JP5749477B2 - Heat dissipation board and electronic components - Google Patents

Description

The present invention relates to a heat dissipation board and an electronic component having a thermosetting resin that seals the outer periphery of the electronic component and the semiconductor element.

As electronic parts molded with mold resin, there are Patent Document 1 and Patent Document 2. These electronic components have been improved in insulation and heat dissipation to cope with the recent increase in power of electronic components.

JP 2005-150595 A JP 2004-165281 A

The present invention provides a heat dissipation board and an electronic component that can improve the insulation between the adhesive layer and the hardened layer by reducing the breakage of the interface between the adhesive layer and the hardened layer.

In the present invention, a metal plate, a hardened layer, and an adhesive layer are laminated in this order, the hardened layer has a C-stage shape and has heat dissipation, and the surface of the hardened layer on the adhesive layer side has a surface roughness of 0.1 μm or more. The heat dissipation substrate is 20 μm or less, and the adhesive layer has a B-stage shape.

The cured layer and adhesive layer of the heat dissipation substrate are made of an epoxy resin, a curing agent, and an inorganic filler, the curing rate calculated from the differential scanning calorimeter of the cured layer is 90% or more, and the curing rate of the adhesive layer is 10% or more. It is preferably 75% or less.

It is preferable that the hardened layer of the heat dissipation substrate is made of multiple layers of the same material.

It is preferable that the cured layer and the adhesive layer are thermosetting.

The inorganic filler is preferably composed of one or more of silicon oxide, aluminum oxide, aluminum nitride, boron nitride, and silicon nitride, and the filling rate of the inorganic filler is preferably 45% by volume or more and 85% by volume or less.

Another aspect of the invention is an electronic component having the above-described heat dissipation substrate and a lead frame mounted on an insulating layer of the heat dissipation substrate.

Another aspect of the invention is an electronic component including the electronic component, a semiconductor element electrically connected to a lead frame, and a thermosetting resin that seals the outer periphery of the electronic component and the semiconductor element.

The heat dissipation board and the electronic component according to the present invention have high thermal conductivity and high thermal radiation, which makes it difficult for the component to malfunction, deteriorate or deteriorate performance, and further reduce reliability due to heat.

Explanatory drawing which showed typically the heat dissipation board which concerns on this invention

1 Adhesive layer 2 Hardened layer 3 Metal sheet

Hereinafter, embodiments for carrying out the present invention will be described in detail.

In the present invention, a metal plate, a hardened layer, and an adhesive layer are laminated in this order, the hardened layer has a C-stage shape and has heat dissipation, and the surface of the hardened layer on the adhesive layer side has a surface roughness of 0.1 μm or more. The heat dissipation substrate is 20 μm or less, and the adhesive layer has a B-stage shape.

The heat dissipation substrate and the mold resin used for the electronic component are placed in a high temperature and high pressure environment when both are fixed. At that time, due to the curing shrinkage of the mold resin and the linear expansion coefficients of the metal plate, lead frame, and mold resin of the heat dissipation board, peeling occurs at the interface between the adhesive layer and the hardened layer, resulting in a decrease in insulation of the heat dissipation board, ie, electrons. There was a problem of lowering the insulation of parts.

In the present invention, the cured layer surface of the heat dissipation substrate is roughened to improve the adhesion between the adhesive layer and the cured layer, the surface on the adhesive layer side has a surface roughness of 0.1 μm to 20 μm, and the adhesive layer is Since it is a B-stage heat dissipation substrate, the insulation between the adhesive layer and the hardened layer can be improved by eliminating the destruction of the interface.

The metal plate used for the heat dissipation substrate is preferably a metal or an alloy thereof, copper or copper alloy having good thermal conductivity, light aluminum or aluminum alloy, iron or iron alloy having a low linear expansion coefficient, aluminum / silicon / carbon alloy. There are aluminum / carbon alloys and copper / carbon alloys, and it is preferable to subject the surface to various surface treatments such as alumite treatment, roughening treatment, coupling agent, and plating treatment.

If the surface roughness of the surface of the adhesive layer on the hardened layer is too small, peeling may occur between the hardened layer and the adhesive layer when an electronic component is produced. It takes more time than necessary to adjust the thickness to 0.1 μm or more and 20 μm or less, and preferably 0.5 μm or more and 10 μm or less.

As a method of roughening the surface of the adhesive layer side of the hardened layer, a method of transferring a film made of polyethylene terephthalate with unevenness or unevenness of the electrolytic copper foil roughening treatment surface, a sandblasting method, or an alkali permanganate is used. There are a desmear treatment, an electrical surface treatment such as plasma and corona discharge, a cutting treatment with a water jet, and a method of exposing the surface by high filling with an inorganic filler.

Epoxy resins used for the hardened layer and the adhesive layer include bisphenol A type epoxy resin and bisphenol F type epoxy resin. Specifically, naphthalene type, phenylmethane type, tetrakisphenolmethane type, biphenyl type, bisphenol A alkylene oxide. There are adduct-type epoxy resins, bisphenol A-type hydrogenated epoxy resins, polypropylene glycol-type epoxy resins, polytetramethylene glycol-type epoxy resins, and polysulfide-modified epoxy resins, and these can be used in combination.

Examples of the curing agent include a simple substance or a mixture of curing agents selected from the group consisting of aromatic amine resins, acid anhydride resins, phenol resins, and dicyanamide. In order to control the curing reaction, it is preferable to add a curing agent or a catalyst.

Examples of the catalyst include an imidazole compound, an organic phosphate compound, a tertiary amine, and a quaternary ammonium simple substance or mixture. The blending ratio when blending is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the epoxy resin.

As the inorganic filler, those excellent in electrical insulation and thermal conductivity are preferable. Specifically, there are silicon oxide, aluminum oxide, aluminum nitride, boron nitride, and silicon nitride alone or in a mixture.

As for the compounding ratio of an inorganic filler, 45 volume% or more and 85 volume% or less are preferable with respect to the total amount of the composition which comprises a hardening layer and an adhesion layer. If the blending ratio of the inorganic filler is too small, the heat dissipation becomes insufficient, and if it is too large, it tends to be difficult to mold the cured layer and the adhesive layer.

It is preferable to add additives such as coupling agents and dispersants, viscosity adjusting aids such as solvents, and various aids such as titanium oxide, magnesium oxide, and titanium oxide to these fillers.

It is preferable that the epoxy resin, the curing material, and the inorganic filler have few impurities. In particular, chlorine ions, sodium ions, and sulfate ions cause ion migration when electricity is applied at high temperature and high humidity. Therefore, it is preferable to select a material with few impurities.

The curing rate calculated from the differential scanning calorimeter of the cured layer is preferably 90% or more, and the curing rate of the adhesive layer is preferably 10% or more and 75% or less.

The hardened layer is made of the same material and is formed of a single layer or a plurality of layers, and is preferably formed of a plurality of layers. The reason why it is preferable to use a plurality of layers is that, even if there is a problem in forming a void or the like in one layer, the insulation reliability can be improved by another cured layer.

In the cured layer and the adhesive layer, the photo-curing type is preferably a thermo-curing type because it cannot receive light if it is resin-molded.

The material of the mold resin is preferably a material having a thermal contraction rate close to or the same as that of the insulating sheet in order to stabilize the electronic component. As the mold resin, it is preferable to use a mold resin filled with an inorganic filler or a mold resin with improved heat dissipation of the filler material.

In the present invention, by roughening the hardened layer, peeling did not occur even after resin molding, and an electronic component with good insulation could be obtained.

Examples according to the present invention will be described in detail in comparison with comparative examples.

The heat dissipation substrate according to Example 1 of the present invention is laminated in the order of a metal sheet 3 as a metal plate, a hardened layer 2, and an adhesive layer 1, and the hardened layer 2 has a C-stage shape and has heat dissipation properties. 2 is a heat dissipation substrate in which the surface on the adhesive layer side has a surface roughness of 1.0 μm, and the adhesive layer 1 has a B-stage shape.

<Method for manufacturing heat dissipation substrate>
The hardened layer 2 is a bisphenol A type epoxy resin (JER-828 made by Mitsui Chemicals), phenol novolak (H-8 made by Meiwa Kasei Co., Ltd.) is added as a hardener, and fine particle aluminum oxide (AA05 made by Sumitomo Chemical) Coarse aluminum oxide (AS50 manufactured by Showa Denko Co., Ltd.) was combined to make a liquid that was 45% by volume in the insulating layer (spherical coarse particles and spherical fine particles had a mass ratio of 8: 2). On the tough pitch copper, the thickness of the insulating layer was applied to 100 μm. And it hardened at 130 degreeC, the hardened | cured layer 2 was produced for 90% of cure rate.
At this time, the curing rate was measured by using a differential scanning calorimeter and calculating the curing rate from the exothermic peak.

The hardened layer 2 was sprayed with an alkaline permanganate aqueous solution to adjust the surface roughness of the hardened layer 2 to 1.0 μm.

A liquid blended in the same manner as in the cured layer 2 was applied at a thickness of 100 μm, heated and cured at 110 ° C., the curing rate was adjusted to 65%, and the adhesive layer 3 was obtained. At this time, the curing rate of the cured layer 2 was 100%.

The manufactured heat dissipation board is heated and bonded to a lead frame on which a semiconductor chip has been mounted in advance, and then cured, and transfer molded to a bonded body, resin molded, and then additionally cured at 160 ° C. for 5 hours. I got the parts. At this time, the curing rate of the adhesive layer 1 was 100%.

The adhesion between the adhesive layer 1 and the hardened layer 2 was evaluated with an ultrasonic exploration apparatus (FS300II manufactured by Hitachi Finetech). In the evaluation method, when the adhesion between the adhesive layer 1 and the cured layer 2 in this apparatus is poor, that is, when there is peeling, the observation image becomes white. Peeling in Example 1 was not observed.

The insulation was evaluated by placing the electronic component in insulating oil by the step-up method defined in JIS C 2110, withstanding voltage of the lead frame and aluminum bonded to the semiconductor chip. The withstand voltage in Example 1 was as good as 6.0 kV.

(Example 2)
After applying the thickness of the hardened layer 2 to 100 μm on a 0.5 mm thick tough pitch copper, an electroplated copper foil having a roughness of 19 μm as the metal layer 1 is bonded, and the hardening rate is set to 90% by heating. Example 1 is the same as Example 1 except that the foil is etched with a chemical to produce irregularities in the cured layer 2.

The electronic component of Example 2 was not peeled off and had a good insulation property with a withstand voltage of 5.5 kV.

(Comparative example)
On a tough pitch copper with a thickness of 0.5 mm, after the cured layer 2 is applied to a thickness of 100 μm, a SUS mirror plate with a surface roughness of 0.07 μm as the metal layer 1 is bonded, and the curing rate is 90% by heating. I made it. Example 1 is the same as Example 1 except that the mirror plate is etched with a chemical to produce irregularities on the cured layer.

In the electronic component of the comparative example, peeling was observed between the insulating layers, and the withstand voltage was 4.0 kV.

Claims (7)

A metal plate, a hardened layer, and an adhesive layer are laminated in this order, and the hardened layer has a C-stage shape with a cure rate calculated from a differential scanning calorimeter of 90% or more and has a heat dissipation property. A heat dissipation substrate having a B-stage shape having a surface roughness of 1.0 μm or more and 19 μm or less and a curing rate calculated from a differential scanning calorimeter of the adhesive layer of 10% or more and 75% or less . Cured layer and the adhesive layer is an epoxy resin, the heat dissipation substrate according to claim 1, wherein ing a curing agent and an inorganic filler. The heat-radiating substrate according to claim 1, wherein the hardened layer is formed by multilayering with the same material. The heat dissipation substrate according to any one of claims 1 to 3, wherein the cured layer and the adhesive layer are thermosetting. The inorganic filler is made of one or more of silicon oxide, aluminum oxide, aluminum nitride, boron nitride, and silicon nitride, and the filling rate of the inorganic filler is 45% by volume or more and 85% by volume or less. The heat dissipation board | substrate as described in a term. An electronic component having a heat dissipation board according to any one of claims 1 to 5 and a lead frame mounted on an insulating layer of the heat dissipation board. An electronic component comprising: the electronic component according to claim 6; a semiconductor element electrically connected to the lead frame; and a thermosetting resin that seals an outer periphery of the electronic component and the semiconductor element.

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