JP5798155B2 - Insulating resin composition for printed circuit board having low coefficient of thermal expansion and dielectric loss, prepreg and printed circuit board using the same - Google Patents

Description

  The present invention relates to an insulating resin composition for printed circuit boards having a low coefficient of thermal expansion and a dielectric loss rate, and a prepreg and a printed circuit board using the same.

  Recently, as electronic devices are miniaturized and performance-enhanced, a buildup layer serving as an insulating layer in a printed circuit board has been formed into multiple layers, and there is a trend for miniaturization and higher density of wiring.

  On the other hand, the low coefficient of thermal expansion and the low dielectric loss factor are the main characteristics conventionally required for an insulating layer of a printed circuit board, and various attempts have been made to satisfy these main characteristics.

  When the thermal expansion coefficient (CTE) of the insulating layer increases, a warpage defect of the substrate occurs, and when the dielectric loss rate increases, the electrical characteristics of the circuit wiring deteriorate, and unnecessary power loss occurs. Problems such as short-circuiting of circuit wiring occur.

  In order to reduce the thermal expansion coefficient of the insulating layer, an epoxy resin having a relatively high modulus or a liquid crystal oligomer is added, but the thermal expansion depends on the type and amount of the inorganic filler. It is a fact that the most attempts are made to lower the coefficient. In particular, when an inorganic filler such as silica is added in an amount of 80% by weight or more, it is known that the thermal expansion coefficient of the insulating layer can be lowered to the 10 ppm level.

  However, the addition of such an inorganic filler having a low coefficient of thermal expansion can improve the modulus of the substrate, but it is difficult to achieve the low dielectric loss characteristics required by the insulating layer. There is a strong need to improve the modulus of the material and to achieve low dielectric loss characteristics at the same time.

  Therefore, the present inventor solves the above-mentioned problems by simultaneously adding an inorganic filler having a low thermal expansion coefficient and an inorganic filler having a low dielectric loss factor as the inorganic filler contained in the insulating resin composition of the printed circuit board. Based on this finding, the present invention has been completed.

  Accordingly, one aspect of the present invention provides an insulating resin composition for a printed circuit board comprising an epoxy resin, a first inorganic filler having a low coefficient of thermal expansion, a second inorganic filler having a low dielectric loss factor, and a curing agent. There is.

  Another aspect of the present invention is to provide a prepreg in which the insulating resin composition for printed circuit boards according to the present invention is impregnated with glass fibers.

  Another aspect of the present invention is to provide a printed board including the insulating resin composition according to the present invention.

  Another aspect of the present invention is to provide a printed circuit board including the prepreg according to the present invention.

  In order to achieve the above aspect, an insulating resin composition for a printed circuit board (hereinafter referred to as “first invention”) according to the present invention includes an epoxy resin, a first inorganic filler having a low thermal expansion coefficient, and a second having a low dielectric loss rate. It comprises an inorganic filler, a curing agent, and a thermoplastic resin, and the total inorganic filler including the first inorganic filler and the second inorganic filler constitutes 50 to 80% by weight of the total composition.

  In the first invention, the first inorganic filler and the second inorganic filler are included in a weight ratio of 1: 0.5 to 1.5.

  In the first invention, the epoxy resin 20 to 30% by weight, the first inorganic filler 25 to 40% by weight, the second inorganic filler 25 to 40% by weight, the curing agent 5 to 10% by weight, and the thermoplastic resin It contains 1 to 5% by weight.

  In the first invention, the epoxy resin includes naphthalene epoxy resin, biphenyl epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, rubber-modified epoxy resin, and phosphorus ( Phosphorous) type epoxy resin is selected.

  In the first invention, the epoxy resin is a mixture of a novolac epoxy resin, a biphenyl epoxy resin, a naphthalene epoxy resin, and a rubber-modified epoxy resin.

  In the first invention, the first inorganic filler is silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, It is characterized by being selected from the group consisting of barium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate.

  In the first invention, the first inorganic filler has a thermal expansion coefficient of 5 to 10 ppm / ° C.

  In the first invention, the second inorganic filler is diboron trioxide, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, boron. At least one selected from the group consisting of aluminum oxide, barium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate is characterized.

  In the first invention, the second inorganic filler has a dielectric loss rate of 0.0001 to 0.001.

  In the first invention, the first inorganic filler is silica, and the second inorganic filler is diboron trioxide.

  In the first invention, the curing agent includes an active ester curing agent, an amide curing agent, a polyamine curing agent, an acid anhydride curing agent, a phenol novolac curing agent, a polymercaptan curing agent, a third amine curing agent, and an imidazole curing agent. It is characterized by being selected from at least one agent.

  In the first invention, the thermoplastic resin is a group consisting of phenoxy resin, polyester resin, polyacetal resin, polybutyral resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, and polyphenylene ether resin. At least one selected from the group consisting of:

  A prepreg (hereinafter referred to as “second invention”) for achieving another aspect of the present invention is formed by impregnating a glass fiber into the composition of the first invention.

  In the second invention, the glass fiber is at least one selected from E-glass, D-glass, T-glass and NE-glass.

  A printed circuit board (hereinafter referred to as “third invention”) for achieving another aspect of the present invention includes the composition of the first invention.

  A printed circuit board (hereinafter referred to as “fourth invention”) for achieving another aspect of the present invention includes the prepreg of the second invention.

  In the present invention, a high modulus of the printed circuit board can be realized by using the first inorganic filler having a low thermal expansion coefficient, and most important in the insulating layer of the printed circuit board by using the second inorganic filler having a low dielectric loss factor. Therefore, there is an advantage that the role as an insulator required can be maximized.

  In addition, the present invention has an advantage that it is easy to realize the most suitable insulating layer according to the characteristics of the printed circuit board by adjusting the contents of the first inorganic filler and the second inorganic filler.

It is sectional drawing of the general printed circuit board which can apply the insulating resin composition for printed circuit boards which concerns on this invention.

  Before describing the present invention more specifically, the terms or words used in the specification and claims should not be limited to the ordinary and lexical meaning, and the invention is best practiced. Based on the principle that the terminology can be appropriately defined for the purpose of explanation, it should be interpreted with the meaning and concept consistent with the technical idea of the present invention. Therefore, the structure of the Example described in this specification is only a suitable example of this invention, and does not represent all the technical thoughts of this invention. Thus, it should be understood that there are various equivalents and variations that can be substituted at the time of this application.

  Hereinafter, preferred embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily carry out the present invention. In describing the present invention, detailed descriptions of known techniques that may obscure the subject matter of the present invention are omitted.

  Referring to FIG. 1, the insulating layer 131 plays a role of insulating between circuit wirings, and also serves as a base material layer for forming wiring thereon, and the build-up layer 130 is also formed by the printed circuit board 100. In the multilayer printed wiring board composed of multiple layers, it plays the role of the insulating layer 131. In particular, unlike the prepreg in which the glass fiber is impregnated with the insulating resin composition, the buildup layer 130 is configured without the glass fiber.

  Recently, such printed circuit boards are in the trend of thinning and miniaturization. In order to prevent warping of the board and improve heat dissipation characteristics, etc., the insulating resin composition has a low coefficient of thermal expansion and excellent heat transfer efficiency. Add an inorganic filler. Among these inorganic fillers, silica is the most frequently used, and recently, the amount of such silica added has been increasing.

  As described above, the present invention provides an insulating resin composition for a printed circuit board in which a multiple filler system in which a first inorganic filler having a low thermal expansion coefficient and a second inorganic filler having a low dielectric loss factor are mixed is introduced. Is.

  Hereinafter, an insulating resin composition according to the present invention, a prepreg using the insulating resin composition, and a printed board will be described in detail.

  The insulating resin composition for printed circuit boards according to the present invention includes a first inorganic filler having a low thermal expansion coefficient and a second inorganic filler having a low dielectric loss factor in the epoxy resin and the curing agent, and in particular, the sum of the inorganic fillers. Is preferably 50 to 80% by weight of the total composition. If the total inorganic filler content is less than 50% by weight, the mechanical strength of the substrate decreases due to an increase in the coefficient of thermal expansion, causing warpage defects. If the total inorganic filler content exceeds 80% by weight, the inorganic material Since the content of the filler is too high, brittleness of the insulating layer increases, and the problem arises that workability is reduced when forming a build-up film.

  On the other hand, the first inorganic filler and the second inorganic filler are preferably included in the insulating resin composition according to the present invention in a weight ratio of 1: 0.5 to 1.5. When the content of the second inorganic filler is less than 0.5 with respect to the first inorganic filler, the dielectric loss rate of the printed circuit board insulating layer is increased, and the electrical characteristics of the circuit are deteriorated, and unnecessary power loss is reduced. If the first inorganic filler exceeds 1.5, the dielectric loss rate of the insulating layer can be effectively reduced, but the thermal expansion coefficient becomes relatively high, and the print This is because the problem that the mechanical properties of the substrate are lowered occurs.

  Next, a specific composition ratio of each component of the insulating resin composition according to the present invention will be considered.

  It is preferable that the epoxy resin which plays the role of an organic matrix is contained by 20 to 30 weight% with respect to the whole composition. That is, when the epoxy resin is less than 20% by weight, the brittleness of the insulating resin increases and the processability decreases, and the content of the inorganic filler that is exposed on the surface of the insulating layer when the circuit pattern is formed by plating is relatively There is a problem that the plating adhesion is reduced due to an increase. On the other hand, when the content of the epoxy resin exceeds 30% by weight, there arises a problem that the thermal expansion coefficient of the insulating layer increases and the mechanical strength of the printed circuit board decreases.

  The first inorganic filler and the second inorganic filler are each preferably contained in an amount of 25 to 40% by weight based on the entire composition. That is, when the first inorganic filler is contained at less than 25% by weight, the mechanical physical properties of the circuit are reduced due to an increase in the coefficient of thermal expansion, and when the second inorganic filler is contained at less than 25% by weight, the insulating layer The dielectric loss rate increases, the electrical characteristics of the circuit are not good, and unnecessary power consumption occurs. On the other hand, when the content of the first inorganic filler exceeds 40% by weight, there is a problem that it is difficult to achieve the low dielectric loss characteristic of the circuit due to the limitation on the addition amount of the second inorganic filler. When the filler content exceeds 40% by weight, there is a problem that it is difficult to achieve the low thermal expansion characteristics due to the limitation on the amount of the first inorganic filler added.

  The curing agent is preferably included at 5 to 10% by weight with respect to the entire composition. That is, when the content of the curing agent is less than 5% by weight, the curing rate of the insulating composition is delayed to increase the time required for the manufacturing process, and the uncured resin composition remains and the mechanical physical properties of the circuit remain. May also cause a decrease. When the curing agent exceeds 10% by weight, it is uneconomical, and there is a problem that the addition amount of the epoxy resin and the inorganic filler is limited.

  The thermoplastic resin is preferably contained at 1 to 5% by weight with respect to the entire composition. That is, when the content of the thermoplastic resin is less than 1% by weight, a problem of lowering the thermoplasticity of the insulating resin composition and a problem of increasing brittleness occur, and when it exceeds 5% by weight, the heat of the insulating layer is increased. The problem arises that the expansion coefficient increases and the mechanical properties decrease.

  Epoxy resins used in the present invention include naphthalene-based epoxy resins, biphenyl epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, rubber-modified epoxy resins, and phosphorus ( However, the present invention is not necessarily limited to this, and any epoxy resin generally used for printed circuit boards may be used.

  In the present invention, various kinds of epoxy resins may be mixed and used. In particular, when a novolac epoxy resin, a biphenyl epoxy resin, a naphthalene epoxy resin, and a rubber-modified epoxy resin are used in combination, an insulating layer There is an advantage that the dielectric loss factor can be further reduced.

The first inorganic filler having a low thermal expansion coefficient used in the present invention is silica (SiO ₂ ), alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, oxidation Magnesium, boron nitride, aluminum borate, barium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, or calcium zirconate are preferable. In particular, the first inorganic filler is More preferably, it has a thermal expansion coefficient of 5 to 10 ppm / ° C.

The second inorganic filler having a low dielectric loss rate used in the present invention is diboron trioxide (B ₂ O ₃ ), alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, carbonic acid Calcium, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, or calcium zirconate are preferred. More preferably, the second inorganic filler has a dielectric loss factor of 0.0001 to 0.001.

It is preferable to use silica (SiO ₂ ) as the first inorganic filler according to the present invention and simultaneously use diboron trioxide (B ₂ O ₃ ) as the second inorganic filler.

  As shown in Table 1, the present inventor studied the dielectric loss rate of various glass fibers used for the prepreg of a printed circuit board, and as a result, compared with E-glass or T-glass, D-glass or NE-glass. It has been found that the dielectric loss is extremely low.

Based on such results, the present inventors analyzed the composition of D-glass or NE-glass as shown in Table 2, and as a result, D-glass or NE-glass had E-glass or T-glass. It was found that the content of diboron trioxide (B ₂ O ₃ ) is relatively large in common compared with the above. From such research results, it is understood that the present inventor can use diboron trioxide used for a build-up film, not a prepreg of a printed circuit board, as an inorganic filler by uniformly dispersing particles in a resin composition. Therefore, when mixing silica and diboron trioxide, which are commonly used in the past, at an appropriate ratio, the thermal expansion coefficient of the printed circuit board can be lowered, and the dielectric loss ratio can be dramatically reduced. I was able to confirm that

  On the other hand, the curing agent used in the present invention includes an active ester curing agent, an amide curing agent, a polyamine curing agent, an acid anhydride curing agent, a phenol novolac curing agent, a polymercaptan curing agent, a tertiary amine curing agent and It is preferable to use at least one selected from imidazole curing agents.

  The insulating resin composition for printed circuit boards according to the present invention can be processed as a build-up film and can also be used for producing a prepreg by impregnating glass fibers. Since prepreg is impregnated with glass fibers in the resin composition, it has the advantage that the coefficient of thermal expansion is significantly lower than that of build-up film, and there is a limit to manufacturing a thin insulating layer. There are drawbacks.

  The glass fiber used when the prepreg is impregnated with the composition according to the present invention is preferably E-glass, D-glass, T-glass or NE-glass, and particularly D-glass or NE-. When glass is used, there is an advantage that the thermal expansion coefficient and the dielectric loss factor can be further reduced.

  A printed circuit board can be manufactured using the insulating resin composition according to the present invention, and when a build-up film is manufactured using the insulating resin composition according to the present invention, the thermal expansion coefficient is low and mechanical. In addition to excellent characteristics, the dielectric loss factor is low, and a multilayer printed wiring board can be manufactured in a very thin thickness.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to this.

Example 1
A mixed epoxy resin was prepared by mixing 40 g of a novolac epoxy resin, 40 g of a naphthalene epoxy resin, and 40 g of a rubber-modified epoxy resin. To this, 150 g of silica inorganic filler, 150 g of diboron trioxide and 47.39 g of aminotriazine novolak curing agent were mixed, and further, 11.79 g of polyvinyl butyral, 0.25 g of 2E4MZ initiator, and 10.08 g of BYK337 were added. The thus prepared composition was mixed, film casted and cured, and then a 20 × 8 cm specimen having a uniform thickness of about 150 μm was produced. Using the specimen thus prepared, the dielectric constant, dielectric loss factor, and thermal expansion coefficient were measured at 1 to 5 GHz.

(Example 2)
Samples were prepared under the same conditions as in Example 1, but the addition amount of silica was changed to 130 g, the addition amount of diboron trioxide was changed to 170 g, and the dielectric constant and dielectric constant were changed under the same conditions as in Example 1. The loss rate and thermal expansion coefficient were measured.

(Example 3)
Samples were prepared under the same conditions as in Example 1, but the addition amount of silica was changed to 170 g, the addition amount of diboron trioxide was changed to 130 g, and the dielectric constant and dielectric constant were changed under the same conditions as in Example 1. The loss rate and thermal expansion coefficient were measured.

(Comparative Example 1)
A specimen is prepared under the same conditions as in Example 1, but 150 g of silica is further added instead of 150 g of diboron trioxide, and the dielectric constant, dielectric loss factor, and thermal expansion coefficient are measured under the same conditions as in Example 1. did.

(Comparative Example 2)
Specimens were prepared under the same conditions as in Example 1, but 150 g of diboron trioxide was further added instead of 150 g of silica, and the dielectric constant, dielectric loss rate, and thermal expansion coefficient were measured under the same conditions as in Example 1. did.

  From Table 3, it can be seen that in Examples 1 to 3, Comparative Example 1 and Comparative Example 2, the dielectric constant was measured substantially the same.

  However, when comparing the dielectric loss rate, the dielectric loss rate in Example 1 is relatively low at 0.008, 0.002 in Example 2, and 0.009 in Example 3. The measurement was relatively higher than in Example 1. On the other hand, in the case of Comparative Example 1, the dielectric loss factor was very high at 0.02, but in the case of Comparative Example 2, it was found that the dielectric loss factor was 0.004, which was the lowest.

  On the other hand, when the result of measuring the thermal expansion coefficient is considered, when only silica having a low thermal expansion coefficient is added (Comparative Example 1), the thermal expansion coefficient is the lowest measured at 13 and boron trioxide having a low dielectric loss rate is obtained. In the case of Comparative Example 2 to which only No was added, the highest measurement was 30. However, referring to Examples 1 to 3, it can be seen that the thermal expansion coefficient is 13 to 18 and relatively good.

  Summarizing the experimental results, it is analyzed that Examples 1 to 3 are preferable in order to simultaneously satisfy the low thermal expansion coefficient and low dielectric loss required for the insulating layer of the printed circuit board, and among these, Example 1 is analyzed to be most preferable. These experimental results are interpreted as directly showing the effects of the present invention.

  The present invention can be applied to an insulating resin composition for printed circuit boards having a low coefficient of thermal expansion and a dielectric loss rate, a prepreg using the same, and a printed circuit board.

DESCRIPTION OF SYMBOLS 100 Printed circuit board 110 Insulator 120 Electronic component 130 Build-up layer 131 Insulation layer (build-up film or PCC)
132 circuit layer 140 capacitor 150 resistance element 160 solder resist 170 external connection means 180 pad

Claims (13)

Epoxy resin,
A first inorganic filler having a low coefficient of thermal expansion;
A second inorganic filler having a low dielectric loss factor;
A curing agent;
A thermoplastic resin,
The total inorganic filler including the first inorganic filler and the second inorganic filler constitutes 50 to 80% by weight of the total composition,
The insulating resin composition for a printed circuit board, wherein the first inorganic filler is silica and the second inorganic filler is diboron trioxide.   The insulating resin composition for a printed circuit board according to claim 1, wherein the first inorganic filler and the second inorganic filler are included in a weight ratio of 1: 0.5 to 1.5.   20-30% by weight of the epoxy resin, 25-40% by weight of the first inorganic filler, 25-40% by weight of the second inorganic filler, 5-10% by weight of the curing agent, and 1-5% by weight of the thermoplastic resin. The insulating resin composition for printed circuit boards according to claim 1, comprising:   The epoxy resin includes naphthalene type epoxy resin, biphenyl epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, rubber-modified epoxy resin, and phosphorous type epoxy resin. The insulating resin composition for printed circuit boards according to claim 1, wherein at least one kind is selected from the following.   The insulating resin composition for a printed circuit board according to claim 1, wherein the epoxy resin is a mixture of a novolac epoxy resin, a biphenyl epoxy resin, a naphthalene epoxy resin, and a rubber-modified epoxy resin.   The insulating resin composition for a printed circuit board according to claim 1, wherein the first inorganic filler has a thermal expansion coefficient of 5 to 10 ppm / ° C.   The insulating resin composition for a printed circuit board according to claim 1, wherein the second inorganic filler has a dielectric loss rate of 0.0001 to 0.001.   The curing agent is at least one selected from an active ester curing agent, an amide curing agent, a polyamine curing agent, an acid anhydride curing agent, a phenol novolac curing agent, a polymercaptan curing agent, a tertiary amine curing agent, or an imidazole curing agent. The insulating resin composition for printed circuit boards according to claim 1, wherein the insulating resin composition is selected.   The thermoplastic resin is at least one selected from the group consisting of phenoxy resin, polyester resin, polyacetal resin, polybutyral resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, and polyphenylene ether resin. The insulating resin composition for a printed circuit board according to claim 1, wherein:   A prepreg formed by impregnating a glass fiber into the composition of claim 1. The prepreg according to claim 10 , wherein the glass fiber is at least one selected from E-glass, D-glass, T-glass, and NE-glass.   A printed circuit board comprising the insulating resin composition according to claim 1. A printed circuit board comprising the prepreg of claim 10 .

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