WO2012077461A1

WO2012077461A1 - Photoreactive resin composition

Info

Publication number: WO2012077461A1
Application number: PCT/JP2011/076101
Authority: WO
Inventors: 久保田　正博; 修一砥綿
Original assignee: 株式会社村田製作所
Priority date: 2010-12-07
Filing date: 2011-11-11
Publication date: 2012-06-14
Also published as: JPWO2012077461A1; CN103069340A; JP5447691B2; CN103069340B

Abstract

[Problem] To provide a photoreactive resin composition which gives a coating film having excellent developability and which is used in the production of a circuit board, a multilayered substrate, or the like when a desired conductor pattern is formed on a substrate surface or on each of the substrates for constituting the multilayered substrate or the like. [Solution] A photoreactive resin composition which comprises (A) an electroconductive powder, (B) an acrylic copolymer or a cellulosic resin each containing carboxy groups, (C) a mixture of dipentaerythritol pentaacrylate and hexaacrylate, and (D) a photopolymerization initiator. The photoreactive resin composition is characterized in that the mixture of dipentaerythritol pentaacrylate and hexaacrylate (C) has a penta form ratio, represented by (penta form)/[(penta form)+(hexa form)], of 25 mol% or more and an oligomer content, represented by oligomer/[(penta form)+(hexa form)+oligomer], of 33 mol% or less.

Description

Photoreactive resin composition

The present invention relates to a photoreactive resin composition used for forming a desired conductor pattern on a substrate surface or each substrate constituting the multilayer substrate, for example, in the production of a circuit board, a multilayer substrate, or the like. .

In recent years, higher functionality and higher performance of electronic devices are accelerating, and electronic components used in such electronic devices are also required to be downsized. Therefore, the wiring pattern used for such an electronic component is also required to cope with higher density and higher speed. In order to achieve higher density and higher signal speed, it is necessary to refine the wiring pattern and the like.

In order to form fine thick film conductor wiring and via holes on the substrate as described above, after applying a negative photoreactive resin composition containing a photoreactive organic component and conductive powder to the substrate, A photolithography method that performs exposure / development processing is effective.

However, since the conductive powder scatters without transmitting any light, it is difficult for the light during exposure to reach the lower part of the coating film. Therefore, as the acrylic monomer contained in the photoreactive resin composition, a dipentaerythritol pentaacrylate / hexaacrylate mixture having a large number of functional groups and high sensitivity is preferably used (see Patent Document 1).

JP 2000-199954 A

However, when a dipentaerythritol pentaacrylate / hexaacrylate mixture is used as the acrylic monomer, the developability of the coating film is deteriorated, and there is a problem that fine wiring cannot be stably formed.

Therefore, the main object of the present invention is to develop a coating film used for forming a desired conductor pattern on a substrate surface or each substrate constituting the multilayer substrate in the production of a circuit board or a multilayer substrate. It is providing the photoreactive resin composition excellent in the property.

The photoreactive resin composition according to the present invention includes (A) conductive powder, (B) an acrylic copolymer or cellulose resin containing a carboxyl group, (C) a dipentaerythritol pentaacrylate / hexaacrylate mixture, (D) a photopolymerization initiator, and a penta ratio of dipentaerythritol pentaacrylate / hexaacrylate mixture represented by penta / (penta + hexa) is 25 mol% or more, oligomerized / (penta The photoreactive resin composition is characterized in that the amount of oligomerization represented by (body + hexabody + oligomerized body) is 33 mol% or less.

The inventors have found that the amount of hexa- and oligomerized compounds contained in the dipentaerythritol pentaacrylate / hexaacrylate mixture has an influence on the deterioration of the developability of the coating film.
According to the photoreactive resin composition of this invention, the penta ratio of the dipentaerythritol pentamer / hexaacrylate mixture is 25 mol% or more and the oligomerization amount is 33 mol% or less, whereby the wiring formed on the substrate Even if the pattern is fine, a photoreactive resin composition having excellent coating film developability can be obtained.

The above-mentioned object, other objects, features, and advantages of the present invention will become more apparent from the following description of embodiments for carrying out the invention.

Hereinafter, in one embodiment of the present invention, (A) conductive powder constituting the photoreactive resin composition, (B) an acrylic copolymer or cellulose resin containing a carboxyl group, (C) dipentaerythritol Each component of the pentaacrylate / hexaacrylate mixture and (D) photopolymerization initiator will be described.

In one embodiment of the (A) conductive powder present invention, as the conductive powder, Cu, Ni, Ag, Au, can be used Pt and alloys containing at least one.

The conductive powder may have various shapes such as a spherical shape, a flake shape, and a needle shape, but it is preferable to use a spherical shape in consideration of optical characteristics and dispersibility. Here, the average particle size of the conductive powder is preferably in the range of 1 to 5 μm. When the average particle diameter is smaller than 1 μm, when the same volume of conductor powder is added to the resin, the surface area of the powder increases, so that more light is blocked and the light transmittance into the paste is reduced. On the other hand, when the thickness exceeds 5 μm, the surface roughness when the conductive paste is applied is increased, and the pattern accuracy and dimensional accuracy are further reduced.

The composition ratio of the conductive powder in the photoreactive resin composition is preferably 30 to 50% by volume in the components excluding the organic solvent. When the composition ratio of the conductive powder is less than 30% by volume, the line width shrinkage or disconnection of the conductor pattern is likely to occur. On the other hand, when it exceeds 50% by volume, the light transmission is impaired and sufficient light of the composition is obtained. It becomes difficult to obtain curability.

(B) Acrylic copolymer or cellulose resin containing a carboxyl group In one embodiment of the present invention, the acrylic copolymer containing a carboxyl group includes, for example, an unsaturated carboxylic acid and an ethylenically unsaturated compound. It can be produced by copolymerization. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, vinyl acetic acid, and anhydrides thereof. On the other hand, examples of the ethylenically unsaturated compound include acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, and fumaric esters such as monoethyl fumarate.

Moreover, as a cellulose resin containing a carboxyl group, a carboxyl group-containing cellulose derivative represented by the following chemical formula 1 or a compound having a glycidyl group and an unsaturated double bond and / or an isocyanate group in a carboxyl group-containing cellulose derivative And a compound obtained by adding a compound having an unsaturated double bond.
In Chemical Formula 1, R ₁ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, —CR ₂ COOH (R ₂ represents an alkyl group having 2 to 4 carbon atoms, a phenyl group, or a cyclohexyl group), —C ₃ H ₆ represents OH or —COCH ₃ , each R ₁ may be the same or different and contains at least 0.1 mol of —CR ₂ COOH per glucose unit.

In one embodiment of the present invention, the composition ratio of the acrylic copolymer or cellulose resin containing a carboxyl group is preferably 16 to 53 wt% in the total of (B) to (D). If this composition ratio is less than 16% by weight, the distribution of these resins in the coating film to be formed tends to be non-uniform, so it becomes difficult to obtain sufficient photocurability and photocuring depth. Patterning by development becomes difficult. On the other hand, if it exceeds 53% by weight, the pattern is liable to be distorted or the line width is shrunk during firing.

(C) Dipentaerythritol pentaacrylate / hexaacrylate mixture Since the conductive powder scatters without transmitting light at all, the light at the time of exposure hardly reaches the lower part of the coating film. Therefore, a dipentaerythritol pentaacrylate / hexaacrylate mixture having a large number of functional groups and high sensitivity is suitably used as the composition of the photoreactive resin. The dipentaerythritol pentaacrylate / hexaacrylate mixture is produced by esterifying dipentaerythritol with acrylic acid in the presence of an acid catalyst and an organic solvent. The esterification reaction cannot proceed 100%. A partial polymerization reaction occurs during the preparation of the dipentaerythritol pentaacrylate / hexaacrylate mixture. Therefore, actually, it is composed of three types of dipentaerythritol pentaacrylate (penta), dipentaerythritol hexaacrylate (hexa), and oligomerized product. Among these, the hexa-body and the oligomerized body deteriorate the developability of the coating film. Therefore, deterioration of the developability of this coating film can be prevented by controlling the penta ratio to 25 mol% or more and controlling the oligomerization amount to 33 mol% or less. Here, the penta ratio is pentamer / (penta body + hexa body), and the oligomerization amount is defined by oligomerization body / (penta body + hexa body + oligomer body).

Incidentally, examples of the acid catalyst used for esterification include sulfuric acid and paratoluenesulfonic acid. Examples of the organic solvent used for esterification include aromatic hydrocarbons such as toluene, benzene, and xylene, aliphatic hydrocarbons such as hexane and heptane, and ketones such as methyl ethyl ketone.

In one embodiment of the present invention, the composition ratio of the dipentaerythritol pentaacrylate / hexaacrylate mixture is preferably 30 to 70% by weight in the total of (B) to (D). By setting it as such a composition ratio, while the coating-film intensity | strength after photocuring is high, while being able to obtain sufficient photocuring depth, a coating film does not have stickiness and can have favorable handling property.

(D) Photopolymerization initiator The photopolymerization initiator is added to start polymerization for curing the exposed area. Photopolymerization initiators include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (initiator a), 2,4-diethylthioxanthone (initiator b), ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime) (initiator c), bis (2,4,6-trimethylbenzoyl) ) -Phenylphosphine oxide (initiator d) and 1-hydroxy-cyclohexyl-phenyl-ketone (initiator e) are used in combination.

In particular, the content of the initiator c, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime) is 10 to 60% by weight in the initiator is preferred. By setting it as such content, favorable solubility can be given, without increasing a required exposure amount so much. As the initiator c, for example, Irgacure OXE02 manufactured by Ciba Specialty Chemicals can be used.

In one embodiment of the present invention, the composition ratio of the photopolymerization initiator is preferably 12 to 22% by weight in the total of (B) to (D). By setting it as such content, the preservation | save stability of a resin composition can be made excellent, implement | achieving sufficient resolution.

(E) an organic solvent other, in the photoreactive resin composition according to the present invention, if necessary, an organic solvent, pentamethylene glycol and dipropylene glycol monomethyl ether or the like may be contained.

(F) Other organic components Further, in the photoreactive resin composition according to the present invention, a thixotropic agent, a dispersant, an antigelling agent, and a leveling agent may be used as necessary. . As the leveling agent, a special acrylic polymer is used. Preferably, the leveling agent is an ethyl carbitol acetate solution. When used for pentamethylene glycol and dipropylene glycol monomethyl ether, which are organic solvents, the SP value (solubility) of this leveling agent is preferably 8.0 to 9.5.

Further, the photoreactive resin composition according to the present invention may contain inorganic powder such as glass powder and ceramic powder. Thereby, adhesiveness with a board | substrate can be improved. As the glass powder, known glass powder such as borosilicate glass can be used. As the ceramic powder, known low-temperature sintered ceramic powders such as alumina and zirconia, crystallized glass ceramics, glass composite ceramics, non-glass ceramics, and the like can be used.

Photoreactive resin compositions were prepared as follows and evaluated.
1. Production of Photoreactive Resin Composition In this example, each material used for production of the photoreactive resin composition is as follows.

(A) Conductive powder Copper powder: oxygen content 1.2% by weight, average particle size 3 μm, spherical.
Composition ratio: 38% by volume (in the components excluding the organic solvent)
(B) Acrylic copolymer or cellulose resin containing a carboxyl group Polymer a: After copolymerization of methacrylic acid / methyl methacrylate, 0.2 times molar amount of epoxycyclohexylmethyl methacrylate is added to methacrylic acid. An ethylenically unsaturated double bond-containing acrylic copolymer subjected to addition reaction. Weight average molecular weight Mw = 20000. Acid value = 100 mg KOH / g.
Polymer b: After copolymerized methacrylic acid / methyl methacrylate, acrylic copolymer obtained by addition reaction of 0.2 moles of epoxy ethylbenzene relative to methacrylic acid. Weight average molecular weight Mw = 24000. Acid value = 90 mg KOH / g.
(C) Dipentaerythritol pentaacrylate / hexaacrylate mixture Monomer 1: Penta ratio 55 mol%, oligomerization amount 31 mol%
Monomer 2: Penta ratio 45 mol%, oligomerization amount 30 mol%
Monomer 3: Penta ratio 35 mol%, oligomerization amount 31 mol%
Monomer 4: Penta ratio 30 mol%, oligomerization amount 31 mol%
Monomer 5: Penta ratio 25 mol%, oligomerization amount 33 mol%
Monomer 6: Penta ratio 25 mol%, oligomerization amount 35 mol%
Monomer 7: Penta ratio 20 mol%, oligomerization amount 33 mol%
Monomer 8: Penta ratio 30 mol%, oligomerization amount 35 mol%
Monomer 9: Penta ratio 35 mol%, oligomerization amount 44 mol%
Monomer 10: Penta ratio 20 mol%, oligomerization amount 30 mol%
Monomer 11: Penta ratio 10 mol%, oligomerization amount 32 mol%
Monomer 12: Penta ratio 20 mol%, oligomerization amount 35 mol%
Here, the penta ratio is pentamer / (penta body + hexa body), and the oligomerization amount is defined by oligomerization body / (penta body + hexa body + oligomer body).
(D) Photopolymerization initiator Initiator a: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one Initiator b: 2,4-diethylthioxanthone Initiator c: Ethanone , 1- [9-Ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime)
Initiator d: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Initiator e: 1-hydroxy-cyclohexyl-phenyl-ketone (E) organic solvent organic solvent a: pentamethylene glycol organic solvent b: di Propylene glycol monomethyl ether (F) and other organic components Thixotropic agent: Polyamide (solid content 70%)
Dispersant: High molecular weight polycarboxylic acid amidoamine salt (solid content 75%)
Anti-gelling agent: Benzotriazole Leveling agent: Special acrylic polymer (ethyl carbitol acetate solution, solid content 50%, SP value 8.81)

The above materials were weighed and mixed so that the weight ratios shown in Tables 1 and 2 below were obtained, except for the leveling agent. Next, kneading with a three-roll mill was performed, and leveling agents were weighed and mixed so that the weight ratios shown in Tables 1 and 2 were obtained. Samples 1 to 12 of the photoreactive resin composition were produced. The units in each table are% by weight except that the penta ratio and oligomerization amount are mol% and the resolution is μm.

2. Production of Ceramic Green Sheet First, 37.3 g of borosilicate glass powder, 24.9 g of alumina powder, and a copolymer having a copolymerization ratio of methacrylic acid / methyl methacrylate of 25/75 on a weight basis (weight average molecular weight Mw = 50000). ) 6.2 g, 3.1 g of ethanol and 0.5 g of dipropylene glycol monomethyl ether were mixed to prepare a slurry. And the produced slurry was shape | molded by the doctor blade method into the sheet form, and it was made to dry at 100 degreeC for 1 hour, and produced the ceramic green sheet of sheet | seat thickness of 30 micrometers. Dipropylene glycol monomethyl ether dissolves the above-mentioned ceramic green sheet, but does not dissolve when a dipentaerythritol pentaacrylate / hexaacrylate mixture having a weight of 0.5 times or more is added.

3. Measurement of resolution For each sample of the photosensitive conductive paste, after applying screen printing on the entire surface of the ceramic green sheet produced as described above, it was dried at 60 ° C. for 15 minutes to obtain a paste film having a thickness of 10 to 12 μm. Formed. Next, actinic rays having an exposure dose of 500 mJ / cm ² are irradiated from an ultrahigh pressure mercury lamp through a photomask in which a wiring pattern having the same thickness as the line (L) and the space (S) is drawn with a thickness of 12 to 50 μm. As a result, the paste film was exposed. Next, development processing was performed using a 0.5% aqueous sodium carbonate solution for a development time 1.1 times as long as the unexposed area development time.

Next, the wiring pattern was observed, and the resolution of each sample was judged based on the finest wiring pattern obtained. That is, among the wiring patterns in which the fine wiring pattern is not connected in the space (S) and the line (L) is not divided, the thickness value of the finest wiring pattern indicates resolution. Value.

4). Fabrication of Multilayer Substrate Further, the paste film is exposed to an actinic ray of 500 mJ / cm ² from an ultrahigh pressure mercury lamp through a mask drawn with a thickness of 13 μm using the paste of Sample 1 to perform an exposure process on the paste film. went. A pattern of L / S = 13/13 (μm) was formed by performing development with a 0.5% sodium carbonate aqueous solution for a development time 1.1 times as long as the unexposed area development time. Five ceramic green sheets were produced. Subsequently, these ceramic green sheets were superposed and hot pressed for 1 minute under the conditions of 200 MPa and 60 ° C. Next, after performing a degreasing treatment, a multilayer alumina substrate having a pattern of L / S = 10/10 (μm) formed on the inner layer could be produced by firing in N ₂ at 900 ° C. .

As can be seen from Tables 1 and 2, in Samples 1 to 5 in which the penta ratio of the dipentaerythritol pentaacrylate / hexaacrylate mixture is 25 mol% or more and the oligomerization amount is 33 mol% or less, the coating film developability deteriorates. Since it is suppressed, it can be seen that a high resolution of 15 μm or less can be obtained. On the other hand, samples 6 to 12 whose penta ratio is less than 25 mol% and samples whose oligomerization amount exceeds 33 mol% have only a resolution of about 25 to 30 μm because the film developability deteriorates. I understand.

According to the photoreactive resin composition of the present invention, coating film developability is excellent by setting the penta ratio of the dipentaerythritol pentamer / hexaacrylate mixture to 25 mol% or more and the oligomerization amount to 33 mol% or less. A photoreactive resin composition that enables formation of a fine wiring pattern can be obtained.

In addition, when the photoreactive resin composition according to the present invention is used, it is possible to form a fine wiring pattern as described above. Therefore, electronic components for high-frequency circuits such as chip coils, chip capacitors, and chip LC filters. It can be used for forming a conductor pattern for producing a multilayer substrate which is a high-frequency circuit substrate such as a high-frequency module (for example, VOC (voltage controlled oscillator)) or PLL (phase-locked loop)).

For the production of the circuit board or multilayer board in the examples of the present invention, a ceramic green sheet was produced by using alumina powder, and an alumina substrate was produced. However, the invention is not limited to this, but barium oxide, aluminum oxide Further, the substrate may be manufactured using a ceramic green sheet containing a ceramic mainly composed of silica. Moreover, you may produce a board | substrate using the ceramic green sheet containing glass ceramics.

Claims

(A) conductive powder,
(B) an acrylic copolymer or cellulose resin containing a carboxyl group,
(C) Dipentaerythritol pentaacrylate / hexaacrylate mixture,
(D) a photopolymerization initiator,
Containing
In addition, the penta ratio of dipentaerythritol pentaacrylate / hexaacrylate mixture represented by pentamer / (penta + hexa) is 25 mol% or more, and represented by oligomer / (penta + hexa + oligomer). The photoreactive resin composition, wherein the amount of oligomerization is 33 mol% or less.