KR20110138706A - Photosensitization epoxy resin compositions for forming via hole, and method for forming via hole on pcb using the same - Google Patents

Abstract

PURPOSE: A via-hole forming photo-sensitive epoxy resin composition and a method for forming the via-hole of a printed circuit board using the same are provided to prevent the reduction of epoxy intrinsic characteristic in an epoxy resin modifying process and to maintain the material characteristic of an interlayer insulating film. CONSTITUTION: A via-hole forming photo-sensitive epoxy resin composition includes a photo-acid generator and an epoxy resin. The photo-sensitive epoxy resin composition further includes a photo-thickening agent, a thermosetting agent, and inorganic filler. The photo-thickening agent is onium salt. The onium salt is triarylsulfonium or diaryliodonium. The epoxy resin is one or more selected from a group including bisphenol A, bisphenol F, phenol-novolak, cresol-novolak, and rubber-modified epoxy resin.

Description

Photosensitive epoxy resin compositions for forming via hole, and method for forming via hole on PCB using the same}

The present invention relates to a photosensitive epoxy resin composition for via hole forming and a via hole forming method of a printed circuit board using the same. More specifically, a photosensitive epoxy resin composition for forming a via hole containing a photoacid generator and an epoxy resin and a printed circuit board using the same It relates to a method for forming via holes.

In the case of the via hole forming method of the multilayer printed wiring board interlayer insulating film by forming a via hole in the printed circuit board, the conventional technique is to form a cured film by curing the epoxy resin composition with the interlayer insulating film of the multilayer printed wiring board, and then drill a laser drill. Or via a drill tip process. However, the method of the PCB has a problem that a lot of equipment and time should be invested in the recent PCB because the number of via holes exceeds tens of thousands to hundreds of thousands per panel.

In addition, a method of forming a via hole through photolithography is also used. This technique is a technique in which an epoxy resin is modified and a photoinitiator is introduced in order to enable fine pattern formation through an exposure process. However, this is possible to form a fine pattern through the exposure process, but there is a problem that the inherent properties of the epoxy is inhibited in the process of modifying the epoxy resin, after all the method is possible to form the hole at a time by exposure and development Due to the use of an acrylic resin capable of photopolymerization and development, the physical properties of the PCB (heat resistance, adhesiveness, coefficient of thermal expansion, etc.) are lowered, which makes it impossible to use in PKG products requiring high reliability.

Under the technical background as described above, the present inventors have diligently tried to develop a method for forming a fine via hole while maintaining the properties of an interlayer insulating film at low cost. As a result, a photosensitive epoxy resin for forming a via hole including a photoacid generator and an epoxy resin It has been developed a method of forming a via hole of a printed circuit board using the composition.

As a result, an object of the present invention, in order to solve the problem of the conventional via hole forming method, a photosensitive epoxy resin composition for forming a via hole including a photoacid generator and an epoxy resin, and the epoxy resin composition laminated on a printed circuit board, exposure, The present invention provides a method of forming a via hole in a printed circuit board including a developing step.

According to an aspect of the present invention to achieve the above object, there is provided a photosensitive epoxy resin composition for via hole formation comprising a photoacid generator and an epoxy resin.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the photosensitive epoxy resin composition for via hole formation may further include a photosensitizer, a thermosetting agent, and an inorganic filler.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the photoacid generator may be an onium salt.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the onium salt may be a triarylsulfonium salt or a diaryliodonium salt.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the content of the photoacid generator may be 0.1 ~ 10wt% compared to the epoxy resin.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the epoxy resin is selected from the group consisting of bisphenol A type, bisphenol F type, phenol-novolak, cresol-novolak, and rubber-modified epoxy resin. It may be one or more selected.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the photosensitizer may be a thioxanthone-based compound.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the thioxanthone-based compound may be at least one selected from the group consisting of isopropyl thioxanthone, 2-chlorothioxanthone, and diethyl thioxanthone. have.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the content of the photosensitizer may be 200wt% or less than the photoacid generator.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the thermosetting agent may be at least one selected from the group consisting of an acid anhydride, and a latent thermosetting agent.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the latent thermosetting agent may be at least one selected from the group consisting of a pyrazinium salt compound, a pyridinium salt compound, and a piperidinium salt compound. .

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the inorganic filler may be at least one selected from the group consisting of talc, silica, barium sulfate, and titanium oxide.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the diameter of the inorganic filler may be 10 μm or less.

According to another aspect of the invention, preparing a photosensitive epoxy resin composition for via hole formation; Stacking the epoxy resin composition on a printed circuit board; Raising a film or glass mask having a pattern formed on the substrate and exposing with UV; Developing the exposed substrate; There is provided a method of forming a via hole in a printed circuit board comprising the step of drying, heat-treating and post-curing the developed substrate.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the step of laminating the epoxy resin composition on the substrate, it may be performed by a method of directly coating the epoxy resin composition on the substrate.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the step of laminating the epoxy resin composition on a substrate, after manufacturing the dry film by coating and drying the epoxy resin composition on a film, The dry film may be performed by transferring the dry film to a substrate.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the UV wavelength of the exposure step may be 350 to 450nm.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the developing of the exposed substrate may include a method of spray-spraying a developer onto a substrate, a method of shaking the substrate after immersing the substrate in a developer, And it can be carried out by any one selected from the group consisting of a method of immersing the substrate in the developer solution and ultrasonic treatment.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the heat treatment in the post-curing step may be performed for 10 to 90 minutes at 120 to 200 ℃.

According to the present invention, via holes may be formed through exposure and development processes using a photosensitive epoxy resin composition incorporating a photoacid generator. The via hole forming method using the photosensitive epoxy resin composition for via hole formation according to the present invention has advantages in that the process is simpler and the cost can be reduced compared to the existing technology. In addition, since the via hole forming method according to the present invention can maintain the physical properties of the interlayer insulating film, it is possible to solve the disadvantage that the inherent properties of the epoxy are inhibited in the modification process of the epoxy resin of the prior art. In addition, the present invention has the effect of providing a photosensitive epoxy resin composition for via hole formation that can be used in a portion requiring the maintenance of intrinsic properties such as heat resistance, adhesion, chemical resistance, toughness, electrical insulation.

1 is a photograph of a microscopic observation of a via hole on a PCB substrate manufactured using the photosensitive epoxy resin composition prepared according to Example 1. FIG.
2 illustrates a method of forming a via hole in a printed circuit board according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

According to one aspect of the invention, there is provided a photosensitive epoxy resin composition for via hole formation comprising a photoacid generator and an epoxy resin.

The photoacid generator is a compound capable of generating an acid by light, and is not particularly limited as long as it is a compound having such a property. In general, onium salts, latent sulfonic acids, halomethyl-s-triazines, metallocenes, chlorinated acetophenones, or benzoin phenyl ethers can be used as photoacid generators. In particular, in one embodiment of the present invention, the onium salt may be used as a photoacid generator.

The onium salt may be aryl diazonium, diarylidodonium, triaryl sulfonium, triaryl selenium, dialkyl phenacyl sulfonium, triaryl sulfoxonium, aryloxydiaryl sulfoxonium, or dialkylphenacyl Although not particularly limited to sulfoxium salts and the like, in one embodiment according to the present invention, triarylsulfonium salts or diaryliodonium salts are preferred.

The content of the photoacid generator may be 0.1 ~ 10wt% compared to the epoxy resin. This is because when the content of the photoacid generator is less than 0.1wt% of the epoxy resin, not only the required exposure amount is too large, but also the coating film is dissolved during development, so that a fine pattern is not formed, and the content of the photoacid generator is 10wt of the epoxy resin. This is because if the ratio exceeds the unit cost of the composition is increased, it is difficult to control the formation of the desired micropattern.

The epoxy resin is not particularly limited, but according to one embodiment according to the present invention, the epoxy resin is selected from the group consisting of bisphenol A type, bisphenol F type, phenol-novolak, cresol-novolak, and rubber-modified epoxy resin. It may be one or more selected.

The epoxy resins such as the bisphenol A type epoxy resin and the bisphenol F type epoxy resin are methyl ethyl ketone (MEK), dimethyl formamide (DMF), methyl cellosolve (MCS), carbitol acetate, carbitol, PGMEA, One or more selected from PGME, toluene, xylene, NMP, 2-methoxy ethanol and the like can be mixed and dissolved as a solvent for use. Moreover, since hardened | cured material with high heat resistance can be obtained and the thermal stability of the formed board | substrate can be improved, it is preferable to use the said phenol novolak or cresol novolak epoxy resin as a novolak-type epoxy resin.

On the other hand, the rubber-modified epoxy resin can be used by mixing DGEBA (diglycidyl ether of bisphenol A) and CTBN (Carboxy terminated butadiene acrylonitrile copolymer). The epoxy resins are methyl ethyl ketone (MEK), demethyl formamide (DMF), methyl cellosolve (MCS), carbitol acetate, carbitol, PGMEA, PGME, toluene, xylene, NMP, 2-methoxy ethanol It can melt | dissolve in mixed solvents, such as these, and can use it.

According to one embodiment of the photosensitive epoxy resin composition for via hole formation according to the present invention, the photosensitive epoxy resin composition for via hole formation may further include a photosensitizer, a thermosetting agent, and an inorganic filler.

The photosensitizer may be added to improve the sensitivity to the exposure wavelength of the epoxy resin composition containing a photoacid generator. According to one embodiment of the invention, the photosensitizer may be a thioxanthone-based compound. According to one embodiment of the present invention, it is preferable to use at least one selected from the group consisting of isopropyl thioxanthone, 2-chloro thioxanthone, and diethyl thioxanthone as the thioxanthone-based compound . The thioxanthone-based compound makes the photoacid generator easily reach an excited state, thereby making it easier to generate an acid. In addition, according to one embodiment of the present invention, the content of the photosensitizer is preferably less than 200wt% compared to the photoacid generator. This is because when the content of the photosensitizer exceeds 200wt%, the effect of reducing the exposure dose becomes insignificant.

In the above, the thermosetting agent may be added to improve the thermal stability of the insulating material. In the present invention, the thermosetting agent may be at least one selected from the group consisting of acid anhydrides, and latent thermosetting agents.

The acid anhydride may include Methyl tetrahydrophthalic anhydride, Methyl hexahydro phthalic anhydride, Methyl hymic anhydride, Tetrahydrophthalic Anhydride, Trialkyl tetrahydrophthalic anhydride, Hexa hydrophthalic anhydride, Methyl cyclo hexane dicarboxylic anhydride, Phthalic anhydride, Trimethylic anhydride, Pyromethylenzophenon, Ethylene glycol bis trimethylic anhydride may be used.

Meanwhile, in one embodiment of the present invention, one or more selected from the group consisting of a pyrazinium salt compound, a pyridinium salt compound, and a piperidinium salt compound may be used as the latent thermosetting agent.

In the present invention, the thermosetting agent can be used within the conventional equivalent ratio of applying the epoxy thermosetting agent to the mixed equivalent of the epoxy resin to be used.

In addition, the inorganic filler may be added in order to improve physical properties such as heat resistance and strength of the epoxy resin composition. A commonly used electrically insulating material may be used as the inorganic filler, and is not particularly limited, but according to one embodiment of the present invention, the inorganic filler may be at least one selected from the group consisting of talc, silica, barium sulfate, and titanium oxide. Can be. According to one embodiment of the invention, the diameter of the inorganic filler may be 10㎛ or less. This is because the via hole is not formed well if the diameter exceeds 10㎛.

Moreover, a pigment, dye, etc. can also be mixed according to the composition of the photosensitive epoxy resin composition for via hole formation which concerns on this invention, and its application object.

According to another aspect of the invention, preparing a photosensitive epoxy resin composition for via hole formation; Stacking the epoxy resin composition on a printed circuit board; Raising a film or glass mask having a pattern formed on the substrate and exposing with UV; Developing the exposed substrate; There is provided a method of forming a via hole in a printed circuit board comprising the step of drying, heat-treating and post-curing the developed substrate. 2 illustrates a method of forming a via hole in a printed circuit board according to the present invention.

According to an embodiment of the present invention, the step of laminating the epoxy resin composition on a printed circuit board, a method of directly coating the epoxy resin composition on a substrate, or coating and drying the film on the film to produce a dry film, the dry It can be carried out by the method of transferring the film to the substrate.

In addition, according to one embodiment of the present invention, the UV wavelength of the exposure step is not particularly limited, but may generally be 350 to 450nm.

In the developing step, as a developer, an organic solvent mixed with a single, mixed organic solvent or water may be used, and one or more surfactants may be included. According to an embodiment of the present invention, the developing of the exposed substrate may include spraying a developer onto a substrate, shaking a substrate after immersing the developer in a developing solution, and immersing the substrate in a developing solution for ultrasonic treatment. It can be carried out by any one method selected from the group consisting of.

A method of forming a via hole in a printed circuit board according to the present invention includes the following steps of drying, heat treating and post-curing the developed substrate. By removing the solvent remaining on the developed substrate through drying, and after curing at high temperature to increase the curing density of the epoxy resin.

According to one embodiment of the method for forming a via hole in a printed circuit board according to the present invention, the heat treatment in the post-curing step may be performed for 10 to 90 minutes at 120 to 200 ℃. This is because when the heat treatment temperature is lower than 120 ° C., there is a problem that the curing rate is slow, and when the heat treatment temperature is higher than 200 ° C., there is a problem that the manufacturing cost increases.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, these Examples are only for illustrating the present invention, and the scope of the present invention will not be construed as being limited by these Examples.

Via Hole  Preparation of Photosensitive Epoxy Resin Composition for Formation

To the composition of Table 1 was prepared according to Examples 1 to 4 and Comparative Examples 1 and 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 YD-128 30 30 30 30 30 - YDCN-500-80P 50 50 50 50 50 30 Epoxy acrylate
resin - - - - - 70 Methyl cellosolve 20 20 20 20 20 - DAI-01 2 2 - - - - TAS-01 - - 2 2 - MS-7 - - - - - 3 Talc 20 20 20 20 20 20 MeTHPA 40 - 40 - 60 - SP-600 - 2 - 2 - - 2MZ - - - - 2 -

   (Unit: g)

YD-128, YDCN-500-80P: Epoxy Resin (Manufacturer-Kukdo Chemical)

Epoxy acrylate resin: (manufacturer-SM)

Methyl cellosolve: (manufacturer-teddy)

DAI-01, TAS-01: Mine Generator (Manufacturer-SM)

MS-7: Photo Initiator (Manufacturer-Miwon Corporation)

Talc: (manufacturer-gin chemical)

MeTHPA: Acid anhydride (manufacturer-Lonza)

SP-600: Latent Thermosetter (Manufacturer-SM)

2MZ: Hardening accelerator (manufacturer-sigma aldrich)

Example  One

30 g of epoxy resin YD-128 and 50 g of YDCN-500-80P were put in 15 g of solvent Methyl cellosolve, and dissolved by stirring at 80 ° C. for 3 hours. 20 g of talc was added to the dissolved epoxy solution, mixed, and milled three times with a three roll mill to completely disperse the talc. To the milled epoxy resin mixture, a solution in which 2 g of a photoacid generator DAI-01 was dissolved in 5 g of methyl cellosolve was added and mixed, and 40 g of MeTHPA was added thereto, followed by mixing at room temperature for 1 hour.

Example  2

To the milled epoxy resin mixture prepared in Example 1, a solution of 2 g of photoacid generator DAI-01 and 2 g of SP-600, a latent thermosetting agent, was added to 5 g of methyl cellosolve, and stirred and mixed at room temperature for 1 hour.

Example  3

A photosensitive epoxy resin composition was prepared in the same manner as in Example 1 except that TAS-01 was used instead of DAI-01.

Example  4

A photosensitive epoxy resin composition was prepared in the same manner as in Example 2 except that TAS-01 was used instead of DAI-01.

Comparative example  One

To the milled epoxy resin mixture prepared in Example 1, a solution of 60 g of MeTHPA and 2 g of 2 MZ of a curing accelerator was added to 5 g of methyl cellosolve, and stirred and mixed at room temperature for 1 hour.

Comparative example  2

30 g of YDCN-500-80P was added to 70 g of epoxy acrylate resin, warmed to 40 ° C., dissolved by stirring for 5 hours, and then 3 g of MS-7 as a photoinitiator was added. Got. 20 g of talc was added to the mixed resin, mixed, and milled three times with a three roll mill to completely disperse the talc.

Experimental Example  : Example  1 to 4 and Comparative example  Comparison of physical properties after curing of compositions according to 1 and 2

The photosensitive epoxy resin composition prepared according to Examples 1 to 4 and Comparative Examples 1 and 2 was directly coated on the PCB substrate as a coating base, and dried to remove the solvent. The PCB board | substrate coated with the coating film from which the solvent was removed was exposed by the exposure machine, it developed in the developing solution which consists of methyl cellosolves, and dried. The dried PCB substrate was post-cured at 180 ° C. for 40 minutes.

Tg (glass transition temperature) and CTE (coefficient of thermal expansion) of each cured composition were measured using a TMA Q 400 thermal analyzer from TA. Tg was measured by the value of the 2nd scanning, and temperature rising temperature was measured at 25-250 degreeC as 10 degree-C / min.

To measure the adhesion, cut the cured film into 100 pieces with Cross-Cut (10x10), attach it with 3M tape, peel off, and perform a peeling test to check the number of pieces that fall off. The number was measured .

In order to measure the hole open, after the exposure and development processes, the formation of the via holes was confirmed under a microscope.

The experimental results are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Tg (℃) 172 168 170 165 170 105 CTE (α ₁ ) 40 38 39 41 43 55 Adhesion 100/100 100/100 100/100 100/100 100/100 100/100 Hole open
(100/60) μm ○ ○ ○ ○ X ○

As can be seen in Table 2, the Tg and CTE values of the comparative examples, Comparative Examples 1 and 2 are difficult to be used as the substrate material, and in the embodiments, the Tg is high and the CTE is low, thus having excellent physical properties compared to the comparative examples. And it was found. In addition, FIG. 1 was a hole observing result obtained by microscopic observation of via holes on a PCB substrate prepared using the photosensitive epoxy resin composition prepared according to Example 1. FIG.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (19)

The photosensitive epoxy resin composition for via hole formation containing a photo-acid generator and an epoxy resin.
The method of claim 1,
The photosensitive epoxy resin composition for via hole formation further comprises a photosensitizer, a thermosetting agent, and an inorganic filler.
The method of claim 1,
The photoacid generator is a photosensitive epoxy resin composition for via hole formation, characterized in that the onium salt.
The method of claim 3,
Said onium salt is a triarylsulfonium salt or the diaryl iodonium salt, The photosensitive epoxy resin composition for via hole formation characterized by the above-mentioned. The method of claim 1,
The content of the photoacid generator is a photosensitive epoxy resin composition for via hole formation, characterized in that 0.1 ~ 10wt% compared to the epoxy resin.
The method of claim 1,
The epoxy resin is at least one selected from the group consisting of bisphenol A type, bisphenol F type, phenol- novolak, cresol- novolak, and rubber-modified epoxy resin, the photosensitive epoxy resin composition for via hole formation.
The method of claim 2,
The photosensitizer is a photosensitive epoxy resin composition for via hole formation, characterized in that the thioxanthone-based compound.
The method of claim 7, wherein
The thioxanthone-based compound is at least one selected from the group consisting of isopropyl thioxanthone, 2-chloro thioxanthone, and diethyl thioxanthone, the photosensitive epoxy resin composition for via hole formation.
The method of claim 2,
The content of the photosensitizer is a photosensitive epoxy resin composition for via hole formation, characterized in that less than 200wt% compared to the photoacid generator.
The method of claim 2,
The thermosetting agent is at least one selected from the group consisting of acid anhydrides and latent thermosetting agents, the photosensitive epoxy resin composition for via hole formation.
The method of claim 10,
The latent thermosetting agent is at least one selected from the group consisting of a pyrazinium salt compound, a pyridinium salt compound, and a piperidinium salt compound.
The method of claim 2,
The inorganic filler is a photosensitive epoxy resin composition for via hole formation, characterized in that at least one selected from the group consisting of talc, silica, barium sulfate, and titanium oxide.
The method of claim 2,
The diameter of the inorganic filler is a photosensitive epoxy resin composition for via hole formation, characterized in that 10㎛ or less.
Preparing a photosensitive epoxy resin composition for forming a via hole according to any one of claims 1 to 13;
Stacking the epoxy resin composition on a printed circuit board;
Raising a film or glass mask having a pattern formed on the substrate and exposing with UV;
Developing the exposed substrate;
Drying and heat-treating the developed substrate, followed by heat curing;
Forming a via hole in the printed circuit board comprising a.
The method of claim 14,
The stacking of the epoxy resin composition on a substrate, the method of forming a via hole in a printed circuit board, characterized in that performed by the method of directly coating the epoxy resin composition on the substrate.
The method of claim 14,
The step of laminating the epoxy resin composition on a substrate, after coating and drying the epoxy resin composition on a film to produce a dry film, and then performing the method by transferring the dry film to the substrate to a printed circuit board How to form via holes.
The method of claim 14,
The UV wavelength of the exposure step is a method for forming a via hole in a printed circuit board, characterized in that 350 to 450nm.
The method of claim 14,
The developing of the exposed substrate may be performed by any one selected from the group consisting of spray spraying the developer onto the substrate, shaking the substrate after immersion in the developer, and immersing the substrate in the developer for ultrasonic treatment. Forming a via hole in the printed circuit board, characterized in that.
The method of claim 14,
The heat treatment in the post-curing step is a method for forming a via hole in a printed circuit board, characterized in that performed for 10 to 90 minutes at 120 to 200 ℃.

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