JP2006011039A - Method of forming resist image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for obtaining a resist image a resist image having proper chemical resistance with respect to the treatment agent of degreasing process, practically sufficient adhesiveness with a substrate to be processed, and further superior separability of resist, in an image forming method using a resist image formation material obtained, by making the image formation material, such as a dry film, adhere to the substrate to be processed by a method of laminate or the like. <P>SOLUTION: In the method for forming the resist image by developing the rest image formation material, after exposing the resist image formation material obtained by adhering a photopolymerizable composition face of the resist image forming material, having a layer of a photopolymerizable composition so as to be contacted on the substrate to be processed, the resist image forming method conducts full surface exposure of a resist image forming face of the resist image obtained by development. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an etching resist, a plating resist by a direct drawing method in the formation of printed circuit boards, plasma display wiring boards, liquid crystal display wiring boards, large scale integrated circuits, thin transistors, semiconductor packages and other fine electronic circuits. The present invention relates to a resist image forming method useful for forming a resist image for a solder resist or the like, and more particularly to a resist image forming method suitable for use in manufacturing a printed wiring board.

  Conventionally, a layer composed of a photosensitive composition is temporarily supported as a method for forming printed circuit boards, plasma display wiring boards, liquid crystal display wiring boards, large-scale integrated circuits, thin transistors, fine electronic circuits such as semiconductor packages, etc. The photosensitive composition layer of a resist image forming material formed on a film and having a dry film resist material whose surface is covered with a coating film, and the coating film is peeled off and laminated on a substrate to be processed The film is exposed through a mask film on which a circuit or electrode pattern is drawn, or directly drawn using a laser beam, and then the temporary support film is peeled off, and the solubility of the exposed and unexposed areas in the developing solution is removed. A resist image corresponding to the circuit pattern is formed by developing using the difference, and this resist image is Then, after processing the substrate to be etched, plated, or soldered, etc., a lithography method is widely used to form a circuit or electrode pattern drawn on the mask film on the substrate by removing the resist image if necessary. It has been.

In recent years, due to remarkable progress in laser technology, the lifetime of light sources has been extended to 10,000 to 20,000 hours, the beam diameter can be narrowed down to 10 μm or less, and it is possible to work under a yellow light. Utilization of a semiconductor laser that can stably oscillate in a blue-violet region of 390 to 430 nm has come into practical use. And various photosensitive compositions having a sensitivity capable of corresponding to direct drawing with the blue-violet laser light and excellent in resolution have been proposed, for example, having specific spectral characteristics on the substrate to be processed, An image forming material having a blue-violet laser photosensitive resist material layer having a sensitivity of 10 mJ / cm ² or less has been proposed (see Patent Document 1).

On the other hand, as a technique for improving the strength (abrasion resistance) of the formed image, a photopolymerizable image forming material in which a photosensitive layer made of a photopolymerizable composition is formed on a support surface is used at a wavelength of 390 to 430 nm. An image forming method is known in which the entire surface is exposed with a light intensity of 20 mW / cm ² or more after image formation by scanning exposure with a laser beam of a region, development processing, and image formation (see Patent Document 2).
JP 2004-86122 A JP 2002-287380 A

In recent years, further miniaturization of circuit patterns has been required due to market demands, and further fine pattern drawing has become possible due to remarkable progress in the technology of laser direct drawing method. However, in the case of the method of forming a resist image by adhering a photopolymerizable composition layer of an image forming material such as a drafilm resist as described in Patent Document 1 to adhere to a substrate to be processed, it is finer than the conventional method. It has been found that further improvement is necessary in that a simple pattern is formed while maintaining practically sufficient adhesion. That is, even if the resist is peeled off by the degreasing process performed prior to the etching process or the like because the resist pattern is not peeled off by the degreasing process due to insufficient adhesion, the processing solution such as the etching process As a result, the problem of processing accuracy and the like due to permeation from the interface between the resist pattern and the substrate to be processed occurs.

  Furthermore, after processing the substrate to be processed using the obtained fine resist pattern as a mask, when the resist pattern is finally peeled off, the peeled piece becomes too small and the peelability becomes worse, or in the peeling bath It has also been found that problems such as difficulty in separating and removing the peeled pieces are likely to occur. That is, the resist pattern is peeled off due to the difference between the swelling ratio of the resist and the substrate in the stripper, but the resist image exposed by laser exposure, particularly a blue-violet laser having a relatively low exposure intensity, is polymerized. Because the rate is low, it may be torn in the stripping solution, and fine resist strips may remain as residuals on the plating side wall, resulting in insufficient stripping. In addition, it is difficult to separate fine strips in the stripping solution, and there is a concern that the stripping solution may be deteriorated or reattached.

  On the other hand, Patent Document 2 describes that the entire image forming surface is exposed after scanning exposure and development. However, in this document, a liquid of a photopolymerizable composition is applied to a support and heated. It is described that an image forming material is obtained by drying, which is different from a method of forming a photopolymerizable composition layer on a substrate to be processed by adhering a resist pattern forming material on the substrate to be processed by lamination or the like. Incidentally, in the technique described in Patent Document 2, since the photopolymerizable composition layer is formed by coating, heating, and drying, the adhesion caused by the method for forming the photopolymerizable layer is different from the case of lamination. The problem is small.

  The present invention has been made in view of the above-described prior art, and an image forming method using a resist image forming material obtained by bringing an image forming material such as a dry film resist into close contact with a substrate to be processed by a method such as laminating. However, even with a fine pattern, a resist image having good chemical resistance against chemicals such as a degreasing treatment agent, practically sufficient adhesion to a substrate to be processed, and excellent resist releasability. An object of the present invention is to provide a resist image forming method for obtaining the resist image.

As a result of intensive studies to solve the above problems, the present inventor has found that the object can be achieved by a resist image forming method including a step of exposing the entire resist image obtained, and has reached the present invention.
That is, the present invention provides a resist image forming material obtained by adhering a photopolymerizable composition surface of a resist image forming material having a layer of a photopolymerizable composition so as to be in contact with a substrate to be processed, after exposure. The gist of the method for forming a resist image by developing is a resist image forming method characterized by exposing the entire resist image forming surface of a resist image obtained by development.

  According to the present invention, in a resist image forming method using an image forming material such as a dry film resist having relatively weak adhesion between a substrate to be processed and a photopolymerizable layer, the resist pattern is practically used for a fine resist pattern with good chemical resistance. It is possible to provide an image forming method that imparts general adhesion and is excellent in releasability after processing such as plating.

<Resist image forming material>
The resist image forming material of the present invention is a so-called dry film resist comprising a photopolymerizable composition layer and a coating film provided as necessary on a temporary support film (hereinafter, resist image forming material is simply dried). Sometimes called film resist).
(Temporary support film)
As a temporary support film, conventionally well-known films, such as a polyethylene terephthalate film, a polyimide film, a polyamideimide film, a polypropylene film, a polystyrene film, are used, for example. At that time, when those films have solvent resistance, heat resistance, etc. necessary for the production of the dry film resist material, the photopolymerizable composition coating solution directly on the temporary support film Can be applied and dried to produce a dry film resist material, and even if those films have low solvent resistance, heat resistance, etc., for example, polytetrafluoroethylene film, release film, etc. First, a photopolymerizable composition layer is formed on a film having releasability, and a temporary support film having low solvent resistance or heat resistance is laminated on the layer, and then a film having releasability. A dry film resist material can also be produced by peeling the film. The temporary support film needs to be transparent, and the turbidity is preferably as low as possible from the viewpoint of resolution, and the haze is preferably 3% or less, particularly preferably 2% or less. Moreover, it is preferable that thickness is about 10-30 micrometers. A polyethylene terephthalate film is preferably used as the support film. (Photopolymerizable composition layer)
As the photopolymerizable composition layer of the resist image forming material of the present invention, known ones can be used, and are not particularly limited, but the following (A) component, (B) component, (C) component and (D) It is preferable to contain a component.

(A) Carboxyl group-containing polymer (B) Ethylenically unsaturated compound (C) Photopolymerization initiator (D) Sensitizing dye In the present invention, the (A) component constituting the photopolymerizable composition layer is preferred. The carboxyl group-containing polymer is intended to improve the formability as a layer of the photopolymerizable composition on the substrate and the developability. Specifically, for example, (meth) acrylic acid [ In the present invention, “(meth) acryl” means “acryl” and / or “methacryl”. ], A copolymer of an ethylenically unsaturated carboxylic acid monomer such as crotonic acid, isocrotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and a vinyl compound monomer copolymerizable therewith. As the unsaturated carboxylic acid, (meth) acrylic acid is particularly preferable.

  Examples of the copolymerizable vinyl compound monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n- or i-propyl (meth) acrylate, n- or i- or t-butyl (meth). ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, dodecyl (meth) acrylate, alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate , Hydroxyalkyl (meth) acrylates such as 2-hydroxypropyl (meth) acrylate, α-substituted alkylstyrenes such as styrene, α-methylstyrene, α-ethylstyrene, o-methylstyrene, m-methylstyrene, p- Methylstyrene, 2, -Nuclear substitution alkyl styrene such as dimethyl styrene, nuclear substitution such as o-hydroxy styrene, m-hydroxy styrene, p-hydroxy styrene, dihydroxy styrene, etc., nuclear substitution such as p-chloro styrene, p-bromo styrene, dibromo styrene Styrenes such as halogenated styrene, glycidyl (meth) acrylate, benzyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N- (meth) acryloylmorpholine, (meth) acrylonitrile, (meth) Examples include other vinyl compounds such as acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, and vinyl acetate.

The carboxyl group-containing polymer of component (A) preferably has an acid value of 100 to 300 mg · KOH / g and a polystyrene equivalent weight average molecular weight of 20,000 to 150,000.
In the present invention, the ethylenically unsaturated compound as the component (B) constituting the preferred photopolymerizable composition layer is described later when the photopolymerizable composition is irradiated with actinic rays (C ) A compound having at least one radically polymerizable ethylenically unsaturated bond in the molecule that undergoes addition polymerization by the action of a photopolymerization initiating system including a photopolymerization initiator as a component, and optionally crosslinks and cures.

  As the ethylenically unsaturated compound, a compound having one ethylenically unsaturated bond in the molecule, specifically, for example, (meth) acrylic acid, crotonic acid, isocrotonic acid, maleic acid, itaconic acid, citraconic acid Unsaturated carboxylic acids such as, and alkyl esters thereof, (meth) acrylonitrile, (meth) acrylamide, styrene, etc. may be used. From the standpoint that the difference in sex can be expanded, a compound having two or more ethylenically unsaturated bonds in the molecule is preferable, and an acrylate compound in which the unsaturated bond is derived from a (meth) acryloyloxy group Particularly preferred.

  As a compound having two or more ethylenically unsaturated bonds in the molecule, typically, esters of unsaturated carboxylic acid and polyhydroxy compound, urethane of hydroxy (meth) acrylate compound and polyisocyanate compound (meta ) Acrylates, and (meth) acrylic acid or epoxy (meth) acrylates of hydroxy (meth) acrylate compounds and polyepoxy compounds.

Of these, esters of unsaturated carboxylic acids and polyhydroxy compounds are preferred. Specific examples of the esters include unsaturated carboxylic acid as described above, ethylene glycol, polyethylene glycol (addition number 2 to 14), propylene glycol, polypropylene glycol (addition number 2 to 14), trimethylene. Glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, nonamethylene glycol, trimethylol ethane, tetramethylol ethane, trimethylol propane, glycerol, pentaerythritol, dipentaerythritol, sorbitol, and their ethylene oxide adducts, propylene Reaction products with aliphatic polyhydroxy compounds such as oxide adducts, diethanolamine, triethanolamine, and more specifically, for example, ethylene glycol di (meth) Acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tripropylene glycol di (meth) ) Acrylate, tetramethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hexamethylene glycol di (meth) acrylate, nonamethylene glycol di (meth) acrylate, trimethylolethane tri (meth) acrylate, tetramethylol Ethane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Limethylolpropane ethylene oxide addition tri (meth) acrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, glycerol propylene oxide addition tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) Acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (Meth) acrylate, sorbitol tri (meth) acrylate, sorbitol tetra (meth) acrylate, so Examples include rubitol penta (meth) acrylate, sorbitol hexa (meth) acrylate, and similar crotonates, isocrotonates, maleates, itaconates, citrates, and the like.

  Furthermore, as the esters, unsaturated carboxylic acids as described above, aromatic polyhydroxy compounds such as hydroquinone, resorcin, pyrogallol, bisphenol F, bisphenol A, or their ethylene oxide adducts or glycidyl group-containing compound adducts In particular, for example, hydroquinone di (meth) acrylate, resorcin di (meth) acrylate, pyrogallol tri (meth) acrylate, bisphenol A di (meth) acrylate, bisphenol A bis [oxyethylene (meth) acrylate] Bisphenol A bis [trioxyethylene (meth) acrylate], bisphenol A bis [pentaoxyethylene (meth) acrylate], bisphenol A bis [hexaoxyethylene (meth) acrylate] Bisphenol A bis [glycidyl ether (meth) acrylate] and the like, and a reaction product of an unsaturated carboxylic acid as described above and a heterocyclic polyhydroxy compound such as tris (2-hydroxyethyl) isocyanurate, specifically, For example, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tri (meth) acrylate, etc., and a reaction product of unsaturated carboxylic acid, polycarboxylic acid and polyhydroxy compound, specifically For example, a condensate of (meth) acrylic acid, phthalic acid and ethylene glycol, a condensate of (meth) acrylic acid, maleic acid and diethylene glycol, a condensate of (meth) acrylic acid, terephthalic acid and pentaerythritol, Condensates of (meth) acrylic acid, adipic acid, butanediol, and glycerin. It is.

  As the ethylenically unsaturated compound of the component (B), ester (meth) acrylates are particularly preferable in the present invention. Among the ester (meth) acrylates, polyethylene glycol, polypropylene glycol, or bisphenol A polyethylene is preferable. Particularly preferred are ester (meth) acrylates having a polyoxyalkylene group such as an oxide adduct and having two or more (meth) acryloyloxy groups.

  In the present invention, the photopolymerization initiator of the component (C) constituting the preferred photopolymerizable composition layer is increased when irradiated with light in the presence of the sensitizing dye of the component (D). A radical generator that receives photoexcitation energy of a dye and generates an active radical and leads to polymerization of the ethylenically unsaturated compound of component (B), for example, a hexaarylbiimidazole compound, a titanocene compound Halomethylated s-triazine derivatives, halomethylated 1,3,4-oxadiazole derivatives, diaryliodonium salts, organoborates, and organic peroxides. Among them, hexaarylbiimidazole compounds, titanocene compounds, and organoborates are preferable from the viewpoint of sensitivity as a photopolymerizable composition, adhesion to a substrate, and storage stability, and hexaarylbiimidazole compounds. Compounds are particularly preferred.

As the hexaarylbiimidazole compound, specifically, for example, 2,2′-bis (o-methoxyphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′- Bis (p-methoxyphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (fluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2 , 2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra ( p-methylphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-methoxyphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) ) -4,4 ', 5,5'-tetra o, p-dimethoxyphenyl) biimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetra (p-methoxyphenyl) biimidazole, 2,2′-bis (O-chlorophenyl) -4,4 ′, 5,5′-tetra (p-ethoxycarbonylphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (P-chlorophenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole, 2,2′-bis (o, p-
Dichlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p- Fluorophenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dibromophenyl) biimidazole, 2,2′-bis (o-bromo) Phenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetra (p -Iodophenyl) biimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (o-chloro-p-methoxyphenyl) biimidazole, 2,2'-bis (O-chlorophenyl) -4,4 ′, 5,5′-tetra p- chloronaphthyl) biimidazole. Among them, a hexaphenylbiimidazole compound is preferable, and a compound in which the o-position of the benzene ring bonded to the 2,2′-position on the imidazole ring is substituted with a halogen atom is more preferable. Particularly preferred are those in which the benzene ring bonded to the 4 ′, 5,5′-position is unsubstituted or substituted with a halogen atom or an alkoxycarbonyl group.

  In the present invention, the sensitizing dye of component (D) constituting the preferred photopolymerizable composition layer efficiently absorbs light in the wavelength region of the exposure light source used for image formation and its photoexcitation energy. Is transmitted to the photopolymerization initiator of the component (C), the photopolymerization initiator is decomposed, and light having a sensitizing function for generating active radicals that induce polymerization of the ethylenically unsaturated compound of the component (B) It is an absorbing dye. In the image forming method of the present invention, when a blue-violet laser is used as an exposure light source, the polymerization rate of the photopolymerizable layer is considered to be relatively low due to the relatively low exposure intensity of the laser. In this case, the sensitizing dye of component (D) preferably has an absorption maximum wavelength in the wavelength range of 355 to 430 nm. Here, the absorption maximum wavelength is a wavelength indicating a maximum value when the sensitizing dye is dissolved in tetrahydrofuran and the absorption wavelength is measured.

  As the sensitizing dye, known ones can be used. When the image forming exposure light source is a blue-violet laser, for example, (i) JP 2000-10277 A, Japanese Patent Application 2002-362326, etc. (Ii) Aminophenyl-benzimidazole / benzoxazole / benzothiazole compound having the following formula as a basic skeleton described in Japanese Patent Application No. 2002-362326, etc. , (Iii) a sulfonylimino compound having the following formula described in Japanese Patent Application No. 2003-424180 as a basic skeleton, and (iv) a following formula described in Japanese Patent Application No. 2003-392404 as a basic skeleton. Aminocarbostyril compounds, (v) the following formulas described in JP-A No. 2002-169282, Japanese Patent Application No. 2003-374432, etc. (Vi) a thiazolidene ketone compound having the following formula as described in JP-A No. 2002-268239, (vii) Japanese Patent Application No. 2003-291606, etc. (Viii) a benzimidazole / benzoxazole / benzothiazole compound having the following formula as a basic skeleton, (ix) a triazole compound having the following formula as a basic skeleton, (x ) A cyanostyryl compound having the following formula as a basic skeleton, (xi) a stilbene compound having the following formula as a basic skeleton, (xii) an oxadiazole / thiadiazole compound having the following formula as a basic skeleton, and (xiii) (Xiv) a coumarin compound having the following formula as a basic skeleton, (xv) based on the following formula described in Japanese Patent Application No. 2003-435212, etc. A triphenylamine-based compound having a skeleton, (xvi) an acridone-based compound having the following formula described in Japanese Patent Application No. 2003-340924 and the like, (xvii) described in Japanese Patent Application No. 2003-435212, and the like Examples include carbazole compounds having the following formula as a basic skeleton.

In the following formulae, X and Z each independently represent a nitrogen atom, an oxygen atom, a sulfur atom, or C—R, Y represents an arbitrary linking group, and n is an integer of 1 or more. The compounds of the following formulas showing the basic skeleton are, for example, alkyl groups, cycloalkyl groups, alkenyl groups, cycloalkenyl groups, alkoxy groups, alkylthio groups, aryl groups, aryloxy groups, aralkyl groups, alkenyloxy groups, alkenyls, respectively. Substituents such as thio group, acyl group, acyloxy group, amino group, acylamino group, carboxyl group, carboxylic acid ester group, carbamate group, carbamoyl group, sulfamoyl group, sulfonic acid ester group, saturated or unsaturated heterocyclic group These substituents may further have a substituent, and a plurality of substituents may be bonded to each other to form a cyclic structure.

In the present invention, the carboxyl group-containing polymer as the component (A) constituting the preferred photopolymerizable composition, the ethylenically unsaturated compound as the component (B), and the photopolymerization initiator as the component (C) And the content ratio of the sensitizing dye of the component (D) is 20 to 80% by weight of the component (A), 20 to 80% by weight of the component (B), based on the total amount of the photosensitive composition. C) component 0.1
It is preferable that it is -20 weight% and (D) component is 0.01-10 weight%.

In addition, in the present invention, the photopolymerizable composition layer that is preferred includes, in addition to the components (A) to (D), a hydrogen-donating compound, a polymerization inhibitor, and the like for the purpose of improving photopolymerization initiation ability. Contains antioxidants, plasticizers, colorants, discoloring agents, adhesion promoters, surface tension modifiers, stabilizers, chain transfer agents, antifoaming agents, flame retardants, solvents, surfactants, etc. You may do it.
(Creation of image forming materials)
In forming the photopolymerizable composition layer of the dry film resist used in the present invention on the temporary support film, the photopolymerizable composition is dissolved in an appropriate solvent to form a coating solution, which is coated and dried on the temporary support film. It is common. The solvent used here is not particularly limited as long as it has sufficient solubility with respect to the components used and gives good coating properties, but for example, solubility, surface tension, viscosity, and ease of drying. In view of the above, a single or mixed solvent such as methyl ethyl ketone, methanol, isopropanol, and toluene is preferable. The use ratio of the solvent is usually in the range of about 0.5 to 2 times by weight with respect to the total amount of the photopolymerizable composition.

  As the coating method, a conventionally known method such as a knife coating method, a roll coating method, a spray coating method, a spin coating method or the like can be used. The coating amount at that time is usually 5 μm or more in terms of dry film thickness (thickness of the photopolymerizable composition layer) from the viewpoint of image formability and subsequent processability such as etching and plating. The material is preferably 10 μm or more, more preferably 15 μm or more, and from the viewpoint of sensitivity or the like, it is preferably 200 μm or less, and more preferably 100 μm or less. That is, when the dry film thickness is relatively thick as 5 μm or more, the effect of the entire surface exposure described later tends to be remarkable. The drying temperature at that time is, for example, about 30 to 150 ° C., preferably about 30 to 130 ° C., and the drying time is, for example, about 5 seconds to 60 minutes, preferably about 10 seconds to 30 minutes. It is done.

In addition, the dry film resist preferably covers the surface of the formed photopolymerizable composition layer with a covering film until it is laminated on the substrate to be processed. Examples of the covering film include polyethylene film, polypropylene film, A conventionally known film such as a tetrafluoroethylene film is used, but a polyethylene film is preferable from the viewpoint of price, flexibility, strength, hardness, and the like. Further, the thickness is preferably 1.0 to 40 μm, and more preferably the number of foreign matters called fish eyes is smaller.
<Resist image forming material>
The dry film resist is laminated by peeling off the coating film when the photopolymerizable composition layer side is covered with a coating film, and heating, pressurizing, depressurizing, etc. using a laminator or the like by a conventional method. By doing so, a photopolymerizable composition layer is formed on the substrate to be processed to obtain a resist image forming material.
(Processed substrate)
The substrate to be used here is a circuit or electrode formed on the surface of the photopolymerizable composition layer by exposing or developing the photopolymerizable composition layer using a direct drawing method or the like as a resist by etching or plating. Etc., and may be a metal plate itself such as copper, aluminum, gold, silver, chromium, zinc, tin, lead, nickel, etc., but usually, for example, epoxy resin, polyimide resin, Thermosetting resins such as bismaleimide resin, unsaturated polyester resin, phenol resin, melamine resin, saturated polyester resin, polycarbonate resin, polysulfone resin, acrylic resin, polyamide resin, polystyrene resin, polyvinyl chloride resin, polyolefin resin, fluorine resin Resin such as thermoplastic resin such as paper, glass, alumina, silica It consists of inorganic materials such as barium sulfate and calcium carbonate, or composite materials such as glass cloth base epoxy resin, glass nonwoven base epoxy resin, paper base epoxy resin, paper base phenol resin, etc., and its thickness is 0 On the surface of the insulating support of about 0.02 to 10 mm, the metal or metal foil such as indium oxide, tin oxide, indium oxide doped tin oxide or the like is heated and pressure-bonded laminated, or the metal is sputtered, vapor-deposited, A metal-clad laminate in which a conductive layer having a thickness of about 1 to 100 μm is formed by a method such as plating is preferably used.
(Resist image forming method)
In the resist image forming method of the present invention, the photopolymerizable composition layer of the resist image forming material having a photopolymerizable composition layer on a substrate to be processed is exposed and developed to form a resist image. In that case, it exposes from the temporary support film of the said dry film resist normally.
(Exposure for image formation)
In the resist image forming method of the present invention, a well-known exposure method and light source for image formation are used. For example, ultraviolet light from a high pressure mercury lamp, ultrahigh pressure mercury lamp, carbon arc lamp, xenon lamp, metal halide lamp, chemical lamp, etc. Examples include batch exposure by irradiation, polygon scanning using an argon ion laser, helium ion laser, YAG laser, and semiconductor laser, and scanning exposure using a DMD method. Among these, as the light source, a light source that generates light in the blue-violet region having a wavelength range of 390 to 430 nm is preferable. Further, the effect of the present invention by the whole surface exposure described later is more remarkable when the exposure for image formation is performed with a laser. Among these, a light source that generates laser light in a blue-violet region, in which the light intensity of the exposure light source is relatively low, is preferable, and is particularly effective when a light source that generates laser light in the wavelength range of 400 to 420 nm is used.

The amount of exposure for image formation varies depending on the composition of the photopolymerizable composition layer and the exposure source, but is usually 0.1 to 500 mJ / cm ² , and in particular, in the case of laser exposure, 0.1 to 10
0 mJ / cm ² is preferable, and when using a light source that emits laser light in the blue-violet region, which is preferable as described above, usually 0.1 to 50 mJ / cm ² , preferably 0.5 to 30 mJ /
cm ² . If it is too small, it is practically difficult to form an image. If it is too large, there is a problem of throughput.
(developing)
In the resist image forming method of the present invention, the development treatment after the exposure is performed by peeling the temporary support film, and an alkaline developer having a pH of 9 to 12, for example, 0.3 to 2 weight of an alkali salt such as sodium carbonate or potassium carbonate. % Dilute alkaline aqueous solution is used. A surfactant, an antifoaming agent, an organic solvent as a development accelerator and the like may be added to the alkaline aqueous solution.

The development is usually performed by immersing the resist image forming material in the developer, or by a known developing method such as a spray method or a paddle method in which the developer is sprayed on the resist image forming material, preferably 10 to 50 ° C. The temperature is about 15 to 45 ° C., preferably about 5 seconds to 10 minutes, preferably about 10 seconds to 2 minutes.
(Full exposure)
The resist image forming method of the present invention is characterized by further exposing the entire resist image forming surface after the development processing. Here, the entire exposure of the resist image forming surface means surface exposure of the surface of the substrate to be processed on which the resist image is formed. The light source is not particularly limited, and examples thereof include a carbon arc, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, and a halogen lamp. The light emitted from these light sources may be used while being wavelength-limited by a filter or the like. In addition, the light used in the entire surface exposure is more effective if it contains light in the absorption wavelength region of (C) a photopolymerization initiator and (D) a sensitizing dye constituting the photopolymerizable composition layer. Therefore, when a light source that emits light in the blue-violet region is used for exposure for image formation, it is preferable to include light in the wavelength region of 300 to 450 nm.

The exposure amount of the entire surface exposure depends on the composition of the photopolymerizable composition layer, the exposure amount for image formation performed before development, and the like, and is not particularly limited, but is usually 10 to 2000 mJ. / Cm ² or so. In addition, the exposure amount in the exposure for image formation performed before development is αmJ / c
m ² , when the exposure amount in the entire exposure performed after development is βmJ / cm ² , if α <β, it is more effective in terms of adhesion of the resist image to the substrate to be processed and releasability. The overall exposure amount is preferably 1.1 times or more, more preferably 2 times or more, and particularly preferably 4 times or more with respect to the exposure amount before development. However, since the effect is saturated even if it is too large, the upper limit is about 100 times.

Further, the light intensity of the overall exposure is preferably 500 mW / cm ² or less. The larger the light intensity, the more effective the shortening of the processing time, but if it is too large, the effect is saturated and causes an economic disadvantage, and the radiant heat from the light source increases, so that the thermal expansion of the substrate and resist becomes remarkable, The adhesive gap may be adversely affected by the gap of the expansion coefficient. However, a certain amount of radiant heat or aggressive heating may have a role of improving the overall exposure after development.

  The substrate to be processed on which the resist image obtained by the entire surface exposure is formed is subjected to processing such as degreasing by a conventional method, and then subjected to processing such as etching processing or plating processing using this as a resist, and then the resist is peeled off. In the image forming method of the present invention, since the releasability of the resist image is good, the resist image used in the method is peeled off after processing the substrate to be processed such as an etching resist or a plating resist. Is particularly effective.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
Examples 1-3, Comparative Example 1
As the photopolymerizable composition, the following carboxyl group-containing polymer (A1), ethylenically unsaturated compounds (B1 to B2), photopolymerization initiator (C1), sensitizing dye (D1), colorant and the like (X1 ~ X2) in the formulation shown in Table 1 in addition to the following solvent (Y1), the coating solution prepared by stirring at room temperature to prepare a coating solution of 100 μm on a polyethylene terephthalate film (thickness 25 μm) as a temporary support film Using an applicator, it is applied in an amount that results in a dry film thickness of 25 μm, air-dried at 25 ° C. for 1 minute, and then dried in an oven at 85 ° C. for 1 minute. On the formed photopolymerizable composition layer, a coating film is formed. A polyethylene film (thickness 25 μm) was laminated to prepare a dry film resist material.

<Carboxyl group-containing polymer>
(A1) Methacrylic acid / methyl methacrylate / n-butyl methacrylate / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / styrene copolymer (wt% = 20/35/10/10/15/10, weight average molecular weight 46, 000)
<Ethylenically unsaturated compound>
(B1) The following compound
(B2) The following compound

<Photopolymerization initiator>
(C1) 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole <Sensitizer>
(D1) The following compound (when the sensitizing dye is diluted 60,000 times with tetrahydrofuran and the UV extinction coefficient is measured in the wavelength region of 300 to 500 nm, the absorption maximum existing at the longest wavelength is 388 nm)

<Colorants, etc.> (X1) Leuco Crystal Violet
(X2) Malachite Green <Solvent>
(Y1) Methyl ethyl ketone Separately, the surface of the copper foil of a polyimide resin copper-clad laminate (thickness 1.5 mm, size 250 mm × 200 mm) bonded with a 35 μm thick copper foil was applied to “Scotch Bright SF” manufactured by Sumitomo 3M Limited. Use buffol polishing, wash with water, dry with air flow and adjust the surface, then preheat it to 80 ° C. in an oven, then on the copper foil of the copper clad laminate, the dry film obtained above By laminating the resist material on the peeling surface while peeling the polyethylene film using a hand-type roll laminator at a roll temperature of 100 ° C., a roll pressure of 0.3 MPa, and a laminating speed of 1.5 m / min. A resist image forming material having a photopolymerizable composition layer formed on a laminated substrate was produced.

The resulting photopolymerizable composition layer of each resist image forming material was exposed and developed under the conditions shown below, and further exposed to the entire surface after development. The resulting resist image was degreased and plated under the conditions shown below. And the peeling process was performed, it evaluated on the following reference | standard, and the result was shown in Table 1.
Exposure and development conditions Using a blue LD slot module “NDAV520E2” manufactured by Nichia Corporation with an oscillation wavelength of 407 nm and a rated light output of 500 mW, with an exposure amount of 8 mJ / cm ² , line / space = 17.5 μm / 17.5 μm Scanning line exposure and line / space = 10 μm / 20 μm assembly line. After 20 minutes from the exposure, the polyethylene terephthalate film is peeled off and removed, and then a 0.7 wt% sodium carbonate aqueous solution is added at 25 ° C. as a breakpoint (time until the non-exposed portion is completely dissolved). Developed by spraying at 0.15 MPa with a development time of .75 times.

Post-development overall exposure After development, the resulting pattern image was exposed in accordance with Table 1 under the following conditions.
Condition 1 (Example 1): High-pressure mercury lamp (Mercury lamp “H03-L3 manufactured by Eye Graphics Co., Ltd.)
1)) and exposure at 100 mJ / cm ² .
Condition 2 (Example 2): High-pressure mercury lamp (Mercury lamp “H03-L3 manufactured by Eye Graphics Co., Ltd.)
1)) and exposure at 50 mJ / cm ² .

Condition 3 (Example 3): It was exposed to a white fluorescent lamp for 1 hour at a distance of 2 m from the light source and at an illuminance of 450 Lx.
Condition 4 (Example 4): It was exposed to a white fluorescent lamp for 3 hours at a distance of 2 m from the light source and at an illuminance of 450 Lx.
Degreased exposure, development, and a resist image obtained in the same manner except that the substrate (Examples 1 to 4) on which the resist image was formed and the overall exposure were not performed were formed. The substrate (Comparative Example 1) was degreased by immersing it in a 5-fold dilution of a neutral degreasing agent OPC Clean 65 (trade name, manufactured by Okuno Pharmaceutical Co., Ltd.) at 35 ° C. for 1 minute.

The substrate after the plating treatment degreasing treatment was performed using a copper sulfate plating bath (Shipley intervia 8510 electrolytic copper plating solution) at a bath temperature of 25 ° C. for 3 minutes at a cathode current density of 1 A / dm ² for 1.5 minutes.
Current was applied at A / dm ² for 38 minutes and at 2 A / dm ² for 4 minutes to carry out plating with a thickness of 20 μm.
After the resist stripping treatment, at a spray pressure of 0.15 Pa, first, a 3% NaOH aqueous solution at 45 ° C. was showered for 2 minutes and warm water at 45 ° C. was showered for 30 seconds to strip the resist.

Evaluation 1 (Adhesion / degreasing treatment)
The state of the circuit pattern after the degreasing treatment and after the resist peeling treatment was observed to evaluate the adhesion (degreasing treatment).
A: No peeling of resist image after degreasing treatment. Further, in any of the patterns of 10 μm / 20 μm and 17.5 μm / 17.5 μm, there is no abnormality of the substrate due to the penetration of the plating solution on the base surface after the resist is stripped.

○: No peeling of resist image after degreasing. In the 17.5 μm / 17.5 μm pattern, there is no abnormality of the substrate due to the penetration of the plating solution on the base surface after the resist is stripped. However, with respect to the pattern of 10 μm / 20 μm, a trace of the plating solution soaking is observed on the substrate surface after the resist is peeled off.
Δ: Peeling is not observed in the resist image in the pattern of 17.5 μm / 17.5 μm by the degreasing treatment. However, peeling of the resist image is observed in a 10 μm / 20 μm pattern.

X: Peeling off was observed in the resist image in any pattern of 10 μm / 20 μm and 17.5 μm / 17.5 μm by degreasing treatment.
Evaluation 2 (Peelability)
The state after resist peeling was observed with SEM and evaluated as follows.
A: The resist is peeled cleanly in both patterns of 10 μm / 20 μm and 17.5 μm / 17.5 μm.

Δ: The resist is peeled cleanly in the pattern of 17.5 μm / 17.5 μm, but in the pattern of 10 μm / 20 μm, the resist is not completely peeled off.
X: In any pattern of 10 μm / 20 μm and 17.5 μm / 17.5 μm, there is a portion where the resist is not completely peeled off.

Claims (7)

After exposure, a resist image forming material obtained by bringing the photopolymerizable composition surface of a resist image forming material having a photopolymerizable composition layer on a temporary support film into close contact with the substrate to be processed is exposed, A method of forming a resist image by developing, wherein the resist image forming surface of the resist image obtained by developing is exposed entirely.   The resist image forming method according to claim 1, wherein the photopolymerizable composition layer has a thickness of 5 μm or more. 3. The resist image forming method according to claim 1, wherein the entire surface is exposed using a light source including light in a wavelength region of 300 to 450 nm. Development before exposure, an exposure with a laser, a resist image forming method according to any one of claims 1 to 3 that the exposure amount is characterized in that it is a 0.1~50mJ / cm ^2. The exposure amount in exposure before development is αmJ / cm ² , and the exposure amount in overall exposure after development is β
The resist image forming method according to claim 1, wherein α <β when mJ / cm ² is satisfied. The photopolymerizable composition layer is composed of a blue-violet laser-sensitive composition containing the following components (A), (B), (C) and (D): The resist image forming method according to any one of the above.
(A) carboxyl group-containing polymer (B) ethylenically unsaturated compound (C) photopolymerization initiator (D) sensitizing dye having an absorption maximum wavelength in the wavelength range of 355 to 430 nm 7. The resist image forming method according to claim 1, wherein the resist image is peeled after the substrate to be processed is processed using the resist image.