and re-attached with a new one, but this increases the cost. turn into. On the other hand, in the case of the protective film transferred by the protective film-forming multilayer sheet, it is impossible to reattach the entire surface of the protective film after the transfer because the thickness of the protective film is extremely thin.

Therefore, the present invention has been made in order to solve the above problems, and in order to prevent the photomask itself from being a defective product, it is transferred to the photomask and then transferred. Another object of the present invention is to provide a protective film transfer sheet for a photomask, which can transfer the protective film so that a part of the protective film can be easily removed together with foreign matter.

[0007]

A protective film transfer sheet for a photomask of the present invention is a protective film transfer sheet in which a protective film is provided on a peelable support, and the protective film comprises the protective film. When a portion of the protective film that is not adhered to the photomask image surface occurs when transferred to the photomask image surface, the unadhered portion of the protective film is partially transferred from the protective film after transfer. It is characterized in that it can be removed.

Further, the protective film transfer sheet for a photomask of the present invention is removed by using an adhesive member when the protective film partially removes an unbonded portion of the protective film from the transferred protective film. It is characterized by being able to.

The protective film transfer sheet for a photomask of the present invention is characterized in that the protective film is formed by laminating a protective layer and an adhesive layer in this order from the support side.

Further, the protective film transfer sheet for a photomask of the present invention is characterized in that the protective layer and the adhesive layer each have a thickness of 0.5 to 3.0 μm.

Further, the protective film transfer sheet for a photomask of the present invention is characterized in that the protective layer and the adhesive layer are made of at least a thermosetting resin or an ionizing radiation curable resin. Is.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the protective film transfer sheet for a photomask of the present invention will be described below.

The protective film transfer sheet for a photomask of the present invention comprises a releasable support and a protective film provided thereon.
The separator can be used by being laminated on the protective film, if necessary. And, this protective film is a portion where the protective film is not adhered to the photomask image surface after transfer of the protective film to the photomask image surface (hereinafter,
“Unbonded portion”), the unbonded portion can be partially removed from the protective film after transfer.

Here, in particular, the protective film in the present invention can be easily removed by using an adhesive member when partially removing the unbonded portion from the transferred protective film. Here, the adhesive member is not particularly limited as long as it is a material such as an adhesive tape or an adhesive roller that has a surface that can be repeatedly attached and peeled by at least partially having adhesiveness. can do. To be more specific about the removal method, for example, when the adhesive member is an adhesive tape, the adhesive tape should be rubbed over the non-adhesive part and then attached, and then the adhesive tape should be peeled off vigorously. Can be done by

Next, the support in the protective film transfer sheet for a photomask of the present invention serves as a base material when the protective film is provided, and has a function of transferring the protective film to the image surface of the photomask with good workability. It is a responsibility.

The support is not particularly limited as long as the protective film can be peeled off, but the protective film can be cured by irradiating the protective film with ionizing radiation through the support. As such, it is desirable to have ionizing radiation transparency. Examples of such a support include polyethylene terephthalate,
Transparent plastic films such as polycarbonate, polypropylene, polyethylene, polyvinyl chloride, polyethylene naphthalate, polystyrene are used. In particular, a biaxially stretched polyethylene terephthalate film is excellent in strength, heat resistance and dimensional stability, and is therefore preferably used. The thickness of the support is 6 in consideration of handleability.
˜125 μm is preferred.

Further, as the support, in order to improve the releasability of the protective film, a support which has been subjected to a release treatment such as a release layer on the surface of the plastic film may be used.

The release layer in this case is a layer that remains on the surface of the plastic film after transfer and facilitates peeling from the protective film. Such a release layer is a melamine resin,
It can be appropriately selected from silicone resin, aminoalkyd resin, urethane resin, urea resin, epoxy resin, fluororesin, polyvinyl alcohol resin, polyvinyl methyl ether / maleic anhydride copolymer and the like. Preferably, a water-soluble resin such as a polyvinyl alcohol resin or a polyvinyl methyl ether / maleic anhydride copolymer is preferably used from the viewpoint of peeling force and laminating property. Further, when the surface after transfer is desired to be uneven, a matting agent may be contained in the release layer. Further, when the release layer is provided, an easy-adhesion layer for improving the adhesiveness may be provided between the release layer and the plastic film.

Next, in the protective film of the present invention, after the protective film is transferred to the photomask image surface, the unbonded portion where the protective film is not adhered to the photomask image surface,
There is no particular limitation as long as it can be partially removed from the protective film after transfer. Therefore, as such a material, it is particularly preferable that the protective layer and the adhesive layer are laminated in this order from the support side.
By forming the protective film into a two-layer structure of the protective layer and the adhesive layer in this way, sufficient adhesiveness to the image surface of the photomask required for the protective film and resistance such as photoresist resistance and solvent resistance are required. In addition to being excellent in chemical properties, it is possible to easily find an unbonded portion where the protective film is not adhered to the photomask image surface, which is caused by, for example, a foreign substance being sandwiched between the photomask image surface and the protective film. become able to. Although the reason why the unbonded part of the protective film can be easily found is not clear, the protective film having a double-layer structure is probably more suitable than the protective film having only one protective layer before transfer. The rigidity of the protective film can be easily obtained, and even if there is a foreign matter on the image surface of the photomask, a relatively large unbonded portion can be obtained centering on the foreign matter without following the irregularities of the foreign matter. It is thought that there is.

Here, since such a protective layer is transferred to the image surface of the photomask and then comes to the outermost surface, it has an influence on the scratch resistance and solvent resistance of the protective film, and it is partially In addition to being removable, it is required to have high scratch resistance and chemical resistance.

Here, as a means for enabling partial removal of the protective layer and enhancing scratch resistance and chemical resistance, a composition comprising at least a thermosetting resin or an ionizing radiation curable resin is used. It is preferable to form the protective layer by coating the product by a conventionally known coating method and then curing the product.

Conventionally known coating methods referred to here include knife coating, doctor coating,
Bar coating, roll coating, blade coating, kiss coating, spray coating,
Examples thereof include spin coating and dip coating.

Further, as the thermosetting resin, those which crosslink and cure a crosslinkable resin such as silicone type, melamine type, epoxy type, aminoalkyd type, urethane type, acrylic type, polyester type or phenol type by heat are used. Can be used. Among these, an acrylic thermosetting resin having good light resistance and ionizing radiation transparency is preferably used. These can be used alone, but are crosslinkable,
In order to further improve the hardness of the crosslinked cured coating film, it is desirable to add a curing agent.

As the curing agent, compounds such as polyisocyanate, amino resin, epoxy resin and carboxylic acid can be appropriately used according to the compatible resin.

As the ionizing radiation curable resin, it is preferable to use a resin formed of a coating material which can be crosslinked and cured by at least irradiation of ionizing radiation (ultraviolet rays or electron beams). As such an ionizing radiation curable coating, one or a mixture of two or more kinds of a photocationically polymerizable resin capable of photocationically polymerizing, a photopolymerizable prepolymer or a photopolymerizable monomer capable of radical photopolymerization, etc. Can be used.

Examples of the cationic photopolymerizable resin include epoxy resins such as bisphenol epoxy resin, novolac epoxy resin, alicyclic epoxy resin and aliphatic epoxy resin, and vinyl ether resin.

Examples of the photopolymerizable prepolymer include polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, polyether (meth) acrylate and polyol (meth).
Various (meth) acrylates such as acrylate and melamine (meth) acrylate can be used.

Examples of the photopolymerizable monomer include, for example,
Styrene-based monomers such as styrene and α-methylstyrene, methyl (meth) acrylate, (meth) acrylic acid-2
-Ethylhexyl, methoxyethyl (meth) acrylate,
Butoxyethyl (meth) acrylate, Butyl (meth) acrylate, Methoxybutyl (meth) acrylate, Phenyl (meth) acrylate, Ethyl (meth) acrylate, Propyl (meth) acrylate, Ethoxy (meth) acrylate Methyl, (meth) acrylic acid esters such as lauryl (meth) acrylate, unsaturated carboxylic acid amides such as (meth) acrylamide, (meth) acrylic acid-2- (N, N)
-Diethylamino) ethyl, (meth) acrylic acid-2-
Substituted amino alcohol esters of unsaturated acids such as (N, N-dibenzylamino) ethyl, (meth) acrylic acid-2- (N, N-diethylamino) propyl, ethylene glycol di (meth) acrylate, diethylene glycol di ( (Meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth)
Acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, nonapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri ( (Meth) acrylate,
Pentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, tris- (2-hydroxyethyl) -isocyanuric acid ester (meth) acrylate, 2,2-bis [4- ( Acryloxydiethoxy) phenyl] propane, 3-phenoxy-2-propanoyl acrylate, polyfunctional compounds such as 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, and trimethylolpropane trithio A polythiol compound having two or more thiol groups in the molecule such as glycolate, trimethylolpropane trithiopropylate, and pentaerythritol tetrathioglycolate can be used.

In addition to these, various additives may be added to such an ionizing radiation-curable coating material. If ultraviolet rays are used for curing, a photopolymerization initiator, an ultraviolet sensitizer, etc. should be added. Is preferred. As the photopolymerization initiator, acetophenones, benzophenones, Michler's ketone, benzoin, benzyl methyl ketal, benzoyl benzoate, α-acyloxime esters, photoradical polymerization initiators such as thioxanthones, onium salts, sulfonates, and organic compounds. Examples include photo-cationic polymerization initiators such as metal complexes, and as the UV sensitizer, n-butylamine,
Examples include triethylamine and tri-n-butylphosphine.

Next, the adhesive layer has a pressure-sensitive adhesive property at room temperature and can be adhered to the photomask image surface, and it is crosslinked and cured by heating or irradiation of ionizing radiation to have an adhesive property to the photomask image surface. It is preferable that it is increased.

Such an adhesive layer preferably contains at least a curable resin.

Examples of such curable resins include thermosetting resins and ionizing radiation curable resins.

The thermosetting resin used here may be the same as that used in the protective layer. In particular, it is desirable to use, as the curing agent, a curing agent which does not react at all at room temperature and causes a cross-linking reaction when heated to a certain temperature or higher so as to cause a crosslinking reaction. As such a curing agent, a blocked isocyanate or the like in which a technique of blocking a catalyst or a functional group is used can be used.

The blocked isocyanate is a polyisocyanate masked with a masking agent,
It does not react at all at room temperature and does not proceed with the curing reaction, and when heated above the temperature at which the masking agent dissociates, active isocyanate groups are regenerated to cause a sufficient crosslinking reaction. In addition, such blocked isocyanate,
Since it contains an isocyanate component, it adheres well to the emulsion layer of the photomask and also serves to improve the durability of the protective film.

The polyisocyanate is obtained by polymerizing or copolymerizing an isocyanate monomer, and can be used without particular limitation. As the isocyanate monomer, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 1,3- or 1,4-diisocyanate cyclohexane, m- or p-tetramethylxylene diisocyanate,
1,4-tetramethylene diisocyanate, 1,12-
Examples include dodecamethylene diisocyanate.

The masking agent can be used without particular limitation, and examples thereof include phenol-based agents, alcohol-based agents, and
Examples thereof include active methylene type, mercaptan type, acid amide type, acid imide type, lactam type, imidazole type, urea type, oxime type, amine type, imide type and hydrazine compounds. Specifically, phenol, cresol, 2-hydroxypyridine, butyl cellosolve, propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, ethanol, diethyl malonate, ethyl acetoacetate, acetylacetone, butyl mercaptan, acetanilide, acetic acid amide, succinimide. , Ε
-Caprolactam, imidazole, urea, thiourea, acetaldoxime, acetone oxime, cyclohexane oxime, diphenylamine, aniline, carbazole, ethyleneimine, dimethylhydrazine and the like can be mentioned.

The dissociation temperature of the masking agent is preferably 100 ° C. or higher. When the temperature is 100 ° C. or higher, the pressure-sensitive adhesive property of the adhesive layer can be maintained at room temperature without being lost. When the base material of the photomask is poor in heat resistance such as a plastic film, the dissociation temperature of the masking agent is preferably 120 ° C. or lower. By setting the dissociation temperature of the masking agent to 120 ° C. or lower, it is possible to prevent the precision of the photomask from being deteriorated due to the dimensional change due to heat shrinkage of the plastic film.

As the ionizing radiation curable resin, the same ones as those usable in the protective layer can be used.

The adhesive layer may be formed by mixing a thermoplastic resin such as an acrylic adhesive resin in addition to the curable resin.

Here, the thickness of the protective film is 1.0 to 6.
The thickness of the protective layer and the adhesive layer is preferably 0.5 to 3.0 μm. By setting the thickness of the protective film to 1.0 μm or more and the thickness of the protective layer and the adhesive layer to 0.5 μm or more, respectively,
The scratch resistance and the chemical resistance required for the protective film can be easily obtained. By making the thickness of the protective film 6.0 μm or less and the thickness of the protective layer and the adhesive layer 3.0 μm or less, respectively, It is possible to easily remove a part of the protective film.

The separator, which is laminated on the protective film as necessary, is for preventing the workability from being deteriorated by the pressure-sensitive adhesive property of the protective film. Here, as the separator, those obtained by subjecting the surface of a plastic film such as polyester, polyethylene, polypropylene or the like or paper to a release treatment such as a silicone-based release agent can be used.

[0042]

EXAMPLES Examples of the present invention will be described below.
In addition, "part" and "%" are based on weight unless otherwise specified.

1. Preparation of protective film transfer sheet for photomask [Example 1] A release layer coating solution having the following composition was applied to one surface of a polyethylene terephthalate film (T-600E: Mitsubishi Kagaku Polyester Film Co., Ltd.) having a thickness of 50 µm. Then, by drying, a support provided with a release layer having a thickness of about 1 μm was prepared.

[0044]

Then, a protective layer coating solution and an adhesive layer coating solution a having the following compositions are successively applied on the release layer of the support and dried to give a protective layer having a thickness of about 2 μm and a thickness of about 2 μm. An adhesive layer of about 2 μm was laminated. At that time, the protective layer was dried and then irradiated with ultraviolet rays by a high pressure mercury lamp to be cured. Further, a release-treated surface of a separator (ester film E7006: Toyobo Co., Ltd.) having a thickness of 38 μm was bonded on the adhesive layer to obtain a protective film transfer sheet for a photomask.

[0046]

[0047]

[Example 2] Coating liquid a for adhesive layer of Example 1
A protective film transfer sheet for a photomask was obtained in the same manner as in Example 1 except that the following adhesive layer coating liquid b was used instead of.

[0049]

2. Evaluation of Protective Film Transferred from Photomask Protective Film Transfer Sheet The adhesive layer exposed by removing the separator from the photomask protective film transfer sheet obtained in Examples 1 and 2 was used as a circuit wiring pattern on the glass surface. It was adhered to the image surface of the photomask on which the circuit pattern was formed by a heat roll heated to 100 ° C. using a laminator.

Next, in the protective film transfer sheet for a photomask obtained in Example 1, the adhesive layer was cured by irradiating it with ultraviolet rays from a high pressure mercury lamp, and then the support was peeled from the protective film to form the protective film. It was transferred to the image side of the photomask. In the protective film transfer sheet for photomask obtained in Example 2, the masking agent of blocked isocyanate was dissociated by heating at 140 ° C. for 180 minutes to cure the adhesive layer, and then the support was peeled from the protective film. Then, the protective film was transferred onto the image surface of the photomask.

Next, the protective film is not adhered to the photomask image surface because a foreign substance having a diameter of about 300 μm is sandwiched between the transferred protective film and the photomask image surface. Was found, and cellophane adhesive tape (CT-405A-18: Nichiban Co., Ltd.) was pressed against the unbonded portion while rubbing with a nail. Then, when the adhesive tape was peeled off vigorously, both the protective film transferred from the protective film transfer sheet for the photomask of Examples 1 and 2 was easily partly removed from the protective film along with the foreign matter. I was able to get rid of it.

[0053]

According to the protective film transfer sheet for a photomask of the present invention, after the protective film is transferred to the photomask, the protective film is transferred to the unbonded part which is not adhered to the photomask. Therefore, even if a foreign substance or the like is trapped between the transferred protective film and the photomask, it is possible to remove a part of the protective film together with the foreign substance. After that, since the defective portion of the protective film can be repaired with a repairing liquid or the like, it becomes possible to prevent the photomask itself from becoming a defective product.

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Claims (5)

[Claims] 1. A protective film transfer sheet having a protective film provided on a peelable support, wherein the protective film is the photomask when the protective film is transferred to a photomask image surface. When a part not adhered to the image surface is generated, a non-adhered part of the protective film can be partially removed from the protective film after transfer. Membrane transfer sheet. 2. The protective film can be removed by using an adhesive member when partially removing the unbonded portion of the protective film from the transferred protective film. The protective film transfer sheet for a photomask according to claim 1. 3. The protective film transfer sheet for a photomask according to claim 1, wherein the protective film is formed by laminating a protective layer and an adhesive layer in this order from the support side. 4. The protective film transfer sheet for a photomask according to claim 3, wherein the protective layer and the adhesive layer each have a thickness of 0.5 to 3.0 μm. 5. The protective film transfer sheet for a photomask according to claim 3, wherein the protective layer and the adhesive layer include at least a thermosetting resin or an ionizing radiation curable resin. .