JPH08234427A - Photosensitive resin composition for thick film electrically conductive circuit and production of thick film electrically conductive circuit using the same - Google Patents

Abstract

PURPOSE: To obtain high density and low resistance circuit parts connected at different pitches by forming conductors each having a high aspect ratio and circuits each having a small interval between conductors and to relatively easily produce a stable product with high industrial productivity at a low cost. CONSTITUTION: This photosensitive resin compsn. used in 20-400μm film thickness at 300-420μm wavelength of light has 15-75% light transmissivity and contains an oligomer or prepolymer having ethylenically unsatd. groups and a mol.wt. of 500-50,000, at least one kind of polymerizable monomer having at least one acryloyl or methacryloyl group in one molecule, 0.1-10wt.% photopolymn. initiator having 5-1,0001/mol.cm molar extinction coefft. at the light absorption max. in the wavelength range and 0.01-1wt.% light absorber. The thick film conductor circuit is produced using this photosensitive resin compsn. as a plating resist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the field of electronic components or circuit components that are becoming smaller and more multifunctional in recent years, and the data found in ultra-compact and high-performance small motor coils or compact discs. Manufacture of parts such as optical pickups, which are read parts of
A circuit board including a fine wiring part of the above, and further, a photosensitive resin composition for a thick film conductive circuit, which is suitable for the production of a circuit element for connection such as a display element, which is becoming more and more high definition, and the same. The present invention relates to a method for manufacturing a thick film conductive circuit. In particular, the present invention relates to a high-density and low-resistance different-pitch connection wiring component including a portion where the minimum wiring pitch is less than 100 μm.

[0002]

2. Description of the Related Art In LSIs (Large Scale Integrated Circuits) and the like, which have ever-increasing performance, the number of pins is increasing with the demand for higher performance, and the pitch of the pins is becoming narrower. Also, as seen in liquid crystal displays, as the demand for higher definition increases, the number of display scanning lines increases, and at the same time the wiring spacing becomes extremely narrow, making it difficult to mount an IC that controls display. ing.

In such a technological trend, high density and low density for connecting parts having greatly different circuit wiring intervals, for example, an IC or LSI having pins with a narrow pitch and a mother board (the circuit wiring interval is large due to the manufacturing method). There is an increasing demand for resistive different-pitch connection wiring components. There are documents that define such parts as "interposers", but (Nikkei Electronics 1995.1.16 (No. 626)
In the present invention, this is referred to as a different pitch connection wiring component.

The required performance of the different pitch connection wiring parts is as follows.
For example, as described on pages 43 to 46 of the 6th Microelectronics Symposium, there is a report that when a CPU is operated at a high-speed operation clock frequency, signal pulses are attenuated as wiring resistance increases. Further, it is said that if the wiring resistance of the connection between the control IC of the high-definition liquid crystal display element and the liquid crystal substrate increases, the S / N ratio decreases and the image becomes unstable. As a result, different-pitch connection wiring components are required to have a low resistance circuit wiring and a small wiring pitch. Therefore, the circuit wiring is required to have a large cross-sectional area, that is, a high conductor height.

Further, as has been found in printed circuit boards and the like, conventionally, the following three methods have been mentioned as methods for forming a conductive circuit. That is, a subtractive method for forming a desired circuit by etching or the like using a cured resin image (hereinafter referred to as a resin image in the present invention) of a photosensitive resin composition formed on a conductive substrate as a protective film ( It is also called the etching method), and a resin image is formed on the insulating substrate,
The additive method of forming a conductor circuit by performing electroless copper plating or the like, and the semi-additive method, which is an intermediate method between the two, are mentioned.

Among the above-mentioned methods, the subtractive method is currently the mainstream, but the miniaturization of the components themselves,
In the technological trend where the demand for higher circuit density is increasing,
There is a technical limit in forming a circuit having a wiring pitch of 50 μm or less. Even if it can be technically formed, the reliability of the circuit is deteriorated, or the electrical characteristics, especially the resistance value becomes large, and the function as a circuit or a component cannot be satisfactorily exhibited. . Furthermore, even if it can be manufactured, the process is extremely complicated, which lowers the industrial utility value.

As another method for forming high-density and low-resistance circuit wiring, for example, JP-A-52-137666 and JP-A-57-162489 disclose a method of filling a resist pattern with a thick film paste material. JP-A-55-4172
No. 9 publication mixes a thick film paste and a positive resist,
A method of exposing and developing is disclosed. JP 59-1
Japanese Patent Publication No. 98792 discloses a method for producing a thick film pattern conductor by repeating resist lamination and exposure, followed by development and electroplating, using a conductive substrate as a base.

Further, JP-A-56-94690 and JP-A-60-161605 disclose a method of forming a fine pattern circuit by anisotropic electroplating by combining a conductive substrate and photolithography.

[0009]

However, since the circuit wiring conductor obtained by the method of combining the copper-clad substrate, photolithography and etching is extremely difficult to suppress the side etching phenomenon during the etching of the copper foil, It prevents the high density and low resistance. Further, since this phenomenon becomes more remarkable as the conductor height increases, the thickness of the copper foil of the copper-clad substrate that is normally used is about 18 to 35 μm, but the wiring density is about 10 wires / mm, that is, If the wiring pitch is about 100 μm or less, the resistance cannot be made sufficiently low, and technically the wiring pitch is about 50 μm.

Further, in the thick film pattern conductor obtained by the method of forming the high density and low resistance circuit wiring, pores are formed in the conductor during firing of the paste, and as a result, the conductor resistance is increased to deteriorate the circuit characteristics. In Japanese Patent Laid-Open No. 59-198792, it is expected that a resist pattern having a relatively high aspect ratio can be obtained, but the process is complicated, and the stacking
There are many problems such as the introduction of defects due to the positional deviation during exposure, the defective resist shape, and the accompanying short circuit of the circuit.
Further, JP-A-56-94690 and JP-A-60-1
In the method of Japanese Patent No. 61605, since the conductor design is controlled by the plating start width and the conductor shape is spherical, the thickness cannot be increased with respect to the width of the conductor, and the high density / low resistance circuit is provided. Wiring cannot be obtained.

In any of these methods, a circuit wiring conductor having a conductor wiring density of 20 wires / mm or more, that is, a wiring pitch of 50 μm or less and a conductor aspect ratio of 1.0 or more has not been practically obtained. Therefore, the present invention obtains a high-density and low-resistance different-pitch connection wiring component by forming a conductor having a high aspect ratio and a circuit having a small distance between conductors, and is relatively simple, inexpensive, and industrial. It is an object of the present invention to provide a highly productive and stable method for producing a product.

[0012]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies based on these technological trends, and as a result, the film thickness of 20 to
In a photosensitive resin composition used at 400 μm and a light wavelength of 300 to 420 μm, an oligomer or prepolymer having an ethylenically unsaturated group and a molecular weight of 500 to 50,000, and at least one acryloyl group or methacryloyl in one molecule. At least one polymerizable monomer having a group, and 0.1 to 10% by weight of a photopolymerization initiator having a molar absorption coefficient of 5 to 1000 liter / mol · cm at the light absorption maximum at the above wavelength, 0.0% absorbent
1 to 1% by weight, and a light transmittance of 15 to 75% was found. Further, the photosensitive resin composition for a thick film conductor circuit is applied on a conductive substrate, exposed and developed to form a thick film resin image, and then a thick film plating is applied on the conductive substrate to form a conductive substrate. The inventors have found a method for manufacturing a thick film conductive circuit, which is characterized in that Further, the conductive substrate is preferably copper or aluminum.

In the present invention, the oligomer or prepolymer having an ethylenically unsaturated bond is an alcohol component of either an alkyl diol or a diol having 5 or less ether bonds in the molecule, or an alcohol composed of a mixture thereof. A component obtained by condensation polymerization of a dicarboxylic acid having an ethylenically unsaturated bond alone or an acid component comprising a mixture of a dicarboxylic acid having no ethylenically unsaturated bond and a dicarboxylic acid having an ethylenically unsaturated bond. Particularly preferable images are obtained when the polyester is saturated. If the molecular weight is less than 500, the sensitivity of the photosensitive resin composition is too low to withstand use, and if it exceeds 50,000, the developability after irradiation with high energy rays is remarkably decreased and the high resolution is high. I can't get it. Further, the molecular weight of 1200 to 25,000 is a preferable range for the composition for conductive circuits from the viewpoint of sensitivity and resolution.

As the oligomer or prepolymer which can be used as the photosensitive resin composition of the present invention, unsaturated polyester, unsaturated polyurethane, oligoester acrylates or oligoester methacrylates, unsaturated polyamides, unsaturated polyimides, unsaturated Examples thereof include polyethers, unsaturated polyacrylates or unsaturated polymethacrylates, various modified products, mixtures thereof, and compounds having a carbon-carbon double bond. Among these, unsaturated polyesters or unsaturated polyurethanes are preferable examples for obtaining an image having a large image height to width ratio (hereinafter referred to as an aspect ratio).

Examples of the unsaturated polyesters include unsaturated dibasic acids such as maleic acid, fumaric acid and itaconic acid or acid anhydrides thereof and ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin, trimethylolpropane, Polyesters reacted with polyhydric alcohols such as pentaerythritol, 1,4-polybutadiene having a terminal hydroxyl group, hydrogenated or non-hydrogenated 1,2-polybutadiene, butadiene-styrene copolymer, and butadiene-acrylonitrile copolymer In addition, polyesters in which a part of the acid component is replaced with a saturated polybasic acid, or polyesters modified with a dry oil-and-fat acid or a semi-dry oil-and-fat acid, etc.

Examples of unsaturated polyurethanes include the above-mentioned polyhydric alcohols and polyester polyols,
Polyols such as polyether polyols, 1,4-polybutadiene having terminal hydroxyl groups, hydrogenated or non-hydrogenated 1,2-polybutadiene, butadiene-styrene copolymers, butadiene-acrylonitrile copolymers, etc., and tolylene diisocyanate. , Diphenylmethane, 4, 4 '
-Compounds in which an unsaturated group is introduced by utilizing the reactivity of the terminal isocyanate group or the hydroxyl group of polyurethanes derived from polyisocyanates such as diisocyanate and hexamethylene diisocyanate. That is, a hydroxyl group, a carboxyl group, an unsaturated group is introduced by a reaction between a compound having active hydrogen such as an amino group and an isocyanate, or an unsaturated group is introduced by a reaction between a carboxyl group and a hydroxyl group, or And unsaturated polyesters linked with polyisocyanates.

As a particularly preferred example, an alcohol component comprising a mixture of alkyl diols and diols having 5 or less ether bonds in the molecule, dicarboxylic acids having an ethylenically unsaturated bond alone or ethylenically unsaturated bond Molecular weight of 500 to 5000 obtained by polycondensation of an acid component consisting of a mixture of a dicarboxylic acid having no carboxylic acid and a dicarboxylic acid having an ethylenically unsaturated bond.
0 unsaturated polyesters.

As the polymerizable monomer having at least one acryloyl group or methacryloyl group in one molecule, various known compounds can be used. Preferred examples include polyethylene glycol mono- or diacrylates and methacrylates. Propylene glycol mono- or diacrylates and methacrylates, cyclohexanediacrylates and methacrylates, bisphenol A mono- or diacrylates and methacrylates, isobornyl acrylates and methacrylates, acrylamides and their derivatives, methacrylamides and their derivatives, trimethylolpropane triacrylate And methacrylate, di- or triacrylates and methacrylates of glycerol,
Mention may be made of compounds such as pentaerythritol di-, tri- or tetra-acrylates and methacrylates, and ethylene oxide or propylene oxide adducts of these compounds.

The monomer can be detected by liquid chromatography or gas chromatography. The photopolymerization initiator used in the present invention preferably has a molar extinction coefficient of 5 to 1000 liter / mol · cm at the light absorption maximum in the wavelength range of 300 to 420 nm. That is, when a photopolymerization initiator having a molar extinction coefficient of more than 1000 liter / mol · cm is used, light does not reach the inside of the photopolymerization composition having a thick film of 20 to 400 μm, and the photopolymerization composition can be sufficiently cured. Absent. Further, if the exposure time is increased, even the portion that should not be cured will be cured, and the conductor cannot be formed by plating.

On the other hand, the molar extinction coefficient is 5 liter / mol.
The sensitivity of the photosensitive resin composition is too low to be practically used with a photopolymerization initiator of less than cm. The molar extinction coefficient and the light transmittance can be measured by an ordinary spectrophotometer. Examples of such a photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin propyl ether, benzoin isobutyl ether, benzoin butyl ether, 2,2-dihydroxy-2-phenylacetophenone, 2,2. -Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone and the like can be mentioned.

The light absorber in the present invention has a wavelength of 300 to
Any substance such as a dye or an ultraviolet absorber may be used as long as it has absorption in the range of 420 nm and can be uniformly dissolved or dispersed in the photosensitive resin composition. This light absorber efficiently absorbs the wraparound of light due to scattering and reflection of the exposure system,
It has an effect of preventing the photosensitive resin composition, which should not be cured, from being cured to such an extent that it cannot be removed by the developing liquid.

In the present invention, it is important to control the light transmittance of the photosensitive resin composition by the combination of the photopolymerization initiator and the light absorber. The film thickness is 20 to 400 μm, and the light wavelength is 300.
When used at ˜420 nm, the molar absorption coefficient at the light absorption maximum at the wavelength is 5 to 1000 liter / mo.
0.1 to 10% by weight of 1 · cm of a photopolymerization initiator, and 0.01% of a light absorber so that the light transmittance is 15 to 75%.
When it is contained in the range of 1 to 1% by weight, the unexposed portion of the photosensitive resin composition can be prevented from being cured.
Even with a thick film of 0 μm, a high resolution of 50 μm or less in resolution pitch can be exhibited, and the developability of the unexposed area can be improved. Therefore, when a conductor is formed on the conductive substrate by plating or the like, the wire is broken or the conductor is thin. It is possible to form a highly reliable, low-resistance thick film conductor with very little deterioration. As a more preferable range, the photopolymerization initiator of the photosensitive resin composition is in the range of 0.5 to 5% by weight, and the light transmittance is in the range of 20 to 60%. That is, the sensitivity of the photosensitive resin composition to ultraviolet rays is in a practically more preferable range from the viewpoint of exposure time and ease of handling.

Next, a method for forming a thick film conductor using the photosensitive resin composition will be described. That is, the photosensitive resin composition for a thick film conductive circuit of the present invention is coated on a conductive substrate by 2
It is applied to a thickness of 0 to 400 μm, subjected to imagewise exposure with a high energy ray, and then the unexposed portion of the photosensitive resin composition is dissolved or dispersed with a developing liquid to remove it on a conductive substrate. This is achieved by forming an image, forming a conductor by a plating method, and then removing the conductive substrate.

The high energy radiation source is preferably a collimated light source. When a parallel light source is used, the cross section of the resin image pattern has a rectangular shape, and a pattern having a higher aspect ratio can be obtained. As a method of removing the conductive substrate, for example, a method of etching with an acid, alkali, or salt aqueous solution,
A method of scraping off by polishing, a method of mechanically peeling, a method of combining these, or the like can be selected.

The coating thickness of the photosensitive resin composition is 20-40.
Within the range of 0 μm, it is determined by the required conductor thickness of electronic components and precision circuit boards. The conductive substrate is not particularly limited, but a substrate made of aluminum, copper or the like is preferably used. In order to improve the adhesion between the conductive substrate and the photosensitive resin composition or the plating film, if necessary,
The conductive substrate may be subjected to physical or chemical surface treatment.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to Examples. The present invention is not limited to the examples.

[0027]

Example 1 Diethylene glycol, propylene glycol, adipic acid, fumaric acid, isophthalic acid in a molar ratio of 0.4 / 0.1 / 0.2 / 0.15 / 0.15 in a nitrogen atmosphere at a reaction temperature. An unsaturated polyester prepolymer having a number average molecular weight of 1500 was produced by polycondensation under reduced pressure at 200 ° C. for a reaction time of 4 hours.

To 100 parts by weight of this prepolymer, 12 parts of tetraethylene glycol dimethacrylate, 5 parts of diethylene glycol dimethacrylate, 8 parts of 2-hydroxyethyl methacrylate, 15 parts of pentaerythritol trimethacrylate, 5 parts of mono (methacryloyloxyethyl) phosphate, 2,2-dimethoxy-2-phenylacetophenone 2 parts as a photopolymerization initiator, 4-tert-butyl catechol 0.05 part, and Nippon Kayaku Co., Ltd. Kayaset Red A-2G 0.15 parts as a light absorber. The mixture was well stirred and mixed to obtain a photosensitive resin composition.

The molar extinction coefficient of 2,2-dimethoxy-2-phenylacetophenone in ethanol is 181.
It was liter / mol · cm (336 nm). Further, when the photosensitive resin composition has a film thickness of 100 μm,
The light transmittance was 24%. Next, this photosensitive resin composition was applied on an aluminum plate to a thickness of 100 μm,
Ultraviolet rays of a mercury short arc lamp were irradiated through a photomask corresponding to a wiring pattern having a density of m (wiring pitch 40 μm), and the unexposed portion was removed with a 1% sodium borate aqueous solution to form a resin image. Next, electrolytic copper plating is applied to the aluminum plate on which the resin image is formed, and the aluminum plate is
The wiring density is 25 wires / mm by etching away with 0% hydrochloric acid,
A thick film conductor wiring board having a conductor thickness of 100 μm was obtained.

[0030]

Comparative Example 2,2-dimethoxy-2-in Example 1
A photosensitive resin composition was prepared in the same manner as in Example 1 except that 1 part of 2-methylanthraquinone was used instead of 2 parts of phenylacetophenone. The molar extinction coefficient of 2-methylanthraquinone is 3800 liter / mol · cm (32
6 nm), and the light transmittance of this photosensitive resin composition at a film thickness of 100 μm was 1.8%.

Next, this photosensitive resin composition was applied on an aluminum plate to a thickness of 100 μm, and was irradiated with ultraviolet rays from a mercury short arc lamp through a photomask corresponding to a wiring pattern having a density of 25 lines / mm. When the exposed portion was removed with a 1% sodium borate aqueous solution, light did not reach the aluminum plate, and the resin image did not remain on the aluminum plate. When the irradiation time of the ultraviolet rays was made five times so that the light reached the aluminum plate, the resin in the unexposed area was also cured, and the conductor could not be formed by plating.

[0032]

[Example 2] Toyo Aluminum Co., Ltd., thickness 100μ
The aluminum substrate of m was subjected to a surface treatment at 30 ° C. for 80 seconds using a AZ401 treatment liquid manufactured by Uemura Industry Co., Ltd. Next, a number obtained by polycondensing diethylene glycol, propylene glycol and adipic acid, itaconic acid, and fumaric acid at a molar ratio of 0.45 / 0.05 / 0.20 / 0.15 / 0.15, respectively. 100 parts of unsaturated polyester resin having an average molecular weight of 1700, 15 parts of pentaerythritol trimethacrylate, 3 parts of diethylene glycol dimethacrylate, 7.5 parts of tetraethylene glycol dimethacrylate, 3 parts of 2-hydroxyethyl methacrylate, 1.5 parts of diacetone acrylamide. Parts, 3.6 parts of mono (methacryloyloxyethyl) phosphate, 1 part of benzoin isobutyl ether, 0.04 part of 4-tert-butyl catechol, OPLAS Yellow 130, 0.014 part as a light absorbing agent manufactured by Orient Chemical Co., Ltd. And mix well. To obtain a photosensitive resin composition A.

Further, 2 parts of 2,2-dimethoxy-2-phenylacetophenone was used in place of 1 part of benzoin isobutyl ether of the composition A, and O produced by Orient Chemical Co., Ltd. was used.
A photosensitive resin composition B was prepared in the same manner as the composition A except that 0.05 parts of Oil Yellow 3G manufactured by Orient Chemical Co., Ltd. was used instead of PLAS Yellow 130. The transmittance of the composition A at 365 nm was measured with a U-3210 type spectrophotometer manufactured by Hitachi Ltd., and a film thickness of 4 was obtained.
It was 25% at 00 μm and 71% at 100 μm film thickness.
Similarly, the light transmittance of the composition B was 26% at a film thickness of 50 μm and 59% at a film thickness of 20 μm.

The prepared photosensitive resist was coated on the above-treated aluminum substrate using an SR-B apparatus manufactured by Asahi Kasei Corporation. At this time, the resist layers are shown in Table 1 respectively.
The thickness was adjusted with a spacer. Mask exposure / development (sodium borate 1% solution, 40 ° C., discharge pressure 0.1 kg / cm ² ) was performed using a predetermined glass mask and a parallel light source manufactured by Oak Co., and a width of 6 to 40 μm was applied on an aluminum substrate. , A resin image pattern having a predetermined height was prepared.

On the resulting resin image pattern, a copper copper plating solution having a thickness shown in Table 1 was deposited using a copper pyrophosphate plating solution manufactured by Hersho Murata Co., Ltd. under conditions of a current density 3 A / dm ² of the cathode, A pattern conductor was formed. Adhesive (cemedine EP008, EP170) on the surface of the obtained substrate
Was screen-printed, transferred and adhered to a glass epoxy insulating substrate, and the aluminum substrate was removed by etching with 10% hydrochloric acid to obtain a thick film pattern conductor.

The obtained substrate was cut into 2 cm square pieces, cured with an epoxy resin, the cross section was mirror-polished with a polishing machine, the pattern shape was observed, and the resistance value per unit length was measured. The results are shown in Table 1. As is clear from the results in Table 1, the thick film patterned conductor obtained in the present invention is capable of high-density wiring with a wiring pitch of less than 100 μm, and has a very small resistance value per cm.

[0037]

Example 3 A photosensitive resin composition was prepared in the same manner as in the composition B of Example 2 except that the light absorbers were used in the respective types and concentrations shown in Table 2, and the thickness was 80 μm and the wavelength was 365 nm. The transmittance was measured. Next, using a photosensitive resin prepared in the same manner as in Example 1 and using an exposure / developing apparatus, 40 μm
A resist pattern having a pitch (25 lines / mm wiring) and a height of 80 μm is prepared, and a copper copper film having a thickness of 80 μm is formed under the condition of a cathode current density of 3 A / dm ² using a copper pyrophosphate plating solution manufactured by Harshaw Murata. Precipitation was performed to form a patterned conductor.

An adhesive (cemedine EP008, EP170) was screen-printed on the surface of the obtained substrate, transferred and adhered on a glass substrate, and then an aluminum substrate was made 10%.
It was removed by etching with hydrochloric acid to obtain a thick film patterned conductor. Table 3 shows the shape and resistance of the obtained conductor. In Table 3, the sample No. Reference numerals 5 and 6 are implementation exceptions of the present invention and are comparative examples. If the transmittance of the photosensitive resin composition is 75% or more, or 15% or less, the wiring pitch is 50 μm.
It can be seen that high-density wiring of less than m is extremely difficult.
When the transmittance is 75% or more, the plated conductor is not partially deposited due to the fogging phenomenon at the time of exposure / development, and the disconnection is likely to occur. Further, when the transmittance is 15% or less, the resist is not sufficiently cured and the resist pattern is peeled off at the time of development, or the plated copper is sunk between the resist and the substrate at the time of plating, which is likely to cause a short circuit between the conductors.

On the other hand, the sample No. In Nos. 7 and 8, high-density wiring with a wiring pitch of less than 50 μm is possible, and the resistance value per unit is 0.1Ω or less, which is extremely low resistance.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

EFFECTS OF THE INVENTION The photosensitive resin composition of the present invention uses a combination of a photopolymerization initiator and a light absorber to adjust the transmittance of the liquid photosensitive resist to 15 to 75%, so that the light circling to the unexposed area can be efficiently absorbed. Since it can be absorbed well, the resolution is high, and there are very few resin residues in the unexposed area, so there are very few disconnections due to defective plating, and it is possible to manufacture thick film conductor circuits with high wiring density and low resistance, and different pitch connection parts. it can.

Claims (2)

[Claims] 1. A film thickness of 20 to 400 μm and a light wavelength of 300.
In the photosensitive resin composition used in the range of ~ 420 μm,
It has an ethylenically unsaturated group and has a molecular weight of 500 to 5,000.
0 oligomer or prepolymer, at least one polymerizable monomer having at least one acryloyl group or methacryloyl group in one molecule, and a molar absorption coefficient at a light absorption maximum at the above wavelength of 5 to 1000 liter / A thick film comprising 0.1 to 10% by weight of a mol · cm photopolymerization initiator and 0.01 to 1% by weight of a light absorber, and having a light transmittance of 15 to 75%. Photosensitive resin composition for conductive circuits. 2. The thick film conductive circuit photosensitive resin composition according to claim 1 is applied onto a conductive substrate, exposed and developed to form a thick film resin image, and then the thick film is applied onto the conductive substrate. A method of manufacturing a thick film conductive circuit, which comprises performing film plating and removing the conductive substrate.