JP2010237302A - Photomask blank and photomask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photomask blank which is hardened with high sensitivity by exposure to light even when containing a large quantity of a light shielding material and is superior in storage stability and safelight aptitude, and a photomask which is manufactured by using the photomask blank and allows an image to be formed with high resolution and has high linearity of image edge parts. <P>SOLUTION: The photomask blank has, on a substrate, a photosensitive composition layer containing a sensitizing dye (A) expressed by general formula (1), a polymerization initiator (B), a compound (C) having an ethylenically unsaturated bond, a binder polymer (D), and a light shielding material (E). In general formula (1): A represents an S atom or NR<SP>7</SP>; Y represents a non-metallic atomic group which forms a basic nuclear of dye in cooperation with an adjacent A and a carbon atom; R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>, and R<SP>6</SP>each independently represent a hydrogen atom, or a monovalent group comprising non-metallic atoms; and R<SP>7</SP>represents an alkyl group or an aryl group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photomask blank and a photomask. More specifically, a flat panel display such as PDP, FED, LCD, etc., a shadow mask for CRT, a printed wiring board, a photomask blank capable of producing a photomask that can be used in a photolithography process in the field of semiconductors, and the like is obtained. Relates to a photomask.

  Photomasks used in photolithography processes in the fields of flat panel displays, CRT shadow masks, printed wiring boards, semiconductors, etc. include Cr masks with a metallic chromium layer (Cr layer), and Em with a silver halide emulsion layer. A mask (emulsion mask) is known (for example, see Non-Patent Document 1).

A Cr mask is formed by forming a chromium layer on a transparent substrate such as quartz or glass by a sputtering method, then providing an etching resist on the chromium layer, applying etching using a HeCd laser (442 nm), or etching using an aqueous alkali solution. The resist patterning, the chromium etching, and the etching resist peeling are performed. Cr masks have the merits of being able to correct defects such as pinholes, high resolution, high durability (scratch resistance), and excellent cleaning properties, but they are expensive due to the complexity of the manufacturing process, and are chrome etched during manufacturing. There is also an environmental problem such as waste liquid treatment due to the fact that it is performed.
The Em mask is prepared by providing a silver halide emulsion layer (photosensitive layer) on a transparent substrate such as quartz or glass, and exposing, developing, and fixing with a YAG laser or the like. Although the Em mask has high sensitivity to light, the resolution is not so high due to the photosensitive material (about 3 μm), it is unsuitable for producing extremely fine patterns, has poor durability, and defect correction is practical. Have the disadvantage of being difficult.

  As another type of photomask, a photomask blank containing a black material such as a black pigment and a photo-radical polymerizable component and having a photosensitive layer capable of forming an image with near ultraviolet light or visible light is used. What is produced using it is known (for example, refer patent documents 1 and 2). The photosensitive layer possessed by the photomask blank is highly sensitive because of its low absorbance in the near ultraviolet to visible region irradiated at the time of photomask fabrication, while the absorption property of light in the ultraviolet region irradiated when using the photomask is high. Since it is favorable, a photomask with excellent resolution can be obtained by exposing and developing the photosensitive layer. In addition, since this photomask does not require a metal film and is a relief image, it can be easily corrected for defects, has a good balance of sensitivity, resolution, etc., is inexpensive and has a low environmental impact. .

  When using a photomask blank contained in a photosensitive layer using a photo-radical polymerizable composition containing a black material for producing a photomask, a scanning exposure system using a semiconductor laser using a short-wave light source such as 350 nm to 450 nm It is also possible to form a pattern. However, when a photomask having such a photosensitive layer is exposed to form an image, the black material absorbs the exposure light, so that the curing is not sufficient in the deep part of the photosensitive layer and in the vicinity of the substrate. It has been found that sometimes the deep part of the photosensitive layer is removed to form a ridge shape and the resolution and linearity of the image edge part deteriorate. Further, when exposed under strong exposure conditions, an unexpected curing reaction in which a portion that should be a non-cured portion is cured may occur, resulting in a problem that the resolution of the obtained photomask is lowered.

In addition, in the case of having a radical polymerization type photosensitive layer, an oxygen blocking layer is provided in order to suppress a reduction in sensitivity due to the inhibition of polymerization by oxygen, but the function of the oxygen blocking layer prevents fogging due to an increase in sensitivity. Occurrence was also a problem.
As for the oxygen barrier layer, for example, in the field of photopolymerization negative lithographic printing plate precursors, it has been proposed to improve the handleability such as suitability for safelight by controlling the oxygen permeability of the oxygen barrier layer. (For example, refer to Patent Document 3).

The problem of photomask blanks used for laser scanning exposure is that, as described above, by balancing both sensitivity and storage stability, the on-images formed in the laser light irradiated part and the unirradiated part are The point is how to expand off.
In addition, in photopolymerizable photosensitive compositions, hexaarylbiimidazole compounds have long been known as suitable photopolymerization initiators, particularly in the ultraviolet region. Further, for example, hexaarylbiimidazole compounds and ketocoumarin compounds Although the use of a compound is described (see, for example, Patent Document 4), since this initiation system has absorption at a wavelength of about 480 nm, it is insensitive to a violet laser having a wavelength of 350 nm to 450 nm, and a yellow light It is inferior to safe light under.

  As described above, photomask blanks made of a photosensitive composition that achieves high sensitivity and storage stability and satisfies the resolution and linearity of the image edge have not been provided yet. The current situation is what is required.

JP 2005-283914 A JP 2001-343734 A JP 2004-117669 A Japanese Patent Publication No. 5-88244

Educational Literature Society, “Photofabrication”, published by Japan Photofabrication Association, 67-80 pages, June 1992

This invention is made | formed in view of the problem in the said prior art, and makes it a subject to achieve the following objectives.
That is, the present invention uses a photomask blank that is cured with high sensitivity by exposure and excellent in storage stability and safelight suitability even when it contains a large amount of a light-shielding material, and the photomask blank. An object of the present invention is to provide a photomask that is capable of forming an image with high resolution and has high linearity at an image edge portion.

Means for solving the above-mentioned problems are as follows.
<1> On a substrate, (A) a sensitizing dye represented by the following general formula (I) (hereinafter, appropriately referred to as “specific sensitizing dye”), (B) a polymerization initiator, and (C And (E) a photosensitive composition layer containing an ethylenically unsaturated bond (hereinafter, appropriately referred to as “ethylenically unsaturated compound”), (D) a binder polymer, and (E) a light-shielding material. Photomask blanks.

In the general formula (1), A represents an S atom or NR ⁷ , Y represents a nonmetallic atomic group that forms a basic nucleus of the dye together with the adjacent A and carbon atoms, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a monovalent group consisting of a hydrogen atom or a nonmetallic atom, and R ⁷ represents an alkyl group or an aryl group.

<2> The photomask blank according to <1>, wherein the substrate is a transparent glass having a thickness of 0.1 mm to 20 mm.
<3> The polymerization initiator is at least one polymerization initiator selected from the group consisting of hexaarylbiimidazole compounds, metallocene compounds, triazine compounds, oxime ester compounds, and organoborates. The photomask blank according to <1> or <2>.
<4> The photomask according to any one of <1> to <3>, wherein the content of the light-shielding material is 10% by mass or more and 60% by mass or less with respect to the total solid content in the photosensitive composition layer. Blanks.

<5> A photomask having a light-shielding layer formed by developing the photosensitive composition layer of the photomask blank according to any one of <1> to <4> after imagewise exposure.
<6> The photomask according to <5>, wherein a line width of a line and space (L / S) in the light shielding layer is 0.1 μm or more and 10 μm or less.

Moreover, the further preferable aspect of the photomask of this invention and a photomask is given below.
<7> The photomask blank having an oxygen barrier layer having an oxygen permeability at 25 ° C. of 1.0 ml / m ² · day · atm to 2000 ml / m ² · day · atm on the photosensitive composition layer. .
<8> The photomask, wherein the thickness of the light shielding layer is 1.0 μm or more and 2.0 μm or less, and the optical density (OD) at 365 nm is 3.5 or more.

The high sensitivity and excellent storage stability exhibited by the photomask blank of the present invention are based on the fact that the photosensitive composition layer contains a specific sensitizing dye as an essential component. The mechanism of action is not clear, but is presumed as follows.
First, as a factor that the specific sensitizing dye contributes to high sensitivity, the specific sensitizing dye exhibits a high-intensity emission (fluorescence and / or phosphorescence) spectrum. Since dye-sensitive dyes have a relatively long lifetime in the excited state, it is presumed that they have an effect on the efficiency of the reaction with the polymerization initiator. As another possibility, the molecular structure of the specific sensitizing dye contributes to the efficiency of the initial process of sensitization reaction (electron transfer, etc.) and the efficiency of the reaction that continues after the polymerization initiator decomposition. There is also a possibility.
Next, as a factor that the specific sensitizing dye contributes to the improvement in storage stability, the specific sensitizing dye has less dye aggregation, association, etc. under natural aging conditions, so that a decrease in sensitizing efficiency is suppressed. It is presumed that the fact that it is a thing has an influence. The sensitizing dye plays an important role in the photoinitiated reaction, and aggregation or association in the photosensitive composition greatly affects the decrease in the amount of radicals generated by exposure (decrease in sensitivity), that is, the decrease in storage stability. Therefore, it is considered that the specific sensitizing dye having little dye aggregation, association, and the like greatly contributes to the improvement of the storage stability of the photosensitive composition layer, that is, the photomask blank.

  According to the present invention, even when a large amount of a light-shielding material is contained, the photomask blank is cured with high sensitivity by exposure, and has excellent storage stability and safelight suitability, and the photomask blank is used. It is possible to provide a photomask that can be formed with high resolution and has high linearity at the image edge portion.

  Hereinafter, the photomask blank of the present invention and the photomask produced thereby will be described in detail.

[Photomask blanks]
The photomask blank of the present invention comprises, on a substrate, (A) a sensitizing dye represented by the following general formula (I), (B) a polymerization initiator, and (C) a compound having an ethylenically unsaturated bond; (D) It has the photosensitive composition layer containing a binder polymer and (E) light-shielding material, It is characterized by the above-mentioned. Moreover, according to the objective, it can also have other layers, such as an oxygen barrier layer, on this photosensitive composition layer.

(Photosensitive composition layer)
The photosensitive composition layer of the photomask blank of the present invention is a layer containing at least a light shielding material and capable of forming an image with ultraviolet light or visible light. That is, the photosensitive composition layer is a layer capable of forming an image by developing with a developer after image-like exposure with near ultraviolet light or visible light.
The photosensitive composition layer is preferably an alkali development type in view of environmental problems. In the present invention, a negative type layer in which an exposed portion is cured and insolubilized in an alkali developer is used.
Hereinafter, each component contained in the photosensitive composition layer according to the present invention will be described in detail.
<(A) Sensitizing dye represented by general formula (I) (specific sensitizing dye)>
The photosensitive composition layer of the photomask blank of the present invention contains a sensitizing dye (specific sensitizing dye) represented by the following general formula (I).
A sensitizing dye is a dye capable of transferring absorbed light energy to a photopolymerization initiator by energy transfer or electron transfer. The absorption wavelength of the sensitizing dye is not particularly limited as long as it is a sensitizing dye having this function, and is appropriately selected depending on the wavelength of the laser used for exposure. In the present invention, particularly, the absorption is in the wavelength range of 360 nm to 450 nm. The following sensitizing dyes having the maximum are used.

In general formula (1), A represents an S atom or NR ⁷ , and R ⁷ represents an alkyl group or an aryl group. Alkyl group and the aryl group in R ⁷ may have a substituent.
Preferable examples when R ⁷ represents an alkyl group include linear, branched and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group S-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group. it can. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

  The alkyl group may have a substituent, and examples of the substituent that can be introduced here include a halogen atom (—F, —Br, —Cl, —I), an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. N-alkylamino group, N, N-dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxy Carbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfa group Moyl group, N, N-dialkylsulfamoyl N-arylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonate group, dialkyl phosphono group, diaryl phosphono group, monoalkyl phosphono group, alkyl phosphonate group, monoaryl A phosphono group, an aryl phosphonate group, a phosphonooxy group, a phosphonate oxy group, an aryl group, an alkenyl group, an alkylidene group (methylene group, etc.) can be mentioned.

Preferred examples when R ⁷ represents an aryl group include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group and a naphthyl group are more preferable.
Examples of the substituent that can be introduced when the aryl group has a substituent include the alkyl group that may have a substituent, and the substituents that can be introduced into the alkyl group. it can.

  Next, Y in the general formula (1) will be described. Y represents a nonmetallic atomic group necessary for forming a heterocyclic ring in cooperation with the above-mentioned A and adjacent carbon atoms. Examples of such heterocycles include 5-, 6-, and 7-membered nitrogen-containing heterocycles or sulfur-containing heterocycles that may have a condensed ring, and preferably 5- or 6-membered heterocycles.

Examples of nitrogen-containing heterocycles include, for example, LGBrooker et al., J. Am. Chem. Soc., 73, 5326-5358 (1951) and the heterocycles constituting the basic nucleus in merocyanine dyes described in the references. Any structure known as a ring can be suitably used.
Specific examples include thiazoles, benzothiazoles, naphthothiazoles, oxazoles, benzoxazoles, naphthoxazoles, selenazoles, benzoselenazoles, naphthoselenazoles, thiazolines, 2-quinolines, 1- Examples thereof include isoquinolines, 3-isoquinolines, benzimidazoles, 3,3-dialkylindolenines, 2-pyridines, 4-pyridine and the like. Moreover, the substituents of these rings may combine to form a ring.

Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759.
Specific examples include benzodithiols, naphthodithiols, dithiols and the like.

  In general formula (1), the nitrogen-containing or sulfur heterocycle (the following partial structure) formed by Y in combination with A and the adjacent carbon atom is represented by the following general formula (1-A). A heterocyclic ring-containing partial structure is preferable, and a dye having such a partial structure is particularly preferable because it provides a photopolymerizable composition having high sensitizing ability and very excellent storage stability.

In general formula (1-A), A is synonymous with general formula (1), R < ⁸ >, R < ⁹ > represents the group which consists of a monovalent | monohydric nonmetallic atomic group each independently, R < ⁸ >, R < ⁹ > They may combine with each other to form a 5- to 8-membered ring.
R ⁸ and R ⁹ are particularly preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. More specific examples of these substituents may be those listed as examples of R ₇ described above. Particularly preferably, R ₈ and R ₉ are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, a phenyl group which may have a substituent, or a furyl which may have a substituent. A group, a thienyl group, and an alkoxycarbonyl group. Further, when R ⁸ and R ⁹ are bonded to each other to form a 5-, 6-, or 7-membered ring, particularly preferable ring structures are a benzene ring, a naphthalene ring, trimethylene (— (CH ₂ ) ₃ —. ) Or tetramethylene (— (CH ₂ ) ₄ —).
The ring structure represented by the general formula (1-A) may further have a substituent. Examples of the substituent that can be introduced include an oxy group, a mercapto group, a thio group, an amino group, a carbonyl group, A sulfo group, a sulfonate group, a sulfinyl group, a sulfonyl group, a phosphono group, a phosphonate group, a cyano group, a nitro group, a silyl group, an acyloxy group, an acryloyl group, a methacryloyl group, an allyl group, and a vinyl group can be mentioned.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the general formula (1) each independently represent a hydrogen atom or a group consisting of a monovalent nonmetallic atomic group, and more preferably a hydrogen atom or , Halogen atom, alkyl group, substituted alkyl group, aryl group, substituted aryl group, alkenyl group, substituted alkenyl group, hydroxyl group, substituted oxy group, mercapto group, substituted thio group, amino group, substituted amino group, substituted carbonyl group, A monovalent substituent selected from the group consisting of a sulfo group, a sulfonate group, a substituted sulfinyl group, a substituted sulfonyl group, a phosphono group, a substituted phosphono group, a phosphonate group, a substituted phosphonate group, a cyano group, a nitro group, and a silyl group Can be mentioned. In addition, when these monovalent substituents further have a substituent, as examples of the substituent that can be introduced, any of those exemplified as the above-mentioned examples for R ⁷ can be suitably used.

R ¹ and R ² may combine with each other to form an aliphatic ring, and may form a spiro ring with a ring containing the carbon atom to which they are bonded. Preferred aliphatic rings include 3-membered, 5-membered, 6-membered, 7-membered and 8-membered aliphatic rings, and more preferably 3-membered, 5-membered and 6-membered rings. A cyclic aliphatic ring can be mentioned. They further may have a substituent on the carbon atoms constituting these, examples of the substituent that can be introduced, can be used earlier suitably any those listed as examples of R _7.
Further, a heteroaliphatic ring in which a part of the ring-constituting carbon is substituted with a hetero atom (oxygen atom, sulfur atom, nitrogen atom, etc.) may be used. Preferred examples of these include cyclopropane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane, cyclo-1,3-dioxapentane ring, cyclopentene ring, cyclohexene ring, cyclohexane Examples include a heptene ring, a cyclooctene ring, a cyclo-1,3-dioxapentene ring, and a cyclo-1,3-dioxahexene ring.

Further, those in which R ³ and R ⁴ , R ⁴ and R ⁵ , R ⁵ and R ⁶ are bonded to each other to form an aliphatic or aromatic ring can also be suitably used. Examples of such aliphatic rings include 5-membered, 6-membered, 7-membered and 8-membered aliphatic rings, and more preferably 5-membered and 6-membered aliphatic rings. A ring can be mentioned. These may further have a substituent on the carbon atom constituting them, and as examples of the substituent that can be introduced, any of those exemplified above for R ⁷ can be preferably used.
Further, a heteroaliphatic ring in which a part of the ring-constituting carbon is substituted with a hetero atom (oxygen atom, sulfur atom, nitrogen atom, etc.) may be used.
Preferable specific examples of the heteroaliphatic ring structure formed by combining R ³ and R ⁴ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ include a benzocyclopentene ring, a benzocyclohexene ring, a benzocycloheptene ring, Examples include a benzocyclooctene ring, a 1,3-benzocyclohexadiene ring, a 1,3-dihydro-1,3-dioxaindene ring, and a julolidine ring.
Examples of forming an aromatic ring include those that form a naphthalene or anthracene ring in cooperation with a benzene ring containing a carbon atom to which they are bonded, and more preferably those that form a naphthalene ring. It is done.
May further have a substituent on the carbon atoms constituting them are all it can be suitably used those described as examples in R ₇ above as the substituent which can be introduced.

Among them, more preferable examples of R ¹ and R ² are independently a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a substituted carbonyl group, or a trialkylsilyl group. R ³ , R ⁴ , R ⁵ and R ⁶ are more preferably hydrogen atom, halogen atom, alkyl group, substituted alkyl group, aryl group, substituted aryl group, hydroxyl group, substituted oxy group, mercapto group, substituted thio group. , An amino group, a substituted amino group, or a substituted carbonyl group.
In the present invention, specific preferred examples [Exemplary compounds (A-1) to (A-5)] are listed below, but the present invention is not limited thereto.

  The specific sensitizing dye represented by the general formula (1) can be synthesized by the method described in JP-A-2007-206217. In addition, the specific examples described in paragraph numbers [0057] to [0062] of the publication can also be suitably used as the specific sensitizing dye in the present invention.

  The sensitizing dye used in the present invention can further be subjected to various chemical modifications for improving the characteristics of the photosensitive layer. For example, sensitizing dye and addition polymerizable compound structure (for example, acryloyl group or methacryloyl group) are bonded by a method such as covalent bond, ionic bond, hydrogen bond, etc. Unnecessary precipitation suppression of the dye from the subsequent film can be performed. In addition, sensitizing dyes and titanocene compounds described below and other radical generating parts (for example, reductive decomposable sites such as alkyl halides, oniums, peroxides, biimidazoles, oniums, biimidazoles, borates, amines, trimethylsilylmethyls) , An oxidatively cleavable site such as carboxymethyl, carbonyl, imine, etc.), the photosensitivity can be remarkably enhanced particularly in a state where the concentration of the starting system is low. Furthermore, for the purpose of improving the processing suitability to an (alkali) aqueous developer, which is a preferred mode of use of the photosensitive layer in the present invention, a hydrophilic moiety (carboxyl group and its ester, sulfonic acid group and its ester, ethylene, Introduction of an acid group such as an oxide group or a polar group) is effective. In particular, ester-type hydrophilic groups have a relatively hydrophobic structure in the photosensitive layer, so that they have excellent compatibility, and in the developer, acid groups are generated by hydrolysis, resulting in increased hydrophilicity. Have. In addition, for example, a substituent can be appropriately introduced in order to improve compatibility in the photosensitive layer and to suppress crystal precipitation. For example, in certain types of photosensitive systems, unsaturated bonds such as aryl groups and allyl groups may be very effective in improving compatibility. By introducing an obstacle, crystal precipitation can be remarkably suppressed. Moreover, the adhesiveness to inorganic substances, such as glass, can be improved by introduction | transduction of a phosphonic acid group, an epoxy group, a trialkoxysilyl group, etc. In addition, a method such as polymerization of a sensitizing dye can be used depending on the purpose.

  Details of the usage such as which structure of these sensitizing dyes are used, whether they are used alone or in combination of two or more, and how much is added, can be appropriately set according to the performance design of the final photosensitive material. . For example, the compatibility with the photosensitive layer can be increased by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film properties of the photosensitive layer.

A sensitizing dye may be used individually by 1 type, and may be used in combination of 2 or more type.
Since the photosensitivity and resolution of the photosensitive layer and the physical properties of the exposed film are greatly affected by the absorbance at the light source wavelength, the addition amount of the sensitizing dye is appropriately selected in consideration of these factors. For example, the sensitivity decreases in a low region where the absorbance is 0.1 or less. Or, the resolution becomes low due to the influence of the relation. However, for example, for the purpose of curing a thick film having a thickness of 5 μm or more, there is a case where such a low absorbance can be increased instead.

For example, when the photosensitive layer in the present invention has a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance of the photosensitive layer is in the range of 0.1 to 1.5, preferably from 0.25. It is preferable to set so as to be in the range of 1. Since the absorbance is determined by the amount of the specific sensitizing dye added and the thickness of the photosensitive layer, the predetermined absorbance can be obtained by controlling both conditions. The absorbance of the photosensitive layer can be measured by a conventional method. As a measuring method, for example, on a transparent or white support, a photosensitive layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a photomask blank is formed, and a transmission type optical densitometer is formed. And a method of measuring a reflection density by forming a photosensitive layer on a reflective support such as aluminum.
The specific addition amount of the sensitizing dye is preferably 0.05 part by mass to 30 parts by mass, more preferably 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of the total solid components constituting the photosensitive layer. More preferably, it is the range of 0.2 mass part-10 mass parts.

<(B) Polymerization initiator>
The photosensitive composition layer in the present invention contains (B) a polymerization initiator.
As the polymerization initiator (B) in the present invention, various photopolymerization initiators known in patent documents and other publications, or a combination system of two or more photopolymerization initiators (photopolymerization initiation system) are appropriately used. You can select and use. In the present invention, a system in which two or more photopolymerization initiators are used in combination is simply referred to as a photopolymerization initiator.

  The polymerization initiator in the present invention is not particularly limited and is appropriately selected depending on the exposure wavelength. For example, when light near 400 nm is used as a light source, benzyl, benzoyl ether, Michler's ketone, anthraquinone, Widely selected from known photopolymerization initiators such as thioxanthone, acridine, phenazine, benzophenone, and hexaarylbisimidazole compounds.

  Among them, as (B) the polymerization initiator, (A) when irradiated with light in the presence of a sensitizing dye, it receives photoexcitation energy of the sensitizing dye and generates active radicals. Hexaarylbiimidazole compounds, titanocene compounds, metallocene compounds, triazine compounds, oxime ester compounds, halogenated hydrocarbon derivatives, diaryliodonium salts, organoborates, which are radical generators that lead to polymerization of unsaturated compounds And organic peroxides, and the like. Further, in terms of exposure sensitivity, adhesion of the photosensitive composition layer to the substrate, storage stability, and the like, hexaarylbiimidazole compounds, metallocene compounds, triazine compounds, Preferred are oxime ester compounds and organoborates, hexaarylbiimidazoles Compounds, and organic boron salts are more preferable, hexaarylbiimidazole compounds are particularly preferable.

  Regarding these polymerization initiators, JP-A No. 2004-317652, JP-A No. 2005-47947, JP-A No. 2005-91618, JP-A No. 2005-134893, JP-A No. 2005-250158, JP-A No. 2005-300650, JP, 2006-267289, JP, 2007-47742, JP, 2007-99836, JP, 2007-206216, JP, 2007-248863, JP, 2007-249036, JP, 2008-242093, Special The polymerization initiators described in each publication of JP 2008-276167 can be used.

The hexaarylbiimidazole compound which is a preferable photopolymerization initiator in the present invention will be described.
As the hexaarylbiimidazole compound, various compounds described in each specification such as European Patent No. 24629, European Patent No. 107792, US Pat. No. 4,410,621, European Patent No. 215453, and German Patent Publication No. 3211312 are used. Is possible. Preferred examples include 2,4,5,2 ′, 4 ′, 5′-hexaphenylbisimidazole and 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetra. Phenylbisimidazole, 2,2′-bis (2-bromophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2,4-dichlorophenyl) -4,5 4 ′, 5′-tetraphenylbisimidazole, 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetrakis (3-methoxyphenyl) -bisimidazole, 2,5,2 ′ , 5′-tetrakis (2-chlorophenyl) -4,4′-bis (3,4-dimethoxyphenyl) bisimidazole, 2,2′-bis (2,6-dichlorophenyl) -4,5,4 ′, 5 '-Tetraphenylbisimidazole, 2 2′-bis (2-nitrophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, 2,2′-di-o-tolyl-4,5,4 ′, 5′-tetraphenylbis Imidazole, 2,2′-bis (2-ethoxyphenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole, and 2,2′-bis (2,6-difluorophenyl) -4,5 Examples thereof include 4 ′, 5′-tetraphenylbisimidazole.
Two or more hexaarylbiimidazole compounds may be used in combination.

When a hexaarylbiimidazole compound is used as a photopolymerization initiator, the amount of the hexaarylbisimidazole compound used is 0.05 to 50 parts by mass with respect to 100 parts by mass of the total amount of the (C) ethylenically unsaturated compound described later. A mass part is preferable, More preferably, it is 0.2 mass part-30 mass parts.
Other photopolymerization initiators may be used in combination with the hexaarylbiimidazole compound.

Photopolymerization initiators are optionally thiol compounds such as 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, amines such as N-phenylglycine, N, N-dialkylamino aromatic alkyl esters It is known that the photoinitiating ability can be further enhanced by using in combination with a hydrogen-donating compound such as a compound. In particular, the above-described hexaarylbiimidazole compound can obtain high sensitivity when used in combination with these hydrogen-donating compounds (chain transfer agents).
Examples of the hydrogen donating compound having a high photoinitiating ability and suitable for the present invention include mercapto group-containing compounds among the compounds listed above.

  The content of the polymerization initiator in the photosensitive composition layer is preferably 0.1 parts by mass to 20 parts by mass, more preferably 0.5 parts per 100 parts by mass of the total solid components constituting the photosensitive composition layer. The range is from 1 to 15 parts by mass, more preferably from 1 to 10 parts by mass.

<(C) Compound having ethylenically unsaturated bond (ethylenically unsaturated compound)>
The photosensitive composition layer contains a compound having an ethylenically unsaturated bond (ethylenically unsaturated compound).
An ethylenically unsaturated compound is a compound having at least one ethylenically unsaturated bond in the molecule and undergoes addition polymerization by the action of a photopolymerization initiator when the photosensitive composition layer is irradiated with actinic rays. Contributes to crosslinking and curing.

  The ethylenically unsaturated compound can be arbitrarily selected from, for example, compounds having at least 1, preferably 2 or more, more preferably 2 to 6 terminal ethylenically unsaturated bonds. It has a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof.

  Examples of ethylenically unsaturated compounds include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably , Esters of unsaturated carboxylic acids and alcohol compounds, amides of unsaturated carboxylic acids and amine compounds, and specifically, [0012] of JP-A No. 2001-343734 and JP-A No. 2003-107697. [0020] to [0025] of JP-A-2003-186176, [0029] to [0038] of JP-A-2003-186176, [0126] to [0140] of JP-A-2006-259558, and JP-A-2007-47742. [0173] to [0187], described in JP 2007-86165 A, [0140] to [0149] Compound is used.

  As the ethylenically unsaturated compound preferably used in the present invention, a compound having a plurality of urethane bonds obtained by addition reaction between a compound having a plurality of isocyanate groups and an acrylate or methacrylate having a hydroxyl group is preferably used. The compounds described in JP-17654 are preferred.

  In addition, content of (C) ethylenically unsaturated compound is preferably 5% by mass to 80% by mass, and more preferably 30% by mass to 70% by mass with respect to the total mass of the photosensitive composition layer. .

<(D) Binder polymer>
The photosensitive composition layer contains a binder polymer.
The binder polymer in the present invention is not particularly limited, but an organic polymer having an acid group is preferable and an organic polymer having a carboxyl group is more preferable from the viewpoints of solubility in an aqueous alkali solution and developability.

As the skeleton of the binder polymer, a polymer skeleton selected from acrylic resin, polyvinyl acetal resin, polyvinyl alcohol resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Particularly preferred are vinyl copolymers such as resins, methacrylic resins and styrene resins, and polyurethane resins. Specifically, [0011] of JP 2001-343734 A, [0017] to [0019] of JP 2003-107697 A, [0022] to [0027] of JP 2003-186176 A, Binder polymers described in [0143] to [0147] of JP 2006-259558 A, [0152] to [0154] of JP 2007-86165 A, and the like are preferably used.
As the binder polymer, acrylic resin, methacrylic resin, and urethane resin are preferably used.

  Among these, the binder polymer contained in the photosensitive composition layer is more preferably a polyurethane resin having a crosslinkable group in the side chain and a (meth) acrylic resin having a crosslinkable group in the side chain.

The polyurethane resin having a crosslinkable group in the side chain particularly preferably used in the present invention includes, for example, (i) a diisocyanate compound, (ii) a diol compound having at least one carboxyl group, and (iii) a diisocyanate compound having a crosslinkable group. And, if necessary, (iv) a diol compound having no carboxyl group can be obtained by a polyaddition reaction.
Diisocyanate compounds and diol compounds, which are raw materials for synthesizing these polyurethane resins, are mentioned in [0050] to [0132] of JP-A-2007-57597, and are preferably used.

Furthermore, as a polyurethane resin having a crosslinkable group in the side chain, suitable as a binder polymer in the present invention, in addition to the above polyurethane resin obtained by introducing a crosslinkable group into the side chain during polyurethane synthesis, JP-A-2003 A polyurethane resin obtained by introducing a crosslinkable group into a polyurethane having a carboxyl group as described in JP-A-270775 by a polymer reaction can also be used.
In the present invention, Japanese Patent Publication Nos. 7-12004, 7-120041, 7-120042, 8-12424, JP 63-287944, JP 63-287947, and JP The polyurethane resins described in JP-A Nos. 1-271741, 2001-109139, 2001-117217, 2001-312062, and 2003-13197 are preferably used.

  Another example of a binder polymer that can be used in the present invention is (a) a repeating unit containing a carboxylic acid (including a salt thereof) (hereinafter referred to as a repeating unit (a) as appropriate). (B) a polymer having a repeating unit imparting radical crosslinkability (hereinafter referred to as a repeating unit (b) as appropriate), and a repeating unit (a) and a repeating unit (b). The copolymer which has is mentioned.

  (A) Although it does not specifically limit as a repeating unit (repeating unit (a)) containing carboxylic acid, The repeating unit represented by acrylic acid, methacrylic acid, and the following general formula (i) is used preferably.

In general formula (i), R ¹ represents a hydrogen atom or a methyl group, and R ² contains two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. It represents a linking group that is composed of 2 to 82 atoms. A represents an oxygen atom or NR ³ - represents, ^{R 3} represents a monovalent hydrocarbon group hydrogen atom or a C1-10. n represents an integer of 1 to 5.

The linking group represented by R ² in the general formula (i) includes two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. The number of atoms is preferably 2 to 82, more preferably 2 to 50, and still more preferably 2 to 30. The linking group represented by R ² may have a substituent. The total number of atoms shown here refers to the number of atoms including the substituent when the linking group has a substituent. More specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1-30, more preferably 3-25, and 4-20. More preferred is 5-10.
The “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the general formula (i), and particularly when there are a plurality of linking paths. Refers to an atom or atomic group that constitutes a path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

As the linking group represented by R ² in the general formula (i), more specifically, alkylene, substituted alkylene, arylene, substituted arylene, or a hydrogen atom on any carbon atom constituting these groups is removed ( n + 1) valent groups are exemplified, and those having a structure in which a plurality of these groups are linked by amide bonds or ester bonds are preferred. In particular, those having 5 to 10 atoms constituting the main skeleton of the linking group are preferable. Structurally, the structure is a chain structure having an ester bond in the structure, or a cyclic structure as described above. What has is preferable.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), carbonization. Examples thereof include a hydrogen group (alkyl group, aryl group, alkenyl group, alkynyl group), alkoxy group, and aryloxy group.
A in the general formula (i) is preferably an oxygen atom or NH— because synthesis is easy.

  The content of the repeating unit (a) in the copolymer is 5 to 50, preferably 5 to 25, more preferably 5 to 15 when the total number of repeating units is 100.

  (B) The repeating unit imparting radical crosslinkability (repeating unit (b)) is not particularly limited, but those having an ethylenically unsaturated group as the radical crosslinkable group are preferably used.

  Specifically, the radical crosslinkable group is an alkenyl group (for example, vinyl group, allyl group, isopropenyl group, etc.), acryloyl group, methacryloyl group, styryl group, alkynyl group (ethynyl group) which may have a substituent. , Propargyl group, etc.), propioroyl group and the like.

  The content of the repeating unit (b) in the copolymer is 5 to 90, preferably 20 to 85, more preferably 40 to 80, when the total number of repeating units is 100.

  Further, the binder polymer in the present invention is not particularly limited, but may contain a repeating unit represented by the following general formula (1) (hereinafter, referred to as repeating unit (1) as appropriate).

In general formula (1), X represents an oxygen atom, a sulfur atom, or an NH— group, Y represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alicyclic alkyl group having 5 to 12 carbon atoms, Alternatively, it represents a group having an aromatic ring having 6 to 20 carbon atoms. Z represents an oxygen atom, a sulfur atom, or an NH— group, and R ₁ represents an alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms, or an aromatic group having 6 to 20 carbon atoms. A group having a ring is represented.

  The content of the repeating unit (1) in the copolymer is 1 to 40, preferably 3 to 25, more preferably 5 to 15 when the total number of repeating units is 100.

  Besides the general formula (1), an acrylic resin, methacrylic resin, or urethane resin having an ester group or an amide group in the side chain is preferably used as the repeating unit.

  The content of these repeating units is 1 to 40, preferably 3 to 25, more preferably 5 to 15 when the total number of repeating units contained in the copolymer is 100.

  From the viewpoint of maintaining the developability of the photosensitive composition layer, the (D) binder polymer molecular weight is preferably 5000 to 300000 in terms of weight average molecular weight, and more preferably 20000 to 150,000.

  (D) The binder polymer can be contained in an arbitrary amount in the photosensitive composition layer, but from the viewpoint of image strength and the like, in the total solid content of the photosensitive composition layer, preferably 10% by mass to 90% by mass, more preferably 30% by mass to 80% by mass.

<(E) Light shielding material>
The photosensitive composition layer in the photomask blank of the present invention contains a light shielding material.
The light-shielding material in the present invention is a material having a function of not transmitting light by reflecting and absorbing light having an active light wavelength to which the photomask is applied. Specifically, an exposure light source used as a mask ( Mercury lamps, metal halide lamps, xenon lamps and the like) can emit substantially light having a wavelength range of 200 nm to 450 nm, preferably about 250 nm to 400 nm, and has an optical density (OD) of 2. It needs to be 5 or more, preferably 3.0 or more.

What is necessary is just to select the light-shielding material in this invention suitably according to the intended purpose etc. of the photomask produced with the photomask blank.
Specific examples of the light-shielding material include paragraphs [0015] to [0016] of JP-A No. 2001-343734, paragraphs [0027] and [0035] to [0038] of JP-A No. 2003-107697, and JP-A No. 2003. 186176, paragraphs [0041] to [0043], and metal particles (including metal compound particles, composite particles, core / shell particles, etc.) according to paragraphs [0038] to [0040] of JP-A-2004-302012, Pigments and other particles, fullerenes and the like are preferably used.
The light shielding material that can be used in the present invention is preferably a black material, and the black material is preferably at least one of a black pigment and metal fine particles.
Hereinafter, the light shielding material applicable to the present invention will be described in detail.

Carbon black is particularly preferable as the light shielding material in the present invention.
When carbon black is used as the light shielding material, the photosensitive composition layer may contain only carbon black, or carbon black and another colorant (for example, other colorant) may be used in combination. When carbon black and another color material are used in combination, if the colorant contained in the photosensitive composition layer is carbon black at 50% by mass or more, the color density of the photosensitive composition layer is increased. This is preferable.

When a pigment is used as a light shielding material, a pigment having an average particle diameter of 100 nm or less is preferable, and a pigment having a mean particle diameter of 1 nm to 60 nm is more preferable.
In addition, it is preferable that the pigment is disperse | distributed with various dispersing agents in the photosensitive composition used for formation of the photosensitive composition layer.

  The content of the light-shielding material (E) in the solid content of the photosensitive composition layer takes into account the concentration and thickness of the photomask produced by photomask blanks, the sensitivity and resolution of the photomask. However, it is preferably 10% by mass to 50% by mass, and more preferably 15% by mass to 35% by mass.

<(F) Other ingredients>
In the photosensitive composition layer of the present invention, various compounds can be used in combination with the essential components (A) to (E) according to the purpose. For example, JP-A-9-25360 Or a thermal polymerization inhibitor described in paragraph [0047] of JP-A No. 2004-302012 can be added.
Furthermore, a known additive such as a plasticizer and a surfactant can be added to the photosensitive composition used in the present invention as necessary.

<Formation of photosensitive composition layer>
The photosensitive composition layer is a spin coater, a slit spin coater, a roll coater, or a die coater on a suitable substrate containing a coating liquid containing the above-described essential components and optional components (coating liquid for forming a photosensitive composition layer). Alternatively, it can be provided by direct application using a curtain coater or the like.

  The film thickness of the photosensitive composition layer is preferably in the range of 0.3 μm to 7 μm from the viewpoints of film thickness uniformity, resolution, and sensitivity. A particularly preferable film thickness is 0.5 μm to 3 μm.

(substrate)
The photomask blank of the present invention can be obtained by forming the photosensitive composition layer and, if desired, an oxygen barrier layer, which will be described later, on an appropriate substrate.
The substrate is appropriately selected according to the purpose. From the viewpoint of forming a photomask with the substrate and repeatedly using it as it is, the substrate that does not absorb the wavelength of the exposure light source for which the photomask is used, for example, visible light When using for a transparent substrate, it is preferable to use a transparent substrate. Here, the transparent substrate means a substrate having no maximum absorption in the wavelength region of 350 to 750 nm.
-Transparent substrate-
As the transparent substrate in the photomask blank of the present invention, a transparent substrate such as a glass plate (for example, quartz glass, soda glass, non-alkali glass) or a transparent plastic film (for example, polyethylene terephthalate) can be applied.
Although the thickness of a transparent substrate can be suitably set with photomask blanks, the range of 0.1 mm or more and 20 mm or less is preferable, the range of 1 mm or more and 7 mm or less is more preferable, and the range of 1 mm or more and 5 mm or less is further more preferable.

(Oxygen barrier layer)
The photomask blank of the present invention preferably has an oxygen barrier layer for appropriately controlling oxygen permeability on the photosensitive composition layer.
Hereinafter, the oxygen barrier layer will be described.
The oxygen barrier layer preferably has an oxygen permeability at 25 ° C. and 1 atm of 1.0 ml / m ² · day · atm to 2000 ml / m ² · day · atm, and 2.0 ml / m ^2. More preferably, it is not less than day · atm and not more than 1500 ml / m ² · day · atm, more preferably not less than 5.0 ml / m ² · day · atm and not more than 1000 ml / m ² · day · atm, and 10 ml / m ² · day · atm. It is most preferably 800 ml / m ² · day · atm or less.

Oxygen permeability of the oxygen barrier layer is within the above range, so that unnecessary polymerization reaction does not occur at the time of production and raw storage of photomask blanks, and an image when producing a photomax. There is no problem of unnecessary fogging and image line thickening during exposure. Therefore, the photomask blank of the present invention having such characteristics can provide a photomask having high resolution and good linearity of the image edge portion.
Various studies have been made on the oxygen-barrier layer having such characteristics. For example, the protective layer is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729. Has been.

In this specification, the oxygen permeability which an oxygen barrier layer has is the oxygen permeability measured by the following measuring method (Mocon method).
-Measurement method of oxygen permeability-
Same as the oxygen barrier layer formed on the photosensitive layer on the polyethylene film with high oxygen permeability (polyethylene laminated paper prepared by dissolving and removing the surface gelatin layer of “Ever Beauty Paper” manufactured by Fuji Film Co., Ltd.) A coating film of the composition is applied and dried to prepare a sample for measurement. In accordance with the gas permeability test method described in JIS-K7126B and ASTM-D3985, oxygen permeability (ml / m ² · day · atm) was used in an environment of 25 ° C. and 60% RH using OX-TRAN 2/21 manufactured by Mocon. ).

  The oxygen permeability of the oxygen barrier layer is controlled, for example, by adjusting the type and content of each component contained in the oxygen barrier layer (specifically, for example, adjusting the saponification degree of polyvinyl alcohol, plasticizer, etc. Etc.), adjustment of the film thickness of the oxygen barrier layer, adoption of a resin exhibiting preferable oxygen permeability, or a combination of these means as appropriate.

<Water-soluble polymer compound>
The oxygen barrier layer preferably contains a water-soluble polymer compound from the viewpoints of oxygen barrier properties and developability.
As the water-soluble polymer, a compound having relatively excellent crystallinity is preferably used. Specifically, for example, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl alcohol / vinyl phthalate. Copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.), acidic cellulose, gelatin, gum arabic, polyacrylic acid, polyacrylamide polyester, polyurethane, etc. Water-soluble polymers are mentioned, and these can be used alone or in combination. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol used in the oxygen barrier layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having the necessary oxygen barrier properties and water solubility. . Moreover, you may use polyvinyl alcohol derivatives, such as acid-modified polyvinyl alcohol.
Similarly, it may be a copolymer having a polymer unit other than the vinyl alcohol unit. Examples of such a copolymer include a vinyl alcohol / vinyl pyrrolidone copolymer.

Highly water-soluble, suitably used to form an oxygen barrier layer having an oxygen permeability of 1.0 ml / m ² · day · atm to 2000 ml / m ² · day · atm at 25 ° C. and 1 atm. Specific examples of the molecular compound include, for example, polyvinyl alcohol described in [0179] of JP-A-2006-259558, vinyl alcohol / oxyalkylene ether copolymer described in JP-A-3-203932, vinyl Alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.), acidic celluloses, Gelatin, gum arabic, polyacrylic acid Polyacrylamide polyester, polyurethane, and the like.

  The content of the water-soluble polymer compound in the oxygen barrier layer is preferably 20% by mass to 95% by mass, more preferably 30% by mass to 90% by mass, based on the total solid content of the oxygen barrier layer.

<Surfactant>
A surfactant can be added to the oxygen barrier layer.
Examples of the surfactant include polyoxyethylene castor oil ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene Polyoxyethylene alkyl allyl ethers such as ethylene nonylphenyl ether, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioxide Sorbitan alkyl esters such as oleate, sorbitan trioleate, glycerol monostearate, glycerol monooleate, etc. Nonionic surfactants such as noglyceride alkyl esters; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; alkyls such as sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, sodium hexyl naphthalene sulfonate, sodium octyl naphthalene sulfonate Anionic surfactants such as naphthalene sulfonates, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, sulfosuccinic acid ester salts such as sodium dilauryl sulfosuccinate; lauryl betaine, stearyl betaine, etc. Amphoteric surfactants such as alkylbetaines and amino acids can be used.

  Moreover, as content of surfactant in an oxygen barrier layer, it is preferable that it is 0.1 mass%-10 mass% in the total solid of an oxygen barrier layer.

<Formation of oxygen barrier layer>
The oxygen blocking layer can be formed by preparing a coating solution for forming the oxygen blocking layer and coating the coating solution on the photosensitive composition layer. With respect to the method for applying the oxygen barrier layer, a method of sequentially coating and a method of applying multiple layers at a time can be applied.

The film thickness of the oxygen barrier layer is preferably 0.05 μm or more and 1.5 μm or less, more preferably 0.1 μm or more and 1.0 μm or less.
As specific embodiments of the oxygen blocking layer, in addition to the above-described matters, paragraph numbers [0177] to [0182] of JP-A-2006-259558 and paragraph number [0346] of JP-A-2007-47742 are disclosed. To [0348], paragraph numbers [0253] to [0257] of JP-A-2007-86165, and paragraphs [0211] to [0259] of JP-A-2008-13981 are also suitably applied. can do.

<Adhesive undercoat layer>
In the photomask blank of the present invention, it is preferable to provide an adhesive undercoat layer on a substrate (transparent substrate). When the adhesive undercoat layer is provided, the photosensitive composition layer is provided on the adhesive undercoat layer. The adhesive undercoat layer enhances the adhesion between the transparent substrate and the photosensitive composition layer in the exposed area when producing a photomask, and in the unexposed area, the transparent substrate of the photosensitive composition layer. Therefore, developability is improved.

The adhesive undercoat layer preferably contains a compound having a silyl group in order to improve the adhesiveness to the transparent substrate.
Further, the adhesive undercoat layer preferably has a polymerizable group in order to improve the adhesiveness with the photosensitive composition layer. As the polymerizable group, a group having an ethylenically unsaturated bond is particularly preferable, and a group contained in the compound described in the above “ethylenically unsaturated compound (compound having an ethylenically unsaturated bond)” is preferably used. As the group having an ethylenically unsaturated bond that the ethylenically unsaturated compound has, a (meth) acryloyl group, a styryl group, and an allyl ether group are preferably used.
A compound having a silyl group and a group having an ethylenically unsaturated bond (polymerizable group) is particularly preferably used for the adhesive undercoat layer.

  Specific examples of the compound contained in the adhesive undercoat layer include 3-aminopropyltrimethoxysilane, octyltrimethoxysilane, 3-cyanopropyltriethoxysilane, and [2- (3,4-epoxycyclohexyl) ethyl]. Trimethoxysilane, phenyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, allyltrimethoxysilane, vinylmethoxysilane, 3- (N, N-diethylamino) propyltrimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxy Silane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane can be mentioned as suitable compounds.

The coating amount of the adhesion primer layer, as a dry ^mass, preferably from ^{2mg / m 2 ~200mg / m 2} , 5mg / m 2 ~100mg / m 2 is more preferred.

  In this way, a photosensitive composition layer containing each of the components (A) to (E) is formed on the substrate, and preferably, an oxygen-blocking layer or a substrate and the photosensitive composition layer are formed on the surface thereof. An adhesive undercoat layer is formed between them to obtain the photomask blank of the present invention.

[Photomask and photomask manufacturing method]
The photomask of the present invention has a light-shielding layer formed by using the photomask blank of the present invention described above and developing the photosensitive composition of the photomask blank after imagewise exposure. And
Specifically, the above-described photomask blank is imagewise exposed with near-ultraviolet light or visible light (exposure process), and the exposed photomask blank is developed using a developing solution. By removing the unexposed portion of the physical layer (development process), a photomask having an image-like light-shielding layer (exposed portion) can be obtained.

As a photomask manufactured using the photomask blank of the present invention (photomask of the present invention), the photomask blank is a laser that emits light of 350 nm to 450 nm (more preferably, light of 390 nm to 450 nm). It is a preferred embodiment that is produced by imagewise exposure using a laser that develops and then developing.
Hereinafter, each process for manufacturing the photomask of the present invention will be described.

[Exposure process]
The exposure step is preferably performed by exposing the photomask blank imagewise through a transparent original image having a line image, a halftone dot image, or the like, or by imagewise exposure by laser light scanning or the like using digital data. For image formation of the photomask blank of the present invention, laser exposure is preferably used.

The exposure light source is preferably a laser that emits light in the range of 350 nm to 450 nm. For example, the following are mentioned. Examples of the gas laser include an Ar ion laser (364 nm, 351 nm), a Kr ion laser (356 nm, 351 nm), a He—Cd laser (441 nm, 325 nm), and the solid laser includes Nd: YAG (YVO ₄ ). SHG crystal × 2 combinations (355 nm), Cr: LiSAF and SHG crystal combination (430 nm), and the like. In a semiconductor laser system, a KNbO ₃ ring resonator (430 nm), a waveguide wavelength conversion element and AlGaAs, InGaAs semiconductor combination (380 nm to 450 nm), a waveguide-type wavelength conversion element with AlGaInP, AlGaAs semiconductor combinations (300nm~350nm), is like AlGaInN (350 nm to 450 nm), as other lasers, N Laser (337 nm), and the like XeF (351 nm).

  Among these, an AlGaInN semiconductor laser (InGaN-based semiconductor laser 400 nm to 410 nm) is particularly preferable in terms of wavelength characteristics and cost.

[Development process]
The developer used in the development step is not particularly limited and may be a known developer. Examples of the developer described in Japanese Patent Publication No. 57-7427 include sodium silicate and silica. Potassium acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, sodium carbonate, An aqueous solution of an inorganic alkaline agent such as potassium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, aqueous ammonia, or an organic alkaline agent such as monoethanolamine or diethanolamine is suitable. Such alkali agents may be used alone or in combination of two or more.
Such an alkaline agent has a concentration of an alkaline aqueous solution containing it of 0.1% by mass to 20% by mass, preferably 0.5% by mass to 15% by mass, and most preferably 1% by mass to 12% by mass. Are added as follows.

  In addition, the alkaline aqueous solution used as a developer may contain a small amount of a surfactant, an organic solvent such as benzyl alcohol, 2-phenoxyethanol, and 2-butoxyethanol as necessary. Examples thereof include those described in US Pat. Nos. 3,375,171 and 3,615,480. Further, the developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, and 56-42860 are also excellent.

  As a particularly preferred developer, a developer containing a nonionic compound described in JP-A No. 2002-202616, having a pH of 11.5 to 12.8, and an electric conductivity of 3 mS / cm to 30 mS / cm. Liquid.

  In the development step, examples of the mode in which the developer is brought into contact with the exposed photomask blanks include manual treatment, immersion treatment, and mechanical treatment.

  Examples of the manual processing include a mode in which a developing solution is sufficiently contained in sponge or absorbent cotton, the entire surface is rubbed, and the surface is thoroughly washed after the processing.

  Examples of the immersion treatment include a method in which the exposed photomask blank is immersed in a vat or deep tank containing a developer and stirred, and then sufficiently washed with water while rubbing with absorbent cotton or sponge. The immersion time is preferably about 60 seconds.

  An automatic developing machine can be used for the mechanical processing. In the case of using an automatic developing machine, for example, a method of pumping up a developing solution charged in a developing tank with a pump and spraying it onto a photomask blank after exposure from a spray nozzle, a liquid in a tank filled with the developing solution. A method that immerses and conveys photomask blanks after exposure using an intermediate guide roll, etc., and supplies substantially unused developer to each photomask blank after exposure for processing. Any of the so-called disposable processing methods can be applied. In any system, those having a mechanism such as high-pressure washing, brush or molton are more preferable. In addition, an apparatus in which a laser exposure unit and an automatic processor unit are integrated can be used.

  Moreover, as a temperature of the developing solution at the time of image development, the range of 20 degreeC-35 degreeC is preferable, and the range of 25 degreeC-30 degreeC is more preferable.

[Other processes]
In addition, the photomask blanks may be subjected to heat treatment before exposure, during exposure, and between exposure and development as necessary. By performing the heat treatment, an image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength, it is also effective to perform whole surface post-heating or whole surface exposure on the developed image.

  Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. On the other hand, very strong conditions can be used for heating after development. Usually, a heat treatment in the range of 150 ° C. to 500 ° C. is performed.

  Further, after image formation on the photomask blanks, a protective film such as a thermosetting epoxy resin may be provided on the image. By providing a protective film on the image, the film strength can be further improved.

  As described above, a photomask (the photomask of the present invention) is obtained using the photomask blank of the present invention.

The thickness of the light shielding layer in the photomask of the present invention is preferably from 0.8 μm to 2.0 μm, and more preferably from 0.8 μm to 1.8 μm.
In the photomask of the present invention, the optical density (OD) at 365 nm is preferably 3.5 or more, and more preferably 4.0 or more.
The most preferred embodiment of the light shielding layer in the photomask of the present invention is the film thickness of the light shielding layer and the O.D. D. Both of these are embodiments that satisfy the above range.

  In addition, since the photomask blank of the present invention can form a high-resolution image, it can form an image with a fine line width with good edge linearity. One preferred embodiment of a photomask formed using such a photomask blank is an embodiment in which the line-and-space (L / S) line width in the light shielding layer is preferably 0.1 μm or more and 30 μm or less. It is. The L / S formed is more preferably 0.1 μm or more and 25 μm or less, and further preferably 0.1 μm or more and 20 μm or less. By the photomask blank of the present invention, the L / S having such a fine line width is formed. A light shielding layer having / S can be formed.

The photomask obtained by using the photomask blank of the present invention can be suitably used in a photolithographic process in the fields of flat panel displays such as PDP, FED, and LCD, shadow masks for CRT, printed wiring boards, and semiconductors. .
When the photomask used in the present invention is used for patterning an ultraviolet photosensitive resist, it is also possible to select an exposure wavelength by incorporating a band pass filter into an ultraviolet exposure machine such as an ultrahigh pressure mercury lamp.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Examples 1 to 5, Comparative Examples 1 to 4]
1. Production of photomask blanks (application of undercoat layer)
On the glass substrate (10 cm × 10 cm, thickness 2.3 mm), the following composition was applied so that the mass of the coating layer after drying was 0.005 g / m ² , dried at 100 ° C. for 1 minute, and the undercoat layer Formed.
<Undercoat composition>
・ 3-Methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) 3.60 g
・ Methyl ethyl ketone 32.40g
(Formation of photosensitive composition layer)
On the glass substrate (10 cm × 10 cm) on which the undercoat layer was formed, the photosensitive composition layer coating solution composition (P-1) having the following composition was applied so that the dry coating mass was 1.4 g / m ^2. And dried at 100 ° C. for 1 minute to form a photosensitive composition layer.

<Coating liquid composition for photosensitive composition layer (P-1)>
-Carbon rack dispersion liquid (dispersion liquid having the following composition) 16.0 parts by mass-Ethylenically unsaturated compound (C-1) (compound having the following structure) 4.2 parts by mass-Binder polymer (D-1) (following structure) Of polymer binder) 3.6 parts by mass (MW: 50000)
Specific sensitizing dye or comparative sensitizing dye (compound described in Table 1 below) 0.21 part by mass Polymerization initiator (B-1) (compound having the following structure) 0.81 part by mass Chain transfer agent (F -1) (Compound with the following structure) 0.3 part by mass / fluorine-based nonionic surfactant 0.05 part by mass (Megafac F780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 58 parts by mass ・ Propylene glycol monomethyl ether acetate 53 parts by mass

  The composition of the carbon black dispersion used for the preparation of the coating composition for photosensitive composition layer (P-1) is as follows.

<Composition of carbon rack dispersion>
・ Carbon black 12g
(Degussa Special Black 350,
DBP = 45 ml / 100 g, nitrogen adsorption specific surface area = 65 m ² / g)
・ Dispersant (Disperbyk182 manufactured by Bykchemie) 6g
・ Propylene glycol monomethyl ether acetate (PGMEA: solvent) 42g
Here, DBP represents the amount of dibutyl phthalate (DBP) absorbed by 100 g of carbon black.
The above composition was added with 200 g of zirconia beads having a particle diameter of 0.5 mm with a motor mill M-50 (manufactured by Eiger) and dispersed at a peripheral speed of 9 m / s for 6 hours to obtain a carbon black dispersion. The dispersion was diluted 1000 times, and the particle size distribution measured by the laser Doppler method was in the range of 0.01 μm to 0.5 μm.

The specific sensitizing dyes (A-1) to (A-5) used in the preparation of the coating composition for the photosensitive composition layer of Examples and Comparative Examples are the compounds described above as exemplary compounds of the specific sensitizing dye. is there. Polymerization initiator (B-1), ethylenically unsaturated bond-containing compound (C-1), binder polymer (D-1), chain transfer agent (F-1) and comparative sensitizer (DR-1) The structure of is shown below.
Polymerization initiator: CGI7460 is a commercially available initiator (organoboronate photopolymerization initiator) manufactured by Ciba-Geigy.

(Formation of oxygen barrier layer)
On this photosensitive composition layer, an oxygen barrier layer coating solution having the following composition was applied and dried at 100 ° C. for 2 minutes to form an oxygen barrier layer. When the film thickness (μm) of the oxygen barrier layer was directly measured with “SURFCOM130A, manufactured by Tokyo Seimitsu Co., Ltd.”, it was 0.2 μm. Further, when the oxygen permeability of this oxygen barrier layer was measured by the above method, it was 170 ml / m ² · day · atm.
<Oxygen barrier coating solution>
・ 87 g of water
・ PVA-405 (Kuraray Co., Ltd.) 6g
・ PVP-K30 (BASF) 6g
・ EMALEX 710 (manufactured by Nippon Emulsion Co., Ltd., surfactant) 1 g

  As described above, Photomax blanks (1) to (5) of Examples 1 to 5 and Comparative Examples 1 to Comparative Examples each having a photosensitive composition layer and an oxygen barrier layer on a transparent substrate. 4 photomask blanks (C1) to (C4) were obtained.

2. Evaluation of photomask blanks (1) Sensitivity evaluation Each photomask blank (10 × 10 cm) of Examples and Comparative Examples obtained as described above was used as a laser plotter, and VILD (manufactured by Dainippon Screen Mfg. Co., Ltd.) (Laser output 350 mW, light source 405 nm violet laser). Next, each photomask blank after exposure was dipped in 1 L of an alkali developer having the following composition at 30 ° C. for 15 seconds, developed, washed with water, and then dried. Further, a heat treatment was performed at 180 ° C. for 30 minutes to obtain a desired photomask. The exposure sensitivity was evaluated by setting the exposure amount capable of reproducing the photomask line / space 20 μm / 20 μm as the optimum exposure amount while changing the exposure amount. It is evaluated that an image can be formed with higher sensitivity as this numerical value is smaller. The results are shown in Table 1 above.
The absorbance at 365 nm of each photomask after development and heat treatment was about 4.0. Moreover, about each photomask after image development and heat processing, the film thickness of the light shielding layer measured by Surfcom 480A by Tokyo Seimitsu Co., Ltd. was 1.5 micrometers, respectively.
The absorbance at 365 nm of the photomask was about 4.0.
Moreover, the film thickness of the light shielding layer measured by Tokyo Seimitsu Co., Ltd. Surfcom 480A was 1.5 micrometers.

<Alkali developer composition>
PH 11.95 aqueous solution consisting of the following composition, potassium hydroxide 0.2g
・ 1K potassium silicate 2.4g
(SiO ₂ / K ₂ O = 1.9)
・ The following compound 5.0 g
・ Ethylenediaminetetraacetic acid ・ 4Na salt 0.1g
・ Water 91.3g

(2) Resolution measurement, image edge portion linearity evaluation Each photomask blank (10 × 10 cm) of Examples and Comparative Examples was used as a laser plotter, VILD (manufactured by Dainippon Screen Mfg. Co., Ltd.) (laser output 350 mW, light source Were exposed by a 405 nm violet laser). Next, each photomask blank after exposure was immersed in 1 L of an alkali developer having the above composition at 30 ° C. for 15 seconds, developed, washed with water, and then dried. Further, a heat treatment was performed at 180 ° C. for 30 minutes to obtain a desired photomask. As for the exposure amount, an image is formed while changing the exposure amount, and the exposure amount when the photomask line / space 20 μm / 20 μm is reproduced is determined as the optimum exposure amount. Lines / spaces of 15, 20, 25, and 30 μm were also drawn, and the finest line among the reproducible lines was taken as the resolution.
In addition, the edge portion of the 20 μm line was photographed with a microscope manufactured by Keyence Corporation, and the variation in linearity of the edge portion was represented by standard deviation σ. The smaller the σ value, the better the linearity.

(3) Storage stability evaluation 2-1) Exposure amount change rate evaluation After storing each photomask blank of Examples and Comparative Examples under high temperature conditions (60 ° C) for 3 days, the same as (1) Sensitivity evaluation described above. Then, the amount of exposure light was varied to determine the amount of exposure when line / space 20 μm / 20 μm was reproduced. The difference (X ⁰ −X ³ ) between the initial optimum exposure amount (X ⁰ ) shown as a result of the (1) sensitivity evaluation and the exposure amount (X ³ ) after storage for 3 days is small, and the following formula It is evaluated that the storage stability is good when the exposure rate change rate (%) indicated by is within 10%.
Exposure change rate (%) = (X ⁰ −X ³ ) / X ⁰ × 100

(4) Suitability for safe light under yellow light Photomask blanks are subjected to yellow light illumination (conditions in which light having a wavelength of about 470 nm or less is blocked) for 1 minute, 2 minutes, 5 minutes, 10 minutes, 20 minutes, 30 After being left for a minute, scanning exposure and development processing are performed in the same manner as in (1) sensitivity evaluation, and the formed L / S image is visually evaluated, and the image formed in (1) sensitivity evaluation In comparison, the standing time in response to the visual change of the image was obtained and evaluated according to the following criteria.
A: Change in the image occurred when the standing time was 20 minutes or more B: Change occurred in the image when the standing time was 10 minutes or more and less than 20 minutes C: Change occurred in the image when the standing time was 1 minute or more and less than 10 minutes D: Change occurred in the image after a neglect time of less than 1 minute

These evaluation results are also shown in Table 1.
As is clear from Table 1, the photomask blanks of each example were capable of forming an image with high sensitivity, and used a sensitizing dye outside the range of the present invention and Comparative Example 3 in which no sensitizing dye was used. Compared with Comparative Examples 1, 2, and 4, it is excellent in safe light properties and storage stability, and each photomask obtained thereby has a higher resolution than that of the comparative example, and linearity of the image edge portion. , It turns out that it is better.

Claims (6)

On the substrate, (A) a sensitizing dye represented by the following general formula (I), (B) a polymerization initiator, (C) a compound having an ethylenically unsaturated bond, (D) a binder polymer, (E) Photomask blanks having a photosensitive composition layer containing a light shielding material.

[In General Formula (1), A represents an S atom or NR ⁷ , Y represents a nonmetallic atomic group that forms a basic nucleus of a dye together with adjacent A and a carbon atom, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a monovalent group consisting of a hydrogen atom or a nonmetallic atom, and R ⁷ represents an alkyl group or an aryl group. ]   The photomask blank according to claim 1, wherein the substrate is a transparent glass having a thickness of 0.1 mm to 20 mm.   The (B) polymerization initiator is at least one polymerization initiator selected from the group consisting of hexaarylbiimidazole compounds, metallocene compounds, triazine compounds, oxime ester compounds, and organoborates. The photomask blank according to claim 1 or 2.   The content of the (E) light-shielding material is 10% by mass or more and 60% by mass or less based on the total solid content contained in the photosensitive composition layer. Photomask blanks.   A photomask having a light-shielding layer formed by developing the photosensitive composition layer of the photomask blank according to any one of claims 1 to 4 after imagewise exposure.   The photomask according to claim 5, wherein a line width of a line and space (L / S) in the light shielding layer is 0.1 μm or more and 10 μm or less.