JP2013089670A - Heat dissipation member, and manufacturing method of semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation member in which an insulating resin layer is formed of a thermosetting adhesive having a relatively high curing reaction rate and excellent long-term sustainability of the adhesion ability, and to provide a method of easily manufacturing a semiconductor module having excellent heat dissipation.SOLUTION: One surface of an insulating resin layer 10 composed of a thermosetting adhesive containing boron nitride particles (A), epoxy resin (B) and phenolic resin (C) is bonded to a bonded body and cured, and heat of the bonded body is dissipated by a heat dissipation member 1 through the insulating resin layer 10. The heat dissipation member 1 contains 40 vol.% or more and 65 vol.% or less of boron nitride particles, contains tris(hydroxyphenyl methane) epoxy resin as the epoxy resin, contains at least one kind of phenol novolac resin, phenol aralkyl resin, tris (hydroxyphenyl methane) phenolic resin as the phenolic resin, and further contains tetra phenyl phosphonium tetra phenyl borate.

Description

  The present invention relates to a heat dissipation member and a method for manufacturing a semiconductor module.

2. Description of the Related Art Conventionally, a semiconductor module packaged by molding a semiconductor element with a resin has been widely used. For example, a power module provided with a power transistor for controlling a power source is widely used as the semiconductor element. It has been.
In a semiconductor module such as this power module, various heat dissipating means are provided to prevent the junction temperature from rising to a certain level due to heat generated by the power transistor.
As such means, there is generally used a method in which a metal block called a heat spreader is used to quickly take away heat generated from a semiconductor element, and the semiconductor element is mounted on the heat spreader and arranged in a semiconductor module. It has been adopted.
However, the heat spreader has a surface exposed to the outer surface of the semiconductor module in a conventional semiconductor module or the like because the ability to take heat away from the semiconductor element decreases as the temperature of the heat spreader increases. A heat radiating member for releasing the heat in the semiconductor module from the module to the outside of the module is provided on the lower surface side of the heat spreader.

  As this type of heat radiating member, a member having a laminated structure of a metal layer and an insulating resin layer is known as shown in Patent Document 1 below, and the insulating resin layer is adhered to the lower surface of the heat spreader and a metal foil is used. In addition, there is known a type that is used by exposing the lower surface of the metal layer formed of a metal plate to the lower surface of the semiconductor module so as to be used as a heat radiating surface.

The insulating resin layer is provided to ensure insulation between the metal layer to be exposed on the surface of the semiconductor module and the heat spreader, and as shown in Patent Document 1 below, It is formed by using a thermosetting adhesive containing an epoxy resin widely used in electrical insulation applications.
In addition, such a heat radiating member is usually used by bonding and curing the insulating resin layer to a heat spreader. However, it is faster than a general thermosetting adhesive in bonding and curing to the heat spreader. It is required to show a curing reaction.
For example, as shown in Patent Document 1 below, when a semiconductor element or heat spreader is molded, a thermosetting resin used for the mold is melted by heat, and the semiconductor element or heat spreader is placed in the heat-melted thermosetting resin. In the case where the insulating resin layer of the heat radiating member is thermally cured together with the thermosetting resin, the heat used for the mold is used for the thermosetting adhesive forming the insulating resin layer. It is required to cause a curing reaction at a rate similar to that of a curable resin.

That is, if the curing behavior of the thermosetting resin used in the mold and the insulating resin layer of the heat radiating member is excessively separated, a gap may be formed at the adhesive interface between the heat spreader and the insulating resin layer. Since there exists a possibility that a crack may arise in a resin layer and insulation reliability may be reduced, it is calculated | required to approximate these hardening behavior.
On the other hand, if a highly reactive formulation such as a general thermosetting resin is applied to the thermosetting adhesive that forms the insulating resin layer, the pot life may be short. There is a possibility that the adhesiveness to the adherend such as a heat spreader is lost in a short time after the heat radiation member is manufactured.

By the way, since the heat radiating member is required to efficiently dissipate heat of the heat spreader through the insulating resin layer and the metal layer, the thermosetting adhesive used for forming the insulating resin layer is used. Are filled with an inorganic filler excellent in thermal conductivity such as boron nitride particles together with an epoxy resin.
However, even if the thermal conductivity is improved by highly filling the thermosetting adhesive with an inorganic filler, if the adhesion between the insulating resin layer and the heat spreader is not good enough, the interfacial thermal resistance will increase and heat dissipation will be good. May not be done.
For these reasons, thermosetting adhesives for forming the insulating resin layer of the heat dissipating member are strongly demanded to improve both the curing reaction rate and the long-term sustainability of the adhesive ability.

However, no thermosetting adhesive has been found that satisfies the above requirements, and no thermosetting adhesive suitable for forming the insulating resin layer of the heat radiating member has been found.
Therefore, in the method of manufacturing a semiconductor module, in molding a semiconductor element or a heat spreader with a heat-melted thermosetting resin, the thermosetting resin is thermoset and the insulating resin layer of the heat radiating member is thermoset. However, it is difficult to match the curing behavior of the molding resin and the insulating resin layer, and it is difficult to obtain a semiconductor module with excellent heat dissipation.

JP 2004-165281 A

  The present invention has been made in view of the above problems, and a heat radiating member in which an insulating resin layer is formed of a thermosetting adhesive having a relatively high curing reaction rate and an excellent long-term sustainability of adhesive ability. It is an object of the present invention to provide a semiconductor module manufacturing method that can easily manufacture a semiconductor module excellent in heat dissipation.

  As a result of intensive studies by the inventor in order to solve the above-mentioned problems, the curing reaction rate is improved by curing a specific epoxy resin with a specific phenol resin and using a specific curing catalyst. The present invention has been completed by finding that a thermosetting adhesive can be obtained which is relatively fast and excellent in long-term durability of the adhesive ability.

  That is, the present invention relating to a heat radiating member for solving the above-mentioned problems is an insulating resin layer comprising a thermosetting adhesive containing boron nitride particles (A), an epoxy resin (B), and a phenol resin (C). A heat-dissipating member used to dissipate the heat of the adherend through the insulating resin layer by bonding and curing one surface side of the insulating resin layer to the adherend, and forming the insulating resin layer In the thermosetting adhesive, the boron nitride particles (A) are contained in a proportion of 40% by volume to 65% by volume, and the epoxy resin (B) is a trishydroxyphenylmethane type epoxy resin. (B1) is contained, and as the phenol resin (C), a phenol novolac resin (C1), a phenol aralkyl resin (C2), and a trishydroxyphenylmethane type phenol resin ( At least one kind are contained in the three) and it was characterized that is contained more tetraphenylphosphonium tetraphenylborate (D1).

  Moreover, this invention which concerns on the manufacturing method of the semiconductor module for solving the said subject has at least 2 layer structure of the insulating resin layer and base material layer which consist of a thermosetting adhesive, and the one surface side is the said insulating resin layer And a heat spreader having a semiconductor element mounted thereon, and the heat spreader is molded with a thermosetting resin together with the semiconductor element, and the semiconductor element. A semiconductor module having an insulating resin layer of the heat radiating member bonded and cured on a surface opposite to the mounting surface is formed so that the base material layer of the heat radiating member is exposed on the surface. A method for manufacturing a semiconductor module, comprising: a first step of placing an insulating resin layer of the heat dissipation member in contact with the opposite surface of the heat spreader; While the base material layer side of the member is exposed, the thermosetting resin used for the mold is melted by heat so that the heat spreader side is molded with the thermosetting resin, and the thermosetting resin is mixed with the thermosetting resin. A second step of embedding a heat spreader, and the insulating material comprising the thermosetting adhesive containing boron nitride particles (A), epoxy resin (B), and phenol resin (C) as the heat dissipation member The boron nitride particles (A) are contained in the thermosetting adhesive having a resin layer and forming the insulating resin layer in a proportion of 40% by volume to 65% by volume, and the epoxy resin ( B) contains a trishydroxyphenylmethane type epoxy resin (B1), and the phenol resin (C) includes a phenol novolac resin (C1) and a phenol aral. A heat-dissipating member that contains at least one of ruthenium resin (C2) and trishydroxyphenylmethane type phenolic resin (C3), and further contains tetraphenylphosphonium tetraphenylborate (D1), The second step is characterized by thermosetting the thermosetting resin for molding and thermosetting the insulating resin layer of the heat radiating member.

  According to the present invention, it is possible to obtain a heat radiating member that can be easily matched with a thermosetting resin used for molding a heat spreader or the like in a semiconductor module or the like and can be cured and cured with good adhesion to the heat spreader. Therefore, it is possible to easily manufacture a semiconductor module excellent in heat dissipation.

The schematic sectional drawing which shows the member for thermal radiation. The schematic sectional drawing of the semiconductor module which shows the usage method of the member for thermal radiation.

Below, about preferable embodiment which concerns on the heat radiating member of this invention, the base material for supporting the insulating resin layer which consists of a thermosetting adhesive containing a boron nitride particle and an epoxy resin, and this insulating resin layer A heat radiating member having a two-layer structure with a layer and the base material layer being a metal layer made of a metal foil will be described as an example.
FIG. 1 is a schematic cross-sectional view showing a cross-sectional structure of a heat-dissipating member 1, wherein reference numeral 10 denotes an insulating resin layer formed of a thermosetting adhesive, and 20 is a metal made of the metal foil. Represents a layer (base material layer).

In the present embodiment, a case where the heat radiating member 1 is employed as a constituent member of a specific semiconductor module as shown in FIG. 2 will be described.
That is, in the present embodiment, the semiconductor module 2 including the semiconductor element 50 therein and the heat radiating member for transferring the heat to the heat radiating surface for radiating the heat generated by the semiconductor element 50 is illustrated. The present invention will be described with reference to the drawings.

First, the semiconductor module 2 will be described with reference to the drawings.
FIG. 2 shows a cross section of the semiconductor module 2, and as shown in this figure, the semiconductor module 2 according to this embodiment is molded and integrated with a thermosetting resin that is thermoset, The overall shape is a flat rectangular plate shape, more specifically, a match box shape.
And in the semiconductor module 2, the said semiconductor element 50 and the heat spreader 30 are accommodated in the state embedded in the cured thermosetting resin.

The heat spreader 30 is formed of a metal block sufficiently larger than the semiconductor element 50 so that the heat of the semiconductor element 50 can be quickly taken away, and is connected to the semiconductor element 50 via a solder 40.
More specifically, the heat spreader 30 has a thickness of about half the height of the semiconductor module 2 and has a rectangular plate shape having an area slightly smaller than the area of the semiconductor module 2 in a top view, and has a central portion on the upper surface. The semiconductor element 50 is mounted in a semiconductor module.

In addition, the heat spreader 30 is soldered to the upper surface of the other end portion of a terminal 70 a having one end side extended outward from the side surface of the semiconductor module 2.
Further, the heat spreader 30 is configured such that another terminal 70b disposed so as to face the terminal 70a via the semiconductor element 50 and the semiconductor element 50 are electrically connected by a bonding wire 60. An electric flow path is formed between the terminals.
That is, when the semiconductor module 2 is energized, the heat spreader 30 is configured so that a current flows therein, and in addition to the heat generated by the semiconductor element 50, a temperature rise due to Joule heat accompanying the current flowing through the heat spreader 30 occurs. I will let you.
In the semiconductor module 2, the semiconductor element 50 and the like are embedded in the thermosetting resin 90 leaving the lower surface side of the heat spreader 30.

The heat radiating member 1 in the present embodiment has a larger area than the lower surface of the heat spreader 30 and a smaller area than the lower surface of the semiconductor module 2, and covers the entire lower surface of the heat spreader 30. The upper surface of the insulating resin layer 10 is bonded to the lower surface of the semiconductor module 2.
The heat radiating member 1 exposes the lower surface (hereinafter also referred to as “surface”) of the metal layer 20 on the lower surface of the semiconductor module 2, and uses the surface 20 a of the metal layer 20 as a heat radiating surface of the semiconductor module 2. Be prepared to get.
That is, the lower surface of the semiconductor module 2 according to the present embodiment exposes the surface 20a of the metal layer 20 at the center, and surrounds the exposed metal layer 20 with the thermosetting resin 90. ing.
In addition, the semiconductor module 2 according to the present embodiment is formed so that the exposed surface of the thermosetting resin 90 and the surface 20a of the metal layer 20 are substantially flush with each other on the lower surface thereof, such as a radiator. So that the heat generated by the semiconductor element 50 can be dissipated to the radiator through the insulating resin layer 10 and the metal layer 20 by bringing the surface of the radiator into contact with the surface 20 a of the metal layer 20. Is formed.

In the heat radiating member 1 according to this embodiment, a thermosetting adhesive containing boron nitride particles and an epoxy resin is used for forming the insulating resin layer 10.
In general, the thinner the insulating resin layer 10, the lower the thermal resistance from the heat spreader 30 to the metal layer 20, which is advantageous for heat dissipation.
On the other hand, if the thickness of the insulating resin layer 10 is thin, the reliability in electrical insulation may be reduced.
Therefore, the insulating resin layer 10 is usually formed to have a thickness of 100 to 300 μm with a thermosetting adhesive having a volume resistivity of 1 × 10 ¹³ Ω · cm or more after thermosetting. The

The thermosetting adhesive for forming the insulating resin layer 10 has a curing reaction rate equivalent to that of a general thermosetting resin for molds, and has good adhesion even when stored for a long period before use. Therefore, it is important to contain the epoxy resin (B) and the phenol resin (C) together with the boron nitride particles (A).
In such a point, it is important to contain a triphenylborane-based curing catalyst in the thermosetting adhesive, and it is particularly important to contain tetraphenylphosphonium tetraphenylborate (D1).

It is important that the boron nitride particles (A) are contained so that the proportion of the entire thermosetting adhesive is 40% by volume or more and 65% by volume or less.
Note that it is important that the volume of boron nitride particles in the thermosetting adhesive for forming the insulating resin layer 10 is within the above range. If the volume is less than the above range, sufficient heat conduction to the insulating resin layer is achieved. This is because it becomes difficult to impart the properties, and when boron nitride particles are contained exceeding the above range, it is difficult to sufficiently bond the insulating resin layer to the heat spreader and defects such as pinholes are likely to occur.

The boron nitride particles preferably contain at least a part thereof in the form of aggregated particles in order to form a favorable heat transfer path in the thickness direction of the insulating resin layer 10.
As described above, this agglomerated particle is an effective component for forming a good heat transfer path, and 50% of the boron nitride particles contained in the insulating resin layer 10 are contained in the point that the excellent thermal conductivity can be exhibited. It is preferable to contain at least mass% in the form of aggregated particles.
The primary particles of boron nitride are usually hexagonal plates, and the aggregated particles have a nearly spherical shape in which a plurality of primary particles are aggregated. If observed, it can be easily determined whether or not the boron nitride particles are contained as aggregated particles.

In the present invention, it is preferable that the inorganic filler contained in the thermosetting adhesive is substantially only boron nitride particles in order to allow the insulating resin layer 10 to exhibit good thermal conductivity. If so, other inorganic fillers may be contained within a range in which the effects of the present invention are not significantly impaired.
Examples of other inorganic fillers that can be contained in the thermosetting adhesive include silicon oxide particles, aluminum oxide particles, zirconium oxide particles, titanium oxide particles, barium titanate particles, hafnium oxide particles, and zinc oxide particles. And metal oxide particles such as iron oxide particles.
Further, as other inorganic fillers, for example, aluminum nitride particles, silicon nitride particles, gallium nitride particles, silicon carbide particles, diamond particles, and the like can be employed.

In the thermosetting adhesive, it is important to employ a trishydroxyphenylmethane type epoxy resin (B1) as the epoxy resin. As the phenol resin, a phenol novolac resin (C1), xylylene novolac phenol or biphenylene novolac is used. It is important to employ at least one of phenol aralkyl resin (C2) such as phenol and trishydroxyphenylmethane type phenol resin (C3).
In addition, it is important that the thermosetting adhesive contains tetraphenylphosphonium tetraphenylborate (D1) as a curing catalyst.

The phenol novolak resin (C1), the phenol aralkyl resin (C2), and the trishydroxyphenylmethane type phenolic resin (C3) have a total content in the thermosetting adhesive of the trishydroxyphenylmethane type epoxy resin (B1). It is preferable to adjust by content of.
That is, the heat of the phenolic resin and epoxy resin as the ratio of the number of phenolic hydroxyl groups (n _POH) and the number of epoxy groups _{(n EPX) (n POH /} n EPX) is 0.8 to 1.2 It is preferable to adjust the content in the curable adhesive.
Moreover, it is preferable that the said tetraphenyl phosphonium tetraphenyl borate (D1) is contained in the ratio used as 0.5-3 mass parts with respect to 100 mass parts of said epoxy resins.

In this embodiment, the resin component of the thermosetting adhesive is substantially 1 of the phenol novolac resin (C1), the phenol aralkyl resin (C2), and the trishydroxyphenylmethane type phenol resin (C3). It is preferable to use only a seed or more, trishydroxyphenylmethane type epoxy resin (B1), and tetraphenylphosphonium tetraphenylborate (D1). For example, cresol novolak type epoxy resin, phenol novolak type epoxy resin , Dicyclopentadiene type epoxy resin, tetrakishydroxyphenylethane type epoxy resin, epoxy resin having three or more epoxy groups in the molecule, biphenyl type epoxy resin, bisphenol A type epoxy resin, modified bisphenol A type epoxy resins, bisphenol F type epoxy resin, replacing the epoxy resin such as modified bisphenol F type epoxy resin in a part of tris-hydroxyphenyl methane type epoxy resin (B1), may be contained in the thermosetting adhesive.
For example, if the ratio of the total to the trishydroxyphenylmethane type epoxy resin (B1) does not become excessively large, the other epoxy resin (Bx) exemplified above is used as the resin component of the thermosetting adhesive. It is also possible to adopt as.

  Similarly, the ratio of the phenol novolak resin (C1), the phenol aralkyl resin (C2), and the trishydroxyphenylmethane type phenol resin (C3) to the total contained is too large. If not, other phenol resin curing agents (Cx) such as cresol novolak resin, tert-butylphenol novolak resin, novolak type phenol resin such as nonylphenol novolak resin, resol type phenol resin, polyoxystyrene such as polyparaoxystyrene Etc. can also be employed as the resin component of the thermosetting adhesive.

  Furthermore, if the proportion of the total with tetraphenylphosphonium tetraphenylborate (D1) does not become excessively large, a triphenylborane-based curing catalyst other than tetraphenylphosphonium tetraphenylborate (D1), It is also possible to employ one or more of imidazole-based curing catalyst, triphenylphosphine-based, and amino-based curing catalyst as the resin component of the thermosetting adhesive.

  Examples of the triphenylborane-based curing catalyst other than tetraphenylphosphonium tetraphenylborate (D1) include tetraphenylphosphonium tetra-p-triborate, benzyltriphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and the like.

  Examples of the imidazole-based curing catalyst include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2- Phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 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-di Mino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl -S-triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like.

  Examples of the triphenylphosphine-based curing catalyst include triorganophosphine such as triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, and diphenyltolylphosphine. Tetraphenylphosphonium bromide, methyltriphenylphosphonium, methyltriphenylphosphonium chloride, methoxymethyltriphenylphosphonium, benzyltriphenylphosphonium chloride, and the like.

  Furthermore, examples of the amino curing catalyst include monoethanolamine trifluoroborate and dicyandiamide.

  In addition to these, formulations commonly used in resin products such as dispersants, tackifiers, anti-aging agents, antioxidants, processing aids, stabilizers, antifoaming agents, flame retardants, thickeners, pigments, etc. A chemical can be appropriately contained in the thermosetting adhesive for forming the insulating resin layer 10 within a range not impairing the effects of the present invention.

The metal layer 20 laminated on the insulating resin layer 10 can be formed of a metal foil having a thickness of less than 1 mm (for example, 20 μm to 300 μm) made of a metal such as copper, aluminum, nickel, iron, or an alloy thereof.
The metal foil may be a clad foil formed by bonding different metals or a plating foil plated with different metals.
Moreover, as a metal foil which comprises this metal layer 20, in order to improve the adhesive force with the insulating resin layer 10, it is preferable that the surface of the interface side with the insulating resin layer 10 is roughened.
This surface roughening can be performed by sandblasting or oxidizing the surface of the metal foil.

In the case of using an electrolytic metal foil, the mat surface (roughened surface) can be used as a laminated interface with the insulating resin layer, and no special treatment such as sandblasting or oxidation is required. Is preferred.
In that case, it is also preferable in that a shining surface (glossy surface) having a smooth surface can be used as a heat radiating surface.
In the present embodiment, it is preferable to use an electrolytic copper foil for forming the metal layer 20 because it is relatively inexpensive, excellent in corrosion resistance, and has high thermal conductivity.
Furthermore, as this electrolytic copper foil, it is preferable to use what has a zincate treatment on the mat surface.

In addition, in this embodiment, although the case where the base material layer of a heat radiating member is made into the metal layer which consists of metal foil is illustrated, the metal layer which consists of metal plates, such as a 1-5 mm-thick copper plate and an aluminum plate, for example It is good also as a base material layer.
Furthermore, the base material layer may be formed of another member such as a ceramic fiber sheet, and it is also possible to employ a sheet-like heat radiating member made of only an insulating resin layer without providing the base material layer.

Moreover, as the heat radiating member of the present embodiment, it is preferable that the insulating resin layer has a two-layer structure in that the insulation reliability can be ensured more reliably.
Note that the heat dissipating member of the present invention may have a multi-layer structure of three or more insulating resin layers in order to ensure higher reliability.
Alternatively, the insulating resin layer may have a single layer configuration in order to simplify the labor required for manufacturing.
When the insulating resin layer has a plurality of layers, it is not necessary to share the blending contents of all layers, and the blending contents may be different between one layer and another layer.

Next, a heat radiating member having an insulating resin layer 10 in which thermosetting adhesives are laminated in two layers on a metal layer made of metal foil will be described as an example, and a manufacturing method thereof will be described.
In order to produce the said heat radiating member, the method of implementing the process of following a)-e) in order is mentioned, for example.
a) Trishydroxyphenylmethane type epoxy resin, phenol novolak resin, phenol aralkyl resin, and trishydroxyphenylmethane type phenolic resin are dissolved in an organic solvent capable of dissolving them to obtain a desired concentration and dissolved in this resin solution. A coating liquid preparation step of preparing a coating liquid by mixing the boron nitride particles and the tetraphenylphosphonium tetraphenylborate;
b) a coating step of coating the coating liquid on the metal foil for forming the metal layer 20;
c) a drying step of introducing the metal foil coated with the coating liquid into a drying furnace to remove the organic solvent and forming a dry film of the coating liquid on the metal foil;
d) Two metal foils on which the dry film is formed are prepared, stacked so that the dry film is on the inside, and hot-pressed so that the two dry films are laminated and integrated to form a two-layered insulating resin. Hot pressing process to form a layer,
e) A peeling step of forming a heat radiating member in which a metal layer and an insulating resin layer are laminated by peeling off one excess metal foil after the hot pressing step.

In addition, the said coating liquid preparation process can be implemented using stirring apparatuses, such as a ball mill, a planetary mixer, a homogenizer, and a 3 roll mill.
However, it is preferable to select an apparatus in which such a phenomenon is unlikely to occur because there is a possibility that aggregated particles of boron nitride may be crushed if shearing is excessively applied to the coating solution.
Further, it is preferable to adjust the operating conditions of the apparatus so that the aggregated particles are not crushed.

  The coating process can be performed using a coating apparatus such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a knife coater, a comma coater, or a direct coater, and the drying process is performed using a general heating and drying furnace. Can be implemented.

The coating liquid contains at least 40% by volume to 65% by volume of boron nitride particles in total with respect to the solid content. Usually, when this amount of inorganic filler is included, fine particles are contained in the dry film. There is a possibility that a small gap portion is formed, and the apparent film thickness may be increased.
The hot pressing step is effective in preventing the formation of defects penetrating in the thickness direction with a two-layer structure of the insulating resin layer. However, the voids are formed in the insulating resin layer due to the voids. This is also effective in suppressing the formation of such defects.
In addition, it can be said that the hot pressing process is also effective in bringing boron nitride particles close to each other and forming a heat transfer path mainly composed of aggregated particles.

In terms of being able to exert the effects as described above more remarkably, it is preferable to carry out the hot pressing step at a higher temperature and a higher pressure. However, if excessive heat is applied to the insulating resin layer in the hot pressing step, There is a possibility that the curing reaction of the epoxy resin or the like proceeds excessively and the adhesive force to the heat spreader is greatly reduced.
Therefore, it is preferable to carry out the hot pressing process under conditions that do not impair the adhesion to the heat spreader.

  The method for adhering the heat radiating member to the heat spreader is not particularly limited. For example, the semiconductor module 2 has a structure as shown in FIG. The heat-dissipating member 1 having at least a two-layer structure, one surface side formed of the insulating resin layer 10 and the other surface side formed of the metal layer 20, and a heat spreader 30 on which a semiconductor element 50 is mounted are provided. A semiconductor module in which the heat spreader 30 is molded with a thermosetting resin 90 together with the semiconductor element 50 and the insulating resin layer 10 of the heat radiating member 1 is bonded and cured on the surface opposite to the semiconductor element mounting surface. When the metal layer 20 is formed so as to be exposed on the surface, when the mold with the thermosetting resin 90 is performed The insulating resin layer 10 of the heat dissipating member 1 by spreader 30 may be adhered cured.

That is, the semiconductor module having the structure shown in FIG. 2 can be manufactured as follows.
(First step)
In the present embodiment, as a first step for manufacturing a semiconductor module, the heat spreader 30 on which the semiconductor element 50 is mounted is placed with the semiconductor mounting surface on the upper side, and the heat dissipating member 1 on the surface opposite to the semiconductor mounting surface. The insulating resin layer 10 is placed in contact therewith.
At this time, for example, a casting mold having a flat rectangular plate-shaped cavity (internal space) corresponding to the outer shape of the semiconductor module to be manufactured is prepared, and the heat dissipating member 1 and the heat spreader 30 are positioned relative to each other. The first step can be performed by setting in the cavity so as to coincide with the positional relationship in the semiconductor module to be manufactured.
More specifically, the heat radiating member 1 is set with the insulating resin layer 10 facing upward in the casting mold to which the terminals 70a and 70b are fixed, and the semiconductor element 50 soldered to the upper surface side. Is set at a predetermined position on the heat dissipating member 1, and the insulating resin layer 10 of the heat dissipating member 1 is in contact with the surface (lower surface) opposite to the semiconductor element mounting surface of the heat spreader 30. Thus, the first step can be performed by arranging these.

(Second step)
After the step (the first step), the thermosetting resin used for the mold is melted in an uncured state to expose the lower surface side of the metal layer 20 while the heat spreader on the upper side from the metal layer 20 is exposed. The heat-melted thermosetting resin is poured into a casting mold so that the side is buried with the heat-melted thermosetting resin.
Then, the thermosetting resin used for the mold in the second step is thermoset, and the insulating resin layer 10 is formed using the heat of the thermosetting resin and the injection pressure into the casting mold. The thermosetting adhesive that is being used is bonded and cured to the heat spreader 30.

As described above, after the heat radiation member 1 and the heat spreader 30 are bonded simultaneously with the manufacture of the semiconductor module 2, the heat spreader 30 is processed in the course of the thermosetting of the insulating resin layer 10 and the molded thermosetting resin 90. In the conventional case, strong shear stress is easily applied to the adhesive interface between the insulating resin layer 10 and the insulating resin layer 10 and the adhesive interface between the insulating resin layer 10 and the thermosetting resin 90 due to the difference in the curing reaction rate. However, in this embodiment, because the predetermined compounding prescription is applied to the insulating resin layer 10, interfacial peeling may occur between the heat spreader 30 and the like. The occurrence of cracks in the insulating resin layer 10 is suppressed, and there is a low possibility of causing an unexpected decrease in insulation and heat dissipation performance.
That is, by producing the semiconductor module 2 using the heat radiating member 1 according to the present invention, it is possible to easily obtain the semiconductor module 2 having excellent heat dissipation and excellent insulation reliability.

In addition, about the heat radiating member provided with base material layers other than the metal layer which consists of metal foil, it can utilize for the manufacturing method of a semiconductor module similarly to the above, In that case, it is excellent also in heat dissipation, and insulation. The point that a highly reliable semiconductor module can be easily obtained is the same as the above case.
Also, a semiconductor module in which one side of the heat radiating member is bonded and cured to the surface opposite to the semiconductor element mounting surface of the heat spreader using a sheet-shaped heat radiating member consisting only of an insulating resin layer not provided with a base material layer The method of manufacturing a semiconductor module including the first and second steps as described above can also be adopted when forming the heat dissipation member so that the other surface side of the heat dissipation member is exposed on the surface. .

  Further, although further detailed description is omitted here, the heat dissipating member of the present invention and the method of manufacturing the semiconductor module are not limited to the above examples, and are conventionally known technical matters in these technical fields. As long as the effects of the present invention are not significantly impaired.

(Examples 1-5, Comparative Examples 1-5)
(Sample preparation)
First, a coating solution having a composition as shown in Table 1 was prepared.
Although not shown in the table, each coating solution contains boron nitride particles (containing aggregated particles, a coupling agent-treated product) so that the proportion of the solid content is 58% by volume.
In preparing this coating liquid, first, an epoxy resin and a phenol resin are dissolved in methyl ethyl ketone so that the coating liquid has a viscosity suitable for coating, and a curing accelerator is dispersed therein, and the boron nitride is dispersed. The particles were added and mixed with a planetary mixer.
The obtained coating solution was roll-coated on a matte surface of an electrolytic copper foil having a thickness of 105 μm by adjusting the wet thickness so that the coating thickness after drying was about 200 μm, and dried at 100 ° C. for 5 minutes. A dry film was formed.
Prepare two copper foils on which this dry film is formed, and stack them so that the dry film is on the inside. Then, heat press at a pressure of 10 MPa at 120 ° C. for 20 minutes to laminate two dry films. After the integration, the copper foil on one side was removed, and a heat radiating member in which an insulating resin layer having a thickness of 200 μm was laminated on the metal layer made of the copper foil was produced.

(Curing rate evaluation)
The obtained heat-dissipating member was a strip-shaped sample having a width of 10 mm and a length of 50 mm, and a curing rate evaluation sample.
This strip sample is set in a TA Instruments viscoelasticity measuring device, model name “ARES”, heated from room temperature to 175 ° C. at a rate of 40 ° C./min, and then constant at a temperature of 175 ° C. Viscosity measurement was performed in the torsion mode, and the time from when the lowest viscosity was observed to when it reached 9 × 10 ⁷ [Pa · s] was read.

(Preservation evaluation)
About 8 mg of a sample collected from the insulating resin layer of the heat dissipating member was measured for glass transition temperature (Tg) at a heating rate of 3 ° C./min using a differential scanning calorimeter (DSC) manufactured by TA Instruments. .
The heat dissipating member was stored in an environment of 25 ° C., and the change with time in Tg was evaluated.
Specifically, the heat dissipation member is stored for one month in an environment of 25 ° C., and when the difference between the initial Tg and the Tg after storage is less than 10 ° C., the storage stability is good (“◯” judgment) Judgment was made, and the case where Tg changed by 10 ° C. or more was judged as poor storage stability (“x” judgment).

(Mold evaluation)
A strip-shaped sample having a width of 60 mm and a length of 60 mm is set in a casting mold having an internal volume of 60 mm in width, 70 mm in length, and 10 mm in depth, with the insulating resin layer side facing upward, and the width is set on this Two copper blocks (heat spreaders) of 46 mm, 27 mm in length, and 3 mm in thickness are placed side by side, a thermosetting epoxy resin mold compound with a gel time of 12 seconds (GT12s) is injected, and thermosetting is performed at 175 ° C. for 1.5 minutes. Then, a sample simulating a semiconductor module in which an insulating resin layer of a strip-shaped sample was adhered and cured on the lower surface of the copper block and the copper foil was exposed on the lower surface side was produced (mold evaluation (A)).
When the underside of the simulated sample is observed with an ultrasonic flaw detector (SAT) and the peeling between the copper block and the insulating resin layer is detected, the determination is “x”, and the case where no peeling is detected is indicated with “○”. Judgment was made.
Similarly, a thermosetting epoxy resin mold compound having a gel time of 39 seconds (GT39s) was injected, thermosetting was performed at 175 ° C. for 3 minutes, and mold evaluation was performed based on the presence or absence of peeling (mold evaluation (B) ).

Of the two evaluations described above, those showing good matching with the curing behavior of any of the mold thermosetting resins are evaluated as “◯”, and those in which neither of the curing behaviors is matched are determined as “ X ”was determined (mold evaluation (C)).

(Characteristics of cured product)
A strip-shaped sample is set in a TA instrument viscoelasticity measuring apparatus (model name “ARES”), heated from room temperature to 175 ° C. at a rate of 40 ° C./min, and then kept constant at a temperature of 175 ° C. While measuring the viscosity in the torsion mode, the time from when the lowest viscosity was observed to when the highest viscosity was observed was read to evaluate the properties of the cured product.
Specifically, the case where this time was less than 30 minutes was determined as “◯”, and the case where it was 30 minutes or more was determined as “x”.

The above evaluation results are shown in Table 1 below.

As described above, in the examples, those having a relatively high curing reaction rate and excellent long-term adhesion ability are obtained.
In Comparative Example 4, the result of obtaining a comparatively high curing reaction rate and excellent long-term adhesion ability is shown, but in Comparative Example 4, the properties of the cured product are shown. As a result, there was a problem with the evaluation results for the material, and it was practically difficult to use it as a heat radiating member.
Also from this, according to the present invention, it is possible to obtain a heat radiating member having an insulating resin layer formed of a thermosetting adhesive having a relatively fast curing reaction rate and excellent long-term adhesion capability. It can be seen that a semiconductor module excellent in heat dissipation can be easily manufactured.

  1: member for heat dissipation, 3: semiconductor module, 10: insulating resin layer, 20: metal layer (base material layer), 20a: surface (heat dissipation surface), 30: heat spreader, 50: semiconductor element

Claims (7)

It has an insulating resin layer made of a thermosetting adhesive containing boron nitride particles (A), epoxy resin (B), and phenol resin (C), and one surface side of the insulating resin layer is bonded and cured to an adherend. A heat dissipating member used to dissipate the heat of the adherend through the insulating resin layer,
The thermosetting adhesive forming the insulating resin layer contains the boron nitride particles (A) in a proportion of 40% by volume to 65% by volume, and the epoxy resin (B) is tris. Hydroxyphenylmethane type epoxy resin (B1) is contained, and at least one of phenol novolak resin (C1), phenol aralkyl resin (C2), and trishydroxyphenylmethane type phenol resin (C3) as the phenol resin (C). A heat-dissipating member containing seeds and further containing tetraphenylphosphonium tetraphenylborate (D1).   A metal layer made of a metal foil or a metal plate and the insulating resin layer are laminated, and the metal layer is disposed on a side opposite to the one surface side of the insulating resin layer bonded to the adherend, The heat radiating member according to claim 1, wherein the heat radiating member is used to radiate heat through the insulating resin layer and the metal layer. The said thermosetting adhesive, wherein as the ratio of the number of phenolic hydroxyl groups and (n _POH) the number of epoxy groups _{(n EPX) (n POH /} n EPX) is 0.8 to 1.2 The epoxy resin and the phenol resin are contained, and the tetraphenylphosphonium tetraphenylborate is contained at a ratio of 0.5 to 3 parts by mass with respect to 100 parts by mass of the epoxy resin. 2. A heat radiating member according to 2.   The heat radiating member according to any one of claims 1 to 3, wherein a part or all of the boron nitride particles are aggregated and contained in the insulating resin layer. A heat radiating member having at least a two-layer structure of an insulating resin layer made of a thermosetting adhesive and a base material layer, one side formed with the insulating resin layer and the other side formed with the base material layer; and a semiconductor And a heat spreader on which the element is mounted. The heat spreader is molded with a thermosetting resin together with the semiconductor element, and the insulating resin layer of the heat dissipating member is bonded and cured on the surface opposite to the semiconductor element mounting surface. A semiconductor module manufacturing method for forming a semiconductor module provided so as to be in a state in which a base material layer of the heat dissipation member is exposed on the surface,
A first step of placing the insulating resin layer of the heat dissipation member in contact with the opposite surface of the heat spreader; and
The thermosetting resin used for molding is thermally melted so that the heat spreader side is molded with the thermosetting resin while the base material layer side of the heat radiating member is exposed. A second step of embedding the heat spreader therein,
The heat radiating member has the insulating resin layer made of a thermosetting adhesive containing boron nitride particles (A), an epoxy resin (B), and a phenol resin (C), and the insulating resin layer is formed. In the thermosetting adhesive, the boron nitride particles (A) are contained in a proportion of 40% by volume to 65% by volume, and the epoxy resin (B) is a trishydroxyphenylmethane type epoxy resin (B1). And at least one of phenol novolak resin (C1), phenol aralkyl resin (C2), and trishydroxyphenylmethane type phenol resin (C3) is contained as the phenol resin (C). In the second step, using a heat radiating member containing phenylphosphonium tetraphenylborate (D1), The method of manufacturing a semiconductor module, characterized in that thermally curing the insulating resin layer of the heat-radiating member with the thermosetting resin for Rudo thermal curing.   The method for manufacturing a semiconductor module according to claim 5, wherein the heat radiating member is a metal layer made of a metal foil or a metal plate. A sheet-like heat radiating member composed only of an insulating resin layer made of a thermosetting adhesive and a heat spreader on which a semiconductor element is mounted are provided, and the heat spreader is molded together with the semiconductor element by a thermosetting resin. And a semiconductor module having one surface side of the heat radiating member bonded and cured to the surface opposite to the semiconductor element mounting surface so that the other surface side of the heat radiating member is exposed on the surface. A method of manufacturing a semiconductor module to be formed,
A first step of placing one surface side of the heat dissipation member in contact with the opposite surface of the heat spreader; and
In the thermosetting resin, the thermosetting resin used in the mold is thermally melted so that the heat spreader side is molded with the thermosetting resin while the other surface side of the heat radiating member is exposed. And a second step of burying the heat spreader,
The heat radiating member has the insulating resin layer made of a thermosetting adhesive containing boron nitride particles (A), an epoxy resin (B), and a phenol resin (C), and the insulating resin layer is formed. In the thermosetting adhesive, the boron nitride particles (A) are contained in a proportion of 40% by volume to 65% by volume, and the epoxy resin (B) is a trishydroxyphenylmethane type epoxy resin (B1). And at least one of phenol novolak resin (C1), phenol aralkyl resin (C2), and trishydroxyphenylmethane type phenol resin (C3) is contained as the phenol resin (C). In the second step, using a heat radiating member containing phenylphosphonium tetraphenylborate (D1), The method of manufacturing a semiconductor module which comprises bringing the thermosetting resin for Rudo thermoset with the thermosetting adhesive which forms the heat radiating member is thermally cured.

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