TWI425892B - A method for forming a transfer film and an aluminum wiring for forming an aluminum wiring - Google Patents

Description

Transfer film for forming aluminum wiring and method for forming aluminum wiring

The present invention relates to a transfer film for forming an aluminum wiring formed by a metal foil, and a method for forming an aluminum wiring. More specifically, it is possible to easily form a thick-film aluminum wiring and obtain excellent electrical characteristics or smoothness. A transfer film for forming aluminum wiring of aluminum wiring.

In recent years, the processing of aluminum wiring in a circuit board or a display panel has progressed toward higher density and higher definition. With the increase in density and high definition, the size of the aluminum wiring is required to be small. For example, since the line width of the wiring is reduced, the conductivity is further required.

In the past, it has been known to form a metal film by a plating method, a vapor deposition method of a vacuum process, a sputtering method, or the like, apply a photoresist, perform exposure, development, and then form an aluminum wiring with an etching solution. The method.

However, the above plating method, the vapor deposition method of the vacuum process, and the sputtering method are slow in the production amount in the step, and in particular, in order to improve the conductivity, forming the metal film into a thick film may cause a problem that the production amount is slower. In addition, if the surface smoothness of the underlayer is poor, there is also a problem of poor followability with the underlying layer and smoothness of the metal film.

The present invention has been completed based on the above problems.

A first object of the present invention is to provide a transfer of aluminum wiring suitable for forming aluminum wiring (for example, a printed circuit board, a multilayer circuit board, a multi-chip module, an LSI, an electrode of a flexible panel display, a reflector, etc.) A film and a method of forming an aluminum wiring using the transfer film for forming an aluminum wiring.

A second object of the present invention is to provide an aluminum wiring manufacturing method which is excellent in manufacturing efficiency even when a metal film is formed into a thick film, in comparison with the conventional manufacturing method.

A third object of the present invention is to provide a method of forming an aluminum wiring excellent in surface smoothness.

The present invention for solving the above object is a transfer film for forming an aluminum wiring, characterized in that a (A) photoresist layer, (B) an aluminum layer, and (C) an adhesive layer are laminated on a support film, and the preferred aspect is the above. In the transfer film for forming an aluminum wiring, the (B) aluminum layer is formed of an aluminum foil, and the (B) aluminum layer has a thickness of 1 to 20 μm, and the (C) adhesive layer is a thermosetting resin composition.

Further, the present invention provides a method of forming an aluminum wiring, comprising the steps of: forming a laminate on a substrate by transferring an adhesive layer of the aluminum wiring forming transfer film to a substrate; a step of exposing the (A) photoresist layer constituting the laminate to form a latent image of a resist pattern; and subjecting the (A) photoresist layer to development processing to develop a photoresist pattern And the step of etching the aluminum layer (B) to form an aluminum wiring corresponding to the photoresist pattern.

According to the method for forming a transfer film for forming an aluminum wiring and an aluminum wiring according to the present invention, it is possible to manufacture an electrode which is excellent in workability, has an excellent manufacturing efficiency when the aluminum layer is a thick film, and has a low resistance value. Further, since it is not affected by the surface roughness of the substrate, the surface smoothness is excellent, and an excellent aluminum wiring which can also be used as a reflector can be obtained.

<Transfer film for forming aluminum wiring>

In the transfer film for forming an aluminum wiring of the present invention, the (A) photoresist layer, the (B) aluminum layer, and the (C) adhesive layer are sequentially laminated on the support film. Further, the transfer film for forming an aluminum wiring of the present invention may be one in which the (B) aluminum layer and the (C) adhesive layer are sequentially laminated on the support film.

(A) photoresist layer

As the material for forming the photoresist layer in the present invention, a conventional photoresist can be used. The photoresist is either a negative type or a positive type, but it is preferable that the negative type is easy to form the transfer film for forming an aluminum wiring of the present invention.

The photoresist layer in the present invention contains, for example, a photosensitive monomer, a photopolymerization initiator, and a binder.

Photosensitive monomer

The photosensitive monomer is a substance which changes solubility in a developing solution by exposure polymerization, and for example, by exposure polymerization, the exposed portion becomes a substance which is insoluble in alkali or insoluble in alkali. As for the photosensitive monomer, when a substance which becomes alkali-insoluble or the like by the exposure is used, it is possible to easily give a contrast between the exposed portion and the unexposed portion, and the aluminum wiring is highly refined or the aluminum wiring shape is easily controlled. The advantages. As the substance which becomes alkali-insoluble or the like by the exposure, for example, a compound containing an ethylenically unsaturated group is preferable, and a polyfunctional (meth) acrylate is preferable.

Specific examples of the compound containing an ethylenically unsaturated group include di(meth)acrylates of alkylene glycols such as ethylene glycol and propylene glycol; and polyalkylene glycols such as polyethylene glycol and polypropylene glycol. Acrylates; bis(meth)acrylates of hydroxylated polymers at both ends, hydroxypolybutadiene, hydroxypolyisoprene, hydroxypolycaprolactone, etc.; glycerol, Poly(meth)acrylates of trivalent or higher polyvalent alcohols such as 1,2,4-butanetriol, trimethylolane, tetramethylolane, pentaerythritol, dipentaerythritol, etc.; Poly(meth)acrylates of polyalkylene glycol adducts of alcohols; poly(meth)acrylates of cyclic polyols such as 1,4-cyclohexanediol and 1,4-benzenediol ; polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, alkyd (meth) acrylate, polyoxy oxy resin (methyl) An oligo (meth) acrylate such as an acrylate or a spirane resin (meth) acrylate, or the like may be used alone or in combination of two or more.

Among these, trimethylolpropane triacrylate is preferably used.

The molecular weight of the above polyfunctional (meth) acrylate is preferably from 100 to 2,000.

The content ratio of the photosensitive monomer in the photoresist layer of the present invention is usually 5 to 200 parts by mass, preferably 30 to 130 parts by mass, per 100 parts by mass of the binder resin.

Photopolymerization initiator

Specific examples of the photopolymerization initiator include benzyl, benzoin, benzophenone, camphorquinone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-hydroxycyclohexyl. Benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-[4'-(methylthio)phenyl]-2-morpholin-1-propanone, 2-benzyl a carbonyl compound such as benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butan-1-one; an azo compound or a stack of azoisobutyronitrile or 4-azidobenzaldehyde Nitrogen compound; organic sulfur compound such as thiol disulfide or bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide; benzamidine peroxide, di-t-butyl group Oxide, tert-butyl hydroperoxide, cumyl hydroperoxide, p-menthane hydrogen peroxide and other organic peroxides; 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl a trihalomethane such as -1,3,5-triazine, 2-[2-(2-furyl)vinyl]-4,6-bis(trichloromethyl)-1,3,5-triazine An imidazole dimer such as 2,2'-bis(2-chlorophenyl)4,5,4',5'-tetraphenyl 1,2'-bisimidazole. These may be used alone or in combination of two or more.

The photopolymerization initiator in the photoresist layer of the present invention is contained in an amount of usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, per 100 parts by mass of the photosensitive monomer.

Adhesive resin

Although various resins can be used for the adhesive resin, it is preferable to use an adhesive resin containing an alkali-soluble resin in a ratio of 30 to 100% by mass. Here, the "alkali-soluble resin" is a property which can be dissolved by an alkaline developing solution to achieve the solubility of the target image forming treatment. When an alkali-soluble resin is used, there is an advantage that the dissolution rate with respect to the alkali developing solution or the shape of the aluminum wiring can be controlled, for example, by changing the content of the monomer having a carboxyl group.

Specific examples of the alkali-soluble resin include, for example, a (meth)acrylic resin, a hydroxystyrene resin, a novolac resin, a polyester resin, and the like.

Among these alkali-soluble resins, the most preferred ones are copolymers of the following monomers (A) and monomers (C), and copolymers of monomer (A), monomer (B) and monomer (C). Acrylic resin.

Monomer (A): a monomer containing a carboxyl group

Acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, seccoic acid, cinnamic acid, succinic acid mono(2-(methyl) propylene methoxyethyl ester), Ω-carboxy-polycaprolactone mono(meth)acrylate and the like.

Monomer (B): Monomers containing OH groups

Monomers containing hydroxyl groups such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate; o-hydroxystyrene, m-hydroxybenzene A monomer containing a phenolic hydroxyl group such as ethylene or p-hydroxystyrene.

Monomer (C): Other copolymerizable monomer

Methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, (methyl) (meth) acrylates other than monomers (methyl) such as benzyl acrylate, glycidyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate; methyl Acrylate having α-hydroxymethyl group such as α-(hydroxymethyl)acrylate, ethyl-α-(hydroxymethyl)acrylate, n-butyl-α-(hydroxymethyl)acrylate; styrene , aromatic vinyl monomers such as α-methylstyrene; conjugated dienes such as butadiene and isoprene; polystyrene, poly(methyl) acrylate, poly(methyl) A macromonomer having a polymerizable unsaturated group such as a (meth) acrylonitrile group at one end of a polymer chain such as ethyl acrylate or polybenzyl (meth) acrylate.

The copolymer of the above monomer (A) and monomer (C), and the copolymer of monomer (A), monomer (B) and monomer (C) are derived from the monomer (A) The presence of a polymeric component results in an alkali-soluble one. Among them, the copolymer of the monomer (A), the monomer (B) and the monomer (C) is most preferable from the viewpoint of the dispersion stability of the (A) inorganic powder or the solubility of the alkali developing solution described later.

The content of the copolymer component derived from the monomer (A) in the copolymer is preferably from 5 to 60% by mass, preferably from 10 to 40% by mass, based on the content of the copolymerized component of the monomer (B). It is preferably from 1 to 50% by mass, preferably from 5 to 30% by mass.

The optimum composition of the alkali-soluble resin used in the present invention is exemplified by methacrylic acid/benzyl methacrylate/cyclohexyl methacrylate copolymer, methacrylic acid/2-hydroxypropyl methacrylate/methacrylic acid. a n-butyl ester copolymer, and a methacrylic acid/succinic acid mono(2-(methyl) propylene methoxyethyl ester)/2-hydroxypropyl methacrylate/n-butyl methacrylate copolymer.

The molecular weight Mw of the above alkali-soluble resin is preferably from 5,000 to 5,000,000, more preferably from 10,000 to 300,000.

The photoresist layer of the present invention is preferably cured by heating or exposure. When the photoresist layer can be cured, the photoresist layer and the aluminum layer are subsequently strengthened by curing the photoresist layer before the etching step of the aluminum layer described later, and the light can be prevented even if the etching treatment is performed under strong conditions. The resist layer is detached from the aluminum layer.

The thickness of the photoresist layer of the present invention is usually from 0.1 to 40 μm, preferably from 0.5 to 20 μm.

Optional ingredient

The photoresist layer of the present invention may further contain a pigment, a tackifier, a plasticizer, a dispersant, a development accelerator, a secondary auxiliary agent, a halo preventing agent, a leveling agent, a preservation stabilizer, an antifoaming agent, an antioxidant, and the like. Various additives such as an ultraviolet absorber, a sensitizer, and a chain transfer agent are optional components.

(B) aluminum layer

The aluminum layer of the present invention contains substantially no components other than aluminum.

The aluminum layer is preferably formed of a metal foil. The method for producing the metal foil is not particularly limited, and an aluminum foil produced by a calendering method, an electroforming method, or the like can be used.

The thickness of the aluminum layer is preferably from 1 to 20 μm. When the thickness of the aluminum layer is less than 1 μm, it is difficult to bond the photoresist layer or the adhesive layer when the transfer film for forming an aluminum wiring is formed. If the thickness of the aluminum layer is more than 20 μm, it takes a long time to dissolve and remove the aluminum layer during etching, and during this period, problems such as peeling of the photoresist layer from the aluminum layer are likely to occur.

(C) adhesive layer

The adhesive layer is preferably a thermosetting resin composition which is interposed between the aluminum layer and the substrate and has a function of attaching the aluminum layer to the substrate when the aluminum wiring is produced from the film of the present invention.

Thermosetting resin composition

The thermosetting resin used in the thermosetting resin composition of the present invention may, for example, be phenol resin, epoxy resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane, polyimine. , (meth)acrylic resin, polyester resin, and the like.

Further, as the thermosetting resin composition, a composition containing the above resin and a crosslinking agent can also be used.

The crosslinking agent is not particularly limited, but a crosslinkable compound containing two or more ethylenically unsaturated bonds, an epoxy group, or an (alkoxy) melamine group in the same molecule is preferred. These compounds can be used in combination with a crosslinking reaction aid or a catalyst such as a radical generator, an acid generator, a basic catalyst, or a polyvalent carboxylic anhydride, depending on the conditions of use.

The crosslinking agent having an ethylenically unsaturated double bond can be exemplified by a polyfunctional (meth) acrylate as a preferred compound. Specifically, the difunctional (meth) acrylate is exemplified by, for example, ARONICS M-210, ARONICS M-240, ARONICS M-6200 (manufactured by East Asian Synthetic Chemical Industry Co., Ltd.), KAYARAD DDDA, KAYARAD HX-220, KAYARAD. R-604 (made by Nippon Kayaku Co., Ltd.), V260, V312, V335HP (made by Osaka Organic Chemical Industry Co., Ltd.) (commercial product). The trifunctional or higher (meth) acrylate is exemplified by, for example, trimethylolpropane triacrylate, pentaerythritol triacrylate, decyl decyl oxyethyl phosphate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and the like. Pentaerythritol hexaacrylate and the like. Specifically, for example, ARONICS M-309, ARONICS M-400, ARONICS M-405, ARONICS M-450, ARONICS M-7100, ARONICS M-8030, ARONICS M-8060 (manufactured by East Asia Synthetic Chemical Industry Co., Ltd.) , KAYARAD DPHA, KAYARAD TMPTA, KAYARAD DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60, KAYARAD DPCA-120 (Nippon Chemical Co., Ltd.), V-295, V-300, V-360, V- Commercial products such as GPT, V-3PA, V-400 (made by Osaka Organic Chemical Industry Co., Ltd.) and PPZ (Ishigaku Petrochemical Co., Ltd.).

Among these, a trifunctional or higher polyfunctional (meth) acrylate such as ARONICS M-400 or KAYARAD DPHA can be preferably used. The crosslinking agent having an ethylenically unsaturated double bond as described above may also be used in combination of two or more.

Preferred compounds of the crosslinking agent having an epoxy group are exemplified by polyfunctional glycidyl ethers. Specific examples are bisphenol A type epoxy resins such as EPICOTE 1001, EPICOTE 1002, EPICOTE 1003, EPICOTE 1004, EPICOTE 1007, EPICOTE 1009, EPICOTE 1010, EPICOTE 828 (trade name; oil-based clamshell epoxy) ; bisphenol P type epoxy resin such as EPICOTE 807 (trade name; oil-based clamshell epoxy); EPICOTE 152, EPICOTE 154 (trade name; oil-based clamshell epoxy), EPPN 201, EPPN a bisphenol novolak type epoxy resin such as 202 (trade name; manufactured by Nippon Kayaku Co., Ltd.); EOCN 102, EOCN 103S, EOCN 104S, 1020, 1025, 1027 (trade name; manufactured by Nippon Kayaku Co., Ltd.), A phenol novolac type epoxy resin such as EPICOTE 180S75 (trade name; oil-based clamshell epoxy); polyphenols such as EPICOTE 1032H60 and EPICOTE XY-4000 (trade name; oil-based clamshell epoxy) Type epoxy resin, CY-175, CY-177, CY-179, ALUDALIGHT CY-182, ALUDALIGHT CY-192, 184 (trade name; Ciba Jiaji (share) system), ERL-4234, 4299, 4221 4206 (trade name; manufactured by UCC), SHODAIN 509 (trade name; Showa Electric Co., Ltd.), EPICLON 200, EPICLON 400 (trade name; Dainippon Ink (share) ), a cyclic aliphatic epoxy resin such as EPICOTE 871, EPICOTE 872 (trade name; manufactured by oyster shell epoxy), ED-5661, ED-5662 (trade name; CELANESE coating). An aliphatic polyglycidyl ether such as EPOLIGHT 100MF (manufactured by Kyoei Oil & Fat Chemicals Co., Ltd.) or EPIOL TMP (manufactured by Nippon Oil & Fats Co., Ltd.).

The crosslinking agent having an (alkoxy) melamine structure can be exemplified by, for example, hexamethylol melamine, hexahydroxybutyl melamine, partially methylolated melamine and its alkylate, tetramethylol benzoguanamine, partial hydroxy group. Methylated benzoguanamine and its alkylate.

The content of the crosslinking agent in the thermosetting resin composition is usually 1 to 1000 parts by weight, preferably 1 to 200 parts by weight, per 100 parts by weight of the above-mentioned binder resin.

Further, in order to strengthen the strength and suppress shrinkage during thermal curing, a filler may be contained in the adhesive layer.

Support film

The transfer film for forming an aluminum wiring of the present invention is formed by laminating (A) a photoresist layer on a support film, laminating (B) an aluminum layer on the (A) photoresist layer, and layering the (B) aluminum layer on the (A) photoresist layer. The (C) adhesive layer is formed.

The support film is preferably a flexible resin film having heat resistance and solvent resistance. By making the support film flexible, the paste composition can be applied by a roll coater, and can be stored and supplied in a roll-like state. The resin forming the support film can be exemplified by, for example, polyethylene terephthalate, polyester, polyethylene, polypropylene, polystyrene, polyimine, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride, etc. Resin, nylon, cellulose, etc. The thickness of the support film may be, for example, 20 to 100 μm. The surface of the support film is preferably subjected to release treatment. Thereby, the peeling operation of the support film can be easily performed in the transfer step.

Protective film

The transfer film for forming an aluminum wiring of the present invention can be provided with a protective film on the adhesive layer. As the protective film, for example, polyethylene terephthalate, a polyethylene film, a polyvinyl chloride film or the like can be exemplified.

Method for producing transfer film for forming aluminum wiring

The transfer film for forming an aluminum wiring of the present invention can be produced, for example, as follows.

Formation of photoresist layer

The paste-like photoresist composition is kneaded by mixing the above components contained in the photoresist layer, and is applied onto a support film to form a photoresist layer. The method of applying the photoresist composition can be exemplified by various methods such as screen printing, roll coating, spin coating, and casting coating. After coating, the composition can be dried as needed.

Formation of aluminum layer

A method of forming an aluminum layer on the photoresist layer can be exemplified by a method of laminating a metal foil such as an aluminum foil on a photoresist layer.

Adhesive layer formation

The adhesive layer is formed by coating on the above aluminum layer. The method of applying the adhesive layer is preferably to form a coating film having a large film thickness excellent in film thickness uniformity, specifically, a method of coating by a roll, a coating method by a squeegee, and a curtain type. A method of coating, a method of coating by a metal wire, and the like.

Subsequently, the aluminum wiring forming transfer film is dried as needed. The drying temperature is usually 50 to 150 ° C, and the drying time is usually 0.5 to 30 minutes.

<Aluminum wiring forming method>

The aluminum wiring forming method of the present invention comprises a lamination step (i) of sequentially laminating (C) an adhesive layer, (B) an aluminum layer, and (A) a photoresist layer forming laminate on a substrate, and exposing the laminate Processing, exposing step (ii) of forming a latent image of the photoresist pattern on the (A) photoresist layer, subjecting the laminate subjected to the exposure step to development processing, and performing light on the (A) photoresist layer The resisting step (iii) of the resist pattern is developed, and the laminate subjected to the above-described developing step is subjected to an etching treatment to form an etching step (iv) of the aluminum wiring corresponding to the aluminum layer of the photoresist pattern.

(i) lamination step

The laminating step is a step of laminating (B) an aluminum layer on the (C) adhesive layer, and laminating (A) the photoresist layer on the (B) aluminum layer in this order to form a laminate on the substrate.

The substrate is not particularly limited, and a glass substrate, a plastic substrate, or the like can be used depending on the application. Further, the surface of the substrate may be subjected to a treatment such as a drug treatment such as a decane coupling agent, a plasma treatment, an ion plating method, a sputtering method, a gas phase reaction method, or a vacuum vapor deposition method before the film formation treatment.

The method for forming the above-mentioned laminate can be exemplified by, for example, a method of transferring the (A) photoresist layer, (B) aluminum layer, and (C) adhesive layer onto a glass substrate using the transfer film for forming an aluminum wiring of the present invention. .

Here, the transfer conditions are, for example, a surface temperature of the heating roll of 40 to 140 ° C, a roll pressure of the heating roll of 0.1 to 10 kg/cm ² , and a moving speed of the heating roll of 0.1 to 10 m/min. These operations (transfer steps) can be performed by a laminating device. Moreover, the substrate may be preheated, and the preheating temperature may be, for example, 40 to 140 °C.

Further, a transfer film for forming an aluminum wiring having one or two layers of (A) a photoresist layer, (B) an aluminum layer, and (C) an adhesive layer may be used, and these may be sequentially transferred onto a glass substrate. Alternatively, in the same manner as the method for producing a transfer film for forming an aluminum wiring according to the present invention, an adhesive composition may be applied onto the substrate, dried to form an adhesive layer, and a metal foil may be laminated thereon and then coated thereon. The photoresist composition is dried to form a photoresist layer.

(ii) Exposure step

The latent image of the aluminum wiring is formed on the photoresist layer by a method of selectively irradiating (exposure) ultraviolet rays or the like on the surface of the photoresist layer by exposure to a photomask, or by scanning laser light.

The radiation irradiation apparatus can use an ultraviolet irradiation apparatus generally used in the lithography method, an exposure apparatus, a laser apparatus, and the like used in the manufacture of a semiconductor or a liquid crystal display device, and is not limited to a particular one.

(iii) imaging steps

The laminate is subjected to development processing to visualize the photoresist pattern on the photoresist layer.

The development processing conditions are not particularly limited, and the type, composition, concentration, development time, development temperature, and development method (for example, dipping method, vibration method, and rinsing method) of the developing solution can be appropriately selected depending on the type of the photoresist layer. Method, spray method, paddle method, etc.), developing device, etc.

Imaging liquid

The developing solution used in the developing step of the production method of the present invention is preferably an alkali developing solution.

The active ingredient of the alkali developing solution can be exemplified by, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium hydrogen phosphate, diammonium hydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, ammonium dihydrogen phosphate, dihydrogen phosphate. Inorganic basic compound such as potassium, sodium dihydrogen phosphate, lithium niobate, sodium citrate, potassium citrate, lithium carbonate, sodium carbonate, potassium carbonate, lithium borate, sodium borate, potassium borate, ammonia, etc.; tetramethylammonium hydroxide An organic basic compound such as trimethylhydroxyethylammonium hydroxide, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine or ethanolamine.

The alkali developing solution can be prepared by dissolving one or two or more of the above basic compounds in water or the like. The concentration of the basic compound in the alkaline developing solution is usually 0.001 to 10% by mass. After the alkali imaging solution is developed, it is usually subjected to a water washing treatment, and the development temperature is usually 20 to 50 °C.

(iv) etching step

The laminate subjected to the above-described developing step is subjected to an etching treatment to dissolve and remove unnecessary portions of the aluminum layer, thereby forming an aluminum wiring corresponding to the aluminum pattern of the photoresist pattern.

The etching treatment conditions are not particularly limited, and the type, composition, concentration, treatment time, treatment temperature, and treatment method (for example, dipping method, shaking method, rinsing method, spray method, etc.) of the etching liquid can be appropriately selected depending on the type of the aluminum layer. Blade method), processing device, and the like.

Etching treatment method

In the etching treatment method of the present invention, a dipping method in which the above laminate is immersed in an etching liquid can be used. The type of the etching liquid used in the immersion method is not particularly limited as long as it can etch the metal forming the aluminum layer, but an acidic aqueous solution or an alkaline aqueous solution can be used, for example. As the acidic aqueous solution, nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, and a mixed aqueous solution thereof can be used. The alkaline aqueous solution can be used in the same manner as the above-described alkali developing solution. The concentration may be, for example, 0.01 to 10% by mass. Further, the immersion temperature in the etching liquid may be, for example, 20 to 50 ° C, and the immersion time may be, for example, 1 to 60 minutes.

As for the etching liquid, if the type of the photoresist layer can be selected in the same manner as the developing solution used in the developing step, the developing step and the etching step can be continuously performed in the same step, which can be simplified by the steps. And to achieve an increase in manufacturing efficiency. When an alkali-soluble resin is used for the binder resin to be added to the photoresist layer, the developing solution and the etching solution can be made into the same alkaline solution, whereby the development step and the etching step can be carried out in the same step. In this case, for the above reasons, it is preferred to immerse the laminate in a solution which is an etching liquid and is a developing liquid, and to perform a developing step and an etching step.

Photoresist hardening

Further, in the present invention, there is a phenomenon in which the photoresist layer is peeled off from the aluminum layer in the etching step. In order to prevent this, it is effective to cure the photoresist layer and carry out the subsequent treatment of the strong photoresist layer and the aluminum layer. As a method of hardening the photoresist layer, for example, heat curing of the laminate to heat the photoresist layer, exposure curing of the laminate to expose the photoresist layer, and the like can be exemplified. That is, in the present invention, it is preferable to perform the heat hardening step before the exposure step after the exposure latent image forming step, or before the etching step after the developing step, or the exposure hardening step before the etching step after the developing step.

The temperature at the time of heat hardening is usually 100 to 300 ° C, preferably 120 to 220 ° C. The hardening time is 2 to 60 minutes.

When exposure hardening is performed, it is preferred to irradiate (exposure) radiation such as ultraviolet rays. As for the radiation irradiation device, the same device as the user in the above exposure step can be used.

The method of hardening the photoresist layer is more effective in preventing the photoresist layer from being peeled off from the aluminum layer, and is preferably cured by heat.

(v) other steps

For the aluminum wiring obtained in the above etching step, the peeling of the photoresist layer and the hardening of the adhesive layer may be performed as needed.

As for the peeling method of the photoresist, it can be appropriately selected by ashing with ozone or plasma, and stripped with an alkaline aqueous solution such as sodium hydroxide solution or sodium carbonate solution, and monoethanolamine, dimethyl hydrazine, and N-methyl group. The organic solvent such as the pyrrolidone solution is peeled off.

When the thermosetting resin is used on the adhesive layer, the adhesive layer is hardened.

The curing conditions are preferably carried out under heating under the characteristics of the thermosetting resin of the adhesive layer, but it is usually from 100 to 300 ° C, preferably from 180 to 300 ° C. The hardening time is 30 to 120 minutes. The heating method can appropriately select a heating plate, an oven, or the like.

By curing the adhesive layer, the chemical resistance or the durability due to thermal cycling or the like can be improved, and the reliability of the formed aluminum wiring can be improved.

Use of aluminum wiring

In the present invention, aluminum wiring can be formed using a plating process other than the conventional plating method or a vapor deposition method or a sputtering method in a vacuum process. Further, a thick film can be easily formed on the aluminum wiring, and an aluminum wiring excellent in electrical characteristics and smoothness can be obtained. The use of the aluminum wiring obtained by the present invention can be exemplified by aluminum wiring or a reflecting plate of a printed circuit board, a multilayer circuit board, a polycrystalline module, an LSI, and a flat panel display.

[Examples]

The embodiments of the present invention are described below, but the present invention is not limited thereto. In addition, the following "parts" means "parts by mass". Further, each evaluation method in the examples will be described below.

[Molecular weight of alkali-soluble resin]

The weight average molecular weight converted to polystyrene was measured by a gel permeation chromatography (GPC) (trade name: HLC-802A) manufactured by Tosoh Corporation.

<Example 1> (1) Production of transfer film for forming aluminum wiring

100 parts of benzyl methacrylate/cyclohexyl methacrylate/methacrylic acid=50/35/15 (% by mass) copolymer (Mw=30,000) was used as the alkali-soluble resin, and 33.3 parts of polypropylene glycol acrylate (n) ≒12, "M270" made by East Asia Synthetic as a photosensitive monomer, and 16.6 parts of trimethylolpropane EO modified triacrylate (n≒2, "M360" manufactured by Toagosei), and 15 parts 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butan-1-one ("IRG369" manufactured by Kabate Chemicals Co., Ltd.) as a photopolymerization initiator After the kneading in the stirring and defoaming device, the photoresist composition was prepared by dispersing in three rolls, and a support film composed of a polyethylene terephthalate film (width 200 mm) by a doctor blade applicator. The photoresist composition was coated on a length of 30 m and a thickness of 38 μm to form a photoresist layer having a thickness of 10 μm.

An aluminum foil having a thickness of 12 μm was laminated on the photoresist layer to form an aluminum layer having a thickness of 12 μm.

100 parts of n-butyl methacrylate / benzyl methacrylate = 30 / 70 (% by mass) copolymer (Mw = 100,000), 50 parts of dipentaerythritol hexaacrylate as a crosslinking agent, and 40 parts of methoxypropyl acetate as a solvent were prepared by kneading in a stirring and defoaming apparatus, and then dispersing by three rolls to prepare an adhesive composition. The adhesive composition was applied onto an aluminum layer by a blade coater to form an adhesive layer having a thickness of 5 μm.

A transfer film for forming an aluminum wiring was produced as described above.

(2) Formation of aluminum wiring (i) lamination step

The transfer film for forming an aluminum wiring is transferred onto a substrate having a surface roughness Ra of about 5,000 angstroms, and a laminate in which an adhesive layer, an aluminum layer, and a photoresist layer are laminated in this order is formed on the substrate.

(ii) exposure latent image forming step

With respect to the above-mentioned laminated photoresist layer, a long negative-type exposure mask having a line width of 60 μm and a space width of 60 μm is used to irradiate an i-line (ultraviolet light having a wavelength of 365 nm) with an ultrahigh pressure mercury lamp, and the exposure amount is 365 nm. The laser measurement was converted into an illuminance of 200 mJ/cm ² .

(iii) imaging steps

The aqueous solution of 0.3% by mass of sodium carbonate having a liquid temperature of 30 ° C was used as a developing solution, and the laminate subjected to the exposure latent image forming step was subjected to development treatment for 60 seconds by a showering method, followed by washing with ultrapure water.

(iv) etching step

The laminate subjected to the above heat curing step was immersed in an etching solution having a liquid temperature of 25 ° C and a 4 mass % sodium hydroxide aqueous solution for 20 minutes to form an aluminum wiring.

(3) Evaluation of the obtained aluminum wiring

The obtained aluminum foil aluminum wiring had a low electrical resistivity of 3.2 μΩ·cm, and it was confirmed that the surface was glossy and the surface smoothness was good.

<Example 2>

A transfer film for forming an aluminum wiring was produced in the same manner as in Example 1 except that the adhesive composition was changed to the following.

50 parts of EPICOTE 1004 (Mw=1600, made by oily clamshell epoxy) and 50 parts of glycidyl methacrylate/acrylonitrile/methyl methacrylate = 50 parts of epoxy resin as thermosetting resin The /20/30 (% by mass) copolymer (Mw = 110,000) was dissolved in 50 parts of butyl ketone acetate to form a uniform resin solution. Subsequently, 5 parts of an imidazole-based compound of 2P4MHZ (manufactured by Shikoku Chemicals Co., Ltd.) was added as an epoxy hardener to obtain an adhesive composition.

An aluminum wiring was formed as in the first embodiment using the above-described film for forming an aluminum wiring. The obtained aluminum foil aluminum wiring had a low electrical resistivity of 3.2 μΩ·cm, and it was confirmed that the surface was glossy and the surface smoothness was good.

<Comparative Example 1> (1) Forming a metal film by evaporation

A substrate having the same surface roughness as that of the users of Examples 1 and 2 was placed in a vacuum vapor deposition machine, and a vapor deposition material Al was used to evacuate to 10 ^-4 torr to form an Al vapor-deposited film of 2 μm. Since it was directly vapor-deposited on the substrate with poor smoothness, there was a portion which was not vapor-deposited, and the surface was dull, and it was confirmed that the surface smoothness was inferior.

On the above-mentioned metal film formed by vapor deposition, the same photoresist composition as in Example 1 was applied by a doctor blade to form a photoresist layer having a thickness of 10 μm. Subsequently, exposure, development, and etching were carried out in the same manner as in Example 1 to obtain an aluminum wiring.

The obtained aluminum wiring was observed to be defective, and it was dull, and the surface smoothness was in a bad state.

<Comparative Example 2> (1) Forming a metal film with an aluminum paste

100 parts of flake aluminum powder, 20 parts of n-butyl methacrylate / 2-ethylhexyl methacrylate = 40/60 (% by mass) copolymer (Mw = 100,000), 10 parts as a binder resin The mixture of dipentaerythritol hexaacrylate and 10 parts of terpineol as a solvent was kneaded by a stirring and defoaming device, and then dispersed in three rolls to prepare an aluminum paste composition. The obtained aluminum paste was applied onto a substrate having the same degree of surface roughness as that of the users of Examples 1 and 2 by a blade coater, and dried at 100 ° C for 10 minutes. Subsequently, post-baking was carried out at 280 ° C for 30 minutes to obtain a metal film having a film thickness of 10 μm. The resistivity measurement result was a value of 100 μΩ·‧ cm or more, which was a result of poor conductivity.

Claims (6)

A transfer film for forming an aluminum wiring, characterized in that (A) a photoresist layer, (B) an aluminum layer, and (C) an adhesive layer are sequentially laminated on a support film. The transfer film for forming an aluminum wiring according to the first aspect of the invention, wherein the (B) aluminum layer is formed of an aluminum foil. The transfer film for forming an aluminum wiring according to the first aspect of the invention, wherein the (C) adhesive layer is a thermosetting resin composition. The transfer film for forming an aluminum wiring according to the first aspect of the invention, wherein the (B) aluminum layer has a thickness of 1 to 20 μm. The transfer film for forming an aluminum wiring according to the first aspect of the patent application is used for a flat panel display. A method for forming an aluminum wiring, comprising: (A) photoresist after bonding an adhesive layer of a transfer film for forming an aluminum wiring according to claim 1 of the invention to a substrate The layer composed of the layer, the (B) aluminum layer and the (C) adhesive layer is transferred onto the substrate to form a laminate of the (C) adhesive layer, the (B) aluminum layer, and the (A) photoresist layer. a step of exposing the (A) photoresist layer constituting the laminate to form a latent image of a resist pattern; and subjecting the (A) photoresist layer to development processing to visualize the photoresist pattern And the step of etching the aluminum layer (B) to form an aluminum wiring corresponding to the photoresist pattern, wherein The (A) photoresist layer has a thickness of 0.1 to 40 μm, the (B) aluminum layer has a thickness of 1 to 20 μm, and the photoresist layer contains a photosensitive monomer, a photopolymerization initiator, and a binder resin, and the above-mentioned photosensitivity. The content ratio of the monomer is 5 to 200 parts by mass based on 100 parts by mass of the binder resin, and the content ratio of the photopolymerization initiator is 1 to 100 parts by mass based on 100 parts by mass of the photosensitive monomer.