JP2012216650A - Composition for forming insulation layer, film for forming insulation layer, and substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for forming insulation layer and a film for forming insulation layer capable of forming an insulation layer having superior thermal conductivity and insulation properties, and to provide a substrate having superior heat dissipation and reliability.SOLUTION: A composition for forming insulation layer is used for forming an insulation layer, and constituted by including a resin material and a filler composed of an aluminum oxide. A moisture content of the filler is 0.1 mass.% or more and 0.3 mass.% or less. Moreover, the filler content is 30 vol.% or more and 70 vol.% or less of the whole composition for foaming the insulation layer.

Description

  The present invention relates to an insulating layer forming composition, an insulating layer forming film, and a substrate.

  A substrate is known in which wiring is formed on a metal plate made of a metal material via an insulating layer (see, for example, Patent Document 1).

  Such a substrate can efficiently release heat from an electronic component such as a semiconductor element or a light-emitting element mounted on the substrate as compared with a substrate mainly composed of a resin material and a fiber base material.

  In such a substrate, the insulating layer includes a resin material and an inorganic filler. Thereby, the heat from an electronic component can be efficiently transmitted to a metal plate through an insulating layer.

  Incidentally, in recent years, with the increase in the amount of heat from electronic components, such a substrate is required to further improve heat dissipation.

  However, the conventional substrate has a problem that the thermal conductivity of the insulating layer is not sufficient, and as a result, the heat dissipation of the substrate cannot be improved while ensuring the necessary insulating properties of the insulating layer. That is, conventionally, it has been impossible to realize an insulating layer having excellent thermal conductivity and insulating properties.

JP 2001-196495 A

  An object of the present invention is to provide an insulating layer forming composition and an insulating layer forming film capable of forming an insulating layer having excellent thermal conductivity and insulating properties, and excellent heat dissipation and reliability. It is providing the board | substrate which has.

Such an object is achieved by the present inventions (1) to (10) below.
(1) An insulating layer forming composition used for forming an insulating layer,
Resin material,
Comprising a filler composed of aluminum oxide,
The composition for forming an insulating layer, wherein the filler has a water content of 0.1% by mass to 0.3% by mass.

  (2) The composition for forming an insulating layer according to (1), wherein the content of the filler is 30 vol% or more and 70 vol% or less of the whole.

  (3) Content of the said resin material is a composition for insulating layer formation as described in said (1) or (2) which is 30 to 70 vol% of the whole.

  (4) The composition for forming an insulating layer according to any one of (1) to (3), wherein the resin material is a curable resin.

  (5) The composition for forming an insulating layer according to any one of (1) to (4), wherein the viscosity is 30 P or less.

  (6) A film for forming an insulating layer comprising an insulating layer forming layer formed by layering the composition for forming an insulating layer according to any one of (1) to (5) above.

(7) The film for forming an insulating layer according to (6), further including a support layer for supporting the insulating layer forming layer.
(8) The said support layer is a film for insulating layer formation as described in said (7) which is metal foil.

(9) a metal plate made of a metal material;
An insulating layer provided on the metal plate and composed of a cured product or a solidified product obtained by forming the insulating layer forming composition according to any one of (1) to (5) into a layer;
And a conductive layer provided on a surface of the insulating layer opposite to the metal plate.

(10) a metal plate made of a metal material;
An insulating layer provided on the metal plate and including a resin material and a filler made of aluminum oxide;
A substrate having a conductor layer provided on a surface of the insulating layer opposite to the metal plate,
The substrate is characterized in that the water content of the filler is 0.1% by mass or more and 0.3% by mass or less.

  According to the composition for forming an insulating layer of the present invention, even if the filler content is increased, the viscosity can be suppressed and the desired flow property can be obtained. Therefore, it is possible to form an insulating layer having excellent thermal conductivity while preventing generation of voids in the insulating layer. That is, an insulating layer having excellent thermal conductivity and insulating properties can be formed.

  Moreover, according to the insulating layer forming film of the present invention, an insulating layer having excellent thermal conductivity and insulating properties can be formed relatively easily.

  Moreover, according to the board | substrate of this invention, since it has the insulating layer which has the outstanding heat conductivity and insulation, it is excellent in heat dissipation and reliability.

It is sectional drawing which shows schematic structure of the board | substrate which concerns on embodiment of this invention. It is a partial expanded sectional view which shows typically the insulating layer of the board | substrate shown in FIG. It is a figure for demonstrating the manufacturing method of the board | substrate shown in FIG. It is the schematic which shows an example of the electronic circuit using the board | substrate of this invention.

  Hereinafter, the composition for forming an insulating layer, the film for forming an insulating layer, and the substrate of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  1 is a sectional view showing a schematic configuration of a substrate according to an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view schematically showing an insulating layer of the substrate shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a schematic diagram illustrating an example of an electronic circuit using the substrate of the present invention. In the following, for convenience of explanation, the upper side in FIGS. 1 to 4 is also referred to as “upper” and the lower side is also referred to as “lower”. In each drawing, for convenience of explanation, the substrate and its respective parts are schematically shown exaggeratedly, and the size and ratio of the substrate and its respective parts are greatly different from actual ones.

(substrate)
A substrate 1 shown in FIG. 1 includes a metal plate 2, a conductor layer 3, and an insulating layer 4, and the metal plate 2 and the conductor layer 3 are joined via the insulating layer 4. That is, the substrate 1 has a metal plate 2, an insulating layer 4, and a conductor layer 3 laminated in this order.

  Such a substrate 1 can transmit heat from the conductor layer 3 side to the metal plate 2 through the insulating layer 4, and can radiate heat by the metal plate 2.

Hereinafter, each part which comprises the board | substrate 1 is demonstrated in detail sequentially.
The metal plate 2 has a function of supporting the conductor layer 3. In addition, the metal plate 2 also has a function as a heat radiating part that releases heat from the electronic components mounted on the substrate 1 when the substrate 1 is used in an electronic circuit as will be described later.

Such a metal plate 2 is made of a metal material.
Although it does not specifically limit as this metal material, It is preferable to use aluminum or aluminum alloy. By constituting the metal plate 2 with aluminum or an alloy thereof, the thermal conductivity of the metal plate 2 can be made excellent. As a result, the heat dissipation of the substrate 1 can be made excellent.

  The thickness of the metal plate 2 is not particularly limited as long as the conductor layer 3 can be supported. For example, the thickness is preferably 1 to 5 mm, and more preferably 1 to 2 mm. By setting the thickness of the metal plate 2 in such a numerical range, it is possible to reduce the thickness of the substrate 1 while ensuring the necessary mechanical strength of the substrate 1.

A conductor layer 3 is bonded to one surface of such a metal plate 2 via an insulating layer 4.
The conductor layer 3 is provided on the surface of the insulating layer 4 opposite to the metal plate 2 and is patterned by a process such as etching when the substrate 1 is used for an electronic circuit as will be described later. Etc. That is, the conductor layer 3 is a conductor foil formed uniformly over the entire surface of the insulating layer 4, and becomes a conductor pattern by being patterned.

  Such a conductor layer 3 is made of a conductive material. Specifically, the constituent material of the conductor layer 3 is not particularly limited. For example, a metal material is preferably used, and in particular, copper or a copper alloy because of its low electrical resistance and low cost. Is preferably used.

  Moreover, although the thickness of the conductor layer 3 is not specifically limited, For example, it is preferable that it is 10-200 micrometers, and it is more preferable that it is 18-70 micrometers.

  The insulating layer 4 is provided between the metal plate 2 and the conductor layer 3 and has a function of bonding (bonding) these. The insulating layer 4 has an insulating property. Thereby, the insulation state of the metal plate 2 and the conductor layer 3 is ensured.

  Furthermore, the insulating layer 4 has thermal conductivity. Thereby, the insulating layer 4 can transfer the heat on the conductor layer 3 side to the metal plate 2. The higher the thermal conductivity of the insulating layer 4 is, the better. Specifically, it is preferably 1 W / m · K or more, and more preferably 3 W / m · K or more. Thereby, the insulating layer 4 can efficiently transfer the heat on the conductor layer 3 side to the metal plate 2.

  The thickness (average thickness) of the insulating layer 4 is not particularly limited, but is preferably about 10 μm to 200 μm, and more preferably about 20 μm to 150 μm. Thereby, the thermal conductivity of the insulating layer 4 can be improved while ensuring the insulating property of the insulating layer 4.

  As shown in FIG. 2, in the insulating layer 4, fillers 42 are dispersed in a resin portion 41 composed of a resin material as a main material.

The resin part 41 has a function as a binder for bonding the fillers 42 together.
The filler 42 has a thermal conductivity higher than that of the resin portion 41. Thereby, the thermal conductivity of the insulating layer 4 can be increased.

  In particular, the filler 42 is prepared so that the water content is 0.10 mass% or more and 0.30 mass% or less. Thereby, the heat conductivity and insulation of the insulating layer 4 can be made excellent. As a result, the heat dissipation and reliability of the substrate 1 can be made excellent.

  Such an insulating layer 4 is formed by curing or solidifying an insulating layer forming composition containing a resin material (binder) and a filler, as will be described later. That is, the insulating layer 4 is composed of a cured product or a solidified product obtained by forming the insulating layer forming composition into a layer shape. In addition, about the composition for insulating layer formation, it explains in full detail in description of the manufacturing method of the board | substrate 1 mentioned later.

(Substrate manufacturing method)
Next, an example of a method for manufacturing the substrate 1 as described above will be described with reference to FIG.

[1]
First, as shown in FIG. 3A, a conductor layer 3 is prepared. More specifically, for example, a conductor foil such as a copper foil is prepared as the conductor layer 3.

[2]
Next, as shown in FIG. 3B, an insulating layer forming layer 4 </ b> A is formed on the conductor layer 3. Thereby, the film 10 for insulating layer formation is obtained.

  This insulating layer forming layer 4A is obtained by forming an insulating layer forming composition into a layer shape. And this insulating layer formation layer 4A turns into the insulating layer 4 by hardening or solidifying in process [3] mentioned later.

  Here, the conductor layer 3 constitutes a support layer that supports the insulating layer forming layer 4 </ b> A in the insulating layer forming film 10. Thus, by supporting the insulating layer forming layer 4A with the conductor layer 3, the handleability of the insulating layer forming film 10 can be improved.

  Moreover, it is preferable that the conductor layer 3 which comprises a support layer in this way is metal foil. Thereby, the insulating layer forming layer 4 </ b> A can be stably supported by the conductor layer 3. Therefore, the handleability of the insulating layer forming film 10 can be improved. Further, the conductivity and workability of the conductor layer 3 can be made excellent. Therefore, a conductor pattern having excellent characteristics can be obtained by processing the conductor layer 3.

Such an insulating layer forming composition includes a resin material and a filler.
The resin material contained in the composition for forming an insulating layer is not particularly limited, and various resin materials such as a thermoplastic resin and a thermosetting resin can be used.

  Examples of the thermoplastic resin include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, modified polyolefins, polyamides (eg, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12). , Nylon 6-12, nylon 6-66), thermoplastic polyimide, aromatic polyester and other liquid crystal polymers, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, polyether, polyether ether ketone, polyether imide, polyacetal, Styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, salt Various thermoplastic elastomers, etc., or a copolymer of these His polyethylene type or the like, blends, polymer alloys and the like, can be used as a mixture of two or more of them.

  On the other hand, examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, melamine resin, polyester (unsaturated polyester) resin, polyimide resin, silicone resin, polyurethane resin, and the like. Or 2 or more types can be mixed and used.

  Among these, as a resin material used for the composition for forming an insulating layer, it is preferable to use a curable resin (particularly a thermosetting resin), and it is more preferable to use an epoxy resin from the viewpoint of availability. Thereby, the heat resistance of the insulating layer 4 obtained can be made excellent. Further, the metal plate 2 and the conductor layer 3 can be firmly bonded via the insulating layer 4. Therefore, the durability and reliability of the obtained substrate 1 can be made excellent.

  Examples of the epoxy resin include bisphenol A, bisphenol F, bisphenol AD, hydroquinone, methylhydroquinone, dimethylhydroquinone, dibutylhydroquinone, resorcin, methylresorcin, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, phenol novolak resin, cresol novolak. Various epoxy resins such as resin, bisphenol A novolak resin, dicyclopentadiene phenol resin, terpene phenol resin, phenol aralkyl resin, and naphthol novolak resin can be used.

  Further, the content of the resin material is preferably 30 vol% or more and 70 vol% or less, and more preferably 40 vol% or more and 60 vol% or less of the entire composition for forming an insulating layer (excluding the solvent). Thereby, the mechanical strength and thermal conductivity of the insulating layer 4 obtained can be made excellent.

  On the other hand, when the content is less than the lower limit value, the resin material cannot sufficiently exhibit the function as a binder for bonding fillers, and the mechanical strength of the insulating layer 4 to be obtained is lowered. Show the trend. In addition, depending on the constituent material of the insulating layer forming composition, the viscosity of the insulating layer forming composition becomes too high, and it becomes difficult to perform filtration work and layer forming (coating) of the insulating layer forming composition (varnish). In some cases, the flow of the composition for forming an insulating layer becomes too small, and voids are generated in the resulting insulating layer 4.

  On the other hand, when the content exceeds the upper limit, it is difficult to ensure the thermal conductivity of the insulating layer 4 while ensuring the insulating properties of the insulating layer 4 to be obtained.

  Further, the insulating layer forming composition contains a curing agent as necessary depending on the kind of the resin material described above.

  The curing agent is not particularly limited, and examples thereof include amide curing agents such as dicyandiamide and aliphatic polyamide, amine curing agents such as diaminodiphenylmethane, methanephenylenediamine, ammonia, triethylamine, and diethylamine, bisphenol A, and bisphenol F. And phenolic curing agents such as phenol novolac resin, cresol novolak resin, p-xylene-novolak resin, and acid anhydrides.

  In addition, the composition for forming an insulating layer may further contain a curing catalyst (curing accelerator). Thereby, the sclerosis | hardenability of the composition for insulating layer formation can be improved.

  Examples of the curing catalyst include amine catalysts such as imidazoles, 1,8-diazabicyclo (5,4,0) undecene, phosphorus catalysts such as triphenylphosphine, and the like. Of these, imidazoles are preferred. Thereby, especially the quick-hardening property and the preservability of the composition for insulating layer formation can be made compatible.

  Examples of imidazoles include 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2- Phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ′)]-Ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl-4′methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 -[2'-Methylimidazolyl- (1 ')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole Null acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-vinyl-s-triazine, 2,4-diamino -6-vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine isocyanuric acid adduct, etc. Can be mentioned. Among these, 2-phenyl-4,5-dihydroxymethylimidazole or 2-phenyl-4-methyl-5-hydroxymethylimidazole is preferable. Thereby, especially the preservability of the composition for insulating layer formation can be improved.

  Moreover, the content of the curing catalyst is not particularly limited, but is preferably about 0.01 to 30 parts by mass, more preferably about 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin material. preferable. When the content is less than the lower limit, the curability of the composition for forming an insulating layer may be insufficient. On the other hand, when the content exceeds the upper limit, the composition for forming an insulating layer It shows a tendency to decrease the storage stability.

  The average particle diameter of the curing catalyst is not particularly limited, but is preferably 10 μm or less, and more preferably 1 to 5 μm. When the average particle size is within the above range, the reactivity of the curing catalyst is particularly excellent.

  Moreover, it is preferable that the composition for insulating layer formation contains a coupling agent further. Thereby, the adhesiveness of the resin material with respect to a filler, the conductor layer 3, and the metal plate 2 can be improved more.

  Examples of such coupling agents include silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like. Of these, silane coupling agents are preferred. Thereby, the heat resistance of the composition for insulating layer formation can be improved more.

  Among these, as the silane coupling agent, for example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyl Dimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysila N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, bis (3 -Triethoxysilylpropyl) tetrasulfane and the like.

  Although content of a coupling agent is not specifically limited, It is preferable that it is about 0.01-10 mass parts with respect to 100 mass parts of resin materials, and it is more preferable that it is especially about 0.5-10 mass parts. . When the content is less than the lower limit, the effect of improving the adhesion as described above may be insufficient. On the other hand, when the content exceeds the upper limit, the insulating layer 4 is formed. May cause outgassing and voids.

Moreover, the filler (filler 42) in the composition for insulating layer formation is comprised with the aluminum oxide (alumina).
And the moisture content of a filler is 0.10 mass% or more and 0.30 mass% or less.

  According to the composition for forming an insulating layer using such a filler, even if the filler content is increased, the composition has an appropriate viscosity and flowability. Therefore, it is possible to form the insulating layer 4 having excellent thermal conductivity while preventing generation of voids in the obtained insulating layer 4. That is, the insulating layer 4 having excellent thermal conductivity and insulating properties can be formed.

  Here, the relationship between the water content of the filler and the characteristics of the composition for forming an insulating layer will be described more specifically.

Aluminum oxide (alumina) has hygroscopicity.
The present inventor prepared a plurality of types of fillers having different moisture contents by appropriately performing moisture absorption treatment and drying treatment on the filler composed of aluminum oxide, and the filler moisture content and the insulating layer forming composition As a result of investigating the relationship with the flow property, it was found that as the moisture content of the filler increases, the flow property of the composition for forming an insulating layer increases and the withstand voltage of the resulting insulating layer 4 increases.

  Here, it is considered that the withstand voltage of the insulating layer 4 obtained is increased because the generation of voids in the insulating layer 4 is prevented by increasing the flowability of the insulating layer forming composition.

  The water content of such a filler may be 0.10% by mass or more and 0.30% by mass or less, more preferably 0.10% by mass or more and 0.25% by mass or less, and 0.12% by mass. % Or more and 0.20% by mass or less is more preferable.

  On the other hand, when the water content is too low, the flowability of the composition for forming an insulating layer is lowered, voids in the insulating layer 4 are generated, and the voltage resistance of the insulating layer 4 tends to be lowered. On the other hand, when the water content is too high, the flowability of the composition for forming an insulating layer becomes too high, and it becomes difficult to secure a desired thickness of the insulating layer 4, and as a result, the withstand voltage of the insulating layer 4 is increased. May become low. Moreover, when there is too much this water content, while the water | moisture content exerts a bad influence on the sclerosis | hardenability of the resin material in an insulating layer formation composition, when forming the insulating layer 4 by heating-pressing the composition for insulating layer formation, When the water vapor is diffused in the composition for forming an insulating layer, voids in the obtained insulating layer 4 tend to increase.

  In addition, the moisture content of the filler in the composition for insulating layer formation before hardening or solidifying is substantially equal to the moisture content of the cured product or solidified product of the composition for insulating layer formation, that is, the filler in the insulating layer 4.

  Aluminum oxide can be obtained by firing aluminum hydroxide. The resulting aluminum oxide is composed of a plurality of primary particles, and the average particle size of the primary particles can be set according to the firing conditions.

  In the aluminum oxide that has not been treated at all after the firing, the primary particles are aggregated due to fixation. Therefore, the final filler can be obtained by solving the aggregation of the primary particles as necessary by pulverization. The average particle diameter of the final filler can be set according to the pulverization conditions (for example, time).

  During the pulverization, the aluminum oxide has extremely high hardness, so that the primary particles themselves are hardly broken, and the average particle size of the primary particles is maintained even after pulverization. It will be almost maintained.

  Therefore, as the grinding time becomes longer, the average particle size of the filler approaches the average particle size of the primary particles. And when grinding | pulverization time becomes more than predetermined time, the average particle diameter of a filler will become equal to the average particle diameter of a primary particle.

  Further, the filler (filler 42) dispersed in the insulating layer forming composition has a thermal conductivity higher than that of the resin portion 41. Thereby, the thermal conductivity of the insulating layer 4 can be increased.

  Further, for example, the primary particles of aluminum oxide obtained by firing aluminum hydroxide as described above have a shape having a flat surface such as a scaly shape instead of a spherical shape. Therefore, the contact area between fillers can be increased. As a result, the thermal conductivity of the obtained insulating layer 4 can be increased.

  The average particle size of the filler 42 is not particularly limited, but is preferably about 0.1 μm to 25 μm, and more preferably about 0.25 μm to 20 μm. Thereby, the viscosity and flow property of the composition for insulating layer formation can be made moderate, and the heat conductivity and insulating property of the insulating layer 4 obtained can be made excellent.

  Further, the coefficient of variation (that is, narrow particle size distribution; CV value) of the particle size of the filler 42 is not particularly limited, but is preferably 30% or less, more preferably 20% or less, and more preferably 10%. More preferably, it is as follows.

  Moreover, it is preferable that it is 30 vol% or more and 70 vol% or less of the whole insulating resin composition (except a solvent), and, as for content of a filler, it is more preferable that it is 40 vol% or more and 60 vol% or less. Thereby, while making the viscosity and flow property of the composition for insulating layer formation (varnish) moderate, the thermal conductivity of the insulating layer 4 obtained can be made excellent.

  On the other hand, when the content is less than the lower limit, it is difficult to make the insulating layer 4 excellent in thermal conductivity while securing the insulating property of the insulating layer 4 to be obtained. On the other hand, if the content exceeds the upper limit, depending on the constituent material of the insulating layer forming composition, the viscosity of the insulating layer forming composition becomes too high, and the varnish is filtered or formed into a layer (coating). ) May be difficult, or the flow of the insulating layer forming composition may be too small, and voids may be generated in the resulting insulating layer 4.

Further, the specific surface area (BET specific surface area) of the filler is preferably 0.5 m ² / g or more and 3.0 m ² / g or less, and is 0.7 m ² / g or more and 2.5 m ² / g or less. Is more preferable.

  The larger the average particle size of the filler, the smaller the specific surface area of the filler. On the other hand, the smaller the average particle size of the filler, the larger the specific surface area of the filler. Moreover, the larger the average particle size of the primary particles of the filler, the smaller the specific surface area of the filler. On the other hand, the smaller the average particle size of the primary particles of the filler, the larger the specific surface area of the filler.

  Thus, the average particle diameter A of the filler, the average particle diameter B of the primary particles, and the specific surface area of the filler have a correlation with each other. And the relationship of A and B as mentioned above can be satisfy | filled by making the specific surface area of a filler into the range as mentioned above.

  Moreover, in addition to the component mentioned above, the composition for insulating layer formation may contain additives, such as a leveling agent and an antifoamer, in the range which does not impair the objective of this invention.

  Moreover, the composition for insulating layer formation contains solvents, such as methyl ethyl ketone, acetone, toluene, a dimethylformaldehyde, for example. Thereby, the composition for insulating layer formation will be in a varnish state, when resin material etc. melt | dissolve in a solvent.

  Such an insulating layer forming composition in a varnish state is coated on the conductor layer 3 using a comma coater, a die coater, a gravure coater or the like, and dried to obtain the insulating layer forming layer 4A.

  The viscosity of the composition for forming an insulating layer in such a varnish state is preferably 30 P or less, and more preferably 20 P or less. Thereby, the filtration operation | work and coating of the composition for insulating layer formation are attained.

[3]
Next, the insulating layer forming layer 4A and the metal plate 2 are bonded together, and then heated and pressurized. Thereby, as shown in FIG.3 (c), the board | substrate 1 is obtained.

Such heating and pressurization are not particularly limited, and are performed at 150 to 200 ° C. and 20 to 100 kg / cm ² for 30 to 240 minutes, for example.

(Application examples of substrates)
Next, an application example of the substrate 1 described above will be described with reference to FIG.

  A control device 100 shown in FIG. 4 is mounted on the automobile 20 and controls driving of a headlight (light source) 201 that emits light toward the front thereof. In the present embodiment, the headlight 201 is one in which a plurality of light emitting diode elements (LEDs) 202 are arranged.

  The control device 100 includes a substrate 1A, semiconductor elements 51 and 52 and a connector 53 provided on the substrate 1A.

  The substrate 1 </ b> A has a metal plate 2, a conductor layer 3 </ b> A, and an insulating layer 4, and the metal plate 2 and the conductor layer 3 </ b> A are joined via the insulating layer 4.

  Here, the conductor layer 3A is a conductor pattern formed by patterning the conductor layer 3 of the substrate 1 described above by etching or the like. That is, the substrate 1 </ b> A is obtained by patterning the conductor layer 3 of the substrate 1.

  On the conductor layer 3A of the substrate 1A, semiconductor elements 51 and 52, a connector 53, and the like are provided, and these form a circuit 6.

  In the present embodiment, a coating layer (solder resist layer) 7 is provided on the upper surface of the insulating layer 4 to cover a portion where the conductor layer 3A is not formed. Thereby, the conductor layer 3 can be protected, and the deterioration and short circuit of the circuit 6 can be prevented. The constituent material of the coating layer 7 is not particularly limited as long as it has insulating properties. For example, various resin materials such as epoxy resin, cyanate resin, and phenol resin can be used. The covering layer 7 may be omitted.

  The semiconductor elements 51 and 52 are provided with a wiring pattern made of a conductive metal material such as copper. This wiring pattern is electrically connected to a plurality of terminals protruding from the lower surface. Each terminal is joined to the conductor layer 3A, whereby the semiconductor elements 51 and 52 are electrically connected to the conductor layer 3A. Each terminal can be composed mainly of various brazing materials such as solder, silver brazing, copper brazing, and phosphor copper brazing.

  In addition, the mold parts 512 and 522 which comprise the exterior part of the semiconductor elements 51 and 52 are comprised by thermosetting resins, such as an epoxy resin and a phenol resin, for example.

  The connector 53 is connected to the headlight 201 via the relay cable 204. A connector 205 connected to the connector 53 is installed at the end of the relay cable 204 opposite to the headlight 201.

  The connector 53 is a so-called “male side” connector, and includes a plurality of pins (terminals) 531 and a housing 532 that collectively stores these pins 531. Each pin 531 is made of a conductive metal material such as copper, and is electrically connected to the conductor layer 3A. Each pin 531 is connected to each terminal (not shown) of the so-called “female side” connector 205 by fitting.

  The housing 532 is formed of a cylindrical body and is erected with respect to the substrate 1A. Each pin 531 accommodated in the housing 532 is also erected vertically with respect to the substrate 1A, that is, vertically upward. Accordingly, when connecting the connector 205 of the relay cable 204 to the connector 53, the connector 205 can be inserted from above, and the connection work can be easily performed.

  Although it does not specifically limit as a constituent material of the housing 532, For example, the thermosetting resin similar to the constituent material of the mold parts 512 and 522 of the semiconductor elements 51 and 52 can be used.

  Further, the control device 100 includes a protective member 8 that covers the conductor layer 3 and the semiconductor elements 51 and 52, particularly the connection portion between the conductor layer 3 and the semiconductor elements 51 and 52.

  The protection member 8 is made of a hard resin material, and is provided in a layer shape. Thereby, the semiconductor elements 51 and 52 and the connector 53 can be fixed collectively. Therefore, even if the vibration is transmitted to the control device 100 when the automobile 20 is traveling, it is possible to reliably prevent the semiconductor elements 51 and 52 and the connector 53 from being detached due to the vibration. Further, for example, the semiconductor elements 51 and 52 can be protected without covering the control device 100 with a casing. Further, since the semiconductor elements 51, 52 and the like are embedded in the protective member 8, a waterproof / dustproof function for these can be exhibited.

  The hard resin material constituting the protective member 8 is not particularly limited, but for example, a thermosetting resin similar to the material constituting the mold parts 512 and 522 of the semiconductor elements 51 and 52 and the housing 532 can be used. Particularly preferred are epoxy resins and phenol resins.

  Here, the resin material constituting the protective member 8 is preferably filled with a metal oxide such as alumina, and an electrically insulating and highly thermally conductive filler typified by a nitride such as boron nitride. Thereby, heat dissipation of the heat generated by the semiconductor elements 51, 52 and the like by energization is promoted through the protective member 8. And this heat dissipation and heat dissipation through the metal plate 2 combine, and the control apparatus 100 becomes the thing which was extremely excellent in heat dissipation as a whole.

  As mentioned above, although the illustrated embodiment of the composition for forming an insulating layer, the film for forming an insulating layer, and the substrate of the present invention has been described, the present invention is not limited to this. Each part constituting the layer-forming film and the substrate can be replaced with any part that can exhibit the same function. Moreover, arbitrary components may be added.

  Moreover, it cannot be overemphasized that the use of the board | substrate of this invention is not limited to the thing of embodiment mentioned above, It can use suitably as a board | substrate used for the various apparatuses which require heat dissipation. For example, the board | substrate of this invention can be used as a board | substrate which mounts an LED light emitting element.

  Hereinafter, specific examples of the present invention will be described. Note that the present invention is not limited to this.

1. Production of substrate A substrate was produced as follows.

Example 1
1.1 Preparation of insulating layer forming composition (varnish) Bisphenol F / bisphenol A phenoxy resin (Mitsubishi Chemical, 4275, weight average molecular weight 6.0 × 10 ⁴ , ratio of bisphenol F skeleton to bisphenol A skeleton = 75: 25) 12.0% by mass, 12.0% by mass of bisphenol A type epoxy resin (manufactured by DIC, 850S, epoxy equivalent 190), 0.5 part by mass of 2-phenylimidazole (2PZ manufactured by Shikoku Kasei), as a silane coupling agent 0.5 part by mass of γ-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Silicone), alumina 1 (manufactured by Nippon Light Metal, average particle size A2.58 μm, primary particle size B2.50 μm, average particle size A / primary A commercial product having a particle size B = 1.03 was dried at 200 ° C. for 24 hours, and then allowed to stand at 85 ° C. and 85% for 12 hours. 75.0 parts by mass of water having a water content of 0.12% by mass was dissolved and mixed in cyclohexanone and stirred using a high-speed agitator to obtain an insulating layer forming composition (varnish) having a solid content of 70% by mass. It was. The water content of the alumina was calculated from the difference in mass between 25 ° C. and 500 ° C. measured using a differential thermal balance apparatus (TG-DTA).

1.2 Production of Insulating Layer Forming Film A 70 μm thick copper foil (GTSMP, manufactured by Furukawa Circuit Foil) was used as the metal foil (conductor layer). The composition for forming an insulating layer was applied with a comma coater, dried by heating at 100 ° C. for 3 minutes and at 150 ° C. for 3 minutes, and the insulating layer forming film having a thickness of 100 μm (insulating layer) A copper foil with a forming composition) was obtained.

1.3 Production of Substrate The insulating layer forming film obtained in 1.2 above and a 2 mm-thick aluminum plate as a metal plate are bonded together, and using a vacuum press, the press pressure is 30 kg / cm ² at 80 ° C. for 30 minutes. The substrate was obtained by pressing at 200 ° C. for 90 minutes.

(Examples 2-5 and Comparative Examples 1-2)
An insulating layer forming composition and a substrate were produced in the same manner as in Example 1 except that the insulating layer forming composition was prepared according to the formulation shown in Table 1.

In addition, the following were used for alumina 2-7.
Alumina 2: A commercially available product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours and then allowed to stand for 48 hours at 85 ° C. and 85% to give a water content of 0.16% by mass.

  Alumina 3: A commercial product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours and then left at 85 ° C. and 85% for 120 hours to obtain a water content of 0.20% by mass.

  Alumina 4: A commercial product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours and then left at 85 ° C. and 85% for 4 hours to obtain a water content of 0.10% by mass.

  Alumina 5: A commercially available product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours and then allowed to stand at 85 ° C. and 85% for 240 hours to obtain a water content of 0.25% by mass.

  Alumina 6: A commercial product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours to a moisture content of 0.01% by mass.

  Alumina 7: A commercially available product similar to that used in Alumina 1 was dried at 200 ° C. for 24 hours and then left at 120 ° C. for 100 hours to obtain a water content of 0.40% by mass.

2. Evaluation The following evaluation was performed about the composition for insulating layer formation and board | substrate which were obtained by each Example and each comparative example.

2.1 Viscosity of composition for insulating layer formation About the composition for insulating layer formation of each Example and each comparative example, a viscosity is measured on 25 degreeC and shear rate 5.0rpm conditions using an E-type viscosity meter. did.

2.2 Appearance For the substrates of each Example and each Comparative Example, the copper foil (conductor layer) was removed by etching, the appearance of the insulating layer was visually observed, and the presence or absence of voids or scum was evaluated. Further, the length of the flow amount (distance between the outer peripheral edge before pressing of the insulating layer and the outer peripheral edge after pressing) was measured.

2.3 Solder heat resistance After the substrate of each example and each comparative example was cut to 50 mm × 50 mm with a grinder saw, the copper foil was removed by etching so as to leave only a quarter, thereby preparing a sample. The solder heat resistance was evaluated in accordance with JIS C 6481. This evaluation is based on whether or not there is an abnormality in the appearance after immersion in a solder bath at 288 ° C. for 30 seconds in the case where pretreatment is not performed and in the case where 121 ° C., 100%, (PCT treatment) is performed for 4 hours. Based on the following evaluation criteria.

Evaluation criteria: No abnormality (no bulges)
: Swelled (there is a bulge on the whole)

2.4 Dielectric breakdown voltage After cutting the substrate of each example and each comparative example to 100 mm × 100 mm with a grinder saw, the copper foil in the outer portion is removed by etching from a position of about 30 mm from the edge of the substrate. Samples were prepared and dielectric breakdown voltage was evaluated. Such evaluation is performed by using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics), bringing the electrode into contact with the copper foil and the metal plate, and increasing the voltage to both electrodes at a rate of 1 kV / sec. Was applied, and the voltage when the insulating layer was broken was defined as a dielectric breakdown voltage.

These evaluation results are shown in Table 1.
As is clear from the evaluation results shown in Table 1, each example is excellent in solder heat resistance, has a sufficiently high dielectric breakdown voltage value, and has a high thermal conductivity.

1, 1A Substrate 2 Metal plate 3, 3A Conductor layer 4 Insulating layer 4A Insulating layer forming layer 41 Resin part 42 Filler 51, 52 Semiconductor element 512, 522 Mold part 53 Connector 531 Pin (terminal)
532 Housing 6 Circuit 7 Covering layer 8 Protective member 10 Insulating layer forming film 20 Automobile 100 Control device 201 Headlight 202 Light emitting diode element 204 Relay cable 205 Connector

Claims (10)

An insulating layer forming composition used for forming an insulating layer,
Resin material,
Comprising a filler composed of aluminum oxide,
The composition for forming an insulating layer, wherein the filler has a water content of 0.1% by mass to 0.3% by mass.   2. The composition for forming an insulating layer according to claim 1, wherein the content of the filler is 30 vol% or more and 70 vol% or less of the whole.   The composition for forming an insulating layer according to claim 1 or 2, wherein the content of the resin material is 30 vol% or more and 70 vol% or less of the whole.   The composition for forming an insulating layer according to claim 1, wherein the resin material is a curable resin.   The composition for forming an insulating layer according to any one of claims 1 to 4, wherein the viscosity is 30 P or less.   An insulating layer forming film comprising an insulating layer forming layer obtained by forming the insulating layer forming composition according to claim 1 into a layer shape.   The film for forming an insulating layer according to claim 6, further comprising a support layer for supporting the insulating layer forming layer.   The film for forming an insulating layer according to claim 7, wherein the support layer is a metal foil. A metal plate made of a metal material;
An insulating layer formed of a cured product or a solidified product, which is provided on the metal plate and formed into a layer shape from the composition for forming an insulating layer according to any one of claims 1 to 5,
And a conductive layer provided on a surface of the insulating layer opposite to the metal plate. A metal plate made of a metal material;
An insulating layer provided on the metal plate and including a resin material and a filler made of aluminum oxide;
A substrate having a conductor layer provided on a surface of the insulating layer opposite to the metal plate,
The substrate is characterized in that the water content of the filler is 0.1% by mass or more and 0.3% by mass or less.

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