JP4259510B2 - Epoxy resin inorganic composite sheet, circuit board, 3D circuit board - Google Patents

Description

  The present invention relates to an epoxy resin inorganic composite sheet mainly used for manufacturing a multilayer printed wiring board, and a circuit board and a three-dimensional circuit board manufactured using the epoxy resin inorganic composite sheet.

  In recent years, with the demand for smaller and more functional electronic devices, printed wiring boards have been actively manufactured by build-up methods, etc., in order to achieve higher integration of semiconductors, shorter wiring distances, and smaller printed wiring boards. Has been done.

  In manufacturing printed wiring boards by the build-up method, an insulating sheet material is used, but as the insulating sheet material, additive prepreg, copper foil with resin, resin film for build-up, etc. are currently used. (For example, refer to Patent Document 1). However, each of these insulating sheet materials has advantages and disadvantages.

  Since the prepreg for additive contains a substrate such as glass, the dimensional property (low linear expansion) accompanying temperature change is excellent, but the laser processability in via formation is inferior. Further, the substrate surface smoothness after molding also has a problem that undulation of the cross is likely to occur. Furthermore, the presence of the glass substrate increases the dielectric constant and dielectric loss tangent in terms of electrical characteristics, which is disadvantageous for higher speed and higher frequency.

  On the other hand, in the resin-coated copper foil and the build-up resin film, since the glass base material is not included, the linear expansion coefficient is increased, which is disadvantageous in terms of conduction reliability and mounting reliability.

Therefore, it is conceivable to use an inorganic filler such as silica or alumina having a high Q value (reciprocal of dielectric loss tangent) in place of the glass cloth as a concept for combining the advantages of both, thereby forming a glass substrate-less prepreg.
JP 2004-123874 A

  By the way, in order to obtain the linear expansion coefficient in the XY direction equivalent to that of the glass cloth, it is necessary to add about 80% by weight of the inorganic filler. However, it is very difficult to apply such a material to the surface of a film-like carrier material such as polyester and to dry it to obtain an uncured insulating sheet material. The insulating sheet material thus made is brittle and has poor flexibility. Also, even if the flexibility of the insulating sheet material can be maintained by weakening the degree of drying, it is difficult to peel it off, and the insulating sheet material will stretch or tear when peeled off. Thus, it cannot be handled as an insulating sheet material for molding. In other words, in order to be able to be peeled off from the carrier material, sheet mechanical properties having both flexibility and strength are required.

  On the other hand, in the insulating sheet material, a material having a low flow at the time of molding can be set to a higher molding pressure, which is advantageous in terms of conduction reliability of the paste via. Therefore, a low flow material is required. Furthermore, it has been found that even in the production of a circuit board with a cavity, it is difficult to produce a three-dimensional circuit board by direct pressure molding unless the flow is low.

  Therefore, a method of designing to be a low-flow insulating sheet material at the time of molding is required, but generally used methods are (1) increase of inorganic filler and (2) aspect ratio. Addition of a high inorganic filler, and (3) addition of a high softening point epoxy component. However, in any case where an uncured insulating sheet material is manufactured by such a method, the insulating sheet material is hard and brittle as a reward for realizing a low-flow material, resulting in a low flexibility material and poor handling. Therefore, it was impossible to achieve both low flow and handleability.

  The present invention has been made in view of the above points, and provides an epoxy resin inorganic composite sheet, a circuit board, and a three-dimensional circuit board that can be peeled off from a carrier material and can be handled alone and have low resin fluidity. It is the purpose.

  The epoxy resin inorganic composite sheet according to claim 1 of the present invention is a carrier material obtained by subjecting an epoxy resin composition containing (A) an epoxy resin, (B) an elastomer component, and (C) an inorganic filler to a release treatment. In the epoxy resin inorganic composite sheet 1 formed by applying it to the surface of 2 and drying it until it becomes a semi-cured state, (B) as an elastomer component, (B1) polybutadiene or butadiene random copolymer rubber, (B2) A copolymer having a hard segment and a soft segment, wherein the soft segment is selected from the group consisting of polybutadiene or butadiene random copolymer rubber, and having a weight average molecular weight of 20,000 to 1,000,000. Along with the total amount of the epoxy resin composition, (B) the elastomer component Yes weight of 0.5 to 4.5% by weight, characterized in that a 70 to 90 wt% content of (C) an inorganic filler.

The invention of claim 2, Oite in claim 1, is (B1) butadiene random copolymer rubber, characterized in that acrylonitrile-butadiene rubber.

The invention of claim 3 is characterized in that in claim 1 or 2 , (C) the inorganic filler is selected from silica, alumina, and barium titanate.

A circuit board according to a fourth aspect of the present invention is characterized by being formed by laminating the epoxy resin inorganic composite sheet 1 according to any one of the first to third aspects and forming a circuit.

A three-dimensional circuit board according to a fifth aspect of the present invention is formed by punching a part of the epoxy resin inorganic composite sheet 1 according to any one of the first to third aspects to provide an opening 4. The cavity portion 5 is formed by the opening portion 4 by lamination molding, and a circuit is formed in the cavity portion 5.

  According to the inorganic composite sheet of the epoxy resin according to claim 1 of the present invention, since the inorganic filler is contained at a relatively high ratio, high frequency characteristics, low moisture absorption, dimensional stability (particularly in the Z direction), high Physical properties such as elastic modulus, thermal strength, thermal elasticity, and low ionic properties are added. As a result, the cured product is extremely excellent in reliability (connection reliability, insulation reliability, heat resistance reliability, and mounting reliability). It will be. In addition, the conventional insulating sheet highly filled with an inorganic filler has not been able to achieve sufficient toughness until now, but according to the present invention, the toughness can be obtained in a semi-cured state. When peeled from the carrier material, the epoxy resin inorganic composite sheet does not stretch or tear, can be handled without the carrier material, and good handling properties can be obtained. That is, the epoxy resin inorganic composite sheet can be easily peeled off from the carrier material without heating, and can be handled without the carrier material. In addition, low flow during molding (decrease in resin fluidity) and toughening of the epoxy resin inorganic composite sheet can be achieved at the same time, making it easy to manufacture via-paste initial connectivity and substrates with cavities such as three-dimensional substrates. Is something that can be done.

According to the invention of claim 2, since the compatibility with the epoxy resin is good and the separated state of the rubber phase after drying is good, the cured product can obtain high toughness.

According to the invention of claim 3 , the following effects can be obtained. In other words, when using silica, it is possible to achieve low linear expansion, low moisture absorption, low dielectric constant, low dielectric loss tangent, high strength and high elastic modulus, as well as heat resistance and surface smoothness. It can be obtained high. In addition, when alumina is used, the same effect as silica can be obtained, and heat dissipation can be enhanced. Further, when barium titanate is used, the dielectric constant can be increased, and a substrate with a built-in capacitor can be manufactured.

According to the circuit board according to claim 4 of the present invention, since it does not include a base material such as a glass cloth, it is excellent in laser processability in via formation. Moreover, it is excellent in the smoothness of the substrate surface after molding, and is advantageous in increasing the speed and frequency due to the absence of the base material in terms of electrical characteristics.

According to the three-dimensional circuit board according to the fifth aspect of the present invention, the opening for forming the cavity is easily punched, the three-dimensional workability is good, and the fluidity at the time of molding is low and the substrate with the cavity is formed. Excellent in properties. In addition, since it does not contain a substrate such as glass cloth, it is excellent in laser processability in via formation. In addition, the smoothness of the substrate after molding is excellent, and in terms of electrical characteristics, the absence of a base material is advantageous for high speed and high frequency.

  Embodiments of the present invention will be described below.

  FIG. 1 shows an example of an embodiment of the present invention. An epoxy resin inorganic composite sheet according to the present invention includes (A) an epoxy resin, (B) an elastomer component, and (C) an epoxy containing an inorganic filler. After the resin composition is applied to the surface of the carrier material 2 that has been subjected to the mold release treatment, it is formed by drying it until it is in a semi-cured state. Although FIG. 1 shows the epoxy resin inorganic composite sheet 1 formed on one side of the carrier material 2, the epoxy resin inorganic composite sheet 1 may be formed on both sides of the carrier material 2. A cover film (not shown) may be provided on the surface of the epoxy resin inorganic composite sheet 1.

  In the present invention, the epoxy resin (A) is preferably a liquid epoxy resin, an epoxy resin having a softening temperature of 80 ° C. or lower, more preferably an epoxy resin having a softening temperature of 60 ° C. or lower. This is because such an epoxy resin is suitable for increasing the filling of the inorganic filler. Moreover, when a biphenyl aralkyl type epoxy resin is used, excellent reliability can be obtained and high drop impact resistance can be obtained. Further, (A) epoxy resin includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolak type epoxy resin, aralkyl type epoxy resin, biphenol type epoxy resin, naphthalene. Type epoxy resins, dicyclopentadiene type epoxy resins, epoxidized products of condensation products of phenols and aromatic aldehydes having a phenolic hydroxyl group, triglycidyl isocyanurate, alicyclic epoxy resins, etc. can be used. It is not limited to things.

  In the present invention, as the (B) elastomer component, one selected from the later-described (B1) component and (B2) component is used. However, any component having a weight average molecular weight of 20,000 to 1,000,000 is used. When the weight average molecular weight is lower than 20000, the film properties of the epoxy resin inorganic composite sheet 1 are deteriorated. Conversely, when the weight average molecular weight is higher than 1000000, the thixotropy is very high, and the epoxy resin inorganic composite sheet 1 is manufactured. When it does, the film-forming property of a coating film will deteriorate.

  As the component (B1), polybutadiene or butadiene random copolymer rubber is used. Here, the butadiene-based random copolymer rubber is not particularly limited, but acrylonitrile butadiene rubber is preferably used. Among the butadiene-based random copolymer rubbers of component (B1), acrylonitrile butadiene is particularly preferable because of its good compatibility with the epoxy resin and good separation of the rubber phase after drying. This is because high toughness can be obtained.

  On the other hand, as the component (B2), a copolymer having a hard segment and a soft segment, wherein the soft segment is polybutadiene or butadiene random copolymer rubber is used. Although a hard segment is not specifically limited, For example, it is amide and polyamide. The soft segment butadiene random copolymer rubber is, for example, acrylonitrile butadiene rubber. Specific examples of the component (B2) include a polyamide liquid rubber copolymer.

  And content of the (B) elastomer component is 0.5 to 4.5 weight% with respect to the epoxy resin composition whole quantity. Thereby, (C) the epoxy resin inorganic composite sheet 1 containing the inorganic filler in a high ratio of 70% by weight or more can be handled as if it were a thermoplastic film, and high handling properties can be obtained. is there. Furthermore, even if the thickness of the epoxy resin inorganic composite sheet 1 is as thin as 100 μm or less, it can be peeled off from the carrier material 2 and handled alone, and even when handled alone, it is torn or cracked. There is nothing. However, if the content of the (B) elastomer component is less than 0.5% by weight, cracks may occur around the punched part or the cut part when part of the epoxy resin inorganic composite sheet 1 is punched or cut. And powder fall off. On the contrary, if the content of the (B) elastomer component is more than 4.5% by weight, the resin fluidity becomes too low, and the adhesion to the laminated sheet such as FR grade and the adhesion between the sheets at the time of molding are increased. It is something that cannot be obtained.

In the present invention, (C) the inorganic filler (inorganic filler) is not particularly limited. For example, fused silica (SiO ₂ ), crystalline silica (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), Magnesium oxide (MgO), boron nitride (BN), aluminum nitride (AlN), etc. can be used, high dielectric constant filler such as barium titanate and titanium oxide, magnetic filler such as hard ferrite, hydroxide Inorganic flame retardants such as magnesium, aluminum hydroxide, antimony trioxide, antimony pentoxide, guanidine salt, zinc borate, molybdenum compound, zinc stannate, talc, barium sulfate, calcium carbonate, mica powder, etc. can be used . These can be used alone or in combination of two or more. These inorganic fillers have a high degree of freedom in thermal conductivity, relative permittivity, flame retardancy, particle size distribution, and color tone, and are appropriately blended and designed for particle size when a desired function is selectively exhibited. High filling can be easily performed. In addition, when an inorganic filler having a maximum particle size of 20 μm or less, preferably 10 μm or less, through holes can be accurately and accurately formed by laser processing or drilling, and drill wear is prevented. Is something that can be done.

  In particular, as the inorganic filler (C), a material selected from silica, alumina, and barium titanate is preferably used. When silica is used, low linear expansion, low moisture absorption, low dielectric constant, low dielectric loss tangent, high strength and high elastic modulus can be achieved, and heat resistance and surface smoothness can be increased. It is something that can be done. In addition, when alumina is used, the same effect as silica can be obtained, and heat dissipation can be enhanced. Further, when barium titanate is used, the dielectric constant can be increased, and a substrate with a built-in capacitor can be manufactured. That is, a capacitor layer that functions as a capacitor can be provided in the substrate.

  And content of (C) inorganic filler is 70 to 90 weight% with respect to the epoxy resin composition whole quantity. Thereby, the linear expansion coefficient of the epoxy resin inorganic composite sheet 1 becomes small, which is advantageous in terms of conduction reliability and mounting reliability. However, if the content of the inorganic filler (C) is less than 70% by weight, the strength of the epoxy resin inorganic composite sheet 1 is lowered and it becomes difficult to peel off from the carrier material 2, and if it is forcibly removed, the epoxy resin inorganic composite sheet 1 stretches or breaks. The elongation of the epoxy resin inorganic composite sheet 1 at the time of peeling leads to the elongation in the step of peeling the mask film after filling the via paste, and when this elongation occurs, it is a fatal problem at the time of manufacturing the multilayer laminate. This causes a dimensional shift. On the other hand, when the content of (C) the inorganic filler is more than 90% by weight, the epoxy resin inorganic composite sheet 1 becomes brittle and difficult to handle.

  In the present invention, in order to improve the dispersibility of the inorganic filler in the epoxy resin composition, epoxy silane, mercapto silane, amino silane, vinyl silane, styryl silane, methacryloxy silane, acryloxy silane It is preferable to add a coupling agent such as titanate or the like, or a dispersant such as alkyl ether, sorbitan ester, alkyl polyether amine or polymer.

  Moreover, in this invention, a dicyandiamide, a phenol resin, an acid anhydride, etc. can be contained in an epoxy resin composition as a hardening | curing agent. As the phenol resin, a novolac type, an aralkyl type, a terpene type, or the like can be used. In particular, it is preferable to use a resin having a softening temperature of 80 ° C. or lower, like the epoxy resin. In addition, when using aralkyl type phenol, particularly phenol phenyl aralkyl resin or phenol biphenyl aralkyl resin, impact resistance can be remarkably improved, and it has both low moisture absorption and high adhesion, and is a printed circuit board material. As a coating material for IC and component protection, a highly reliable molded product (cured product) can be obtained. In addition, acid anhydrides can be used in either liquid or crystalline form, but even if the inorganic filler is increased by using liquid or low molecular weight materials at room temperature, the epoxy resin inorganic The flexibility of the composite sheet 1 can be maintained.

  And the epoxy resin inorganic composite sheet which concerns on this invention can be manufactured as follows. That is, an epoxy resin composition is prepared by blending (A) an epoxy resin, (B) an elastomer component, (C) an inorganic filler, and a curing agent as necessary, and this epoxy resin composition is converted into methyl ethyl ketone (MEK). ) And N, N-dimethylformamide (DMF) or the like to prepare a slurry varnish. At this time, it is preferable to use only a solvent having a boiling point of 100 ° C. or less, such as methyl ethyl ketone, thereby making it possible to make drying conditions mild and efficiently without proceeding the reaction between the epoxy resin and the curing agent. The solvent can be removed, and a better epoxy resin inorganic composite sheet 1 can be obtained. Next, after applying the slurry-like varnish obtained by diluting the epoxy resin composition with a solvent as described above to one side of the carrier material 2 subjected to the mold release treatment, this is heated by hot air spraying or the like. To dry until semi-cured. Then, the epoxy resin inorganic composite sheet 1 as shown in FIG. 1 can be obtained.

  Here, as the carrier material 2, a polymer film, a metal film, or the like that has been subjected to mold release treatment on one or both sides can be used. As the polymer film, polyolefin such as polypropylene and polyvinyl chloride, polyester such as polyethylene terephthalate (PET), polycarbonate, acetylcellulose, tetrafluoroethylene, polyphenylene sulfide, and the like can be used. Moreover, metal foils, such as copper foil, aluminum foil, nickel foil, can be used as a metal film. As the carrier material 2, it is preferable to use polyester, particularly polyethylene terephthalate (PET), in terms of cost and heat resistance. The thickness of the carrier material 2 is generally 10 to 200 μm.

  The mold release treatment can be performed by coating the surface of the carrier material 2 with, for example, an organopolysiloxane, a modified organopolysiloxane, a fluorine polymer, or the like. As an index of releasability, the peel strength between the epoxy resin inorganic composite sheet 1 and the carrier material 2 can be used. This peel strength is 0.6 to 100 N / m under the condition of a tensile speed of 50 mm / min. It is preferable to be in the range. In the case where the peel strength is less than 0.6 N / m, problems such as the epoxy resin inorganic composite sheet 1 being peeled off from the carrier material 2 at the winding stage after coating and drying are likely to occur. On the other hand, when the peel strength is greater than 100 N / m, it becomes difficult to peel off, and depending on the balance with the strength of the epoxy resin inorganic composite sheet 1, if it is forcibly peeled off from the carrier material 2, the epoxy resin inorganic There is a concern that the composite sheet 1 is destroyed. Moreover, it is preferable that the tensile strength of the epoxy resin inorganic composite sheet 1 is in the range of 0.5 to 30 MPa, and within this range, it is possible to make it difficult to break during winding.

  The epoxy resin inorganic composite sheet according to the present invention is in a semi-cured state on the surface of the carrier material 2 subjected to the release treatment. The semi-cured state is a so-called B-stage state, which is a state in which the epoxy resin composition is partially reacted by heating the epoxy resin composition. Therefore, like the conventional prepreg, the epoxy resin inorganic composite sheet 1 has the property of being once melted by the heat and pressure of lamination molding and then cured. Moreover, it is preferable that the quantity of the solvent which remains after drying is less than 3 weight% (lower limit is 0 weight%) with respect to the epoxy resin inorganic composite sheet 1 whole quantity. If the amount of the solvent after drying is 3% by weight or more, voids may easily occur during molding.

  Moreover, it is preferable that the thickness of the epoxy resin inorganic composite sheet 1 is 5-500 micrometers. If the thickness is less than 5 μm, the particle size of the inorganic filler that can be used during coating will become finer, which will likely cause problems in filling properties, and the strength of the epoxy resin inorganic composite sheet 1 will decrease. In effect, peeling from the carrier material 2 becomes impossible. On the other hand, if the thickness is greater than 500 μm, it takes an enormous amount of time for drying in order to prevent foaming or voids from being generated on the surface or inside of the epoxy resin inorganic composite sheet 1. Therefore, when obtaining a thing thicker than 500 micrometers, it can be said that it is practically suitable to laminate | stack the epoxy resin inorganic composite sheet 1 thinner than 500 micrometers.

  The epoxy resin inorganic composite sheet according to the present invention does not include a base material such as a glass cloth used for a conventional printed circuit board, and the reliability is improved only by an inorganic filler instead of the base material. At the same time, the flexibility can be secured and the resin fluidity can be lowered. Further, since the surface of the carrier material 2 has been subjected to a mold release treatment in advance, it can be easily peeled off from the carrier material 2 without heating the epoxy resin inorganic composite sheet 1. Since it has a characteristic that it can be peeled off from the carrier material 2 and can be handled alone, for example, by peeling it off from the carrier material 2 before laminating, as shown in FIG. It is possible to press several sheets at once. As a result, even if a defect (void, dent, pinhole, foreign matter, etc.) exists in a part of one epoxy resin inorganic composite sheet 1, the probability of the defect is remarkably increased by overlapping two or more sheets. It is possible to lower the insulation and prevent insulation failure. In addition, the thickness can be adjusted by adjusting the number of sheets to be stacked, but it is particularly easy to increase the thickness by stacking a large number of sheets. It can be suitably used for the sixth application. The conventional build-up resin film cannot be peeled off from the carrier material 2 and handled alone, and cannot be stacked and pressed several times at a time. The process of peeling the material 2 must be repeated a plurality of times. Therefore, the thicker the desired thickness, the longer the drying time must be exponentially proportional and the productivity tends to decrease. This is because it is difficult to increase the thickness of the film unless it is dried for a long time under mild conditions because the probability of occurrence of voids included during drying increases.

  In the present invention, the molded article is a cured product obtained by molding the epoxy resin inorganic composite sheet 1 by press molding. The epoxy resin inorganic composite sheet 1 has, for example, a press pressure of 0.1 to 20 MPa, a temperature of 100 to 200 ° C., 10 It can be cured by heating for up to 240 minutes. Specific examples of the molded product include a circuit board 3 and a three-dimensional circuit board 6 described later.

  FIG. 2B shows an example of a circuit board according to the present invention. The circuit board 3 is formed by laminating a plurality of epoxy resin inorganic composite sheets 1 and forming a circuit (not shown). Can be manufactured. The circuit can be formed by transferring in advance to the epoxy resin inorganic composite sheet 1 or can be formed by an additive method or the like. And in the circuit board 3 shown in FIG.2 (b), since it does not contain base materials, such as a glass cloth, it is excellent in the laser workability in via formation. Moreover, it is excellent in the smoothness of the substrate surface after molding, and is advantageous in increasing the speed and frequency due to the absence of the base material in terms of electrical characteristics.

  FIG. 3 shows an example of the three-dimensional circuit board according to the present invention. The three-dimensional circuit board 6 (substrate with a cavity) can be manufactured as follows. First, a part of the epoxy resin inorganic composite sheet 1 is punched to provide the opening 4. In what is shown in FIG. 3, the two epoxy resin inorganic composite sheets 1 are each provided with a large opening 4a and a small opening 4b, but the number of sheets and the size of the opening 4 are particularly limited. is not. Next, these epoxy resin inorganic composite sheets 1 are laminated and formed. In what is shown in FIG. 3, the epoxy resin inorganic composite sheet 1 provided with the small openings 4b is superimposed on the epoxy resin inorganic composite sheet 1 provided with no openings 4, and a large opening is further formed thereon. The epoxy resin inorganic composite sheet 1 provided with the portion 4a is stacked, and these are heated and pressed to be laminated. Then, the cavity part 5 will be formed in the opening part 4, but since the epoxy resin inorganic composite sheet 1 according to the present invention has low resin fluidity, the shape of the cavity part 5 is not broken even after pressing. It is. The circuit board 6 can be obtained by forming a circuit (not shown) in the cavity portion 5 and mounting various mounting parts (not shown) in the cavity portion 5. The circuit can be formed by transferring in advance to the epoxy resin inorganic composite sheet 1 or can be formed by an additive method or the like. And even if it exists in the three-dimensional circuit board 6 shown in FIG.3 (b), since it does not contain base materials, such as a glass cloth, it is excellent in the laser workability in via formation. Moreover, it is excellent in the smoothness of the substrate surface after molding, and is advantageous in increasing the speed and frequency due to the absence of the base material in terms of electrical characteristics.

  As described above, in the epoxy resin inorganic composite sheet according to the present invention, since the inorganic filler is contained at a relatively high ratio, high frequency characteristics, low moisture absorption, dimensional stability (particularly in the Z direction). , Physical properties such as higher elastic modulus, strength during heat, elasticity during heat, low ionicity are added, and as a result, the cured product is reliable (connection reliability, insulation reliability, heat resistance reliability, mounting reliability) It will be extremely excellent. In addition, the conventional insulating sheet highly filled with an inorganic filler has not been able to achieve sufficient toughness until now, but according to the present invention, the toughness can be obtained in a semi-cured state. When peeled off from the carrier material 2, the epoxy resin inorganic composite sheet 1 does not stretch or tear, can be handled without the carrier material, and good handling properties can be obtained. In addition, low flow during molding (decrease in resin fluidity) and toughening of the epoxy resin inorganic composite sheet 1 can be achieved at the same time. It can be manufactured.

  Hereinafter, the present invention will be specifically described by way of examples.

  As (A) epoxy resin, (A1) biphenyl aralkyl type epoxy resin (“NC3000” manufactured by Nippon Kayaku Co., Ltd.) and (A2) bisphenol F type epoxy resin (“YDF8170” manufactured by Tohto Kasei Co., Ltd.) were used.

  (B) As an elastomer component, (B1) acrylonitrile butadiene rubber (Mw = 300000) (“PNR1H” manufactured by JSR), (B2) polyamide liquid rubber copolymer (Mw = 50000) (“Kayaflex” manufactured by Nippon Kayaku Co., Ltd.) )).

  (C) As inorganic fillers, (C1) spherical silica (“FB3LDX” manufactured by Denki Kagaku Kogyo Co., Ltd.), (C2) spherical alumina (“TS10” manufactured by Tatsumori), (C3) barium titanate (manufactured by Sakai Chemical Co., Ltd.) “BTZ-09”) was used.

  And first, after kneading the components (A) to (C) with a planetary mixer in the blending amounts shown in the following [Table 1], the slurry was blended with methyl ethyl ketone and diluted to adjust the viscosity to 3000 cps. A varnish was obtained. However, in Examples 6, 7, and 10, dilution was performed using a solvent in which methyl ethyl ketone and N, N-dimethylformamide were mixed at a weight ratio of 2: 1. Next, this varnish was applied to a carrier material 2 made of a polyethylene terephthalate (PET) film having a thickness of 75 μm. In addition, as the carrier material 2, a material whose surface was previously subjected to release treatment using organopolysiloxane was used. Thereafter, the carrier material 2 coated with the slurry-like varnish is heated and dried at 120 ° C. for 8 minutes to form a semi-cured (B stage state) epoxy resin composition with a thickness of 100 μm on one side of the carrier material 2 in FIG. An epoxy resin inorganic composite sheet 1 as shown was produced. However, in Examples 8 to 11, the thickness of the epoxy resin inorganic composite sheet 1 was 20 μm, 500 μm, 300 μm, and 40 μm, respectively.

  The following measurement was performed using the epoxy resin inorganic composite sheet 1 produced as described above.

(Residual solvent amount)
A sheet weight equivalent to 5 g was placed in a dryer at 163 ° C./15 minutes to remove volatile components (solvent). The amount of volatile matter relative to the sheet weight (excluding the carrier material 2) was calculated by measuring the weight loss of the sheet before and after the dryer was charged, and this was used as the residual solvent amount.

(Resin fluidity)
A sheet processed into a circular shape of 100 mmφ was press-molded under the condition of 130 ° C./3 MPa, and the amount of resin protruding from the original circular shape of 100 mmφ was measured to determine the outflow rate.

(Crack resistance during punching / cutting)
After the epoxy resin inorganic composite sheet 1 was preliminarily dried at 110 ° C. for 20 minutes with a dryer, punching with an inner diameter of 2 mmφ was performed with a Thomson blade at 25 ° C. Then, the periphery of the punched portion was visually observed to confirm the presence or absence of a crack, and “O” indicates that there was no crack and “X” indicates that there was a crack.

(Elongation of sheet when peeling)
With the carrier material 2 attached, a plurality of via holes were formed, filled with a conductive paste, the carrier material 2 was peeled off, and then molded. And the shift | offset | difference (distance between paste-paste) from the reference | standard position after shaping | molding was measured with the optical microscope, and the average value was made into sheet elongation at the time of peeling.

(Delamination with hygroscopic solder heat resistance)
As shown in FIG. 4, the epoxy resin inorganic composite sheet 1 was molded and cured on both surfaces of the FR-4 substrate 7 at 175 ° C. for 2 hours. The substrate thus obtained was allowed to stand for 3 days under conditions of 85 ° C. and 85% humidity, and then immersed in a solder bath at 260 ° C. for 20 seconds. And after immersion, the peeling state of the interface of FR-4 board | substrate 7 and the epoxy resin inorganic composite sheet 1 was observed, and "(circle)" without delamination was set to "x" with delamination.

  The above results are shown in [Table 1] below.

  Examples 1 to 3 and Comparative Examples 1 and 2 show the results when the content of the elastomer component is changed. As the amount of the elastomer component, 0.5 to 4.5% by weight is the most appropriate amount. It is confirmed that On the other hand, in the case of Comparative Example 1 having less than 0.5% by weight of the elastomer component, it is confirmed that the sheet has an adverse effect on the flexibility of the sheet and cracks are generated during punching. Moreover, in the thing of the comparative example 2 with more elastomer components than 4.5 weight%, resin fluidity | liquidity will fall too much and adhesiveness will fall, and it has confirmed that delamination (delamination) generate | occur | produces. Is done.

  Examples 4 and 5 show the results when the content of the elastomer component was changed to 2% by weight and the content of the inorganic filler was changed, but no cracks occurred during punching, Since delamination does not occur, it is confirmed to be good. In addition, in the thing of Example 4, although the sheet | seat elongation at the time of peeling is large, there is substantially no problem.

  Further, in Examples 6 and 7 in which the type of elastomer component was changed to a polyamide liquid rubber copolymer and the solvent was changed to a mixed solvent of methyl ethyl ketone and N, N-dimethylformamide, Examples 2 and 4 respectively. Compared with, it is confirmed that there is no problem.

  Furthermore, although Examples 8-11 have shown the result at the time of changing the thickness of a sheet | seat and the kind of inorganic filler, it is confirmed that all are satisfactory.

It is sectional drawing which shows an example of embodiment of this invention. It shows another example of the above, and (a) and (b) are sectional views. It shows another example of the above, and (a) and (b) are sectional views. It is sectional drawing which shows another example same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Epoxy resin inorganic composite sheet 2 Carrier material 3 Circuit board 4 Opening part 5 Cavity part 6 3D circuit board

Claims (5)

  (A) An epoxy resin, (B) an elastomer component, and (C) an epoxy resin composition containing an inorganic filler is applied to the surface of a carrier material that has been subjected to a mold release treatment, and then this is in a semi-cured state. In the epoxy resin inorganic composite sheet formed by drying, (B) an elastomer component, (B1) a polybutadiene or butadiene random copolymer rubber, (B2) a copolymer having a hard segment and a soft segment, The soft segment is selected from those which are polybutadiene or butadiene random copolymer rubber, and has a weight average molecular weight of 20,000 to 1,000,000. With respect to the total amount of the epoxy resin composition, (B) the elastomer component The content is 0.5 to 4.5% by weight, and (C) the content of the inorganic filler Epoxy resin-inorganic composite sheet amount is equal to or 70 to 90 wt%. (B1) The epoxy resin inorganic composite sheet according to claim 1, wherein the butadiene-based random copolymer rubber is acrylonitrile butadiene rubber . (C) as the inorganic filler, silica, alumina, an epoxy resin-inorganic composite sheet according to claim 1 or 2, characterized in forming isosamples using those selected from barium titanate. A circuit board formed by laminating the epoxy resin inorganic composite sheet according to any one of claims 1 to 3 and forming a circuit . A part of the epoxy resin inorganic composite sheet according to any one of claims 1 to 3 is punched out to provide an opening, the epoxy resin inorganic composite sheet is laminated to form a cavity part at the opening, and the cavity part A three-dimensional circuit board characterized in that a circuit is formed on the board.

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