JP4477077B2 - Method for exposing photosensitive resin layer - Google Patents

Description

  The present invention relates to a method for exposing a photosensitive resin laminate, and a method for manufacturing a printed wiring board, a TAB substrate, a flexible wiring board, and a lead frame having a metal wiring pattern using the same.

  In recent years, with the progress of miniaturization and high-density mounting of electronic devices toward an advanced information society, circuit miniaturization is also required for printed wiring boards, TAB boards, flexible wiring boards, and the like having metal wiring patterns.

  Printed wiring boards have been rapidly developed mainly for applications such as personal computers and mobile phones. The wiring density of printed wiring boards has increased dramatically, and there is a tendency toward multilayering and finer processing. Recently, a printed wiring board has been attracting attention as a package substrate such as an LSI, which has been expanded to be used for BGA / CSP.

  Until now, TAB substrates have been developed both technically and quantitatively, mainly for LCD (liquid crystal) driver IC applications. Recently, with the change in package technology corresponding to the progress of higher integration, higher pin count and higher speed of LSI, especially the practical use of area array type packages such as BGA, CSP, etc. It has come to occupy an important position as one of packaging materials because of its excellent features such as light weight and large design freedom.

  Chip-on-film mounting, centering on flexible wiring boards, has recently attracted a great deal of attention as it has been adopted as a driver mounting method for mobile phones.

  As an LSI mounting form, a lead frame in which leads are provided on four sides of the package is used as a terminal-type mounting QFP (Quad Flat Package) form.

  Conventionally, as a manufacturing method of a TAB substrate and a flexible wiring board, a positive liquid photoresist is applied on a TAB tape as a base material or a copper foil of a flexible base material, dried, then exposed and developed. A method of forming a metal wiring pattern by forming a resist pattern on a substrate and then peeling off the resist pattern after etching, and optionally plating, has been used. Similarly, positive liquid photoresists have been used in the manufacture of lead frames.

  However, it is difficult to apply a liquid photoresist with a uniform film thickness on a substrate, curing shrinkage occurs depending on drying conditions after application, and the film thickness is reduced from a desired set film thickness. There is a problem that film loss occurs. When such a liquid photoresist with a non-uniform film thickness or a liquid photoresist with reduced film thickness is exposed and developed as it is, cracks are generated in the resulting resist pattern, which is obtained through the subsequent etching process or plating process. It becomes a defect of the formed metal wiring pattern.

  Further, when handling a liquid photoresist, skilled techniques such as viscosity adjustment with respect to environmental changes such as season, room temperature, and humidity are required. Furthermore, since it contains an organic solvent having a high boiling point, the drying time after coating on the substrate is long, and the reduction in productivity has been a problem.

Recently, in order to solve the problems of the above liquid photoresist, a photosensitive resin laminate comprising a support, a photosensitive resin layer, and a protective layer has been used. Since the photosensitive resin laminate can be made as thin as a liquid photoresist, it has the performance to satisfy the resolution and adhesion required for high density and multi-layer metal wiring patterns. It is because it came to have.
The metal wiring pattern forming method using the photosensitive resin layer laminate has come to be used for manufacturing a TAB substrate, a flexible wiring board, a lead frame and the like in addition to the conventional manufacturing of a printed wiring board.

  As a method for producing a photosensitive resin laminate, a photosensitive resin composition is applied onto a support such as light-transmitting polyester and dried, and a protective layer such as polyethylene is laminated on the dried photosensitive resin layer. The method of making it is common.

  When using a photosensitive resin laminate for forming a metal wiring pattern, first the protective layer is peeled off, and then the photosensitive resin layer is thermocompression-bonded to the surface of the base material on which a desired pattern is to be formed, via a photomask. In general, a method of forming an image of a resist pattern by irradiating (exposure) actinic rays, spraying an alkaline aqueous solution or an organic solvent, dissolving and removing unexposed portions, washing with water and drying.

In a method for forming a metal wiring pattern using a photosensitive resin laminate, various attempts have been made to achieve high resolution of the metal wiring pattern.
For example, there is a method in which the support is peeled off before exposure and a photomask is adhered directly on the photosensitive resin layer. Usually, since the photosensitive resin layer has a certain degree of adhesion so that it is in close contact with the substrate, the photomask and the photosensitive resin composition layer are in close contact with each other, and the photomask is difficult to peel off. There have been problems such as a decrease in property and an increase in defects due to contamination of the mask due to adhesion of the composition layer.

As an attempt to increase the compositional resolution, a combination of a compound having two or more phenolic hydroxyl groups on one benzene ring and a specific urethane type monomer as shown in Patent Document 1 is performed. However, the resolution improvement effect is not sufficient, and there is a drawback in that the sensitivity is lowered. As further miniaturization progresses, not only the resolution but also the side surface of the resist pattern (hereinafter referred to as side wall) is not rugged, and the metal wiring pattern is free from defects such as chipping, disconnection, and short circuit. .
JP 2000-162767 A

  The object of the present invention is that the resolution of the cured resist pattern after exposing and developing the photosensitive resin layer is highly excellent, and there is little wobbling of the sidewall, resulting in the metal in the subsequent etching process and plating process. An object of the present invention is to provide an exposure method in the production process of a printed wiring board or the like with few defects such as chipping, disconnection, and short circuit.

As a result of intensive studies to solve the problems in the previous period, the present inventors have used an exposure method in which an image of a photomask is projected through a lens after the support is peeled off before exposure in the exposure process. The inventors have found that the above-described problems can be sufficiently solved, and have completed the present invention.
That is, the present invention is as follows.

(1) A support (A), a negative photosensitive resin layer (B) having a thickness of 1 to 35 μm, and a protective layer on a metal-coated insulating plate having a metal conductor layer on one side or both sides. The photosensitive resin laminate having (C) is laminated so that the negative photosensitive resin layer (B) is in close contact with the metal-coated surface of the metal-coated insulating plate, and when exposed to ultraviolet rays through a photomask, A negative photosensitive resin layer (B) is formed by projecting an image of a photomask through a lens after the support is peeled off before , (a) a thermoplastic polymer binder, (b) molecules 2,2-bis {(4-acryloxypolyethoxy) phenyl} propane having a total number of ethylene glycol units of 2 to 20 as a photopolymerizable monomer having at least one polymerizable ethylenically unsaturated group therein Or 2,2 Bis {(4-methacryloxy polyethoxy) phenyl} propane, as (c) a photopolymerization initiator, to the photosensitive resin layer, characterized in that it contains 2,4,5-triaryl imidazole dimer Exposure method.
(2) The exposure method as described in (1) above, wherein the protective layer (C) is a film having a center line average roughness of less than 0.1 μm .
(3) Following the exposure method described in (1) or (2) above, a cured resist pattern is formed by developing with an aqueous alkali solution, and the metal on the metal-coated surface not covered with the resist pattern is removed with an etching solution. Or metal plating is performed on a metal-coated surface that is not covered with a resist pattern.
(4) While removing the protective layer (C), the negative photosensitive resin layer (B) is laminated so that the negative photosensitive resin layer (B) is in close contact with the metal coated surface of the metal coated insulating plate, and the negative photosensitive resin layer is The method for producing a metal wiring pattern according to the above (3), wherein lamination is performed so as to adhere.

By using the exposure method of the present invention for the production of printed wiring boards, flexible printed wiring boards, TAB tapes, lead frames and the like, the resolution of the cured resist pattern after exposing and developing the photosensitive resin layer is highly superior, Further, since the side wall is less rugged, defects such as chipping, disconnection, and short circuit of a circuit formed in the subsequent etching process or plating process can be reduced.
Further, when a photosensitive resin laminate having an appropriate composition is combined with the exposure method of the present invention, the effects of further improving the resolution and improving the adhesion can be obtained.

The present invention is described in detail below.
The steps in the method for producing a printed wiring board or the like using the photosensitive resin laminate using the exposure method of the present invention will be described in order.

The production process of a printed wiring board or the like performed using the exposure method of the present invention usually comprises the following steps (1) to (5).
(1) Laminating step: While peeling off the protective layer of the photosensitive resin laminate, the photosensitive resin laminate is coated with a metal coating such as a film-like substrate in which the negative photosensitive resin layer has a copper-clad laminate or a conductor layer. A hot roll laminator is used for thermocompression bonding so as to be in close contact with the metal-coated surface of the insulating plate.
(2) Exposure step: After the support is peeled off before exposure, an image of a photomask is projected through a lens for exposure.
(3) Development step: An unexposed portion of the negative photosensitive resin layer is dissolved or dispersed and removed using an alkaline developer to form a cured resist pattern on the substrate.
(4) Circuit forming step: Etching a copper surface not covered with a resist pattern using an etching solution from above the formed cured resist pattern, or copper, solder, nickel and copper surface not covered with a resist pattern A tin plating process is performed.
(5) Stripping step: The cured resist pattern is removed from the metal-coated insulating plate using an alkali stripping solution.

  In the conventional exposure method in the production process of a printed wiring board, a photomask having a desired wiring pattern is brought into close contact with a support and exposed using an ultraviolet light source. It is characterized in that after peeling off, an image of a photomask is projected through a lens and exposed.

  As in the present invention, by using an exposure method in which a support is peeled off before exposure and a photomask image is projected through a lens, the resolution of the cured resist pattern after development is excellent, and the side walls of the cured resist As a result, there is an effect that the metal wiring pattern after etching or plating becomes a good shape.

  The support may be peeled off several hours before exposure or may be peeled off immediately before. When the support is peeled off, it is preferable that the exposure is performed within 15 minutes after peeling because the surrounding dust tends to adhere.

  Examples of the ultraviolet light source used in the exposure process include a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, and a xenon lamp. In order to obtain a finer resist pattern, it is preferable to use a parallel light source.

  As the alkaline aqueous solution used in the step (3), an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or the like is used. In general, a 0.2 to 2% by weight aqueous sodium carbonate solution is used. In order to improve the resolution, an aqueous sodium carbonate solution of 0.2 to 0.6% by mass is preferably used.

  In the (5) stripping step, the resist pattern is stripped by using an alkaline aqueous solution that is stronger than the alkaline aqueous solution used in the development. In general, 1 to 5% by mass of sodium hydroxide, potassium hydroxide or an aqueous solution of amine is used.

  Examples of the metal-coated insulating plate having a metal conductor layer on one side or both sides in the present invention include a copper-clad laminate in which a copper foil is bonded to a glass epoxy substrate and a film-like substrate having a conductor layer.

  A film-like substrate having a conductor layer has a conductor layer made of copper, gold, silver, aluminum or the like on a film-like insulating resin layer. For example, a polyimide film or a polyester film, or a copper resin on an insulating resin layer such as a BT resin. Examples include a flexible base material with a foil and a TAB tape. The thickness of the insulating resin layer of the flexible substrate is generally 30 to 150 μm when there is an adhesive layer between the insulating resin layer and the copper foil, and 12.5 to 125 μm when there is no adhesive layer. Is common. The thickness of the copper foil is usually 9 to 18 μm, and the thickness tends to be thinner. As for the width | variety of a flexible base material, 200-300 mm is common.

  The TAB tape includes a two-layer type in which a copper foil is formed on an insulating resin layer and a three-layer type in which a copper foil is formed on an insulating resin layer via an adhesive layer. The thickness of the insulating resin layer of the TAB tape or the total thickness of the insulating resin layer and the adhesive layer is usually 75 to 125 μm. Moreover, 9-18 micrometers is the mainstream of the thickness of copper foil, The thickness tends to become thinner. The width of the TAB tape is standardized according to its use, but there are 35, 48, 70, 96, and 105 mm. Recently, there is also a wider 158 mm width.

Hereinafter, the photosensitive resin laminate used in the present invention will be described in detail.
The photosensitive resin laminate includes a support (A) and a negative photosensitive resin layer (B), and further includes a protective layer (C).
The photosensitive resin laminate comprising the support (A), the negative photosensitive resin layer (B) and the protective layer (C) is prepared by using the photosensitive resin composition used for the negative photosensitive resin layer (B). It is mixed with the solvent to be dissolved to make a uniform solution, coated on the support (A) using a bar coater or roll coater and dried, and then a negative comprising the photosensitive resin composition on the support (A). It is obtained by laminating a type photosensitive resin layer (B) and laminating a protective layer (C) thereon.

  The support (A) is only required to be able to laminate a photosensitive resin layer. For example, polyethylene terephthalate film, polyethylene naphthalate, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride Examples include a polymer film, a polymethyl methacrylate copolymer film, a polystyrene film, a polyacrylonitrile film, a styrene copolymer film, a polyamide film, and a cellulose derivative film.

  Since the support (A) is peeled off before exposure, it need not have a property of transmitting light. The thickness of the support (A) is preferably 10 to 30 μm, more preferably 12 to 20 μm. When the film thickness of the support (A) is less than 10 μm, the film is too soft and inconvenient to handle.

  The negative photosensitive resin layer (B) is formed of a negative photosensitive resin composition. As the negative photosensitive resin composition, known ones can be used. For example, a water-soluble photopolymer obtained by adding a photosensitive material such as ammonium dichromate to a polymer such as fish glue, polyvinyl alcohol, shellac, or casein. Resist, polyvinyl cinnamate, oil-soluble photoresist combining cyclized rubber with azide, and the like.

Among the negative photosensitive resin compositions, those containing a thermoplastic polymer binder for forming a film are preferably used.
The most preferred negative photosensitive resin layer (B) is (a) a thermoplastic polymer binder, (b) a photopolymerizable monomer having at least one polymerizable ethylenically unsaturated group in the molecule, (c) It comprises a photopolymerizable initiator. Further, (d) a hindered phenol compound may be included.

As the (a) thermoplastic polymer binder of the negative photosensitive resin layer (B), a high molecular weight polymer having an α, β-unsaturated ethylenic monomer unit is used. Examples of the monomer constituting the α, β-unsaturated ethylenic monomer unit include styrenes such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyl chloride, bromide. Vinyl halides such as vinyl, vinyl esters such as vinyl acetate and vinyl propionate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, ( (Meth) acrylic acid isobutyl, (meth) acrylic acid 2-ethylhexyl, α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl methacrylate, (meth) acrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, Vinyl ethers such as vinyl methyl ether and vinyl ethyl ether It is.
These monomers may be used alone or in combination of two or more.

The content of (a) the thermoplastic polymer binder is 100 parts by mass with respect to the total amount of (a) the thermoplastic polymer binder component and (b) the photopolymerizable monomer component of the negative photosensitive resin layer (B). 10 to 90 parts by mass, preferably 30 to 70 parts by mass. Cold flow resistance falls that it is less than 10 mass parts. If it exceeds 70 parts by mass, the photosensitive resin layer becomes brittle.
In particular, for an alkali-soluble thermoplastic polymer binder, a monomer containing a carboxyl group, such as (meth) acrylic acid, fumaric acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester At least one selected from the above is used in combination.

  The content of the carboxyl group contained in such an alkali-soluble thermoplastic polymer binder is a carboxyl group equivalent and is usually selected in the range of 100 to 600, preferably 200 to 450. Here, the carboxyl group equivalent means the gram weight including 1 equivalent of carboxyl group. The carboxyl group equivalent is measured by potentiometric titration with a 0.1 mol / L sodium hydroxide aqueous solution.

  Further, the alkali-soluble thermoplastic polymer binder has a weight average molecular weight of usually 5,000 to 500,000, preferably 20,000 to 400,000. The molecular weight is measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

As the photopolymerizable monomer having at least one polymerizable ethylenically unsaturated group in the molecule (b) of the negative photosensitive resin layer (B), one or more photopolymerizable monomers are used.
Examples of such a photopolymerizable monomer include 2-hydroxy-3-phenoxypropyl acrylate, phenoxytetraethylene glycol acrylate, a half esterified product of phthalic anhydride and 2-hydroxypropyl acrylate, and a reaction product of propylene oxide ( OE-A200 manufactured by Nippon Shokubai Chemical Co., Ltd., 4-normal octylphenoxypentapropylene glycol acrylate, 1,4-tetramethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexane Diol di (meth) acrylate, octapropylene glycol di (meth) acrylate, 2-di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, dipentaene Thritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide modified tri (meth) acrylate of isocyanuric acid, diallyl phthalate A polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bis ( And polyethylene glycol (meth) acrylate) polypropylene glycol. Moreover, the urethanation reaction material of polyvalent isocyanate compounds, such as hexamethylene diisocyanate and tolylene diisocyanate, and hydroxyacrylate compounds, such as 2-hydroxypropyl (meth) acrylate, etc. are mentioned.

  (B) As the photopolymerizable monomer component having at least one polymerizable ethylenically unsaturated group in the molecule, 2,2-bis {(4-acrylic acid) having 2 to 20 ethylene glycol repeating units in total. Roxypolyethoxy) phenyl} propane or 2,2-bis {(4-methacryloxypolyethoxy) phenyl} propane is preferably included. More preferably, (b) 2,2-bis {(4-acryloxypolyethoxy) phenyl} propane, or 2,2-bis {(, wherein the polymerizable monomer has 4 to 15 ethylene glycol repeating units in total. 4-methacryloxypolyethoxy) phenyl} propane. When this photopolymerizable monomer is used, the resolution of the photosensitive resin layer is improved and the adhesion to the substrate is excellent.

  The content of the component (b) is preferably 10 to 90 parts by mass of the component (b) with respect to 100 parts by mass of the total amount of the components (a) and (b) of the negative photosensitive resin layer (B). More preferably, 30 to 70 parts by mass are used. When the component (b) is less than 10 parts by mass, the photocured film becomes brittle, the adhesiveness of the photosensitive resin layer is lowered, and when the amount is more than 90 parts by mass, the storage stability of the photosensitive resin layer is reduced. However, the resolution of the photosensitive resin layer tends to decrease.

  As the photopolymerizable initiator (c) in the negative photosensitive resin layer (B), 2,4,5-triarylimidazole dimer is preferably used. The total amount of component (a) and component (b) in the negative photosensitive resin layer (B) is preferably from 0.01 to 15 parts by mass, more preferably from 0.1 to 10 parts by mass, based on 100 parts by mass. It is done. When the blending amount is less than 0.01 parts by mass, the resolution and adhesion are deteriorated, and when the blending amount is more than 15 parts by mass, the cost is high, and trouble that precipitates in the alkaline developer occurs, and the sensitivity is high. However, it tends to be covered and tends to deteriorate the resolution.

  Examples of 2,4,5-triarylimidazole dimer include 2- (o-chlorophenyl) -4 · 5-diphenylimidazolyl dimer, 2- (o-chlorophenyl) -4 · 5-bis- (m- Methoxyphenyl) imidazolyl dimer, 2- (p-methoxyphenyl) -4 · 5-diphenylimidazolyl dimer, and the like are used.

  In addition to the above photopolymerizable initiator, another photopolymerizable initiator can be added. Specific examples include benzyldimethyl ketal, benzyl diethyl ketal, benzyl dipropyl ketal, benzyl diphenyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin pyropyr ether, benzoin phenyl ether, benzophenone, 9-phenylacridine and other acridines, α , Α-dimethoxy-α-morpholino-methylthiophenylacetophenone, 2,4,6-trimethylbenzoyl phosphine oxide, phenylglycine, and 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 2,3 There are oxime esters such as ethyl dioxo-3-phenylpropionate-2- (o-benzoylcarbonyl) -oxime.

  The negative photosensitive resin layer (B) may contain (d) a hindered phenol compound, and the total amount of the component (a) and the component (b) in the negative photosensitive resin layer (B) is 100 mass. 0.01 to 5 parts by mass, preferably 0.02 to 2 parts by mass with respect to parts. If the blending amount is less than 0.01, the effect on the resolution is small. If the blending amount is more than 5 parts by mass, the sensitivity tends to decrease, and the resolution and adhesion tend to decrease.

  Examples of the hindered phenol compound include pentaerythrityl tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate} (IRGANOX (registered trademark) 1010 manufactured by Ciba Geigy Japan), triethylene glycol- Bis {3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate} (IRGANOX (registered trademark) 245 manufactured by Ciba Geigy Japan), octadecyl-3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate (IRGANOX (registered trademark) 1076 manufactured by Ciba-Geigy Japan).

  Additives such as radical polymerization inhibitors, plasticizers, ordinary dyes and pigments to improve thermal stability and storage stability, as needed, to the negative photosensitive resin layer (B) Can do.

  Examples of the radical polymerization inhibitor include p-methoxyphenol, hydroquinone, pyrogallol naphthylamine cuprous chloride and the like, and examples of the plasticizer include phthalate compounds such as diethyl phthalate and diphenyl phthalate, p- Examples thereof include sulfonamide compounds such as toluenesulfonamide, petroleum resins, rosin, and ethylene glycol-propylene glycol block copolymers.

  Examples of coloring substances such as ordinary dyes and pigments include fuchsin, auramin base, crystal violet, Victoria blue, malachite green, diamond green and the like. Examples of the coloring dye include tris (4-dimethylaminophenyl) methane {leuco crystal violet} and tris (4-diethylamino 2-methylphenyl) methane {leucomalachite green}.

  As for the thickness after drying of a negative photosensitive resin layer (B), 1-35 micrometers is preferable, More preferably, it is 3-25 micrometers. When the thickness of the negative photosensitive resin layer is less than 1 μm, film-forming coating is difficult, and when the thickness exceeds 35 μm, the resolution and adhesion tend to decrease.

  The protective layer (C) usually has a thickness of 30 to 50 μm, preferably 35 to 45 μm. When the thickness of the protective layer (C) is in the range of 30 to 50 μm, the convex portions of the undissolved material of the protective layer raw material generated in the protective layer can be transferred to the photosensitive resin layer to form concave portions in the photosensitive resin layer. As a result, the occurrence of defects such as circuit overhang, disconnection, and short circuit is reduced.

The protective layer (C) is preferably a film having a center line average roughness (Ra) of less than 0.1 μm. When the center line average roughness (Ra) is 0.1 μm or more, sufficient adhesion between the photosensitive resin layer and the protective layer cannot be obtained, and air voids are easily generated. A more preferred centerline average roughness (Ra) is 0.85 μm or less.
In the surface roughness of the protective layer (C), the maximum height (Rmax) is preferably less than 10 μm. Here, the centerline surface roughness (Ra) and the maximum height (Rmax) refer to the centerline average roughness and the maximum height measured with an atomic force microscope.

  Specific examples of the protective layer (C) include polyolefin films such as polyethylene films and polypropylene films, polyester films, and polyester films whose peelability is improved by silicone treatment or alkyd treatment. A polyethylene film is preferably used.

Hereinafter, the present invention will be specifically described by way of examples.
First, the measuring method of the haze value of a support body and the centerline average roughness of a protective layer is demonstrated.
(I) Measurement of haze value of support The haze value is measured using COLOR MEASURING SYSTEM Σ80 (manufactured by Nippon Denshoku Industries Co., Ltd.). The haze value is a value representing turbidity. The haze value H = the total transmittance T irradiated through the lamp and transmitted through the sample and the transmittance D of light scattered in the sample. It is calculated as D / T × 100. These are defined by JIS K 7105 and can be easily measured by a commercially available turbidimeter.
(B) Measurement of the center line average roughness (Ra) of the protective layer Using an atomic force microscope EXPLORER SPM (manufactured by Thermo Microscopes), the measurement mode was set to Contact AFM with a Si ₃ N ₄ contact AFM probe. . The measurement area of 75 μm ² is reciprocated 300 times with a probe, and the center line average roughness (Ra) is measured.
Next, Table 1 shows the compositions of the photosensitive resin compositions used in Examples and Comparative Examples. In addition, Table 2 shows the constituent materials of the photosensitive resin composition represented by abbreviations (B-100 to D-21) in Table 1.

[Example 1, Reference Example 1 ]
Composition 1 (Example 1) and Composition 2 ( Reference Example 1 ) components shown in Table 1 above were mixed to prepare a photosensitive resin composition solution, and a polyethylene terephthalate film (AT301, 16 μm thickness, haze value 0.2) % (Actual value) (manufactured by Teijin DuPont Films)) and dried in a dryer at 90 ° C. for 1 minute to form a negative photosensitive resin layer having a thickness of 5 μm. A polyethylene film (T1-A742A, 35 μm thickness, Ra = 0.065 μm (actual value) (manufactured by Tamapoly Co.)) was laminated on the resin layer to obtain a photosensitive resin laminate.

Using an electrolytic copper foil flexible substrate (manufactured by Nikkan Kogyo Co., Ltd.) having a copper foil thickness of 12 μm, the photosensitive resin layer was peeled off with the hot roll laminator (Asahi Kasei, AL-700, Laminator) was used to laminate at a roll temperature of 105 ° C., a roll pressure of 0.35 MPa, and a laminating speed of 1 m / min.
The support was peeled off from the substrate having the support and the negative photosensitive resin layer, and placed on the substrate set stage of a projection exposure machine (UX-2023SM manufactured by USHIO INC.). A glass chrome photomask having a pattern capable of evaluating the following items was set on a mask holder of an exposure machine, and exposure was performed 10 minutes after peeling the support at an exposure amount of 100 mJ / cm ² through a projection lens.
A 0.4 mass% sodium carbonate aqueous solution was sprayed at 30 ° C. and a spray pressure of 0.15 MPa for 20 seconds to remove unexposed portions and develop.

[Comparative Example 1]
A photosensitive resin laminate was prepared in the same manner as in Examples 1 and 2 except that the two components shown in Table 1 were mixed, and the photosensitive resin laminate was laminated on a flexible substrate in the same manner as in Examples 1 and 2.
The substrate having the support and the negative photosensitive resin layer was placed on the substrate set stage of a projection exposure machine (UX-2023SM manufactured by USHIO INC.). The same glass chrome photomask as used in Examples 1 and 2 was set in the mask holder of the exposure machine, and exposed at an exposure amount of 100 mJ / cm ² through a projection lens and a polyethylene terephthalate film as a support.
The polyethylene terephthalate film was removed, and a 0.4% by mass aqueous sodium carbonate solution was sprayed at 30 ° C. and a spray pressure of 0.15 MPa for 20 seconds to remove unexposed portions and develop.

[Comparative Example 2]
A photosensitive resin laminate was prepared in the same manner as in Examples 1 and 2 except that the two components shown in Table 1 were mixed, and the photosensitive resin laminate was laminated on a flexible substrate in the same manner as in Examples 1 and 2.
The substrate having the support and the negative photosensitive resin layer is supported by the same chromium glass photomask as used in Examples 1 and 2 by using an exposure machine (HMW-801: manufactured by Oak Manufacturing Co., Ltd.) having an ultrahigh pressure mercury lamp. The film was placed on a polyethylene terephthalate film as a body, and exposed through a chromium glass photomask and a polyethylene terephthalate film at an exposure amount of 100 mJ / cm ² .
The polyethylene terephthalate film was removed, and a 0.4% by mass aqueous sodium carbonate solution was sprayed at 30 ° C. and a spray pressure of 0.15 MPa for 20 seconds to remove unexposed portions and develop.

The evaluation results for the samples of Example 1, Reference Example 1 and Comparative Examples 1 and 2 are summarized in Table 3.
The measurement and observation of the evaluation items in Table 3 were performed by the following methods.

(1) A photosensitive resin having a minimum mask width in which a cured resist line obtained by exposure and development using a chromium glass photomask having a resolution line / space of 4 μm / 4 μm to 100 μm / 100 μm is normally formed. Resolution. The smaller the value, the higher the resolution.

(2) Adhesiveness The minimum line width at which the cured resist line obtained by exposure and development using a chromium glass photomask having a line / space of 4 μm / 300 μm to 40 μm / 300 μm and development is in contact with the substrate is photosensitive. Resin adhesion was determined. The smaller the value, the higher the adhesion.

(3) Observation of pattern shape The pattern shape of the cured resist line obtained by exposing and developing through a glass chrome photomask with 10 lines / space of 10 μm / 10 μm, length of 20 mm and 10 lines is developed by scanning electron. They were observed with a microscope (SEM) and ranked as follows.
A: There is no unevenness on the upper surface of the 10 lines. No irregularities on the sidewalls.
○: No irregularities on the upper surface of 10 lines. Almost no side wall irregularities.
Δ: There are irregularities on the upper surface of 10 lines. There are a few irregularities on the side walls.
X: There are irregularities on the upper surface of 10 lines. Many irregularities are seen on the sidewall.

  According to the above results, when the exposure method of the present invention and the metal pattern production method of the present invention are used, a resist pattern that is superior in resolution, adhesion, and pattern shape can be obtained as compared with the conventional method. I understand.

Claims (4)

On a metal-coated insulating plate having a metal conductor layer on one or both sides, a support (A), a negative photosensitive resin layer (B) having a thickness of 1 to 35 μm, and a protective layer (C) Laminate a photosensitive resin laminate having a negative photosensitive resin layer (B) so that it is in close contact with the metal-coated surface of the metal-coated insulating plate, and support it before exposure when exposed to ultraviolet light through a photomask. After peeling off the body, the image of the photomask is projected through a lens, and the negative photosensitive resin layer (B) comprises (a) a thermoplastic polymer binder, (b) at least in the molecule. As a photopolymerizable monomer having one polymerizable ethylenically unsaturated group, 2,2-bis {(4-acryloxypolyethoxy) phenyl} propane having a total number of ethylene glycol units of 2 to 20 or 2, 2-bis (4-methacryloxy polyethoxy) phenyl} propane, (c) a photopolymerization initiator, the exposure method of the photosensitive resin layer, characterized in that it contains 2,4,5-triaryl imidazole dimer . The exposure method according to claim 1, wherein the protective layer (C) is a film having a center line average roughness of less than 0.1 μm .   The cured resist pattern is formed by developing with an alkaline aqueous solution following the exposure method according to claim 1 or 2, and the metal on the metal-coated surface not covered with the resist pattern is removed with an etching solution, or the resist pattern A method for producing a metal wiring pattern, wherein metal plating is performed on a metal-coated surface not covered with metal.   While peeling off the protective layer (C), the negative photosensitive resin layer (B) is laminated so as to be in close contact with the metal-coated surface of the metal-coated insulating plate so that the negative photosensitive resin layer is in close contact with the metal-coated surface. 4. The method for producing a metal wiring pattern according to claim 3, wherein the metal wiring pattern is laminated.