JPH0440454A - Resist pattern forming method - Google Patents

Abstract

PURPOSE:To enable a pattern to be directly formed from digital signals by using a transparent heat sensitive recording material capable of forming a color image by heating a photomask film. CONSTITUTION:The transparent heat sensitive recording material to be used has a color image formed on the photomask film by heating, and is provided on a transparent support with a transparent heat sensitive layer capable of developing color by heating, and as the color developing material, a combination of an electron donative dye precursor and a color developing agent or a that of diazo compound and a coupler is used. As the electron donative dye precursor, a colorless or pale-colored compound is properly selected from compounds giving electrons and receiving a proton, such as acid, and developing color, and are embodies by derivatives of triarylmethane, diphenylmethane, and xanthene, thus permitting a pattern to be directly formed by using digital signals.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a resist pattern, and more particularly to a method for forming a resist pattern using a transparent heat-sensitive recording material as a photomask film used in producing a printed circuit board.

(Prior Art) A method of manufacturing a printed circuit board is well known by providing a photosensitive resin layer on a substrate and performing exposure, development, etching, etc. through a photomask having a circuit pattern on the layer. As a method for manufacturing a photomask used in this case, a method using the principles of photography is generally used. That is, an original image of the circuit pattern is formed, an image of this original image is formed on a film that is the main body of the mask, and the image is exposed.

After that, the exposed film is developed and fixed, and a mask is finally formed.

(Problems to be Solved by the Invention) However, the production of the above-mentioned photomask not only requires time and effort for exposure and development, but also has problems in the working environment because it is a wet process. The disadvantage was that it was not possible to form

Such drawbacks can be solved by the use of optical mask materials (JP-A-63), which are made by integrally forming a heat-reactive member whose light transmittance decreases or increases by rapid cooling or slow cooling after heating, and a transparent heat-absorbing member with excellent heat absorption rate. -177138), but
Such materials suffer from drawbacks in terms of sensitivity and image duration.

As a result of intensive studies to solve the above-mentioned drawbacks, the present inventors have found that a heat-sensitive recording material with excellent transparency can be used in place of a photomask film, and that by using it, the photomask manufacturing process can be improved. Since everything can be done dry, and patterns can be formed directly using digital signals, the resist pattern creation process can be greatly improved, and the process from circuit design to the final printed circuit board can be integrated. The present invention was achieved by discovering that it can also be done as a process.

Accordingly, a first object of the present invention is to provide an improved method of forming resist patterns.

A second object of the present invention is to provide a photomask film that does not require wet processing when producing a photomask and can be produced using digital signals.

(Means for Solving the Problems) The above aspects of the present invention include forming a photosensitive resin layer on a printed circuit board substrate, and then placing a photomask film on the resin layer, exposing it to light, and developing it. The present invention has been achieved by a method for forming a resist pattern, characterized in that the photomask film is a transparent heat-sensitive recording material on which a colored image is formed by heating.

The transparent heat-sensitive recording material used in the present invention is a recording material that has a transparent heat-sensitive layer on a transparent support that develops color when heated.

In the present invention, a combination of an electron-donating dye precursor and a color developer or a combination of a diazo compound and a coupler can be used as a coloring agent that develops color upon heating.

As the electron-donating dye precursor used in the present invention, a colorless or light-colored one is appropriately selected from known compounds that develop color by donating electrons or accepting protons such as acids. Such compounds have partial skeletons such as lactones, lactams, sultones, spiropyrans, esters, and amides, and these partial skeletons are ring-opened or cleaved upon contact with a color developer. Preferred compounds include Examples include triarylmethane compounds, diphenylmethane compounds, xanthine compounds, thiazine compounds, and spiropyran compounds.

Particularly preferred compounds are those represented by the following general formula.

In the formula, R1 is an alkyl group having 1 to 8 carbon atoms, R2 is an alkyl group having 4 to 18 carbon atoms, an alkoxyl group, or a tetrahydrofurfuryl group, and R3 is a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or halogen atom,
R4 represents a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. As the substituent for R4, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a halogenated alkyl group, and a halogen atom are preferable.

The color developer that causes a color-forming reaction upon thermal melting with the electron-donating dye precursor used in the present invention can be appropriately used from among known color developers.

For example, color developers for leuco dyes include phenolic compounds, triphenylmethane compounds, sulfur-containing phenolic compounds, carboxylic acid compounds, sulfone compounds,
Examples include urea-based or thiourea-based compounds, details of which can be found, for example, in Paper Valve Technology Times (1985) 49-
It is described on pages 54 and 6570. Among these, those having a melting point of 50° C. to 250° C. are particularly preferred, and phenols and organic acids that are sparingly soluble in water and having a melting point of 60° C. to 200° C. are particularly desirable. It is preferable to use two or more color developers in combination because the solubility increases.

The amount of color developer used is usually 0.00 parts by weight of the electron-donating dye precursor. 3-160 parts by weight, preferably 0.3-8
It is 0 parts by weight.

Among the color developers used in the present invention, particularly preferred ones are represented by the following general formulas (13 to (IV)).

R1 is an alkyl group, an aryl group or an aralkyl group, with methyl, ethyl and butyl groups being particularly preferred.

m=0-2, n=2-11 (II) R2 is an alkyl group, especially a butyl group, a pentyl group,
Heptyl and octyl groups are preferred.

(IV) R3 is an alkyl group or an aralkyl group.

The diazo compound used in other combinations of heat-sensitive coloring materials according to the present invention is one that reacts with the coupler described below to develop a desired hue, and in particular, decomposes when exposed to light of a specific wavelength before the reaction. However, it is preferable to use a photodegradable diazo compound which no longer has color-forming ability even when a coupler acts on it, since this enables photofixing. The hue in this coloring system is mainly determined by the diazo dye produced by the reaction between the diazo compound and the coupler. Therefore, as is well known, the color hue can be easily changed by changing the chemical structure of the diazo compound or the chemical structure of the coupler, and almost any color hue can be obtained depending on the combination. .

The photodegradable diazo compound used in the present invention mainly means an aromatic diazo compound. Specifically, it refers to aromatic diazonium salts, diazosulfonate compounds, diazoamino compounds, and the like.

The coupler used in combination with the diazo compound used in the present invention is a compound that forms a dye by coupling with the diazo compound (diazonium salt).

Specific examples include 2-hydroxy-3-naphthoic acid anilide, resorcinol, and JP-A-62
-146678 can be mentioned.

Furthermore, by using two or more of these couplers in combination, an image of any color tone can be obtained.

Since the coupling reaction between these diazo compounds and couplers is likely to occur in a basic atmosphere, a basic substance may be added to the layer.

As the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance that generates an alkali upon heating is used. Examples of these are inorganic and organic ammonium salts,
organic amines, amides, urea and thiourea and their derivatives,
Examples include nitrogen-containing compounds such as thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidacillines, triazoles, morpholines, piperidines, amidines, formazines, and pyridines. . Specific examples of these are described in, for example, Japanese Patent Laid-Open No. 61-291183.

Two or more basic substances may be used in combination.

In the present invention, from the viewpoint of shelf life (fogging prevention) such as preventing contact of materials involved in color development at room temperature, and from the viewpoint of controlling color development sensitivity such as developing color with desired applied heating energy, etc. It is preferable to encapsulate a part of the components essential for color development.

The type of microcapsule used in this case is not particularly limited, but microcapsules that are particularly preferred in the present invention prevent contact between substances inside and outside the capsule due to the substance isolation effect of the microcapsule wall at room temperature, and above a certain temperature. Preferably, the permeability of the substance increases only while it is heated. In this case, the permeation start temperature can be freely controlled by appropriately selecting the capsule wall material, capsule core material, additives, etc. In this case, the transmission start temperature corresponds to the glass transition temperature of the capsule wall (eg, JP-A-59-91438).

In order to control the glass transition point specific to the capsule wall, it is necessary to change the type of capsule wall forming agent. Examples of microcapsule wall materials include polyurethane, polyurea, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, and polystyrene. , styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, etc., and two or more of these polymeric substances can also be used in combination.

In the present invention, among the above-mentioned polymeric substances, polyurethane, polyurea, polyamide, polyester, polycarbonate, etc. are preferable, and polyurethane and polyurea are particularly preferable.

The microcapsules used in the present invention emulsify a core material containing one of the components directly involved in the coloring reaction (hereinafter collectively referred to as coloring agent), and then form a wall of polymeric material around the oil droplets. It is preferable to microencapsulate the
In this case, a reactant forming a polymeric substance is added inside the oil droplet and/or outside the oil droplet.

Here, the organic solvent for forming the oil droplets can generally be appropriately selected from among high-boiling point oils, but in particular, when using an organic solvent with excellent solubility in the coloring agent, it is difficult to This is preferable because it increases the color density and color development speed during printing, and also reduces fog.

When making microcapsules, they can be made from an emulsion containing 0.2% by weight or more of the component to be microencapsulated.

The amount of coupler per 1 part by weight of the diazo compound is 0°1 to 10
Part by weight, basic substance is 0. It is preferable to use it in a proportion of 1 to 20 parts by weight. On the other hand, electron-donating dye precursor 1
It is preferable to use the color developer in an amount of 0.3 to 160 parts by weight, preferably 0.3 to 80 parts by weight.

When using the preferable microcapsules produced as described above, the reactive substances contained in the core and outside of the microcapsules can pass through the microcapsule walls and react to form dyes only during heating printing. can.

In the present invention, it is also possible to use a coloring aid.

The color development aid that can be used in the present invention is a substance that increases the color density during thermal printing or lowers the minimum color development temperature, lowers the melting point of a basic substance or color former,
This is to create a situation where diazo compounds, basic substances, couplers, electron-donating dye precursors, color developers, etc. can easily react by lowering the softening point of the capsule wall.

Coloring aids include phenolic compounds, alcoholic compounds, amide compounds, ζ sulfonamide compounds, etc.
Specific examples include p-tart-octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, benzyl carbanylate, phenethyl carbanylate, hydroquinone, dihydroxyethyl ether,
Compounds such as xylylene diol, N-hydroxyethyl-methanesulfonic acid amide, and N-phenyl-methanesulfonic acid amide can be mentioned. These may be contained in the core material or may be added outside the microcapsules as a dispersion.

In the present invention, in addition to the above materials, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid, etc. can be added as acid stabilizers.

In the present invention, in order to make the heat-sensitive recording layer transparent, a color developer or coupler is dissolved in an organic solvent that is sparingly soluble or insoluble in water, and then this is used as a protective colloid containing a surfactant to protect water-soluble polymers. (e.g., JP-A No. 63-92489).
.

The organic solvent for dissolving the color developer or coupler can be appropriately selected from high boiling point oils.

In addition to esters, preferred oils include compounds represented by the following general formulas (V) to (■), triallylmethane (e.g., tritolylmethanetolyldiphenylmethane), terphenyl compounds (e.g., terphenyl ), alkylated diphenyl ethers (e.g. propyl diphenyl ether, hydrogenated terphenyl (e.g.
(hexahydroterphenyl), diphenyl ether and the like.

In the present invention, among these, it is particularly preferable to use esters from the viewpoint of the solubility of the color developer and the emulsion stability of the emulsified dispersion of the color developer.

(V) In the formula, R+ represents hydrogen or an alkyl group having 1 to IB carbon atoms,
R2 represents an alkyl group having 1 to 18 carbon atoms. pl and ql represent integers from 1 to 4, and the total number of alkyl groups is 4.
No more than 100 pieces.

In addition, it is preferable that the alkyl group of R1 and Rz is a C1-C8 alkyl group.

(Vl) In the formula, R3 represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R4 represents an alkyl group having 1 to 12 carbon atoms, and n represents 1 or 2.

pl and q! represents an integer from 1 to 4. When n=1, the total number of alkyl groups is 4 or less, and when n=2, the total number of alkyl groups is 6 or less.

(■) In the formula, R5 and R6 represent a hydrogen atom or the same or different alkyl groups having 1 to 18 carbon atoms. m is 1~1
Represents an integer of 3. p3 and q3 represent integers of 1 to 3, and the total number of alkyl groups is 3 or less.

In addition, it is particularly preferable that the alkyl group of R5 and R6 is an alkyl group having 2 to 4 carbon atoms.

Examples of the compound represented by formula (V) include dimethylnaphthalene, diethylnaphthalene, and diisopropylnaphthalene.

Examples of the compound represented by formula (Vl) include dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, and diisobutylbiphenyl.

Examples of compounds represented by formula (■) include ester-1
-dimethylphenyl-1-phenylmethane, 1-ethyl-1-dimethylphenyl-1-phenylmethane, and 1-propyl-1-dimethylphenyl-1-phenylmethane.

Examples of esters include phosphate esters WI (e.g., triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, talesyl diphenyl phosphate), phthalate esters (dibutyl phthalate, 2-ethylhexyl phthalate, ethyl phthalate, phthalate). octyl, butyl benzyl phthalate) dioctyl tetrahydrophthalate, benzoate ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietate ester (ethyl abietate, benzyl abietate), Dioctyl adipate, isodecyl succinate, dioctyl azelaate, oxalate esters (dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate esters (dimethyl maleate, diethyl maleate, dibutyl maleate), tributyl citrate, Sorbate esters (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate esters (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formate monoesters and diesters, butyrate monoesters and diesters, lauric acid monoesters) esters and diesters, palmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters),
Examples include triacetin, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, boric acid esters (tributyl borate, tripentyl borate), and the like. Among these, it is preferable to use tricresyl phosphate alone or in combination because the emulsion dispersion stability of the color developer or coupler is particularly good.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a low boiling point dissolution aid. Particularly preferred examples of such co-solvents include ethyl acetate, isopropyl acetate, butyl acetate and methylene chloride.

an aqueous phase which is mixed with an oil phase in which a color developer or coupler is dissolved;
The water-soluble polymer to be contained as a protective colloid can be appropriately selected from known anionic polymers, nonionic polymers, and amphoteric polymers, but polyvinyl alcohol, gelatin, cellulose derivatives, etc. are preferable.

In addition, as the surfactant to be included in the aqueous phase, one should be appropriately selected from anionic, nonionic, or amphoteric surfactants that do not interact with the protective colloid to cause precipitation or aggregation. I can do it. Preferred surfactants include sodium alkylbenzenesulfonate (e.g., sodium dodecylbenzenesulfonate), sodium alkylsulfate, dioctyl sodium sulfosuccinate,
Examples include polyalkylene glycol (eg, polyoxyethylene nonylphenyl ether).

The emulsified dispersion of a color developer or coupler in the present invention is prepared by mixing an oil phase containing the color developer or coupler and an aqueous phase containing a protective colloid and a surfactant by high-speed stirring, ultrasonic dispersion, etc.
It can be easily obtained by mixing and dispersing using the means used for ordinary fine particle emulsification.

A color developer and a coupler melting point depressant may be added to this emulsified dispersion as appropriate. Some of these melting point depressants also have the function of controlling the glass transition point of the capsule wall. Examples of such compounds include hydroxy compounds, carbamate ester compounds, sulfonamide compounds, and aromatic methoxy compounds, the details of which are described in, for example, Japanese Patent Application No. 59-244190.

These melting point depressants can be used in an amount of 0.1 to 2 parts by weight, preferably 0.5 to 1 part by weight, per 1 part by weight of the color developer that lowers the melting point. It is preferable to use the color developer, coupler, etc. whose melting point decreases at the same location. When adding to different locations, it is preferable to add 1 to 3 times the above amount.

The heat-sensitive recording material of the present invention can be coated using a suitable binder.

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-phtadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate, etc. Various emulsions such as polymers can be used. The amount used is 0.5 to 5g10f as solid content.

The thermal recording material of the present invention is prepared by preparing a coating liquid containing microcapsules encapsulating an electron-donating dye precursor or a diazo compound, a dispersion in which at least a color developer or a coupler is emulsified and dispersed, and other additives such as a binder. , coated on a transparent synthetic resin film support by a coating method such as bar coating, blade coating, air knife coating, gravure coating, roll coating, spray coating, dip coating, etc., and dried to a solid content of 2.5 to 25 g. /if heat-sensitive layer.

The heat-sensitive layer of the heat-sensitive material produced in this way has extremely good transparency.

In the present invention, a layer containing microcapsules containing the electron-donating dye precursor or diazo compound used in the heat-sensitive layer may be further provided on top of the transparent heat-sensitive layer. In this case, an emulsified dispersion of a color developer or a coupler may be further included if necessary, but the amount thereof must be 20% or less of the total weight of the layer. By providing a layer containing a small amount of color developer emulsified dispersion in this way, the adhesiveness of the heat-sensitive recording material can be reduced, and
Since the electron-donating dye precursor contained in this layer can also contribute to color development, the provision of this layer does not reduce thermal sensitivity.

In the present invention, pigments such as silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, calcium carbonate, etc., and styrene beads are added to the heat-sensitive layer for the purpose of preventing sticking to the heat head and improving writing properties. ,
Fine powder such as urea-melamine resin can be added, but in order to maintain the transparency of the heat-sensitive layer, a protective layer is provided on the heat-sensitive layer by a known method mainly for the purpose of preservation and safety. , is preferably added to this protective layer. Details about the protective layer are described, for example, in R Paper and Pulp Technology Times J (September issue, 1985), pages 2-4.

In particular, when a protective layer containing a combination of silicon-modified polyvinyl alcohol and colloidal silica is used as a main component, the transparency of the protective layer becomes extremely good, and as a result, the transparency of the heat-sensitive recording material can be significantly improved. preferable.

Waxes and metal soaps can also be added to the protective layer to prevent sticking. The amount used is 0.2 to 7 g/n.

Examples of waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and higher fatty acid amides such as stearic acid amide, ethylene bisstearamide, and higher fatty acid esters.

Examples of metal soaps include polyvalent metal salts of higher fatty acids, such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleate.

Further, the coating amount of the heat-sensitive layer is preferably between 3 g/rrr and 20 g/rr, particularly between 5 g/if and 15 g/rrf. Sufficient sensitivity cannot be obtained below 3g/rd;
Even if the coating is applied over rrf, no improvement in quality will be observed, which will be disadvantageous in terms of cost.

The transparent synthetic resin film that serves as the support has excellent abrasion resistance, water resistance, and chemical resistance, and has a thickness and/or rigidity that does not cause curling when the heat-sensitive layer is applied. Any known material can be selected from among known materials that do not deform and have dimensional stability. Examples of such films include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose film, polystyrene films, polypropylene films, polyolefin films such as polyethylene, etc.
These can be used alone or in combination.

The thickness of the support is preferably 20 to 200 μm, particularly preferably about 50 to 100 μm.

In the present invention, an undercoat layer can be provided between the plastic film and the heat-sensitive layer to enhance adhesion between the two layers. Gelatin, synthetic polymer latex, nitrocellulose, etc. are used as the material for the undercoat layer. The coating amount of the undercoat layer is preferably in the range of 0.18/m' to 2.0 g/m', particularly 0.2 g/m' to 1.0 g/m'
" is preferably within the range of
Even if it is increased above, the adhesive force between the film and the heat-sensitive layer has reached saturation, which is disadvantageous in terms of cost.

It is desirable to harden the undercoat layer using a hardening agent since the undercoat layer may swell due to water contained in the heat-sensitive layer when the heat-sensitive layer is applied thereon.

As the hardening agent, glutaraldehyde, dialdehydes such as 2,3 dihydroxy-1,4-dioxane, and boric acid are preferred.

The amount of these hardeners added is based on the weight of the base coat material.
An appropriate addition amount can be selected in the range of 0.20% by weight to 3.0% by weight depending on the coating method and desired degree of curing.

It is also possible to add an antifoaming agent to eliminate foam generated during coating, or to add an activator to improve liquid leveling and prevent coating streaks.

It is also possible to add an antistatic agent if necessary.

Furthermore, before applying the undercoat layer, it is desirable to activate the surface of the film by a known method. As the method of activation treatment, etching treatment with acid, flame treatment with gas burner, corona treatment, glow discharge treatment, etc. are used, but from the point of view of cost or simplicity,
U.S. Patent No. 2,715.075, U.S. Patent No. 2,846,7
No. 27, No. 3,549,406, No. 3,590,
The corona discharge treatment described in No. 107 and the like is most preferably used.

In the present invention, a back layer may be provided on the back surface of the support for the purpose of curl correction, antistatic properties, and improved slipperiness. As the constituent components of the back layer, it is preferable to use the same components as those of the protective layer.

The coating liquid according to the present invention can be applied by a generally well-known coating method,
For example, dip coating method, air knife coating method, curtain coating method, roller coating method, doctor coating method,
Coating can be performed by a wire barcode method, a slide coating method, a gravure coating method, or an extrusion coating method using a hopper as described in US Pat. No. 2,681,294. U.S. Pat. No. 2,761,791 and U.S. Pat. No. 3,508,947 as appropriate.
No. 2,941,898, and No. 3゜526.
Specification No. 528, Yuji Harasaki, "Coating Engineering" 25
It is also possible to apply the coating simultaneously in two or more layers using the method described in page 3 (published by Asakura Shoten in 1973), etc., and an appropriate method can be selected depending on the amount of coating, coating speed, etc. .

Furthermore, a pigment dispersant, a thickener, a flow modifier, an antifoaming agent, a foam inhibitor, a mold release agent, and a coloring agent can be appropriately blended into the coating liquid as required.

In the present invention, a circuit pattern is formed on the transparent thermosensitive recording material obtained as described above using a thermal head, a laser beam, or the like. In particular, when a combination of a diazo compound and a coupler is used as a coloring agent, after pattern creation, the entire surface of the heat-sensitive recording material is irradiated with ultraviolet rays.
It is preferable to decompose the diazo compound in the non-image area and thereby fix the circuit pattern.

Using the circuit pattern of the transparent heat-sensitive recording material obtained as described above as a photomask, a resist pattern can be prepared according to a conventional method.

(Effects of the Invention) As detailed above, since the photomask used in the present invention is a heat-sensitive recording material, not only can all masks be created by a dry process, but also patterns can be created directly from digital signals. I can do it. Therefore, not only from the viewpoint of eliminating the need for wet work in the conventional photomask production process, but also because the photomask production is greatly simplified, the resist pattern forming method itself is also greatly improved.

(Example) The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 Photosensitive resin film (VANXA450 manufactured by Fuji Photo Film ■) on a copper-clad laminate plated with through-hole plating
An image created using a CAD computer was printed out on a transparent thermosensitive film produced by the following method, superimposed as a photomask, exposed and developed to form an etching resist pattern, and then etched to form a circuit. .

The obtained circuit had no disconnections or continuity (it was of good quality).

[Preparation of capsule liquid] Leuco dye Takenate D-11ON represented by the following structural formula (capsule wall material manufactured by Narita Pharmaceutical ■)
20g with 12g of 1-phenyl-1-xylylethane,
It was added to a mixed solvent containing 20 g of methylene chloride and dissolved. This leuco dye solution was mixed with an aqueous solution of 60 g of 8% polyvinyl alcohol aqueous solution using PVA217C (manufactured by Kuraray ■) and ion-exchanged water and 20 g of ion-exchanged water, and mixed with an aqueous solution of 20 g of ion-exchanged water using an Ace homogenizer manufactured by Nippon Seiki ■.
Emulsify at 100yP for 5 minutes, then add 120g of ion-exchanged water.
was added and reacted at 40°C for 3 hours to produce a capsule liquid with a capsule size of 1.0μ.

Note that the above-mentioned Kuraray PVA217C has a reduced amount of sodium ions.

[Preparation of developer emulsion dispersion]

Color developer represented by the following structural formula (a) 5 g, (b)
2 g and 8 g of (c) were dissolved in 1 g of 1-phenyl-1-xylylethane and 7 g of ethyl acetate. The obtained developer solution was mixed with PVA217C and ion-exchanged water.
% polyvinyl alcohol aqueous solution, 35 g of ion-exchanged water, and 0.2 g of dodecylbenzenesulfonic acid triethanolamine acid (surfactant).
10. Using an Ace homogenizer manufactured by Nippon Seiki ■.
Emulsify at room temperature for 5 minutes at 00Orpm, particle size 1.5μ
An emulsified dispersion was obtained.

Color developer (a) Color developer (b) Color developer (C) [Preparation of heat-sensitive recording material] 5.0 g of the above capsule liquid, 10 g of color developer emulsion dispersion, Og
, and 5.0 g of ion-exchanged water were stirred and mixed to a thickness of 75 μm.
A heat-sensitive layer was formed by coating on one side of a transparent polyethylene terephthalate (PET) support with a solid content of 6 g/m'' and drying, and then a protective layer having the following composition:
Using ion-exchanged water, the solid content is 2.5% on the heat-sensitive recording layer.
g/m''.The aqueous dispersion of Kaobrite was subjected to ion exchange treatment using an ion exchange resin Urbanite MB3 (manufactured by Organo ■).

Polyvinyl alcohol 2 parts by weight (PVA217C manufactured by Kuraray ■) Kaobrite (Thiele) 4 parts by weight Boric acid 0. 1 part by weight Zn stearate dispersion 0. 2 parts by weight (Middle East oil and fat■
When the obtained transparent heat-sensitive recording material was measured with a Macbeth transmission density needle (visible range), the transmittance at a wavelength of 360 nm was 90%.
The maximum color density was 1.53.

Patent applicant: Fuji Photo Film Co., Ltd. Reason Man

Claims (1)

[Scope of Claims] 1) A method for forming a resist pattern in which a photosensitive resin layer is formed on a substrate for a printed circuit board, and then a photomask film is placed on the resin layer and exposed and developed. A method for forming a resist pattern, characterized in that the mask film is a transparent heat-sensitive recording material in which a colored image is formed by heating. 2) The method for forming a resist pattern according to claim 1, wherein the transparent thermosensitive recording material has a transmittance of 70% or more at a wavelength of 360 nm and a maximum color density of 1.0 or more.