JP2003057818A - Liquid photosensitive resin composition for thick film conductor circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid photosensitive resin composition for a thick film conductor circuit. SOLUTION: In the liquid photosensitive resin composition comprising a prepolymer having an ethylenically unsaturated group, a polymerizable monomer and a photopolymerization initiator, the prepolymer is a prepolymer obtained by condensing (a) a dicarboxylic acid component, (b) a diol component and (c) a compound containing >=3 carboxyl and/or hydroxyl groups and is an unsaturated polyester containing 0.1-5 mol% of the component (c) based on the total amount [(a)+(b)+(c)] of the prepolymer and having a number average molecular weight of 500-5,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid photosensitive resin composition for thick film circuits, which is used as a resist when manufacturing wiring circuits, electronic parts and the like.

[0002]

2. Description of the Related Art In the field of wiring circuits and electronic parts, the size and functionality of the products are becoming smaller and smaller, and they are found in ultra-compact and high-performance small motor coils, compact discs and digital video discs. Thick film suitable for manufacturing conductor patterns of parts such as optical pickups, which are parts for reading data, circuit boards including fine routing parts of LSIs, and circuit parts for connection such as display elements, which are becoming more and more precise. A photosensitive resin composition for image formation,
Furthermore, wafer level chip size package (WL-
CSP) and fine circuit connection films used in chip-in-package technology, photosensitive resin compositions for the production of plated bumps, or photosensitive resin compositions for the production of anisotropic conductive sheets for inspection of integrated circuit parts That is, high resolution is required.

In particular, LSIs with higher and higher performance
In (large-scale integrated circuits) and the like, the number of pins has greatly increased along with the demand for higher performance, and the pitch of the pins has been rapidly narrowed. In addition, as in the case of liquid crystal displays, as the demand for higher definition increases, the number of display scanning lines increases, and at the same time, the wiring interval becomes extremely narrow, which makes it difficult to mount an IC that controls display. . In such a technological trend, bare chips LS having connection pads with a narrow pitch, for example, parts having circuit wiring intervals greatly different from each other.
There is also an increasing demand for high-density and low-resistance different-pitch connection wiring components for connecting I and the like to a mother board (a circuit wiring interval is large due to the manufacturing method).

The required performance of the different pitch connection wiring parts is as follows.
The 6th Microelectronics Symposium Page 43
46, it is reported that when the CPU is operated at a high-speed operation clock frequency, the signal pulse is attenuated as the wiring resistance increases. Furthermore, for controlling a high-definition liquid crystal display device. It is said that when the wiring resistance of the connection between the IC 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 has a large cross-sectional area,
That is, it is necessary that the conductor height be high.

As can be seen from 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 (etching) in which 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 is used as a protective film to form a desired circuit by etching or the like. (Also referred to as a method), or an additive method of forming a resin image on an insulating substrate and performing electroless copper plating to form a conductor circuit, and a semi-additive method that is an intermediate method between the two. Is mentioned.

However, since the circuit wiring conductor obtained by the subtractive method combining the copper-clad substrate, photolithography and etching is extremely difficult to suppress the side etching phenomenon during etching of the copper foil, the wiring density is increased. , Hindering resistance reduction. Furthermore, since this phenomenon becomes more remarkable as the conductor height increases, the thickness of the copper foil of a copper-clad substrate that is normally used is about 10 to 35 μm, but the wiring density is 20 /
If the wiring pitch is about mm, that is, the wiring pitch is about 50 μm or less, the resistance cannot be sufficiently low, and the wiring pitch is technically limited to about 40 μm. On the other hand, in the additive method that combines photolithography and plating, it is possible to form a conductor having a height approximately equal to the thickness of the resin image formed in the photolithography process, and thus a relatively lower resistance than the subtractive method. Can be manufactured.

However, the conventional ultraviolet cross-linking resist has a width of 10 to 40 μm and a height of 40 to 200 μm.
When the aspect ratio of the resin image is increased, such as m, tilting, tilting or the like occurs due to insufficient strength of the resin, or the amount of light reaching energy becomes small. The polymerizable component of oozes out to cause poor plating adhesion, contaminate the plating solution, or lack of adhesion to the substrate to cause peeling of the resin image, reducing the industrial utility value. It was Further, if the exposure amount is increased in order to prevent these phenomena, the unexposed portion is fogged, and the resolution is lowered.

With respect to these techniques for forming fine pattern conductors, the applicant of the present invention has disclosed a method for producing a thick film fine pattern having a high aspect ratio in Japanese Patent Publication No. 5-81897.
Further, a liquid photosensitive resin having improved adhesiveness to a conductive substrate is disclosed in JP-A-6-283830.
3920 discloses a liquid photosensitive resin composition for thick film conductor circuits, and JP-A No. 11-305421 discloses a photosensitive resin composition for high frequency circuits.

However, in the photosensitive resin compositions disclosed in these publications, for example, in the case of a pattern having a relief width of 20 μm and a wiring width of 30 μm and a pitch of 50 μm, the film thickness is limited to 100 μm. That is, in a lithography process in which the resist thickness is larger than this, when the film thickness reaches 140 μm, for example, as shown in FIG. 1, the resin image cured product has a weak strength, so that the reliefs stick to each other or the reliefs are peeled off from the substrate. It was impossible to form a pattern due to the occurrence of short circuit due to plating digging and the unexposed portion being not completely developed and broken.
Further, even when a pattern was formed with a film thickness of 100 μm, the relief width of the image area was largely shrunk, which was not sufficient in terms of low shrinkability.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when it is used in a thick film conductor circuit, it provides the resin image with strength while maintaining the resolution. Provided are a liquid photosensitive resin composition capable of forming a pattern having a small shrinkage ratio of a relief width, and a method for producing the liquid photosensitive resin composition. The shrinkage of the relief width can be suppressed while exhibiting a resolution higher than that of the photosensitive resin composition described in JP-A-10-73920.

[0011]

Means for Solving the Problems As a result of intensive studies made by the present inventors, a liquid photosensitive resin containing a prepolymer having an ethylenically unsaturated group, a polymerizable monomer, and a photopolymerization initiator. In the composition, it was found that the above problems can be solved by introducing a specific amount of a compound having at least three carboxyl groups or hydroxyl groups as the prepolymer raw material, and the present invention has been completed.

That is, 1. In a liquid photosensitive resin composition containing a prepolymer having an ethylenically unsaturated group, a polymerizable monomer, and a photopolymerization initiator, the prepolymer includes (a) dicarboxylic acid and (b) diol. , (C) contains either or both of a carboxyl group or a hydroxyl group, and the total number of the groups is 3
It is an unsaturated polyester prepolymer having a number average molecular weight of 500 to 5000 obtained by condensation with the above compound, and the raw material of the prepolymer is the component (c) of the prepolymer raw material (a) + (b). A liquid photosensitive resin composition for a thick film conductor circuit, characterized by containing 0.1 to 5 mol% relative to + (c). 2. The polymerizable monomer has 3 or more acryloyl groups or 3 or more methacryloyl groups in one molecule,
And at least one compound having 15 or less carbon atoms or oxygen atoms bonded between the carbon atoms to which the acryloyl group or methacryloyl group is bonded, and 100 parts by weight of the prepolymer of item 1 above 1 to 50 parts by weight, and the molar absorption coefficient at the light absorption maximum in the wavelength range of 300 to 420 nm is 5 to 1000.
0.1 to 10 liter / mol · cm photopolymerization initiator
%, And 0.01 to 1% by weight of a light absorber, and the light transmittance in the wavelength range is 15 to 75%. Resin composition. 3. The compound (c) has the following chemical formulas 1, 2, 3, or 4
The liquid photosensitive resin composition for thick film conductor circuits according to the above item 1 or 2, wherein the liquid photosensitive resin composition is a compound represented by:

[0013]

[Chemical 8]

(Wherein R1, R2, R3, and R4 are-
One of (CH ₂ ) _m OH or-(CH ₂ ) _n COOH is 3 or more, or both are 3 or more,
Otherwise -H, or an -CH _3. However, m =
0-8 and n = 0-8. )

[0015]

[Chemical 9]

(Wherein R1, R2, R3 and R4 are-
One of (CH ₂ ) _m OH or-(CH ₂ ) _n COOH is 3 or more, or both are 3 or more,
Otherwise -H, or an -CH _3. However, m = 0
8 and n = 0-8. )

[0017]

[Chemical 10]

(Wherein R1, R2, R3, R4, R5, R
Of _{6, - (CH 2) m} OH, or - (CH _{2) n} CO
One of OH has 3 or more groups, or a combination of both groups has 3 or more groups, and the other groups represent -H or -CH ₃ .
However, m = 0 to 8 and n = 0 to 8. )

[0019]

[Chemical 11]

(Wherein R1, R2, R3, R4, R5, R
Of _{6, - (CH 2) m} OH, or - (CH _{2) n} CO
One of OH has 3 or more groups, or a combination of both groups has 3 or more groups, and the other groups represent -H or -CH ₃ .
However, m = 0 to 8 and n = 0 to 8. ) 4. The liquid photosensitive resin composition for a thick film conductor circuit according to the above item 1 or 2, wherein the compound (c) is a compound represented by the following chemical formulas 5, 6 or 7 or a dianhydride thereof.

[0021]

[Chemical 12]

(Wherein R1, R2, R3, R4, R5, R
6, R7, among _{R8, - (CH 2) m} OH or -
One or more of (CH ₂ ) _n COOH is 3 or more, or a combination of both is 3 or more, and the other is -H or-.
Represents CH ₃ . However, m = 0-2 and n = 0-2. )

[0023]

[Chemical 13]

(Wherein R1, R2, R3, R4, R5, R
6, R7, R8, R9, of _{R10, - (CH 2) m} O
H, or - or (CH ₂₎ one of _n COOH three groups or more,
Or if both are combined, there will be 3 or more units
H, or an -CH _3. However, m = 0 to 2, n = 0
~ 2. )

[0025]

[Chemical 14]

(In the formula, R1 is --O--, --CO-- or --C (CH ₃ ) _2- , and R2, R3, R4, R5, R
Of R6, R7, R8, R9, R10, and R11,-(C
H _{2) m} OH, or - (CH ₂₎ or one of _n COOH three groups or more, or be more than three groups combined both, otherwise -H, or an -CH _3. However, m = 0
2, n = 0-2. ) 5. The liquid photosensitive resin composition for thick film conductor circuits according to the above items 1 to 3, wherein the compound (c) is citric acid or glycerin.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to an unsaturated polyester prepolymer containing a compound having a carboxyl group or a hydroxyl group or both as a component other than a dicarboxylic acid and a diol, and having a total number of groups of 3 or more. By introducing and specifying the blending ratio,
The present invention has discovered a liquid photosensitive resin composition capable of forming a pattern having high resolution, good developability, low shrinkage and high aspect ratio, which has never been expected so far. A prepolymer containing a compound containing one or both of a carboxyl group and a hydroxyl group in one molecule and having a total number of groups of 3 or more is compared with a conventional prepolymer because of its three-dimensional crosslinked structure. Although it is not generally considered because it may gel during synthesis, or the long-term storage stability of the photosensitive resin composition may be slightly inferior.
On the contrary, it is a resin that is extremely useful as a photosensitive resin for thick-film conductor pattern fabrication, by incorporating the rigidity of the resin due to its three-dimensional crosslinked structure as a physical property, adjusting the compounding ratio, and finding stable synthesis conditions. Found.

That is, the prepolymer in the liquid photosensitive resin of the present invention contains a compound containing a carboxyl group or a hydroxyl group or both in the raw material component before condensation, and the total number of the groups is 3 or more at a specific ratio. By mixing
It has a branched structure in which a part of the main chain of the prepolymer molecule is branched. The prepolymer having this branched structure has a complicated three-dimensional network structure during the curing reaction during exposure, and uncured molecules in the image area are less likely to elute than in conventional linear prepolymers, resulting in shrinkage. It is estimated that it can be suppressed.

The presence of three or more carboxyl groups or hydroxyl groups in one molecule of the prepolymer improves the developability of the unexposed area. as a result,
The resolution in the thick film pattern is extremely good. That is, even when the film thickness is increased to 120 μm, a narrow pitch pattern with a resolution pitch of 48 μm can be resolved.
When the film thickness is 100 μm, the resolution pitch is 36 μm
Resolution up to a narrow pitch pattern of 42 μm is possible. As described above, it is suitable for forming a pattern of a thick film with a narrow pitch, that is, a pattern of a cured resin product having a large aspect ratio with low shrinkage.

The unsaturated polyester prepolymer composition of the present invention can be prepared by using the following components. Examples of the dicarboxylic acid as the component (a) include a dicarboxylic acid component having an unsaturated group such as itaconic acid, fumaric acid, maleic acid, mesaconic acid, citraconic acid and glutaconic acid, and if necessary, adipic acid, phthalic acid, Examples thereof include dibasic acids such as dicarboxylic acids having no unsaturated group such as isophthalic acid and terephthalic acid, or anhydride components thereof. The diol of the component (b) is an alkyl diol or 5 in the molecule.
Examples thereof include diols having not more than 4 ether bonds, or a mixture thereof.

As the compound of the component (c) containing either or both of a carboxyl group and a hydroxyl group, and the total number of the groups is 3 or more, various known compounds can be used, but the compound can be used in the molecule. Dicarboxylic acids having one or more hydroxyl groups and their anhydrides, tricarboxylic acids and their anhydrides, carboxylic acids having a valence of 4 or more and their anhydrides, diols having at least one carboxyl group in the molecule, trihydric alcohols or 4 Examples thereof include alcohols having a valency or more. As the above-mentioned component (c), various known compounds can be used as the dicarboxylic acids having one or more hydroxyl groups in the molecule, but preferred examples include malic acid, tartronic acid, dicrotaric acid, meconic acid, Examples thereof include compounds such as citramalic acid, tartaric acid, grape acid, and dihydroxytartaric acid.

As the above-mentioned component (c), tricarboxylic acids and their anhydrides, or tetracarboxylic or higher carboxylic acids and their anhydrides, various known compounds can be used, but preferred examples are citric acid. , Isocitric acid,
Aconitic acid, nitrilotriacetic acid, tricarballylic acid, carboxycomeronic acid and berberonic acid, which are pyridinetricarboxylic acids, hemimellitic acid, trimellitic acid and trimesic acid, which are benzenetricarboxylic acids, desoxalic acid, ethylenediaminetetraacetic acid and its related compounds, Planeic acid, which is a benzenetetracarboxylic acid,
Such as melophanoic acid and pyromellitic acid, biphenyltetracarboxylic acid and its dianhydride, benzophenonetetracarboxylic acid and its dianhydride, naphthalenetetracarboxylic acid and its dianhydride, benzenepentacarboxylic acid, mellitic acid and mellitic anhydride. A compound can be mentioned.

As the above-mentioned component (c), which is a diol having one or more carboxyl groups in the molecule, various known compounds can be used, but preferred examples are bis (hydroxymethyl) prochionic acid, Examples thereof include glyceric acid, dihydroxybenzoic acids, fluorescin, orseric acid, mevalonic acid, pantoic acid, gallic acid, dihydroxycinnamic acids, dihydroxyphenylacetic acid and the like. Various known compounds can be used as the trihydric alcohol or the tetrahydric or higher alcohol which is the component (c), and preferred examples thereof include glycerin, trihydroxytriphenylmethanes and trihydroxyacetophenone. , Trihydroxyanthraquinones, benzenetriols pyrogallol, hydroxyhydroquinone, and phloroglucinol, naphthalpyrogallol, cyanuric acid, shikimic acid, trihydroxybenzoic acid, pentaerythritol,
Examples thereof include compounds such as tetrahydroxyanthraquinone, tetroquinone, tetrahydroxybenzophenone and hexaphenol.

These compounds containing one or both of a carboxyl group and a hydroxyl group in one molecule and having a total number of the groups of 3 or more may be used in combination of two or more kinds. 0.1 to 5 mol% is contained in the polymer raw material. If it is less than 0.1 mol%, the resolution tends to be low, and if it is more than 5 mol%, gelation tends to occur during synthesis, which is not preferable. More preferably, it is contained in an amount of 0.1 to 3 mol%. More preferably, it is contained in an amount of 0.4 to 2 mol%.

The unsaturated polyester prepolymer used in the present invention is desired by dehydration polycondensation (esterification) of the above (a), (b) and (c) at 200 to 230 ° C. under a nitrogen atmosphere and reduced pressure. The unsaturated bond concentration and the number average molecular weight are adjusted. In the dehydration polycondensation reaction of the ethylenically unsaturated polyester, the dicarboxylic acid component (a) and the diol component (b) contain one or both of a carboxyl group and a hydroxyl group in one molecule, and In the total sum with the compound (c) having a total number of 3 or more, the molar ratio of the carboxyl group is preferably in the range of 0.9 to 1.1 times the molar ratio of the hydroxyl group. When the molar ratio of the carboxyl group is less than 0.9 times or more than 1.1 times the molar ratio of the hydroxyl group, dehydration polycondensation becomes difficult to proceed, and it becomes difficult to control the acid value and the average molecular weight, which is not preferable. .

In the dehydration polycondensation reaction of the ethylenically unsaturated polyester, the reaction temperature can be lowered by using a catalyst as compared with the case where no catalyst is used, and as a result, a dicarboxylic acid having an unsaturated group is obtained. It is preferable in terms of preventing decomposition and gelation of the like. Although various known compounds can be used as the catalyst, preferred examples thereof include paratoluenesulfonic acid monohydrate, sodium paratoluenesulfonate, tetrabutyl zirconate, zirconium naphthenate, tetrabutyl titanate and tetra. Examples include compounds such as octyl titanate, 3/1 stannous oxalate / sodium acetate + zinc acetate, 3/1 stannous oxalate-sodium acetate. The amount added is preferably about 0.1 to 5% by weight based on the total raw materials.

The number average molecular weight of this unsaturated polyester prepolymer is in the range of 500 to 5,000. When the molecular weight is less than 500, there is a problem in practical use because the shrinkage is too large and the sensitivity is too low. On the other hand, when it exceeds 5,000, the viscosity is high and development failure is likely to occur. The photosensitive resin composition using this unsaturated polyester prepolymer is usually used as a liquid photosensitive resin without being diluted with a solvent or the like, and therefore has a molecular weight of 800 to 800 from a practical viewpoint such as viscosity, film-forming property and developability. The range of 4000 is more preferable. The number average molecular weight can be controlled by changing the temperature, pressure and time of the polycondensation reaction. In order to measure the number average molecular weight, it is convenient to titrate with a KOH standard solution to obtain the acid value and then calculate it from the molar concentration of unreacted carboxyl groups.

The polymerizable monomer used in the present invention includes
Although various known compounds can be used, preferred examples include diethylene glycol dimethacrylate,
Mono- or diacrylates and methacrylates of ethylene glycol or polyethylene glycol, including tetraethylene glycol dimethacrylate,
Propylene glycol or polypropylene glycol mono- or diacrylates and methacrylates, glycerol mono-, di- or triacrylates and methacrylates, cyclohexane diacrylates and dimethacrylates, 1,4-butanediol diacrylates and dimethacrylates, 1,6-hexanediol Diacrylates and dimethacrylates, neopentyl glycol diacrylates and dimethacrylates, bisphenol A mono- or diacrylates and methacrylates, benzene trimethacrylate, isobornyl acrylates and methacrylates, acrylamides and their derivatives, methacrylamides and their derivatives, Methylolpropane triacrylate and methacrylate Di pentaerythritol, birds,
Alternatively, compounds such as tetraacrylate and methacrylate, and ethylene oxide or propylene oxide adducts of these compounds can be given.

Even if these polymerizable monomers are used alone, 2
One or more species may be used in combination, and it is preferable to use it in the range of 10 to 75 parts by weight with respect to 100 parts by weight of the prepolymer having an ethylenically unsaturated group of the present invention. further,
In the present invention, the monomer component has 3 or more acryloyl groups or 3 or more methacryloyl groups in one molecule, and has 15 carbon atoms bonded to the acryloyl group or methacryloyl group. Monomers having up to and including 4 carbon or oxygen atoms bonded are pitch 50
It is a preferable component for forming a resin cured product pattern having a high density and a high aspect ratio of less than or equal to μm. That is, in order to prevent the resin pattern from falling or tilting, it is necessary to increase the crosslink density during photopolymerization to give the pattern strength.

On the other hand, the photosensitive resin composition must be completely removed by the developing liquid in order to plate the unexposed portion on the conductive substrate, and the light wraps around due to scattering and reflection of the exposure system. The photosensitive resin composition should not polymerize or crosslink so that it cannot be removed by the developing liquid. That is, since it is necessary to increase the difference in crosslink density between the image portion and the unexposed portion, at least one of the monomer components is a polymerizable monomer having at least three acryloyl groups or methacryloyl groups in one molecule. It is preferable to use a monomer.

When only a polymerizable monomer having 2 or less acryloyl groups or methacryloyl groups is used, or even when a polymerizable monomer having 3 or more acryloyl groups or methacryloyl groups is used, Alternatively, even if a monomer having 16 or more carbon or oxygen atoms between carbon atoms to which a methacryloyl group is bonded is used, a sufficient crosslinked density of a cured resin pattern for carrying out the present invention cannot be obtained, and a pattern May become soft and fall down, or the patterns between adjacent parts may become more tight and stick together.

From the above viewpoints, one molecule has three or more acryloyl groups or three or more methacryloyl groups and 15 or less carbon atoms bonded to the acryloyl groups or methacryloyl groups. Monomers having atoms and bonded are more preferred in the present invention. The number of acryloyl groups or methacryloyl groups contained in this monomer is at least 3 in one molecule, but even if the number is more than necessary, the number of reactive groups involved in photoreaction is limited and contributes to the curing reaction. The degree is small, but rather remains as "scum" (semi-cured resin component residue) on the surface of the unexposed portion of the substrate, causing a serious problem such as defective plating adhesion in the subsequent plating process. The preferred range of the number of acryloyl groups or methacryloyl groups contained in this monomer is 3 to 10.

The meaning of having 15 or less carbon or oxygen atoms between the carbon atoms to which the acryloyl group or methacryloyl group is bonded is explained below. First, the carbon atom to which the acryloyl group or methacryloyl group is bonded is the carbon atom on the side of the hydroxyl group immediately after the ester bond with acrylic acid or methacrylic acid. The meaning of the carbon atom on the side of the hydroxyl group means the carbon atom bonded to the hydroxyl group generated when the ester is hydrolyzed. That is, it means that 15 or less carbon or oxygen atoms are bound to each other and do not include this carbon atom at the shortest. When this number is 0, it means that the carbon atoms are bonded to each other. Also,
It is not included when the carbon atoms are the same. In addition, the number of atoms between the carbon atoms is calculated based on the number of atoms between the carbon atoms among the remaining two or more carbon atoms for any one carbon atom among the three or more carbon atoms. The smallest number is selected and the number of atoms is defined as the number of atoms between the carbon atoms.

To give a specific example for explanation, trimethylolpropane trimethacrylate is an example in which the number of atoms between the carbon atoms is 1, and tri [acryloyl-di (oxyethyl)] trimethylolpropane is an example in which the number of atoms between the carbon atoms is 1.
An example of 0 is glycerol triacrylate, and an example of 1 is dipentaerythritol hexaacrylate. In a molecule, there are 3 or more acryloyl groups or 3 or more methacryloyl groups, and 15 carbon atoms or less are bonded between the carbon atoms to which the acryloyl group or methacryloyl group is bonded to form a bond. Examples of the monomer include trimethylolpropane triacrylate or methacrylate, triacryloyl or trimethacryloylethyl trimethylolpropane, di (ethyleneoxy) trimethylolpropane triacrylate or methacrylate, pentaerythritol triacrylate or methacrylate, pentaerythritol tetraacrylate or Methacrylate, dipentaerythritol tetra / penta / hexaacrylate or methacrylate, glycerol triacrylate or methacrylate, or this A compound having a structure in which a mono- or poly (oxyethyl) group or a mono- or poly (oxypropyl) group is inserted next to an acrylate or methacrylate ester group of the compound and obtained by condensing a compound having three or more hydroxyl groups Specific examples include compounds in which an acryloyl group or a methacryloyl group is introduced into 3 to 10 hydroxyl groups of polyhydric alcohols and alkyl polyols such as vinyl alcohol oligomers.

These monomers may be used alone or 2
You may use combining the component of more than 1 type. If the content of these monomers is too small, the strength of the resin image pattern is low and the effect of the present invention cannot be sufficiently exhibited, and if the content is too large, there are disadvantages such as cracking of the pattern.
Moreover, the preferable content of the above-mentioned monomer with respect to the photosensitive resin composition is 1-50 with respect to 100 parts by weight of the prepolymer.
Parts by weight, more preferably 3 to 50 parts by weight are used. The monomer can be detected by liquid chromatography or gas chromatography.

As the photopolymerization initiator used in the present invention,
For example, benzoin, benzoin alkyl ethers,
2,2-dimethoxy-2-phenylacetophenones,
Examples thereof include benzophenone. The amount of photopolymerization initiator is
0.1 to 10% by weight is preferably used with respect to the photosensitive resin composition. If the amount of the photopolymerization initiator is less than 0.1% by weight with respect to the photosensitive resin composition, the curing of the image area is incomplete, which is not preferable. Is bad and not preferable. 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 liquid photosensitive resin composition to ultraviolet rays is in a practically more preferable range from the viewpoint of exposure time and ease of handling.

The photosensitive resin composition of the present invention may also contain a light absorber. The light absorber in the present invention may be any dye such as a dye or an ultraviolet absorber as long as it has absorption in the wavelength range of 300 to 420 nm and can be uniformly dissolved or dispersed in the photosensitive resin composition. This light absorber efficiently absorbs light wraparound due to scattering and reflection of the exposure system and prevents the photosensitive resin composition of the portion which should not be originally cured from being hardened so that it cannot be removed by the developing liquid. There is.

In the present invention, it is important to improve the resolution by controlling the light transmittance of the liquid photosensitive resin composition by the combination of the photopolymerization initiator and the light absorber.
For example, when the film thickness is set to a constant thickness in the range of 20 to 400 μm and light in the wavelength range of 300 to 420 nm is used, the molar absorption coefficient at the light absorption maximum at the wavelength is 5
0.1 to 10% by weight of a photopolymerization initiator of about 1000 liter / mol · cm, and 0.01 to 1% by weight of a light absorber so that the light transmittance is 15 to 75%. To This can prevent the liquid photosensitive resin composition in the unexposed portion from being hardened, so that the film thickness is 120, for example.
Even with a thick film of μm, high resolution of 50 μm or less in resolution pitch can be exhibited. Moreover, since the developability of the unexposed area can be improved, it is extremely unlikely that the conductor will be broken or thinned when a conductor is formed on the conductive substrate by plating, etc. A membrane conductor can be formed.

Further, the compounding ratio of the photopolymerization initiator and the light absorber is such that the light absorber reduces the light transmittance of the liquid photosensitive resin composition by 15% or more.
When it is 75%, it is substantially effective. Light transmittance of 15%
If it is less than 75%, the curing of the image area is incomplete, which is not preferable, and if it is more than 75%, the developability of the unexposed area deteriorates, which is not preferable. The liquid photosensitive resin composition of the present invention may be added with various components other than those mentioned above as needed for the purpose of obtaining a better resin pattern or for convenience of handling. For example, a polymerizable monomer having a phosphoric acid group in order to further improve the adhesion with a conductive substrate, a thermal polymerization inhibitor in order to improve the storage stability of the liquid photosensitive resin composition, etc. are included as components. Good.

Next, a method of manufacturing a thick film conductor circuit using the liquid photosensitive resin composition will be described. That is, the liquid photosensitive resin composition of the present invention is applied onto a conductive substrate and exposed through a photomask or the like with a high energy ray such as a mercury lamp, and then the unexposed portion of the liquid photosensitive resin composition. Is dissolved or dispersed by a developing solution of a weak alkaline aqueous solution such as a 1% aqueous sodium borate solution or an organic amine-based aqueous solution to form a desired resin pattern on the conductive substrate, and then a conductor is formed by electrolytic plating. This is then achieved by removing the conductive substrate.

As a method of removing the conductive substrate, for example, a method of etching with an aqueous solution of acid, alkali or salt,
A method of polishing and scraping, a method of mechanically peeling, or a combination thereof can be used. Further, in order to improve the strength of the thick film conductor circuit, a method of adhering an insulating material to the surface of the thick film conductor circuit on the side opposite to the conductive substrate may be used before or after the removal of the conductive substrate. Further, a plurality of thick film conductor circuits may be laminated via an insulating material.

If necessary, the resin image portion may be removed before transferring the thick film conductor circuit to the insulating substrate or after removing the conductive substrate by transferring. The coating thickness of the photosensitive resin composition is not particularly limited and is determined by the required conductor thickness of electronic parts, precision circuit boards and the like. The conductive substrate is not particularly limited, but a substrate made of aluminum, copper or the like is preferably used. If necessary, the conductive substrate may be subjected to a physical or chemical surface treatment in order to improve the adhesion between the conductive substrate and the photosensitive resin composition or the plating film.

In particular, a substrate obtained by subjecting an aluminum substrate to zincate treatment (substitution plating of zinc) has high adhesion to the photosensitive resin composition of the present invention, and has a low light diffusion reflectance of 20% or less on the surface. A good resin image without fog can be formed. The present invention will be described in detail below with reference to examples. The present invention is not limited to the examples.

[0054]

Example An unsaturated polyester prepolymer was produced by performing a dehydration polycondensation reaction as described below with various compositions as shown in Tables 1 to 3. That is, each raw material composition was charged into a 2 liter separable flask equipped with a fractionating tube and a decompression device, and 0.25 g of 4-methoxyphenol and 2.5 g of triethanolamine phosphate were added as a thermal polymerization inhibitor. Then, 5 g of paratoluenesulfonic acid monohydrate as a catalyst was added, and the temperature was raised to 150 ° C. under normal pressure while stirring and introducing nitrogen, and kept for 1 hour.
Then, the temperature was raised to 200 ° C. and kept for 2 hours, then 300
The pressure was reduced to Torr and maintained for 2 hours to obtain unsaturated polyester prepolymers 1 to 11 having acid values (number average molecular weight) as shown in Tables 1 to 3.

100 parts by weight of each unsaturated polyester prepolymer, tetraethylene glycol dimethacrylate 10.7 parts, diethylene glycol dimethacrylate 4.3 parts, pentaerythritol trimethacrylate 15 parts, phosphoric acid (monomethacryloyloxyethyl) 3 .6 parts, 2,2-dimethoxy-2-phenylacetophenone 2 parts, 2,6-di-tert-butyl-4-
Methylphenol 0.04 parts, OPL manufactured by Orient Chemical Co., Ltd.
0.11 part of AS Yellow 140 was added and mixed with stirring to prepare photosensitive resin compositions 14 to 24, respectively. These photosensitive resin compositions were made into Examples 1-11. When the light transmittance at 365 nm of the obtained liquid photosensitive resin composition was measured by Hitachi U-3210 type spectrophotometer, it was 25 to 35% at a film thickness of 100 μm.

An aluminum substrate having a thickness of 100 μm made by Toyo Aluminum Co., Ltd. is subjected to buff roll polishing (buff material: 3M, HD
Flap S-SF # 600), and treated with Substar ZN-2 treatment liquid of Okuno Chemical Industries Co., Ltd. at 30 ° C. for 60 seconds for zincate treatment, once etched with 15% nitric acid for 60 seconds, and again treated with zincate. A conductive substrate was produced. Thickness of each of the above-mentioned photosensitive resin compositions of 14 to 24 after curing via a PET film having a thickness of 10 μm on a photomask having a pattern including wiring portions having a pitch of 20 μm to 100 μm (10 to 50 lines / mm) Was uniformly applied at 100 μm and 120 μm, and the conductive substrate was laminated thereon. It was exposed using parallel light from a mercury short arc lamp, developed with a 1% aqueous sodium borate solution, and rinsed with hot water at 90 ° C. for 10 minutes to perform post-curing.

Next, strike plating was performed for 6 minutes at a current density of 3 A / dm ² using a copper pyrophosphate plating solution manufactured by Murata Co., Ltd., and copper sulfate was plated thereon to a thickness of 1
A conductor pattern of 00 to 120 μm was formed. This conductor pattern was transferred to a glass epoxy substrate using an adhesive and the aluminum substrate was etched and removed with hydrochloric acid to prepare a thick film conductor pattern. The thick film conductor pattern was evaluated as follows, and the results are shown in Tables 4 and 5.
It was shown to. If there was no plating due to poor development or the resin was inclined and stuck as shown in FIG. 1, the defective wiring was defined as the minimum wiring pitch that could be resolved. When scum was generated between the resins, it was determined that scum occurred. The rate at which the relief width changed compared to the design value was described as the shrinkage rate.

[0058]

Comparative Example Prepolymer No. 3 in Table 3 Unsaturated polyester prepolymers 12 and 13 were prepared by performing dehydration polycondensation reaction in the same manner as in the examples, except that only the charged composition was changed to a ratio different from that in the examples as shown in 12 and 13. That is, the content of the component of compound (x) or compound (y) containing either or both of a carboxyl group and a hydroxyl group and the total number of the groups is 3 or more is outside the scope of the present invention.

100 parts by weight of each unsaturated polyester prepolymer, tetraethylene glycol dimethacrylate 10.7 parts, diethylene glycol dimethacrylate 4.3 parts, pentaerythritol trimethacrylate 15 parts, phosphoric acid (monomethacryloyloxyethyl) 3 parts .6 parts, 2,2-dimethoxy-2-phenylacetophenone 2 parts, 2,6-di-tert-butyl-4-
Methylphenol 0.04 parts, OPL manufactured by Orient Chemical Co., Ltd.
0.11 part of AS Yellow 140 was added and mixed with stirring to prepare photosensitive resin compositions 25 and 26. These photosensitive resin compositions were designated as Comparative Examples 1 and 2. When the light transmittance at 365 nm of the obtained liquid photosensitive resin composition was measured by Hitachi U-3210 type spectrophotometer, it was 25 to 35% at a film thickness of 100 μm. A thick film conductor pattern was formed and evaluated in the same manner as in the example.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

As can be seen from Tables 4 and 5, in the range of the examples of the present invention, while exhibiting extremely high resolution with a thick film, the shrinkage of the relief width is suppressed and scum is not generated. Even when the conductor thickness is large, it is possible to stably manufacture the thick film conductor circuit.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thick film conductor circuit manufactured by liquid photosensitive resin and plating.

[Explanation of symbols]

1 Photosensitive resin cured product 2 plated conductor 3 short 4 disconnection

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[Procedure amendment]

[Submission date] September 6, 2001 (2001.9.6)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

That is, 1. In the liquid photosensitive resin composition containing a prepolymer having an ethylenically unsaturated group, a polymerizable monomer, and a photopolymerization initiator, the prepolymer is (a) dicarboxylic acid or
Alternatively, the number average molecular weight obtained by condensation of the anhydride thereof , (b) diol, and (c) a compound containing either or both of a carboxyl group or a hydroxyl group and having a total number of the groups of 3 or more is It is an unsaturated polyester prepolymer of 500 to 5000, and the raw material of the prepolymer is the prepolymer raw material (a) + (b) +
A liquid photosensitive resin composition for a thick film conductor circuit, characterized in that it is contained in an amount of 0.1 to 5 mol% with respect to (c). 2. The polymerizable monomer has 3 or more acryloyl groups or 3 or more methacryloyl groups in one molecule,
And at least one compound having 15 or less carbon atoms or oxygen atoms bonded between the carbon atoms to which the acryloyl group or methacryloyl group is bonded, and 100 parts by weight of the prepolymer of item 1 above 1 to 50 parts by weight, and the molar absorption coefficient at the light absorption maximum in the wavelength range of 300 to 420 nm is 5 to 1000.
0.1 to 10 liter / mol · cm photopolymerization initiator
%, And 0.01 to 1% by weight of a light absorber, and the light transmittance in the wavelength range is 15 to 75%. Resin composition. 3. The compound (c) has the following chemical formulas 1, 2, 3, or 4
The liquid photosensitive resin composition for thick film conductor circuits according to the above item 1 or 2, wherein the liquid photosensitive resin composition is a compound represented by:

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

In the dehydration polycondensation reaction of the ethylenically unsaturated polyester, the reaction temperature can be lowered by using a catalyst as compared with the case where no catalyst is used, and as a result, a dicarboxylic acid having an unsaturated group is obtained. It is preferable in terms of preventing decomposition and gelation of the like. Although various known compounds can be used as the catalyst, preferred examples thereof include paratoluenesulfonic acid monohydrate, sodium paratoluenesulfonate, tetrabutyl zirconate, zirconium naphthenate, tetrabutyl titanate and tetra. Examples include compounds such as octyl titanate, 3/1 stannous oxalate / sodium acetate + zinc acetate, 3/1 stannous oxalate / sodium acetate. The amount added is preferably about 0.1 to 5% by weight based on the total raw materials.

Claims (5)

[Claims] 1. A liquid photosensitive resin composition comprising a prepolymer having an ethylenically unsaturated group, a polymerizable monomer and a photopolymerization initiator, wherein the prepolymer is (a) a dicarboxylic acid or a dicarboxylic acid thereof. An anhydride and (b) diol,
(C) A polyester prepolymer obtained by condensation with a compound containing one or both of a carboxyl group or a hydroxyl group and having a total number of groups of 3 or more, wherein the number average molecular weight of the prepolymer is 500 to 5000
And the raw material of the prepolymer is the component (c) of 0.1 to 0.1 with respect to the prepolymer raw material (a) + (b) + (c).
A liquid photosensitive resin composition for a thick film conductor circuit, characterized in that the liquid photosensitive resin composition contains 5 mol%. 2. The polymerizable monomer has 3 or more acryloyl groups or 3 or more methacryloyl groups in one molecule, and between carbon atoms to which the acryloyl group or methacryloyl group is bonded. It is at least one compound having 15 or less carbon atoms or oxygen atoms and bonded, and is contained in an amount of 1 to 50 parts by weight based on 100 parts by weight of the prepolymer of claim 1, and further 300 to 42.
The molar absorption coefficient at the optical absorption maximum in the wavelength range of 0 nm is 5
0.1 to 10% by weight of a photopolymerization initiator of about 1000 liter / mol · cm and 0.01 to 1% by weight of a light absorber.
The liquid photosensitive resin composition for a thick film conductor circuit according to claim 1, wherein the light transmittance in the wavelength range is 15 to 75%. 3. The compound (c) is a compound represented by the following chemical formulas 1 to 3, wherein:
The liquid photosensitive resin composition for a thick film conductor circuit described. [Chemical 1] (Of the formula in R1, R2, R3, R4, - (CH 2) m O
H, or - or (CH ₂₎ one of _n COOH three groups or more,
Or if you put both together in a total of 3 or more,
-H or represents a -CH _3. However, m = 0 to 8, n
= 0-8. ) [Chemical 2] (Of the formula in R1, R2, R3, R4, - (CH 2) m O
H, or - or (CH ₂₎ one of _n COOH three groups or more,
Or if both are combined, there will be 3 or more units
H, or an -CH _3. However, m = 0 to 8, n = 0
~ 8. ) [Chemical 3] (In the formula, among R1, R2, R3, R4, R5, and R6,
One of (CH ₂ ) _m OH or-(CH ₂ ) _n COOH is 3 or more, or both are 3 or more,
Otherwise -H, or an -CH _3. However, m =
0-8 and n = 0-8. ) [Chemical 4] (In the formula, among R1, R2, R3, R4, R5, and R6,
One of (CH ₂ ) _m OH or — (CH ₂ ) _n COOH is 3 or more, or both are 3 or more,
Otherwise -H, or an -CH _3. However, m = 0
8 and n = 0-8. ) 4. The liquid photosensitive material for a thick film conductor circuit according to claim 1, wherein the compound (c) is a compound represented by the following chemical formulas 5, 6 or 7 or a dianhydride thereof. Resin composition. [Chemical 5] (In the formula, R1, R2, R3, R4, R5, R6, R7, R
Of _{8, - (CH 2) m} OH, or - (CH _{2) n} CO
One of OH is 3 or more, or both are 3 or more, and the rest is -H or -CH ₃ . However, m = 0-2 and n = 0-2. ) [Chemical 6] (In the formula, R1, R2, R3, R4, R5, R6, R7, R
8, R9, among _{R10, - (CH 2) m} OH or -
One or more of (CH ₂ ) _n COOH is 3 or more, or a combination of both is 3 or more, and the other is -H or-.
Represents CH ₃ . However, m = 0-2 and n = 0-2. ) [Chemical 7] (In the formula, R1 is -O-, -CO- or -C (CH
₃ ) ₂₋ is replaced with R2, R3, R4, R5, R6, R7, R
8, R9, R10, of _{R11, - (CH 2) m} OH,
Alternatively, one of — (CH ₂ ) _n COOH has 3 groups or more, or a combination of both groups has 3 or more groups;
Or it represents a -CH _3. However, m = 0-2, n = 0-2
Is. ) 5. The liquid photosensitive resin composition for a thick film conductor circuit according to claim 1, wherein the compound (c) is citric acid or glycerin.