JP2006278530A - Solder resist and thermosetting resin composition therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting resin composition that is low in linear expansion coefficient and is excellent in heat resistance; and to provide a thermosetting solder resist that is excellent in reliability of heat resistance, thermal shock properties, and of moisture resistance, and that is capable of drilling excellent fine opening with laser irradiation. <P>SOLUTION: The thermosetting resin composition for solder resist takes as essential components a compound having at least two or more epoxy groups, a compound having at least two or more cyanate groups, and an inorganic filling material. The compound having at least two or more epoxy groups in the thermosetting resin composition preferably contains two kinds of different weight average molecular weights. Further, the compound more preferably contains a compound having at least two or more epoxy groups of a ≥5000 weight average molecular weight and a compound having at least two or more epoxy groups of a weight average molecular weight of 5000 or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermosetting resin composition for solder resist and a solder resist using the same.

  2. Description of the Related Art In recent years, electronic devices have been rapidly becoming lighter, smaller, and more advanced, and semiconductor integrated circuits used in these devices are also becoming smaller and more highly integrated. Therefore, there is a dilemma that the number of wiring pins of an integrated circuit is increased compared to a conventional semiconductor package, but the mounting area and the package area are reduced, and therefore, a BGA (Ball Grid Array) different from the conventional package system is present. ) Method, and a package method with a high mounting density such as a CSP (Chip Scale Package) method has been proposed. In these semiconductor package systems, instead of the lead frame used in the conventional semiconductor package, a printed wiring board for mounting a semiconductor chip composed of various materials such as plastic and ceramics such as a substrate or an interposer is used. The electrical connection between the electrodes of the semiconductor chip and the printed wiring board is performed. Circuits constructed on this printed circuit board for mounting semiconductor chips are introduced into miniaturized and high-density electronic equipment, and the wiring is very thin compared to general printed circuit boards.・ Higher density. Therefore, in such a package format, when the semiconductor chip and the printed wiring board are electrically connected, the fine wiring is connected in a high temperature atmosphere by solder reflow or the like. Need to protect. As the protective layer, solder resists having various resin compositions have been developed.

On the other hand, a solder resist used for semiconductor mounting usually forms a solder pad opening, and a photomask having a pattern formed thereon is stacked at a position where the solder pad is placed, and is exposed by photographic method. A pattern is formed by development with a developer such as sodium carbonate, sodium hydroxide, or tetramethylammonium hydride (TMAH). However, as electronic devices are further reduced in size and capacity, the wiring is further miniaturized, so it is difficult to form fine apertures in the photographic method due to the influence of scattered light. Recently, the opening by laser has attracted attention (see, for example, Patent Document 1). However, when a conventional photosensitive resin is used for a solder resist that is opened by a laser, the photosensitive resin uses a thermosetting resin such as an epoxy resin, and depending on the composition of the resin that constitutes the photosensitive resin. In some cases, the accuracy of drilling due to laser drilling may be inferior, and as the solder reflow temperature increases in the mounting process due to lead-free soldering, cracks may occur during heating. Improvements in heat resistance, thermal shock resistance, moisture resistance reliability, and the like are desired.
JP 2003-101244 A

The present invention provides a thermosetting resin composition for a solder resist that has a low linear expansion coefficient and is excellent in reliability of heat resistance, thermal shock resistance, and moisture resistance when used as a solder resist.
The present invention provides a thermosetting solder resist having a low coefficient of linear expansion, excellent heat resistance, thermal shock resistance, and moisture resistance reliability and capable of forming fine holes by laser irradiation.

  The present inventors use a compound having at least two or more epoxy groups, a compound having at least two or more cyanate groups, and an inorganic filler as essential components, thereby having a low linear expansion coefficient, heat resistance, and thermal shock. Found a thermosetting resin composition for solder resists with excellent heat resistance and hygroscopicity, and further found that a solder resist obtained using the composition can provide fine pores by laser irradiation, leading to the completion of the present invention. It is a thing.

That is, the present invention is a thermosetting resin composition for a solder resist having as essential components a compound having at least two epoxy groups, a compound having at least two cyanate groups, and an inorganic filler.
The compound having at least two or more epoxy groups in the thermosetting resin composition for a solder resist of the present invention preferably includes two kinds having different weight average molecular weights, and more preferably has a weight average molecular weight of 5000 or more. It is more preferable to include a compound having at least two epoxy groups and a compound having a weight average molecular weight of less than 5000 and having at least two epoxy groups.
The compound having at least two epoxy groups is preferably a biphenyl type epoxy resin represented by the following formula (1) or a biphenyl aralkyl resin represented by the following formula (2).

[Wherein R ^{1 to} R ⁴ each represent one selected from a hydrogen atom, an alkyl group, and a phenyl group, and may be the same or different from each other. ]

[Wherein, R ^{5 to} R ¹² each represent one selected from a hydrogen atom, an alkyl group, and a phenyl group, and may be the same as or different from each other. However, a is an integer greater than or equal to 1. ]

The compound having at least two or more cyanate groups is preferably a novolac type cyanate resin.
In addition, the inorganic filler is preferably used by dispersing in a solvent containing a solvent that dissolves the compound having at least two or more epoxy groups and the compound having at least two cyanate groups. preferable.
Moreover, this invention is a thermosetting solder resist which comprises the said thermosetting resin composition for solder resists.

The present invention can provide a thermosetting resin composition for a solder resist having a low linear expansion coefficient and excellent heat resistance, thermal shock resistance, and moisture resistance reliability when a solder resist is used.
INDUSTRIAL APPLICABILITY The present invention can provide a thermosetting solder resist having a low coefficient of linear expansion, excellent reliability in heat resistance, thermal shock resistance, and moisture resistance and capable of forming fine holes by laser irradiation.

The present invention is a thermosetting resin composition for a solder resist having as essential components a compound having at least two epoxy groups, a compound having at least two cyanate groups, and an inorganic filler. Thereby, the thermosetting resin of the present invention is excellent in heat resistance and hygroscopicity, and the solder resist containing the thermosetting resin composition of the present invention is excellent in reliability such as thermal shock resistance and moisture resistance.
The present invention is a thermosetting resin composition for a solder resist, comprising as essential components a compound having at least two epoxy groups, a compound having at least two cyanate groups, and an inorganic filler.
The compound having at least two or more epoxy groups in the thermosetting resin composition for a solder resist of the present invention preferably includes two kinds having different weight average molecular weights, and more preferably has a weight average molecular weight of 5000 or more. It is more preferable to include a compound having at least two epoxy groups and a compound having a weight average molecular weight of less than 5000 and having at least two epoxy groups.
In addition, the compound having at least two epoxy groups in the thermosetting resin composition for solder resists of the present invention preferably includes two kinds having different weight average molecular weights, and further has a weight average molecular weight of 5000 or more. It is more preferable to include a compound having at least two epoxy groups and a compound having a weight average molecular weight of less than 5000 and having at least two epoxy groups.
This facilitates the removal of the resin residue (smear) after the laser opening and improves the opening accuracy, which is more preferable, and further improves the heat resistance of the solder resist.

The present invention will be described in detail below.
First, each component constituting the thermosetting resin composition for a solder resist of the present invention will be described.

  The compound having at least two epoxy groups used in the present invention is not particularly limited as long as it is a compound having at least two epoxy groups. For example, bisphenol type epoxy resin such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac Type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin and dihydroxybenzene type epoxy resin, etc., epoxy resin produced by reacting epichlorohydrin with hydroxyl groups such as phenols, naphthols and phenol resins, Diglycidyl isocyanurate, triglycidyl isocyanurate, biphenyl-4,4′-diglycidyl ether and 3,3 ′, 5,5′-tetra Compounds having an epoxy group, such as chill-4,4' diglycidyl ether, glycidyl methacrylate homopolymers, compounds having a glycidyl methacrylate, such as glycidyl methacrylate / styrene copolymers. Among these, in order to improve heat resistance, the biphenyl type epoxy resin represented by the formula (1) and the biphenyl aralkyl type epoxy resin represented by the formula (2) are preferable.

Here, each of the substituents R ^{1 to} R ⁴ in the biphenyl type epoxy resin represented by the formula (1) represents ^one selected from a hydrogen atom, an alkyl group, and a phenyl group, and these are the same as each other. Or different.
As these substituents R ^{1 to} R ⁴ , in addition to a hydrogen atom and a phenyl group, examples of the alkyl group include a chain or cyclic alkyl group having 1 to 6 carbon atoms. Specific examples thereof include methyl Group, ethyl group, propyl group, butyl group, cyclohexyl group and the like. Among these, a methyl group is particularly preferable. Thereby, it becomes difficult to produce a crack and peeling in the thermal shock test of the thermosetting resin composition for solder resists.

The substituents R ^{5 to} R ¹² in the biphenyl aralkyl type epoxy resin represented by the formula (2) represent one selected from a hydrogen atom, an alkyl group, and a phenyl group, and these are the same as each other. Or different.
As these substituents R ^{5 to} R ¹² , in addition to a hydrogen atom and a phenyl group, examples of the alkyl group include an alkyl group having 1 to 4 carbon atoms. Specific examples include a methyl group, an ethyl group, and the like. Group, propyl group, butyl group and the like are mentioned, and among these, hydrogen is particularly preferable. Thereby, the moisture resistance of the thermosetting resin composition for solder resists is further improved.

  In the formula (2), a represents the average number of repeating epoxy resin units. That is, although a is an integer greater than or equal to 1, the range of 1-10 is preferable and it is more preferable that it is about 1-5. By setting a in the above range, the moisture resistance of the thermosetting resin composition for solder resist is further improved.

  In the present invention, the compound having at least two epoxy groups preferably includes two kinds having different weight average molecular weights, and one of them has a lower limit of the weight average molecular weight of 5,000 or more. It is preferably used, more preferably 8,000 or more, and even more preferably 20,000 or more. Moreover, as an upper limit of a weight average molecular weight, 100,000 is preferable and 80,000 is more preferable. Thereby, it becomes easy to remove the resin residue (smear) in the laser aperture, the aperture accuracy is improved, and the film performance is improved. As the compound having at least two epoxy groups having a molecular weight of 5000 or more, a phenol novolac type epoxy resin, a bisphenol type epoxy resin, a naphthalene type epoxy resin, an arylalkylene type epoxy resin and the like are preferable.

  In the thermosetting resin composition for a solder resist of the present invention, the content of the compound having a weight average molecular weight of 5000 or more and having at least two epoxy groups is not particularly limited, but preferably 3 to 30% by weight. In particular, 5 to 20% by weight is preferable. By setting the content within the range, the thermal shock resistance and moisture resistance are further improved. In the thermosetting resin composition for a solder resist of the present invention, the content of the compound having at least two epoxy groups is preferably 40 to 95% by weight.

In the present invention, as the compound having at least two epoxy groups, those having an upper limit of weight average molecular weight of less than 5,000 are preferably used, and those having 2,000 or less are preferably used. Thereby, the heat resistance is further improved.
In the thermosetting resin composition for a solder resist of the present invention, the content of the compound having a weight average molecular weight of less than 5000 and having at least two epoxy groups is not particularly limited, but is preferably 5 to 60% by weight. In particular, 15 to 40% by weight is preferable. By setting the content within the range, the adhesion to the circuit board is further improved.
In the present invention, as the compound having at least two or more epoxy groups, it is more preferable to use a compound having a weight average molecular weight of 5,000 or more and a compound having a weight average molecular weight of less than 5,000.

  The compound having at least two or more cyanate groups used in the present invention is not particularly limited as long as it has two or more cyanate groups. For example, a cyanogen halide compound and two or more cyanate groups are used. It can be obtained by reacting with phenols having a phenolic hydroxyl group. Specific examples thereof include bisphenol type cyanate resins such as bisphenol A type cyanate resin, bisphenol E type cyanate resin and tetramethyl bisphenol F type cyanate resin, and novolak type cyanate resins. Among these, a novolac-type cyanate resin is preferable for making a solder resist having a lower linear expansion coefficient.

As said novolak-type cyanate resin, what is represented by following formula (3) is mentioned.
As these substituents R ^{13 to} R ²¹ , in addition to a hydrogen atom and a phenyl group, examples of the alkyl group include an alkyl group having 1 to 4 carbon atoms. Specific examples include a methyl group, an ethyl group, Group, propyl group, butyl group and the like are mentioned, and among these, a hydrogen atom is particularly preferable. Thereby, the linear expansion coefficient of the thermosetting resin composition for solder resist becomes smaller.

  In the thermosetting resin composition for a solder resist of the present invention, the content of the compound having at least two or more cyanate groups is not particularly limited, but is preferably 5 to 60% by weight, particularly 15 to 35% by weight. Is preferred. When the content is within the above range, heat resistance and moisture resistance are particularly excellent.

  Examples of the inorganic filler used in the present invention include talc, alumina, glass, silica and mica. Among these, silica is preferable, and fused silica is particularly preferable. The shape is crushed or spherical, but spherical is preferred.

  The average particle size of the inorganic filler is not particularly limited, but is preferably 0.01 to 5 μm, and particularly preferably 0.2 to 2 μm. When the particle size of the inorganic filler is less than 0.01 μm, the viscosity of the varnish becomes high, which may affect the workability in forming the coating film. On the other hand, if the thickness exceeds 5 μm, the inorganic filler may remain in the opening when laser opening is performed, which may hinder solder bonding. Further, spherical fused silica having an average particle size of 5 μm or less is preferable, and spherical fused silica having an average particle size of 0.1 to 0.5 μm is particularly preferable.

  In the production of the thermosetting resin composition for a solder resist of the present invention, the inorganic filler may dissolve a compound having at least two epoxy groups and a compound having at least two cyanate groups. It is preferable to disperse in advance in a solvent that can be used. By dispersing in advance, secondary agglomeration can be prevented, and the inorganic filler does not disperse unevenly in the resist layer. Therefore, after laser irradiation, there is no residue and good opening is performed. be able to. Here, it is more preferable to disperse using the inorganic filler having a fine particle size.

  The solvent is not particularly limited as long as it dissolves the compound having at least two epoxy groups and the compound having at least two cyanate groups. For example, an aliphatic hydrocarbon-based solvent may be used. Solvents, aromatic hydrocarbon solvents, ketone solvents, ether solvents, ethyl acetate and ester solvents, lactone solvents, amide solvents, and the like. Among them, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, Ketone solvents and ether solvents are preferred. Examples of the hydrocarbon solvent include pentane, hexane, heptane, and cyclohexane. Examples of the aromatic solvent include benzene, toluene, xylene, and mesitylene. Examples of the ketone solvent include For example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like can be mentioned, and examples of the ether solvent include diethyl ether and tetrahydrofuran. These solvents can be used alone or in combination.

  In the thermosetting resin composition for a solder resist of the present invention, the content of the inorganic filler is preferably 10 to 60% by weight, particularly preferably 30 to 50% by weight. If the content is less than 10%, the effect of low thermal expansion and low water absorption may be reduced, and if it exceeds 50% by weight, moldability may be reduced due to a decrease in fluidity.

  In the thermosetting resin composition for a solder resist of the present invention, a curing accelerator may be added for the purpose of accelerating the curing of the cyanate resin. Examples of the curing accelerator include imidazole compounds such as 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2,4. -Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazolyl) -ethyl-s-triazine, 2,4 Mention may be made of -diamino-6- [2'-ethyl-4-methylimidazolyl- (1 ')]-ethyl-s-triazine. Among these, an imidazole having two or more functional groups selected from an aliphatic hydrocarbon group such as a methyl group and an ethyl group, an aromatic hydrocarbon group such as a phenyl group, a hydroxyalkyl group, and a cyanoalkyl group Compounds are preferred, and 2-phenyl-4,5-dihydroxymethylimidazole is particularly preferred.

  The thermosetting resin composition for a solder resist of the present invention preferably further contains a coupling agent. The coupling agent improves the heat resistance, particularly the solder heat resistance after moisture absorption, by uniformly fixing the resin and the filler to the substrate by improving the wettability of the interface between the resin and the inorganic filler. For blending.

  As the coupling agent, any of those usually used in solder resist resin compositions can be used. Among these, epoxy silane coupling agents, titanate coupling agents, aminosilane coupling agents, and silicone oil type coupling agents. It is preferable to use one or more coupling agents selected from the inside. Thereby, the wettability with the interface of an inorganic filler can be made high.

  The resin composition of this invention can add additives other than the said component in the range which does not impair a characteristic as needed. Various additives conventionally used widely can be added to the solder resist resin composition known as an additive. For example, curing catalysts for epoxy compounds such as amine catalysts and phosphorus catalysts; 1 molecule Acrylate or methacrylate compounds having at least one hydroxyl group therein, triethylene glycol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate and Diluting agents such as esters of unsaturated carboxylic acids and aliphatic polyol compounds such as esters of methacrylic acid such as glycerol methacrylate and aliphatic polyol compounds; and barium sulfate Inorganic fillers such as silicon oxide, talc and calcium carbonate; colorants such as phthalocyanine blue, barium titanate, carbon black, benzimidazolone and benzimidazolone; And polymerization inhibitors such as hydroquinone monomethyl ether and pyrogallol.

  Examples of the method for producing a thermosetting resin composition for a solder resist of the present invention include, for example, a compound having at least two epoxy groups, a compound having at least two cyanate groups, and an inorganic filler, methyl isobutyl. It can be obtained by dissolving in an organic solvent such as ketone, methyl ethyl ketone, carbitol acetate and cellosolve acetate and, if necessary, adding the above-mentioned additives and stirring at room temperature for 2 to 5 hours.

The solder resist of the present invention is, for example, coated on the base material with the thermosetting resin composition for a solder resist in a thickness of usually about 1 to 60 μm, and at a temperature of about 60 to 180 ° C. for 5 to 10 minutes. By removing the solvent in the solder resist by performing a degree of heat treatment, the film with a base material solidified or prepolymerized is laminated and molded at a predetermined position such as a printed wiring board, and 100 ° C. It can be used after being cured at ˜200 ° C. for 1 to 5 hours.
Furthermore, the solder resist laminated on the printed wiring board is patterned by laser irradiation of a carbon dioxide gas laser, a third harmonic UV-YAG laser, a fourth harmonic UV-YAG laser, an excimer laser, or the like on the portion to be opened. Do. When the aperture diameter is 20 to 100 μm, the 3rd harmonic UV-YAG laser, the 4th harmonic UV-YAG laser and the excimer laser are preferable, and the 3rd harmonic UV-YAG laser is more preferable from the viewpoint of fine workability. A fourth harmonic UV-YAG laser is more preferable, and an excimer laser is particularly preferable. Moreover, when the aperture diameter is 100 micrometers-300 micrometers, it is desirable to process with a carbon dioxide laser. After opening, it permeates the permanganate solution (desmear chemical) to remove the resin residue (smear) in the opening. Furthermore, for example, a semiconductor chip is mounted on the substrate provided with the apertures obtained above.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, this invention is not limited to this.

Example 1
Preparation of Resin Varnish First, 150 g of spherical silica (average particle size 0.53 μm) was previously added as an inorganic filler to 96 g of methyl ethyl ketone, and dispersed with a vacuum devolatilization kneader and stirring device to prepare a silica slurry.
30 parts by weight of biphenyl type epoxy resin (YX-4000HK, Japan Epoxy Resin Co., Ltd., melting point 105 ° C., epoxy equivalent 193, weight average molecular weight 358), novolac type cyanate resin (Lonza Corporation, weight average molecular weight 2300) 40 weight Parts, bisphenol A type, F type mixed epoxy resin (JE Epicoat 4275, weight average molecular weight 57,000) 10 weight, imidazole compound (Shikoku Kasei Kogyo Co., Ltd., 2-phenyl-4,5-dihydroxymethylimidazole) 0 0.7 part by weight was dissolved and dispersed in methyl ethyl ketone. 80 parts by weight of the silica slurry obtained above and 0.5 parts by weight of an epoxy silane coupling agent (manufactured by Chisso) as a coupling agent were added, 0.2 parts by weight of copper phthalocyanine as a colorant, and 0. 2 parts by weight were stirred for 2 hours using a stirrer to obtain a resin varnish.

(Example 2)
Instead of 30 parts by weight of biphenyl type epoxy resin (YX-4000HK manufactured by Japan Epoxy Resin Co., Ltd., melting point 105 ° C., epoxy equivalent 193) in Example 1, biphenyl aralkyl type epoxy resin (NC-made by Nippon Kayaku Co., Ltd.) was used. 3000, softening point 60 ° C., epoxy equivalent 272, weight average molecular weight 960) 35 weight, novolak type cyanate resin (Lonza company, weight average molecular weight 2300) 40 parts by weight, novolak type cyanate resin (Lonza Co., Ltd.) , 40 parts by weight of weight average molecular weight 1300), 5 parts by weight of bisphenol S type epoxy (Toto Kasei Co., Ltd. YPS-007A30, weight average molecular weight 40,000) instead of bisphenol A type and F type mixed epoxy resin, silica slurry Resin crocodile was the same as Example 1 except for 75 parts by weight. I got.

(Example 3)
In Example 1, instead of 30 parts by weight of biphenyl type epoxy resin (YX-4000HK, Japan Epoxy Resin Co., Ltd., melting point 105 ° C., epoxy equivalent 193, weight average molecular weight 358), biphenyl aralkyl type epoxy resin (Nippon Kayaku) Resin varnish was obtained in the same manner as in Example 1 except that NC-3000, softening point 60 ° C., epoxy equivalent 272, weight average molecular weight 960), 30 parts by weight, and 85 parts by weight of silica slurry were used.

Example 4
In Example 1, the biphenyl type epoxy resin (Japan Epoxy Resin Co., Ltd. YX-4000HK, melting point 105 ° C., epoxy equivalent 193, weight average molecular weight 358) was changed to 30 parts by weight, and the biphenyl type epoxy resin (Japan Epoxy Resin Co., Ltd.) was used. ) YX-4000HK, melting point 105 ° C., epoxy equivalent 193, weight average molecular weight (358)) 18 parts by weight, biphenylaralkyl type epoxy resin (Nippon Kayaku Co., Ltd. NC-3000, softening point 60 ° C., epoxy equivalent 272) , Weight average molecular weight 960) 17 parts by weight, novolac type cyanate resin (Lonza Co., Ltd., weight average molecular weight 2300) 40 parts by weight, novolac type cyanate resin (Lonza Co., Ltd., weight average molecular weight 1300) 40 parts by weight, Bisphenol A type, F type mixed epoxy resin (J R Epicote 4275, weight average molecular weight 57,000 (10 weights), bisphenol S type epoxy (Toto Kasei Co., Ltd. YPS-007A30, weight average molecular weight 40,000) 5 parts by weight, silica slurry 75 parts by weight Except for the above, a resin varnish was obtained in the same manner as in Example 1.

(Comparative Example 1)
Example 1 was the same as Example 1 except that no epoxy resin was used.

(Comparative Example 2)
Example 2 was the same as Example 2 except that the cyanate resin was not used.

(Comparative Example 3)
Patent Document: According to Japanese Patent Application Laid-Open No. 2003-101244, 30 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 469, manufactured by Yuka Shell Epoxy Co., Epicoat 1001), cresol novolac type epoxy resin (epoxy equivalent 215, Dainippon Ink and Chemicals, Inc.) Manufactured by Epiclon N-673), 40 parts by weight of a triazine structure-containing phenol novolak resin (phenolic hydroxyl group equivalent 120, Dainippon Ink & Chemicals, Phenolite KA-7052) by 20 parts by weight of ethyl diglycol acetate, It is dissolved by heating in 20 parts by weight of solvent naphtha as a diluent while stirring and 15 parts by weight of terminal epoxidized polybutadiene rubber (manufactured by Nagase Chemical Industries, Denarex R-45EPT) and 2-phenyl-4,5-dihydroxymethylimidazole) .7 layers Parts, spherical silica (average particle size 0.53 .mu.m) 3.3 parts by weight, 0.2 part by weight of copper phthalocyanine as a colorant, to prepare a epoxy resin composition containing a benzimidazolone 0.2 parts by weight.

(Comparative Example 4)
Comparative Example 1 was performed except that 50 parts by weight of spherical silica (average particle size 0.53 μm) was used. Results Dispersibility was poor, and Examples 1 to 3 were stirred for 2 hours to obtain a resin varnish, while Comparative Example 4 was stirred for 8 hours.

[Preparation of thermal resin composition and evaluation results]
[Evaluation methods]
The resin varnish obtained above was applied to a PET substrate film with a thickness of 30 μm, heat-treated at 150 ° C. for 10 minutes, solidified by removing the solvent, and a resin film with a PET substrate was produced. If necessary, a PP cover film was laminated on the resin film to produce a film, and various evaluations were performed. The varnish prepared in Comparative Example 3 was also prepared in the same manner as described above except that it was heat-treated at 100 ° C. for 10 minutes.

[Glass transition temperature measurement]
Using a normal pressure laminator, three of the resin films prepared above were laminated to prepare a 90 μm thick film, and cured at 200 ° C. for 1 hour, a test piece (width 5 mm × length 30 mm × thickness 90 μm) ) And used.
For measurement, a dynamic viscoelasticity measuring device (DMS6100 manufactured by Seiko Instruments Inc.) is used to measure dynamic viscoelasticity by applying a strain of a frequency of 10 Hz while raising the temperature at a rate of 3 ° C./min. The glass transition temperature (Tg) was determined from the peak value.

[Linear expansion coefficient]
Using a normal pressure laminator, two of the resin films prepared above are laminated to produce a 60 μm thick film, and a test piece (width 3 mm × length 20 mm × thickness 60 μm) is formed at 200 ° C. for 1 hour. What was hardened | cured by cutting out into the test piece (width 3mm * length 20mm * thickness 60micrometer) was used. For the measurement, the linear expansion coefficient was measured at 10 ° C./min using TMA (manufactured by TA Instruments). The linear expansion coefficient was determined by an average of 30 ° C to 50 ° C.

[Moisture resistance test]
A conductor circuit pattern formed by etching a copper-clad laminate (ELC-4785GS manufactured by Sumitomo Bakelite Co., Ltd.) is formed, the circuit board is subjected to pretreatment such as degreasing and soft etching, and the film obtained above is laminated. Then, a thermosetting treatment was performed at 200 ° C. for 1 hour, and a portion corresponding to the circuit pattern was irradiated with a laser beam using a UV-YAG laser (605LDX manufactured by MITSUBISHI) to form a hole having a diameter (land diameter) of 50 μm. Then, it permeated the permanganate solution (desmear chemical) to remove the resin residue (smear) in the opening. Furthermore, it was immersed in a mixed solution of ENPLATE MLB-790 (a solution mainly composed of a hydroxylamine sulfate aqueous solution manufactured by Mertec Co., Ltd.), concentrated sulfuric acid and distilled water at 60 to 65 ° C. for 5 to 10 minutes for neutralization treatment. Thereafter, a gold plating process or a preflux process was performed, and the semiconductor chip cut into 50 mm square and formed with bumps was mounted on the bump on the 50 mm square substrate by fusion bonding. Ten substrates on which the chips were mounted were dried at 125 ° C. for 24 hours, placed in a constant temperature and humidity chamber of 85 ° C./60% relative humidity according to JEDEC L2 treatment, and left for 168 hours.
Then, it was passed 3 times through IR reflow at 260 ° C. (in N ₂ flow), and peeling and cracking of the chipped surface were confirmed by an ultrasonic deep scratch device (hereinafter referred to as SAT) (HITACH mi-scope hyper). did. Of the 10 substrates, when the number of defective packages was a, it was a / 10.

[Thermal shock test]
10 substrates on which chips are mounted, similar to those used in the moisture resistance test, are dried at 125 ° C. for 24 hours and placed in a constant temperature and humidity chamber of 65 ° C./60% relative humidity according to JEDEC L3 treatment. , Left for 40 hours. Thereafter, passed 3 times IR reflow _{(N 2} in the flow), -55 ° C. and 125 ° C. the bath is replaced instantly apparatus (ESPEC manufactured THERMAL SHOCK CHAMBER TSA-101S) the substrate was placed 10 sheets 125 ° C. 30 minutes after The peeling and cracking of the chipped surface after 1000 cycles were confirmed by SAT with 1 cycle of −55 ° C. for 30 minutes. When the number of defective packages among the 10 substrates was a, it was set to a / 10.

  From the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4, the examples have high heat resistance and a small coefficient of linear expansion, so that they have excellent thermal shock resistance and excellent moisture resistance. Had a low coefficient of linear expansion and a high Tg. In Comparative Example 1, since there is no epoxy resin, it is presumed that the free volume is increased because the crosslinking of cyanate dominates, and it is easy to absorb moisture, but the moisture resistance is poor. In Comparative Example 2, since there is no cyanate resin, the heat resistance is low, and therefore it is presumed that the thermal shock resistance is lowered. Although it was estimated that Comparative Example 3 had low heat resistance and a large linear expansion coefficient, the results showed poor moisture resistance and thermal shock resistance. In Comparative Example 4, in the moisture resistance test and the thermal shock test, the hole diameter is poor at the time of sample preparation, the solder ball does not enter well, and a defect occurs immediately after the sample preparation. Did not evaluate.

  Since the thermosetting resin composition of the present invention is excellent in heat resistance, low in linear expansion coefficient, excellent in moisture resistance and thermal shock resistance, it is excellent in solder resist, sealing material, molding material, coating material. It can be used for a correlation insulating layer of an interposer or a printed wiring board.

Claims (7)

  A thermosetting resin composition for a solder resist, comprising as essential components a compound having at least two epoxy groups, a compound having at least two cyanate groups, and an inorganic filler.   2. The thermosetting resin composition for a solder resist according to claim 1, wherein the compound having at least two epoxy groups contains two kinds having different weight average molecular weights.   The two compounds having different weight average molecular weights having at least two epoxy groups are a compound having at least two epoxy groups having a weight average molecular weight of 5000 or more, and at least a compound having a weight average molecular weight of less than 5000, The thermosetting resin composition for solder resists according to claim 2, comprising a compound having two or more epoxy groups. The compound having at least two epoxy groups is a biphenyl type epoxy resin represented by the following formula (1) or a biphenyl aralkyl resin represented by the following formula (2). The thermosetting resin composition for solder resists as described.
[Wherein R ^{1 to} R ⁴ each represent one selected from a hydrogen atom, an alkyl group, and a phenyl group, and may be the same or different from each other. ]
[Wherein, R ^{5 to} R ¹² each represent one selected from a hydrogen atom, an alkyl group, and a phenyl group, and may be the same as or different from each other. However, a is an integer greater than or equal to 1. ]   5. The thermosetting resin composition for a solder resist according to claim 1, wherein the compound having at least two cyanate groups is a novolac-type cyanate resin.   The inorganic filler is dispersed in a solvent containing a solvent that dissolves the compound having at least two epoxy groups and the compound having at least two cyanate groups. The thermosetting resin composition for solder resists according to any one of the above.   A thermosetting solder resist comprising the thermosetting resin composition for a solder resist according to claim 1.