JP2013253126A - Composition for forming insulation layer, film for forming insulation layer and substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation layer forming composition and an insulation layer forming film capable of forming an insulation layer having excellent heat-conductivity and insulation properties, and to provide a substrate having excellent heat-dissipation properties and reliability.SOLUTION: There are provided an insulation layer forming composition for forming an insulation layer and constituted of a resin material, a filler composed of an inorganic material and a silane coupling agent having a secondary amino group; an insulation layer forming film having an insulation layer forming layer obtained by forming the insulation layer forming composition in the form of a layer; and a substrate having a metallic plate made of a metallic material, an insulation layer formed on the metallic layer and comprising a cured material or solidified material obtained by forming the insulation layer forming composition in the form of a layer, and a conductive layer formed on a face of the insulation layer opposite to the face having the metallic plate.

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, an insulating layer having excellent thermal conductivity and insulating properties could not be realized.

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 (13) below.
(1) An insulating layer forming composition used for forming an insulating layer,
Resin material,
A filler composed of an inorganic material;
A composition for forming an insulating layer, comprising a silane coupling agent having a secondary amino group.

  (2) The composition for forming an insulating layer according to (1), wherein the filler is composed of at least one of aluminum oxide and aluminum nitride.

(3) The filler is composed of a plurality of primary particles,
When the average particle diameter of the filler is A and the average particle diameter of the plurality of primary particles is B,
A / B is 1.0 or more and 1.5 or less, and
B is the composition for forming an insulating layer according to the above (1) or (2), which is 2.5 μm or more and 4.0 μm or less.

  (4) The content of the secondary amino group-containing silane coupling agent is 0.01 to 10 parts by mass with respect to 100 parts by mass of the resin material. 2. The composition for forming an insulating layer according to item 1.

  (5) The composition for forming an insulating layer according to any one of (1) to (4), wherein the content of the filler is 30 vol% or more and 70 vol% or less of the whole.

  (6) The composition for forming an insulating layer according to any one of (1) to (5), wherein the content of the resin material is 30 vol% or more and 70 vol% or less of the whole.

  (7) The composition for insulating layer formation according to any one of (1) to (6), wherein the resin material is a curable resin.

(8) The insulating layer formation according to any one of (1) to (7), wherein a specific surface area (BET specific surface area) of the filler is 0.5 m ² / g or more and 3.0 m ² / g or less. Composition.

  (9) The composition for forming an insulating layer according to any one of (1) to (8), wherein the viscosity is 3.0 Pa · s or less.

  (10) An insulating layer forming film comprising an insulating layer forming layer obtained by forming the insulating layer forming composition according to any one of (1) to (9) above into a layer shape.

  (11) The film for forming an insulating layer according to (10), further including a support layer that supports the insulating layer forming layer.

  (12) The insulating layer forming film according to (11), wherein the support layer is a metal foil.

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

  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 figure, for convenience of explanation, the substrate and its respective parts are schematically shown exaggerated, and the size and ratio of the substrate and its respective parts are greatly different from the 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 mm or more and 5 mm or less, and more preferably 1 mm or more and 2 mm or less. 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, the thickness of the conductor layer 3 is not particularly limited, but is preferably 10 μm or more and 200 μm or less, and more preferably 18 μm or more and 70 μm or less.

  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.

  As will be described later, the insulating layer 4 is formed by curing and solidifying a composition for forming an insulating layer containing a resin material (binder), a filler, and a silane coupling agent having a secondary amino group. 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. 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, a filler, and a silane coupling agent having a secondary amino group.

  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 Polyethylene type such as various thermoplastic elastomers, etc., or a copolymer of these main, 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. For example, when an epoxy resin is used, a curing agent and a curing catalyst are used to cure the epoxy resin, and these are included in the resin material. In addition, unsaturated polyester resins, silicone resins, and the like use peroxides as curing catalysts, and these are included in the resin material.

  The curing agent is not particularly limited. For example, 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.

  Further, the content of the curing catalyst is not particularly limited, but is preferably about 0.01 parts by mass or more and 30 parts by mass or less, particularly 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the resin material. More preferred is the degree. 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 μm or more and 5 μm or less. When the average particle size is within the above range, the reactivity of the curing catalyst is particularly excellent.

  Moreover, the silane coupling agent contained in the composition for forming an insulating layer is a silane coupling agent having a secondary amino group.

  By using such a silane coupling agent having a secondary amino group, the fluidity of the composition for forming an insulating layer can be improved. Therefore, even if there is much content of the filler contained in the composition for insulating layer formation, while suppressing a viscosity, it can have a desired flow property. Moreover, while improving the adhesiveness of the resin material with respect to a filler, the conductor layer 3, and the metal plate 2, the heat resistance of the composition for insulating layer formation can be improved.

  More specifically, the silane coupling agent having a secondary amino group exhibits weak basicity due to the secondary amino group. In this weak basicity, the fluidity of the composition for forming an insulating layer containing fillers such as aluminum oxide and aluminum nitride is maximized. Therefore, the fluidity | liquidity of the composition for insulating layer formation can be improved by using the silane coupling agent which has a secondary amino group.

  And the silanol produced | generated by hydrolysis of the silane coupling agent which has a secondary amino group is covalently bonded with the filler surface by a dehydration condensation reaction, and silanols condense. Thereby, while improving the adhesiveness of the resin material with respect to a filler, the conductor layer 3, and the metal plate 2, the heat resistance of the composition for insulating layer formation can be improved.

  Specific examples of such a silane coupling agent having a secondary amino group include the following compounds, but are not limited thereto. These may be used alone or in combination of two or more.

Further, the content of the silane coupling agent having a secondary amino group is not particularly limited, but it is preferably about 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the resin material. More preferably, it is about 5 parts by mass or more and 10 parts by mass or less. 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.

  The insulating layer forming composition may contain a silane coupling agent other than the silane coupling agent having a secondary amino group, or a coupling agent other than the silane coupling agent.

  Moreover, the filler (filler 42) in the composition for insulating layer formation should just be comprised with the inorganic material excellent in heat dissipation and insulation, However, At least 1 sort (s) of aluminum oxide (alumina) and aluminum nitride What was comprised by this is used suitably. Hereinafter, a case where the filler is composed of at least one of aluminum oxide (alumina) and aluminum nitride will be described as an example.

Such a filler is composed of a plurality of primary particles.
And when the average particle diameter of the filler is A and the average particle diameter of the plurality of primary particles is B,
A / B is 1.0 or more and 1.5 or less, and
B is preferably 2.5 μm or more and 4.0 μm 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 average particle diameter of the filler and the average particle diameter of the primary particles will be described more specifically.

  For example, 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.

  As described above, the filler such as alumina generally has a difference between the average particle diameter and the average particle diameter of the primary particles. When the average particle size B of the primary particles satisfies the relationship as described above, it has been found that even if the filler content is increased, the viscosity and flow properties are adequate.

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.

  In addition, for example, the primary particles of aluminum oxide obtained by firing aluminum hydroxide as described above are not spherical but have an angular shape such as a scale 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 A / B mentioned above may be 1.0 or more and 1.5 or less, more preferably 1.0 or more and 1.4 or less, and more preferably 1.0 or more and 1.3 or less. Further preferred.

  Further, the average particle size of the primary particles of the filler 42 may be 2.5 μm or more and 4.0 μm or less, more preferably 2.5 μm or more and 3.5 μm or less, and more preferably 2.5 μm or more and 3.0 μm. More preferably, it is as follows.

  Further, the average particle size of the filler 42 is not particularly limited, but is preferably about 0.1 μm or more and 25 μm or less, and more preferably about 0.25 μm or more and 20 μm or less. Thereby, the viscosity and flow property of the composition for insulating layer formation can be made moderate, and the heat conductivity and insulation 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, 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 such a composition for forming an insulating layer in a varnish state is preferably 3.0 Pa · s or less, and more preferably 2.0 Pa · s 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 2 to 10 MPa 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 the 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 described above, the insulating layer forming composition, the insulating layer forming film and the substrate of the present invention have been described with respect to the illustrated embodiments. However, the present invention is not limited thereto, and the insulating layer forming composition and insulating 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 parts by mass, bisphenol A type epoxy resin (DIC, 850S, epoxy equivalent 190) 9.8 parts by mass, 4,4′-diaminodiphenylmethane (Tokyo Chemical Industry) 2.6 parts by mass, 2-phenyl 0.1 part by mass of imidazole (2PZ manufactured by Shikoku Kasei), N-phenyl-3-aminopropyltrimethoxysilane (KBM-573 manufactured by Shin-Etsu Silicone) as a silane coupling agent having a secondary amino group (represented by chemical formula (1) Compound) 0.5 parts by mass, alumina 1 (Nippon Light Metal LS-210B, average particle size A: 2.58 μm) Primary particle size B: 2.50 .mu.m, the average particle size A / primary particle diameter B = 1.03, a specific surface area 1.0m ² /g)75.0 parts by dissolved and mixed in cyclohexanone, a high speed stirring apparatus using By stirring, an insulating layer forming composition (varnish) having a solid content of 70% by mass was obtained.

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. The contents of the resin material and filler (alumina) in the obtained insulating layer forming film were 52 vol% and 47 vol%, respectively, of the entire insulating resin composition.

1.3 Production of Substrate The insulating layer-forming film obtained in 1.2 above and an aluminum plate having a thickness of 2 mm as a metal plate are bonded together, and using a vacuum press, press pressure 2.9 MPa at 80 ° C. for 30 minutes, 200 The substrate was obtained by pressing at 90 ° C. for 90 minutes.

(Examples 2-6 and Comparative Examples 1-3)
An insulating layer forming composition and a substrate were prepared 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, it showed below about the raw material newly used in Examples 2-7 and Comparative Examples 1-3.
N-butyl-3-aminopropyltrimethoxysilane (X-12-806 made by Shin-Etsu Silicone)
3-Glycidoxypropyltrimethoxysilane (Shin-Etsu Silicone KBM-403)
3-aminopropyltrimethoxysilane (Shin-Etsu Silicone KBM-903)
3-aminopropyltriethoxysilane (Shin-Etsu Silicone KBE-903)
Alumina 2 (Nippon Light Metal LS-220, average particle size 3.36 μm, primary particle size 2.50 μm, average particle size / primary particle size = 1.30, specific surface area 0.9 m ² / g)
Aluminum nitride (Toyo Aluminum JC, average particle size 3.24 μm, primary particle size 2.7
(0 μm, average particle size / primary particle size = 1.20, specific surface area 0.9 m ² / g)

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 About the board | substrate of each Example and each comparative example, copper foil (conductor layer) was removed by etching, the external appearance of the insulating layer was observed visually, and the presence or absence of a void or a blur 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 About the board | substrate of each Example and each comparative example, after cutting with a grinder saw to 100 mm x 100 mm, the copper foil of an outer part is removed by an etching from the position of about 30 mm from the edge part. 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.

  On the other hand, in Comparative Examples 1 to 3, there is no flow, voids are generated, solder heat resistance is lowered, and the dielectric breakdown voltage value is low. This is presumed that the fluidity of the resin deteriorates and minute voids are generated in the insulating layer, so that the solder heat resistance is lowered and the dielectric breakdown voltage value is lowered.

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 (13)

An insulating layer forming composition used for forming an insulating layer,
Resin material,
A filler composed of an inorganic material;
A composition for forming an insulating layer, comprising a silane coupling agent having a secondary amino group.   The composition for forming an insulating layer according to claim 1, wherein the filler is composed of at least one of aluminum oxide and aluminum nitride. The filler is composed of a plurality of primary particles,
When the average particle diameter of the filler is A and the average particle diameter of the plurality of primary particles is B,
A / B is 1.0 or more and 1.5 or less, and
The composition for forming an insulating layer according to claim 1, wherein B is 2.5 μm or more and 4.0 μm or less.   The content of the silane coupling agent having the secondary amino group is 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the resin material. Composition for forming an insulating layer.   The composition for forming an insulating layer according to any one of claims 1 to 4, wherein a 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 any one of claims 1 to 5, wherein a 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 any one of claims 1 to 6, wherein the resin material is a curable resin. 8. The composition for forming an insulating layer according to claim 1, wherein the filler has a specific surface area (BET specific surface area) of 0.5 m ² / g or more and 3.0 m ² / g or less.   The composition for forming an insulating layer according to any one of claims 1 to 8, wherein the viscosity is 3.0 Pa · s or less.   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 claim 1.   The film for insulating layer formation of Claim 10 which has a support layer which supports the said insulating layer formation layer.   The insulating layer forming film according to claim 11, 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 layered form of the composition for forming an insulating layer according to any one of claims 1 to 9,
And a conductive layer provided on a surface of the insulating layer opposite to the metal plate.