KR101316105B1 - Manufacturing method for printed circuit board containing flame retardant insulating layer - Google Patents

Abstract

The present invention relates to a method for manufacturing a printed circuit board including a flame retardant insulating layer. The printed circuit board according to the present invention has excellent thermal stability and mechanical strength, and is not only suitable for the imprinting lithography method, but also improves reliability by reducing the thermal expansion rate, and has excellent adhesive strength between the circuit pattern and the insulating layer. .

Description

Manufacturing Method of Printed Circuit Board Including Flame Retardant Insulation Layer {MANUFACTURING METHOD FOR PRINTED CIRCUIT BOARD CONTAINING FLAME RETARDANT INSULATING LAYER}

The present invention relates to a method for manufacturing a printed circuit board including a flame retardant insulating layer.

Recently, high-density mounting is required according to the trend of miniaturization, thinning, and lightening of electronic devices. The conventional method of forming a wiring pattern by using a photolithography method has a limitation in forming fine wirings due to the use of photoresist, and it is cumbersome in the process. Recently, an imprinting lithography method capable of forming microwiring patterns down to nanosize has been proposed. This is a method of forming a pattern as a stamp is applied to the insulating material of the semi-cured state, and by forming a fine pattern by plating a conductive metal inside the pattern. However, in the case of the imprinting lithography method, the choice of a suitable range of hardening is narrow, which not only restricts the processing conditions but also makes it difficult to match the exact curing conditions. In other words, if the curing conditions are not met, there is a problem that the transfer is not performed at all, or the release property of the stamp becomes a problem, thereby increasing the defective rate of the substrate.

In general, with respect to a polymer material (or resin) used as an insulating material for a printed circuit board or a semiconductor mounting substrate, various inorganic fillers are used to improve the disadvantages of the physical properties of each resin and to impart desired functions. However, when a large amount of the inorganic filler is contained in the circuit board, the brittleness of the substrate increases, the adhesion between the used resin and the wiring decreases, and the fluidity in the semi-cured state occurs. Therefore, it is necessary to control the physical properties of the resin so that the inorganic filler can exhibit the properties suitable for performing the imprinting process while maintaining the desired physical properties.

Conventionally, halogen compounds such as bromine and chlorine have been used to impart flame retardancy to substrates, but these materials are known to produce dioxins, which are harmful to humans during combustion, and their use is limited. Therefore, various studies have been made on a technique that can impart flame retardancy using a non-halogen compound.

Prior art in this field includes an insulating composition for a substrate, an insulating film made of the insulating composition and an epoxy resin composition for 2010-0084091 flame retardant semiconductor encapsulation.

The present invention is to solve the above problems of the prior art, an object of the present invention is to provide a method of manufacturing a flame-retardant insulating layer having excellent thermal stability and mechanical strength while reducing the coefficient of thermal expansion and a printed circuit board using the same.

According to one aspect of the invention, (a) 5 to 20 parts by weight of bisphenol A type epoxy resin having an average epoxy resin equivalent of 100 to 700, and 30 to 60 parts by weight of cresol novolac epoxy resin having an average epoxy resin equivalent of 100 to 600 Compound epoxy resin comprising 5 to 15 parts by weight of a rubber-modified epoxy resin having an average epoxy resin equivalent of 100 to 500 and 15 to 30 parts by weight of a phosphorus epoxy resin having an average epoxy resin of 400 to 800; (b) amino triazine based curing agents; (c) curing accelerators; And (d) using a 25 mm diameter pararell plate at a rheometer, including an inorganic filler, at a plate spacing of 1.0 mm, using an initial temperature of 60 ° C., a final temperature of 180 ° C., and a temperature increase rate of 5 ° C. in a temperature sweep mode. The minimum viscosity (complex viscosity (| η * |: unit Pa * sec) obtained when measured at 120 measurement points and 24 minutes of run time at a frequency of 1% strain and 1 Hz under conditions of / min. coating a surface of a substrate with a flame retardant resin composition having a min. viscosity of 1.0 to 250.0 Pa * sec to form a flame retardant insulating layer; precure a substrate having the flame retardant insulating layer formed thereon; roughness of the flame retardant insulating layer A method of manufacturing a printed circuit board is provided, the method including: forming a surface roughness, and forming a printed circuit pattern on a flame-retardant insulating layer having the roughness.

According to one embodiment of the present invention, the amino triazine-based curing agent may be mixed in a ratio of 0.3 to 1.5 equivalents relative to the mixed equivalent of the epoxy groups of the composite epoxy resin.

According to one embodiment of the present invention, the curing accelerator may be included in 0.1 to 1 parts by weight based on 100 parts by weight of the composite epoxy resin.

According to one embodiment of the invention, the inorganic filler may be included in 20 to 50 parts by weight based on 100 parts by weight of the composite epoxy resin.

According to an embodiment of the present invention, the curing accelerator may be an imidazole compound.

According to an embodiment of the present invention, the curing accelerator is 2-ethyl-4methylimidazole, 1- (2-cyanoethyl) -2-alkylimidazole, 2-phenylimidazole and mixtures thereof It may be at least one selected from the group consisting of.

According to one embodiment of the present invention, the inorganic filler barium titanium oxide (barium titanum oxide), barium strontium titanate (barium strontium titanate), titanium oxide (titanium oxide), lead zirconium titanate (lead zirconium titanate), lead Lanthanium zirconate titanate, rim magnesium niobate-lead titanate, silver, nickel, nickel-coated polymer spheres, gold-coated Gold-coated polymer spheres, tin solder, graphite, tantalum nitides, metal silicon nitride, carbon black, silica, gray and It may be at least one inorganic material selected from the group consisting of aluminum borate.

According to an embodiment of the present invention, the inorganic filler may be surface treated with a silane coupling agent.

According to an embodiment of the present invention, the inorganic filler may include spherical fillers of different sizes.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 1.0 ~ 100.0 Pa * sec.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 1.0 ~ 50.0 Pa * sec.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 30.0 ~ 40.0 Pa * sec.

According to one embodiment of the invention, the step of precure may be to maintain 20 to 40 minutes at 140 to 160 ℃.

According to an embodiment of the present invention, the step of forming the roughness is a substrate in which the flame-retardant insulation layer is coated 2- (2-butoxyethoxy) ethanol (2- (2-butoxyethoxy) ethanol) and ethane-1 Treating with 2, -diol (ethane-1,2-diol); Etching with 55 g / L NaMnO ₄ , 18 g / L Na ₂ MnO ₄ , 45 g / L NaOH solution; And neutralizing with 60% H ₂ SO ₄ .

According to one embodiment of the present invention, the step of forming the roughness may further comprise the step of immersing in 20 ~ 60% HF or NH ₄ HF ₂ solution.

According to one embodiment of the invention, when further comprising the step of immersing in the HF or NH ₄ HF ₂ solution can be carried out for 170 ° C / 30 minutes to 60 minutes precure.

Printed circuit board according to the present invention can improve the reliability by reducing the thermal expansion rate while excellent thermal stability and mechanical strength, and has the advantage of excellent adhesion between the circuit pattern and the insulating layer.

1 is a TMA result graph of a resin composition according to an embodiment of the present invention.
2 is a manufacturing process of a printed circuit board according to an embodiment of the present invention.
3 is a schematic diagram showing a cross section of an insulating layer according to an embodiment of the present invention.
Figure 4 is an electron micrograph showing the surface of the flame-retardant insulating layer subjected to the desmear process after being pre-cured under different conditions. (170 ° C / 30 minutes (B) 160 ° C / 30 minutes (C) 140 ° C, 150 ° C / 30 minutes)
5 shows the flame retardant insulating layer after (a) precure, (b) after swelling, (c) after microetching, (d) after reduction, and (e) after acid-dip. (F) is an electron micrograph showing the surface state after chemical plating.
6 is an electron micrograph of the surface (right) of the HF-treated (left) and the non-flammable insulating layer.
7 is a result of measuring the complex viscosity of the flame retardant resin composition according to the present invention.

Hereinafter, the present invention will be described in more detail.

According to one aspect of the invention, (a) 5 to 20 parts by weight of bisphenol A type epoxy resin having an average epoxy resin equivalent of 100 to 700, and 30 to 60 parts by weight of cresol novolac epoxy resin having an average epoxy resin equivalent of 100 to 600 A composite epoxy resin comprising 5 to 15 parts by weight of a rubber-modified epoxy resin having an average epoxy resin equivalent of 100 to 500 and 15 to 30 parts by weight of a phosphorous epoxy resin having an average epoxy resin equivalent of 400 to 800; (b) amino triazine based curing agents; (c) curing accelerators; And (d) using a 25 mm diameter pararell plate at a rheometer, including an inorganic filler, at a plate spacing of 1.0 mm, using an initial temperature of 60 ° C., a final temperature of 180 ° C., and a temperature increase rate of 5 ° C. in a temperature sweep mode. The minimum viscosity (complex viscosity (| η * |: unit Pa * sec) obtained when measured at 120 measurement points and 24 minutes of run time at a frequency of 1% strain and 1 Hz under conditions of / min. forming a flame retardant insulating layer by coating a flame-retardant resin composition having a min. viscosity of 1.0 to 250.0 Pa * sec on a substrate surface; precure the substrate having the flame retardant insulating layer formed thereon; forming roughness on the flame retardant insulating layer. A method of manufacturing a printed circuit board is provided, the method including forming a printed circuit pattern on a flame-retardant insulating layer having the roughness.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 1.0 ~ 100.0 Pa * sec.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 1.0 ~ 50.0 Pa * sec.

According to one embodiment of the invention, the minimum viscosity (min. Viscosity) of the flame retardant resin composition may be 1.0 ~ 40.0 Pa * sec.

The measurement results of the complex viscosity of the flame retardant resin composition according to the embodiment of the present invention are shown in FIG. 7. Referring to Figure 7 it can be seen that the minimum viscosity of the flame retardant resin composition according to an embodiment of the present invention is 5.6 Pa * sec. The advantage obtained through such low minimum viscosity is described in more detail below.

The composite epoxy resin used in the present invention is a halogen-free epoxy resin, and includes a bisphenol A epoxy resin, a cresol novolac epoxy resin, a rubber-modified epoxy resin, and a phosphorus epoxy resin.

Here, it is preferable that the average epoxy resin equivalent of bisphenol-A epoxy resin is 100-700. If the average epoxy resin equivalent is less than 100, it is difficult to exhibit the desired physical properties, and if it exceeds 700, it is not preferable because it is difficult to dissolve in the solvent and the melting point is too high to control. In addition, the bisphenol A epoxy resin preferably occupies 5 to 20 parts by weight of the composite epoxy resin. If the content of the bisphenol A epoxy resin is less than 5 parts by weight, the adhesive strength with the wiring material is lowered, and if the content is more than 20 parts by weight, thermal and electrical properties are deteriorated, which is not preferable. The resin can be used after being dissolved in a mixed solvent such as 2-methoxyethanol, methyl ethyl ketone (MEK), demethyl formamide (DMF), and methyl cellosolve (MCS).

Cresol novolac epoxy resin is used as the novolak type epoxy resin, because it is possible to obtain a cured product having high heat resistance and to improve the thermal stability of the formed substrate. The average epoxy resin equivalent of the cresol novolac epoxy resin is preferably 100 to 600, and occupies 30 to 60 parts by weight in the composite epoxy resin. If the average epoxy resin equivalent is less than 100, it is difficult to exhibit the desired physical properties, and if it exceeds 600, it is difficult to dissolve in the solvent, it is not preferable because the melting point is too high to control. In addition, if the content of the cresol novolac epoxy resin is less than 30 parts by weight can not obtain the desired physical properties, if the content is more than 60 parts by weight, rather the electrical mechanical properties are lowered is not preferred. It can be used by dissolving it in mixed solvents, such as 2-methoxyethanol, methyl ethyl ketone (MEK), demethyl formamide (DMF), and methyl cellosolve (MCS).

The rubber-modified epoxy resin can be obtained by mixing DGEBA (diglycidyl ether of bisphenol A) and ATBN (amine terminated butadiene acrylonitrile copolymer), and the average epoxy resin equivalent is preferably 100 to 500. If the average epoxy resin equivalent is less than 100, it is difficult to exhibit the desired physical properties, and if it exceeds 500, it is not preferable because it is difficult to dissolve in the solvent and the melting point is too high to control. The rubber-modified epoxy resin preferably takes from 5 to 15 parts by weight of the composite epoxy resin. If the content is less than 5 parts by weight, the insulating material is brittle and cracking is desired. If the content is more than 15 parts by weight, the desired physical properties It is not desirable to get it. The resin can be used after being dissolved in a mixed solvent such as 2-methoxyethanol, methyl ethyl ketone (MEK), demethyl formamide (DMF), and methyl cellosolve (MCS).

Phosphorus epoxy resins are excellent in flame retardancy and self-extinguishing. Phosphorus-based epoxy resin may be added to impart flame retardancy of the printed circuit board, and since halogen is not contained, an environmentally friendly flame retardant substrate may be obtained. It is preferable that the phosphorus epoxy resin has an average epoxy resin equivalent of 400 to 800. If the average epoxy resin equivalent is less than 400, it is difficult to exhibit the desired physical properties, and if it exceeds 800, it is not preferable because it is difficult to dissolve in the solvent and the melting point is too high to control. Phosphorus-based epoxy resin is preferably occupied 15 to 30 parts by weight in the composite epoxy resin, if the content is less than 15 parts by weight it is difficult to impart the desired flame retardancy, if the content is more than 30 parts by weight electrical mechanical properties are lowered is not preferred. The resin can be used after being dissolved in a mixed solvent such as 2-methoxyethanol, methyl ethyl ketone (MEK), demethyl formamide (DMF), and methyl cellosolve (MCS).

According to a preferred embodiment, the amino triazine-based curing agent is preferably mixed in a 0.3 to 1.5 equivalent ratio relative to the mixed equivalent of the epoxy groups of the composite epoxy resin. When the equivalent ratio of this range is the degree to which the degree of curing of the cured insulating layer, that is, the substrate, is preferable to perform an imprinting process, the thermal expansion coefficient of the substrate can be reduced as much as possible. If the equivalent ratio is less than 0.3, the flame retardancy of the composition is inferior, and if the equivalent ratio exceeds 1.5, problems such as poor adhesiveness and poor storage stability may occur, which is not preferable. Most preferably, the mixing is at 0.6 equivalent ratio.

The curing agent used in the present invention is for improving the thermal stability of the insulating material. In the present invention, an amino triazine-based curing agent containing a nitrogen-based compound can be used to obtain an excellent resin composition having excellent flame retardancy and low thermal expansion rate. Preferably, the curing agent has a softening point of 100 to 150 ℃, nitrogen content of 10 to 30% by weight, hydroxy group equivalent of 100 to 200 is preferred.

Examples of the curing accelerator used in the present invention include imidazole, but are not limited thereto, 2-ethyl-4methylimidazole, 1- (2-cyanoethyl) -2-alkylimidazole, At least one selected from the group consisting of 2-phenylimidazole and mixtures thereof can be used. Herein, the curing accelerator is preferably included in an amount of 0.1 to 1 parts by weight, and more preferably 0.2 to 0.3 parts by weight, based on 100 parts by weight of the composite epoxy resin. If the content of the curing accelerator is less than 0.1 parts by weight, the curing speed is significantly lowered and uncured may occur, the problem of releasability may occur in the imprinting process, if the content exceeds 1 part by weight fast curing occurs pattern This may not be transferred.

In addition, the addition of a flame retardant aid can lower the content of the phosphorus-based epoxy resin, which is relatively expensive. As the flame retardant aid, a compound such as Al 2 O 3 containing phosphorus may be used.

According to one embodiment of the present invention, the inorganic filler barium titanium oxide (barium titanum oxide), barium strontium titanate (barium strontium titanate), titanium oxide (titanium oxide), lead zirconium titanate (lead zirconium titanate), lead Lanthanium zirconatetitanate, rim magnesium niobate-lead titanate, silver, nickel, nickel-coated polymer spheres, gold-coated polymers Gold-coated polymer spheres, tin solder, graphite, tantalum nitides, metal silicon nitride, carbon black, silica, gray and aluminum It may be at least one mineral selected from the group consisting of aluminum borate.

The inorganic filler used in the present invention is added to reinforce physical properties such as mechanical strength of the cured product of epoxy resin alone, and an insulating material generally used may be used.

Here, the inorganic filler is preferably included in 20 to 50 parts by weight based on 100 parts by weight of the composite epoxy resin. If the content of the inorganic filler is less than 20 parts by weight, it is difficult to expect the improvement of the desired mechanical properties, and if the content exceeds 50 parts by weight, phase separation may occur, which is not preferable.

In addition, the inorganic filler is preferably surface-treated with a silane coupling agent, it is preferable to include spherical fillers of different sizes. The silane coupling agent may be various kinds such as amino, epoxy, acrylic, vinyl, and the like, and may be used without limitation. In addition, by using different sized and spherical fillers as the inorganic filler, the flowability in the resin composition can be increased, and the packing density after curing can be improved to improve thermal and mechanical properties.

The thermal expansion rate of the substrate needs to be as close as possible to the thermal expansion rate of the conductive wiring. This is because the larger the difference in thermal expansion coefficient, the more likely cracks occur between the substrate and the conductive wiring, which may adversely affect the reliability of the substrate.

According to an aspect of the present invention, a flame-retardant insulating layer that can reduce the difference in thermal expansion coefficient with the conductive wiring while maintaining thermal stability and mechanical properties, and a method of manufacturing a printed circuit board including the same can be provided.

The flame retardant resin composition may be used to form a circuit by a general PCB manufacturing process, which is shown in FIG. 2.

The substrate coating the flame retardant insulating layer may be PET, and there is no particular limitation as long as it is a material that can be used in a printed circuit board manufacturing process.

At this time, the thickness of the flame-retardant insulating layer coating may be 25 ~ 80 μm.

If the thickness of the flame-retardant insulating layer coating is less than 25μm, the insulation is inferior, and if it is more than 80μm, the thickness of the printed circuit board is increased, which is not preferable.

Referring to FIG. 2, a copper layer is formed on the flame retardant insulating layer through chemical plating and electroplating, and then a circuit pattern is formed by photolithography.

In terms of the reliability of the PCB, the adhesion between the circuit pattern and the insulating layer beneath it is very important. By measuring the peel strength, it is possible to establish the conditions most suitable for the adhesion.

Factors affecting the peel strength can be largely divided into two types.

The first is interfacial adhesion at the interface between the copper layer and the insulating material.

Second, as shown in Figure 3 is an anchoring effect (anchoring effect) by the roughness formed in the insulating layer.

A more important factor is the anchoring effect.

Surface rouphness can be formed on the flame retardant insulating layer for such an anchoring effect. The "roughness" may also be expressed as surface roughness.

In order to form the roughness, a precure and desmear process may be performed on the resin composition forming the flame retardant insulating layer.

First, in the precure process, the coated flame retardant insulating layer is required to be cured to an appropriate degree of curing through the precure process.

After the precure, a chemical wet process may be performed to form roughness on the surface of the insulating material.

Through this, the adhesive force of the flame retardant insulating layer can be increased.

According to one embodiment of the invention, the precure step may be to maintain for 20 to 40 minutes at 140 to 160 ℃.

Table 1 below shows the degree of cure of the flame retardant resin composition under each condition, and thus the measured peel strength. The degree of cure is according to the measurement of differential scanning calorimeter (DSC). Differential scanning calorimeter (DSC) can measure the degree of curing of the resin by measuring the difference in heat flow generated from the sample by applying the same temperature program to the sample and the inert reference (inert reference).

Curing temperature (℃) / time Curing degree Peel-strength (Kn / cm) 130 ℃ / 30 minutes 56.7 0.1 140 ℃ / 30 minutes 66.6 0.78 150 ℃ / 30 minutes 79.8 0.76 160 ℃ / 30 minutes 87.1 0.48 170 ℃ / 30 minutes 91.7 0.30

Referring to Table 1, it can be seen that when the precure temperature is lower than 140 ° C or higher than 160 ° C, the degree of curing is relatively low and the peel strength is also very low.

That is, when precure at 130 ° C. for 30 minutes, the peel strength is only 0.1 kN / cm.

Sufficient curing is required to prevent the resin on the surface from eluting during the desmear process. Under the above conditions, the curing is not sufficiently performed, and the resin on the surface is eluted by unnecessary attack from other reactants during the desmear process. As a result, the ratio of the silica filler on the surface of the insulating layer becomes excessively high, resulting in peel strength. Lowers.

On the other hand, when precure at 140 ° C. or 150 ° C. for 30 minutes, it can be seen that an excellent peel strength value of 0.6 kN / cm or more is obtained. This indicates that the resin forming the flame retardant insulating layer was cured to an appropriate degree, whereby roughness was effectively formed.

In the case of precure at a temperature of 160 ° C. or higher, the degree of curing is too high, so that an effective etching cannot be achieved during the desmear process. Even in this case, roughness cannot be effectively formed, which results in a drop in the peel strength value.

Figure 4 is an electron micrograph showing the surface of the flame-retardant insulating layer subjected to the desmear process after being pre-cured under different conditions. ((A) 170 degrees Celsius / 30 minutes (B) 160 degrees Celsius / 30 minutes (C) 140 degrees Celsius-150 degrees Celsius / 30 minutes)

Referring to Figure 4, (C) it can be seen that an efficient roughness is formed under the precure conditions of 140 ℃ ~ 150 ℃ / 30 minutes.

As mentioned above, after the precure, the adhesion of the flame retardant insulating layer may be increased by forming roughness on the surface of the flame retardant insulating layer through a chemical wet process.

According to one embodiment of the present invention, the desmear process of forming the roughness comprises the steps of: treating the substrate coated with the flame retardant insulating layer with 2- (2-butoxyethoxy) ethanol and ethane-1,2-diol;

Etching with 55 g / L NaMnO ₄ , 18 g / L Na ₂ MnO ₄ , 45 g / L NaOH aqueous solution; And

Neutralizing with 60% H ₂ SO ₄ .

The desmear condition can be largely divided into three stages. That is, swelling, chemical etching, and reduction.

The swelling conditions include the step of treating with 2- (2-butoxyethoxy) ethanol and ethane-1,2-diol solution.

In the etching step, the surface of the insulating layer is etched with the etching solution.

At this time, the etching solution is composed of 55 g / L NaMnO ₄ , 18 g / L Na ₂ MnO ₄ , 45 g / L NaOH aqueous solution.

In the reducing step, the etching solution remaining after the etching step is neutralized with a 60% H ₂ SO ₄ reducing solution.

According to an embodiment of the present invention, the fill-strength value may be maximized by adding an acid-dip process to the desmear process.

The acid-dip process includes dipping the insulating layer subjected to the desmear process into a bath containing 5 wt% to 10 wt% sulfuric acid solution.

5 shows the surface of the flame retardant insulating layer after (a) precure, (b) after swelling, (c) after micro etching, (d) after reduction, and (e) after acid-dip, (f) Indicates the surface state after chemical plating.

When the acid-dip process is performed for 1 to 5 minutes, it can be seen that a perfect microstructure is formed as shown in FIG. This gives a better peel-strength value.

Referring to Table 4 below, the effect of improving the adhesive strength according to the acid-dip process is shown.

That is, even if the same flame retardant resin composition is treated with the same precure condition and desmear condition, it can be seen that there is a significant difference in peel-strength between the acid-dip process and the non-acid-dip process.

Forming the roughness may further comprise immersing in 20 ~ 60% HF or NH ₄ HF ₂ solution. The treatment of HF or NH ₄ HF ₂ may be carried out simultaneously with the step of reducing the insulating layer subjected to the acid-dip treatment or after the reduction step.

When further comprising the step of immersing in HF or NH ₄ HF ₂ solution, the precure may be performed for 170 ° C / 30 minutes to 60 minutes.

6 shows the surface of the flame-retardant insulating layer subjected to HF treatment and not.

Referring to FIG. 6, it can be seen that more dense surface roughness is formed when the HF treatment is performed (left photograph). This is because HF dissolves the silica filler included in the flame retardant resin composition, thereby more effectively filling voids existing between the filler and the cured resin composition. Through this, the conductive layer formed through the chemical plating and the electroplating process can be combined by a stronger anchoring effect.

In the case of using HF, it is desirable to allow the epoxy resin to cure as much as possible so as not to react with other reactants during the desmear process. For this purpose, it is preferable to perform the precure under the stronger conditions as described above.

Referring to FIG. 6 without HF treatment (right picture), it can be seen that the silica filler is present on the surface of the flame retardant insulating layer in its original form, which does not help to improve the anchoring effect.

It is well known that the same effects as HF can be obtained even in the case of a NH ₄ HF ₂ solution as a silica solubilizer.

In another aspect of the present invention, a printed circuit board having an insulating layer formed using the flame retardant resin composition is provided.

By using the flame-retardant resin composition according to the present invention, such as a flexible printed circuit board (FPCB), a rigid PCB, a hard-flex PCB, a built-up substrate, FCBGA (Flip chip ball grid array), PBGA (Plastic ball grid array) The insulating layer of various board | substrates, such as various BGA, can be formed.

Hereinafter, the present invention will be illustrated by the following examples, but the protection scope of the present invention is not limited only to the following examples.

Example

Preparation of Flame Retardant Resin Composition

85 wt% (solvent: 2-methoxyethanol) bisphenol A epoxy resin (Kukdo Chemical, YD-011), 85 wt% (solvent: 2-methoxyethanol) cresol novolac epoxy resin (Kukdo Chemical, YDCN- 500-01P), rubber modified epoxy resin (Kukdo Chemical, Polydis 3615), 85% by weight (solvent: 2-methoxyethanol) phosphorus flame-retardant epoxy resin (Kukdo Chemical, KDP-550MC65), and 66.7% by weight (solvent : 2-methoxyethanol) amino triazine novolac curing agent (GUN EI Chemical Industry Co., ltd, PS-6313) was added, and the mixture was stirred at 90 ° C. for 1 hour at 300 rpm.

The content of each substance added is shown in Table 2 below.

Subsequently, spherical silica having a size distribution of 0.6 to 1.2 μm was added thereto, followed by stirring at 400 rpm for 3 hours. After the temperature was lowered to room temperature, 2-ethyl-4-methylimidazole was added and stirred for 30 minutes to prepare a flame retardant resin composition.

Composition A Composition B Composition C Composition D Comparative Example Epoxy resin


Bisphenol A type epoxy resin 10 10 10 10 10 Cresol novolac epoxy resin 55 55 55 55 55 Rubber modified epoxy resin 10 10 10 10 10 Phosphorus Flame Retardant Epoxy Resin 25 25 25 25 25 Hardener
Amino Triazine Novolac Curing Agent 32.30 32.30 32.30 32.30 - Phenolic Novolac Curing Agent - - - - 43.7 Hardening accelerator 2-ethyl-4-methylimidazole 5 2.5 1.25 0 0.5 Inorganic filler Spherical silica 81.09 81.09 81.09 81.09 88.04

(Unit: g)

Example  1.flammability, Tg  And CTE Measurement of

The flame retardant resin composition thus prepared was film cast on a PET film and then completely cured by heat treatment at 140 ° C. for 30 minutes and at 120 ° C. for 120 minutes, and flame retardancy, Tg, and CTE were measured. The measurement results are shown in Table 3 below. In addition, the TMA result graph of the composition C according to the above embodiment is shown in FIG. 1.

Flame retardant (UL 94V) The glass transition temperature (Tg) CTE (below Tg) Composition C V-0 160.61 27.58 Comparative Example 1 V-1 155.9 54.4

* Property measurement method

1) Flame retardancy measurement: According to UL 94V (Vertical Burning Test) method, the test piece was placed vertically, and it was evaluated as V-2, V-1, V-0, and 5V according to the degree of fire extinguishing with the burner.

2) Tg and CTE measurement: It was measured by TA TMA Q 400 thermal analyzer, Tg was adopted at the second scanning (scanning) value. The temperature rising temperature was measured at a temperature of 25 ° C to 250 ° C at 10 ° C / min.

As shown in Table 3, in the case of the flame retardant composition according to the present invention, the flame retardancy of V-0, that is, the burning time of the specimen, was 10 seconds or less using an amino triazine-based curing agent, and thus, the flame retardancy was superior to the conventional flame retardant composition. .

In addition, the CTE value was also found to be superior to that of the phenol novolac curing agent. This seems to be because the NH group in the curing agent is further reacted in addition to the OH group reacting with the epoxy group, whereby a cured product having a denser structure is formed.

Example  2. Acid - In dip-dip process  Adhesion measurements

After casting the prepared flame retardant resin composition C in the form of a film, an insulating layer and a wiring pattern were formed according to the steps shown in FIG. However, the difference in adhesion between the acid-dipped step and the non-acid-dipped step in the desmear process is shown in Table 4 below. Experimental results, it can be seen that the stronger adhesion when subjected to acid-dip treatment.

Flame Retardant Resin
Composition Precure
(precure) Swelling
(swelling) Micro Etching
(microetching) restoration
(reduction) Acid Dip
(acid-dip) Peel-strength
(peel-strength) Composition C
140 ℃ / 30 minutes 7 mins 20 minutes 5 minutes 5 minutes 0.78 Kn / cm 140 ℃ / 30 minutes 7 mins 20 minutes 5 minutes - 0.52 Kn / cm

Example  3. HF  Adhesion measurement by treatment

After casting the prepared flame retardant resin composition C in the form of a film, an insulating layer and a wiring pattern were formed according to the steps shown in FIG. 2. However, the difference in the adhesive strength when not subjected to the HF treatment step in the desmear process is shown in Table 5 below. The experimental results show that stronger adhesive force is obtained when the HF is treated.

Flame Retardant Resin Composition Precure
(precure) Swelling
(swelling) Micro Etching
(micro-
etching) restoration
(reduction) HF treatment Peel-strenth center line
Average roughness (Ra) Composition C
170 ℃ / 60 minutes 7 mins 20 minutes 5 minutes 5 minutes 0.82 Kn / cm 0.550 μm 170 ℃ / 60 minutes 7 mins 20 minutes 10 minutes - 0.29 Kn / cm 0.225 μm

Example  4. Curing Time of Epoxy Resin According to Curing Accelerator Content

The curing time of the epoxy resin according to the curing accelerator content was measured through rheological analysis.

Table 6 relates to the curing time according to the amount of 2-ethyl-4-methyl imidazol added.

Rheological analysis was performed in the following manner.

The modulus of elasticity, which represents the ratio of stress and strain, is called modulus. The gel point is defined as the intersection point of the storage modulus (G ′) and the loss modulus (G ″) (G ′ / G ″ = 1).

The elastic storage modulus (G '), loss modulus (G' '), and viscosity were measured at 110 ° C during the curing process using a viscometer (ARES, TA Instrument). Measurements were performed at an internal frequency of 10 Hz in a dynamic time-sweep test mode on a 25 mm disposable plate. At this time, the dynamic time-sweep test mode is selected as the most suitable method for checking the curing rate according to the composition.

The analysis yielded values of storage modulus G 'and loss modulus G' 'and their intersections. The intersection of the two values is defined as the curing time. The results are shown in Table 6.

Flame Retardant Resin
Composition Hardener Curing Accelerator (2E4MZ)
(Input amount per 100g of epoxy resin) Curing time
(sec at 110 ℃) Adhesion
(Relative comparison of peel strength) A Aminotriazine 1.0 g 666 Very low B Aminotriazine 0.5 g 1,048 lowness C Aminotriazine 0.25 g 1,889 Very high D Aminotriazine 0g - Very low

Table 6 shows the curing time and adhesion when the content of the curing accelerator is changed for the prepared compositions A, B, C and D. As the content of the curing accelerator increased, the curing time was shortened and the viscosity of the insulating layer was increased (data not shown).

In order to maximize the adhesion between the circuit pattern and the insulating layer, it is necessary to establish the process conditions optimized for the composition constituting the insulating layer.

As can be seen from the results of the compositions A and B shown in Table 6 above, when the degree of curing is too high, effective roughness cannot be obtained in the desmear process and the adhesive force decreases. As a result, the peel strength was 0.3 Kn / cm for A and 0.48 Kn / cm for B.

The hardening degree when no curing accelerator was added as in composition D was very low and appeared to be not suitable for application to the PCB.

Example  5. Melt viscosity ( Melting viscosity )

According to an aspect of the present invention, the flame retardant resin composition of the present invention uses a 25 mm diameter pararell plate in a rheometer (rheometer) at a plate spacing of 1.0 mm, the initial temperature 60 ℃, final temperature 180 ℃, temperature sweep mode, And complex viscosity (| η * |: unit Pa * sec obtained when measured at 120 measurement points and 24 minutes of run time at a frequency of 1% strain and 1 Hz at a heating rate of 5 ° C / min. ) May have a minimum viscosity of 1.0 to 250.0 Pa * sec, and a minimum viscosity of 1.0 to 100.0 Pa * sec, or 1.0 to 50.0 Pa * sec, 1.0 to 40.0 Pa * sec It has been described.

On the other hand, Figure 7 shows the results of measuring the melt viscosity for the prepared composition C of the present invention. ARES Rheometer from TA was used as a measuring equipment.

Sample preparation and measurement conditions are as follows.

a. The gap was adjusted to 1.0 mm after loading the specimen using a 25 mm diameter parael plate (parallel plate type zig).

b. Measuring conditions

Strain: 1%

Frequency: 1 Hz

Initial Temp .: 60 ° C

Final Temp .: 180 ° C

-Temperature increase rate: 5 ℃ / min

Point of measurement: 120 points

Run time: 24 minutes

c. Measured value: The minimum value of complex viscosity (|? * |) Was recorded as the minimum viscosity (min. Viscosity) in the data measured under the above conditions, and the results are shown in FIG. 7.

Referring to the results of Figure 7, the flame retardant composition according to the present invention can be seen that the lowest viscosity is 5.6, low flowability of less than 100 Pa * sec even in the 78 ~ 100 ℃ section.

Due to the physical properties as described above, the resin composition of the present invention exhibits a property capable of vacuum lamination even at a lower temperature and a shorter time than other epoxy resins having a similar composition ratio.

The vacuum lamination process is a process of thermally compressing and transferring the epoxy resin composition applied on PET at a specific temperature, pressure, and time.

That is, before the precure step of the present invention, the insulating film is transferred to the inner circuit board at a specific temperature and pressure. Through this process, the insulating film coating layer coated on the PET is transferred to the inner circuit and the PET is removed. A cross section of the substrate on which the insulating film coating layer is transferred onto the inner layer circuit is shown at the top of FIG. 2.

Table 7 below is an experimental result for showing the advantages that the flame-retardant resin composition according to the present invention can be exhibited in the vacuum lamination process. Vacuum lamination process can be divided into lamination process and pressurization process, the conditions required for each step is as follows.

The following process conditions compare the lowest conditions needed for lamination processes of the same quality.

Vacuum lamination process Comparative Example Example Lamination process
(Laminate process)


Vacuum holding time
(Vacuum time, sec) 30 15 Pressure (kgf / cm ² ) 7 7 Pressurization time (sec) 30 10 Temperature (℃) 100 80 Pressurization Process
(Press process)
Temperature (℃) 100 80 Pressure (kgf / cm ² ) 5.5 4 Pressurization time (sec) 60 25

The flame retardant resin composition used in the comparative example was used as described in US Patent US7179552. Referring to the experimental results of Table 7, it can be seen that the composition according to the present invention can be vacuum lamination at lower temperatures, lower pressures, and significantly shorter time in each process.

In addition, the flame-retardant resin composition according to the present invention is excellent in room temperature storage stability due to the low minimum viscosity.

That is, the general epoxy insulation composition proceeds the curing reaction at room temperature, which is constrained by storage at room temperature. Therefore, when it is maintained at room temperature for a long time, the curing reaction occurs, the minimum viscosity increases, and the flowability is poor. As a result, the insulation composition does not sufficiently fill the gaps between the wiring patterns, so that a minute pattern is difficult to be formed during the pressing process, and defective products are easily formed.

However, even if the flame-retardant composition according to the present invention is stored for 5 days at room temperature (25 ℃), the increase in the minimum viscosity was found to be less than 10% compared to the initial, the absolute value also appeared to be less than 100 Pa * sec, lamination In the process, there is no problem of not filling between patterns or deteriorating flowability.

As can be seen through the above examples, (a) 5 to 20 parts by weight of bisphenol A epoxy resin having an average epoxy resin equivalent of 100 to 700, and 30 to cresol novolac epoxy resin having an average epoxy resin equivalent of 100 to 600. A composite epoxy resin comprising 60 parts by weight, 5 to 15 parts by weight of a rubber-modified epoxy resin having an average epoxy resin equivalent of 100 to 500, and 15 to 30 parts by weight of a phosphorous epoxy resin having an average epoxy resin equivalent of 400 to 800; (b) amino triazine based curing agents; (c) curing accelerators; And (d) using a 25 mm diameter pararell plate at a rheometer, including an inorganic filler, at a plate spacing of 1.0 mm, using an initial temperature of 60 ° C., a final temperature of 180 ° C., and a temperature increase rate of 5 ° C. in a temperature sweep mode. The minimum viscosity (complex viscosity (| η * |: unit Pa * sec) obtained when measured at 120 measurement points and 24 minutes of run time at a frequency of 1% strain and 1 Hz under conditions of / min. a flame retardant insulating layer is formed by coating a flame-retardant resin composition having a min. viscosity of 1.0 to 250.0 Pa * sec on the surface of the substrate under the same conditions as described above; After the roughness is formed on the flame retardant insulating layer and the printed circuit pattern is formed on the flame retardant insulating layer having the roughness, the printed circuit board having excellent adhesion between the circuit pattern and the insulating layer can be manufactured.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

Claims (16)

(a) 5 to 20 parts by weight of bisphenol A epoxy resin having an average epoxy resin equivalent of 100 to 700, and 30 to 60 parts by weight of cresol novolac epoxy resin having an average epoxy resin equivalent of 100 to 600, and an average epoxy resin equivalent of 100 to 700 A composite epoxy resin comprising 5 to 15 parts by weight of a rubber modified epoxy resin of 500 and 15 to 30 parts by weight of an epoxy resin having an average epoxy resin equivalent of 400 to 800;
(b) amino triazine based curing agents;
(c) curing accelerators; And
(d) inorganic fillers;
In the rheometer (Rheometer), using a 25mm diameter pararell plate with a plate spacing 1.0mm, in the temperature sweep mode (temperature sweep mode) initial temperature 60 ℃, final temperature 180 ℃, and the temperature increase rate 5 ℃ / In terms of minutes, the minimum viscosity (min complex viscosity (| η * |: unit Pa * sec) obtained when measured at 120 measurement points and 24 minutes of run time at a frequency of 1% strain and 1 Hz) coating a surface of the substrate with a flame retardant resin composition having a viscosity of 1.0 to 250.0 Pa * sec to form a flame retardant insulating layer;
Precure a substrate on which the flame retardant insulating layer is formed;
Forming roughness on the flame retardant insulating layer; And
Forming a printed circuit pattern on the flame-retardant insulating layer having the roughness
And a step of forming the printed circuit board.
The method of claim 1,
The amino triazine-based curing agent is a manufacturing method of a printed circuit board is mixed in a ratio of 0.3 to 1.5 equivalents relative to the mixed equivalent of the epoxy groups of the composite epoxy resin.
The method of claim 1,
The curing accelerator is 0.1 to 1 part by weight based on 100 parts by weight of the composite epoxy resin manufacturing method of a printed circuit board.
The method of claim 1,
The curing accelerator is 0.2 to 0.3 parts by weight based on 100 parts by weight of the composite epoxy resin manufacturing method of a printed circuit board.
The method of claim 1,
The inorganic filler is a manufacturing method of a printed circuit board containing 20 to 50 parts by weight based on 100 parts by weight of the composite epoxy resin.
The method of claim 1,
The hardening accelerator is an imidazole compound is a manufacturing method of a printed circuit board.
The method of claim 1,
The curing accelerator is at least one selected from the group consisting of 2-ethyl-4methylimidazole, 1- (2-cyanoethyl) -2-alkylimidazole, 2-phenylimidazole and mixtures thereof. Method of manufacturing a printed circuit board.
The method of claim 1,
The inorganic filler is barium titanum oxide, barium strontium titanate, titanium oxide, lead zirconium titanate, lead lanthanium zirconate titanate ), Magnesium magnesium niobate-lead tiatanate, silver, nickel, nickel-coated polymer spheres, gold-coated polymer spheres, From the group consisting of tin solder, graphite, tantalum nitides, metal silicon nitride, carbon black, silica, gray and aluminum borate Method of manufacturing a printed circuit board is at least one inorganic material selected.
The method of claim 1,
The inorganic filler is a method of manufacturing a printed circuit board surface-treated with a silane coupling agent.
The method of claim 1,
The inorganic filler is a manufacturing method of a printed circuit board comprising a spherical filler of different sizes.
The method of claim 1,
Method for producing a printed circuit board, characterized in that the minimum viscosity (min. Viscosity) of the flame-retardant resin composition is 1.0 ~ 100.0 Pa * sec.
The method of claim 1,
Method for producing a printed circuit board, characterized in that the minimum viscosity (min. Viscosity) of the flame-retardant resin composition is 1.0 ~ 50.0 Pa * sec.
The method of claim 1,
The precure step is to maintain a 20 to 40 minutes at 140 to 160 ℃ manufacturing method of a printed circuit board.
The method of claim 1,
Forming the roughness may include treating the substrate coated with the flame retardant insulating layer with 2- (2-butoxyethoxy) ethanol and ethane-1,2-diol;
Etching with 55 g / L NaMnO ₄ , 18 g / L Na ₂ MnO ₄ and 45 g / L NaOH aqueous solution;
A method of manufacturing a printed circuit board comprising the step of neutralizing with 60% H ₂ SO ₄ .
The method of claim 14, wherein the forming of the roughness further comprises immersing in 20 to 60% HF or NH ₄ HF ₂ solution. 16. The method of claim 15,
If the method further comprises the step of immersing in HF or NH ₄ HF ₂ solution, the method of manufacturing a printed circuit board to perform a precure for 170 ℃ / 30 minutes to 60 minutes.

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