JP2017028129A - Substrate for power module, circuit board for power module, and power module - Google Patents

Abstract

Provided are a power module substrate and a power module circuit board, which are capable of realizing a highly durable power module and have an excellent balance between heat dissipation and insulation.
A power module substrate includes a metal substrate, an insulating resin layer, and a metal layer. The insulating resin layer includes a thermosetting resin and an inorganic filler. With respect to the inorganic filler contained in the ashing residue obtained by heat-treating the insulating resin layer 102 at 700 ° C. for 4 hours, the pore size distribution is measured by mercury porosimetry, and the logarithm differential pore volume (dV / dlogR) is the pore size distribution curve of the inorganic filler, and the first maximum value and the pore size R are in the range of 10 μm to 30 μm in the range of the pore size R of 0.1 μm to 5.0 μm. The difference between the second pore diameter at the second maximum value and the first pore diameter at the first maximum value is 9.9 μm or more and 25 μm or less.
[Selection] Figure 1

Description

  The present invention relates to a power module substrate, a power module circuit substrate, and a power module.

2. Description of the Related Art Conventionally, there has been known a power module in which an insulated gate bipolar transistor (IGBT) and a semiconductor element such as a diode, a resistor, and an electronic component such as a capacitor are mounted on a circuit board.
These power modules are applied to various devices according to their withstand voltage and current capacity. In particular, the use of these power modules in various electric machines is increasing year by year from the viewpoint of environmental problems in recent years and the promotion of energy saving.
In particular, regarding an in-vehicle power control device, it is desired to install the power control device in an engine room along with downsizing and space saving. The engine room has a harsh environment such as a high temperature and a large temperature change, and a substrate having a large heat radiation area is required. For such applications, a metal base circuit board that is further excellent in heat dissipation has attracted attention.

  For example, Patent Document 1 discloses a power module in which a semiconductor element is mounted on a support such as a lead frame, and the support and a heat radiating plate connected to a heat sink are bonded with an insulating resin layer.

JP2011-216619A

  However, such a power module has not yet been sufficiently satisfactory in heat dissipation and insulation at high temperatures. For this reason, it may be difficult to sufficiently dissipate the heat of the electronic component to the outside or to maintain the insulation of the electronic component, and in this case, the performance of the power module is deteriorated.

According to the present invention,
A power module substrate comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer,
The insulating resin layer includes a thermosetting resin and an inorganic filler dispersed in the thermosetting resin,
For the inorganic filler contained in the ashing residue after ashing by heat treatment of the insulating resin layer at 700 ° C. for 4 hours, when pore size distribution measurement was performed by mercury porosimetry,
The pore diameter distribution curve of the inorganic filler measured by the mercury intrusion method when the pore diameter R is the horizontal axis and the logarithmic differential pore volume (dV / dlogR) is the vertical axis,
The pore diameter R has a first maximum value in the range of 0.1 μm or more and 5.0 μm or less,
The pore diameter R has a second maximum value in the range of 10 μm or more and 30 μm or less,
There is provided a power module substrate in which a difference between the second pore diameter at the second maximum value and the first pore diameter at the first maximum value is 9.9 μm or more and 25 μm or less.

The pore diameter distribution curve of the inorganic filler in the insulating resin layer has a first maximum value in the range where the pore diameter R is 0.1 μm or more and 5.0 μm or less, and the pore diameter R is 10 μm or more. The second maximum value is in a range of 30 μm or less, and the difference between the second pore diameter at the second maximum value and the first pore diameter at the first maximum value is 9.9 μm. As described above, the strength of the inorganic filler can be improved, and as a result, the shape and orientation of the inorganic filler can be maintained to some extent before and after manufacturing the power module substrate. Thereby, since the heat conductivity of the board | substrate for power modules can be improved, the heat dissipation of the power module obtained can be improved.
In addition, when the difference between the second pore diameter and the first pore diameter is 25 μm or less, since the thermosetting resin sufficiently enters the inside of the inorganic filler, voids are generated in the insulating resin layer. Few. Thereby, since the insulation of the board | substrate for power modules can be improved, the insulation reliability of the power module obtained can be improved.
Further, when the difference between the second pore diameter and the first pore diameter is 25 μm or less, the filling property of the inorganic filler in the insulating resin layer is high, and the contact area between the inorganic fillers is large. Thereby, the thermal conductivity of the power module substrate can be improved.
As described above, according to the present invention, by controlling the difference between the second pore diameter and the first pore diameter of the inorganic filler in the insulating resin layer within the above range, heat dissipation and insulating properties can be achieved. It is inferred that a power module substrate having an excellent balance can be obtained. Then, by applying the power module substrate to the power module, a highly durable power module can be realized.

Moreover, according to the present invention,
Provided is a power module circuit board obtained by processing the metal layer of the power module board.

Furthermore, according to the present invention,
The power module circuit board;
Electronic components provided on the power module circuit board;
A power module is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the power module board | substrate and power module circuit board which were able to implement | achieve a highly durable power module and was excellent in the balance of heat dissipation and insulation, and a highly durable power module can be provided.

It is sectional drawing of the board | substrate for power modules which concerns on one Embodiment of this invention. It is sectional drawing of the power module which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and detailed description thereof is appropriately omitted so as not to overlap. Moreover, the figure is a schematic diagram and does not match the actual dimensional ratio. In addition, “to” in the numerical range represents the following from the above unless otherwise specified.

[Power Module Substrate]
First, the power module substrate 100 according to the present embodiment will be described. FIG. 1 is a cross-sectional view of a power module substrate 100 according to an embodiment of the present invention.
The power module substrate 100 includes a metal substrate 101, an insulating resin layer 102 provided on the metal substrate 101, and a metal layer 103 provided on the insulating resin layer 102.

<Insulating resin layer>
The insulating resin layer 102 is a layer for bonding the metal layer 103 to the metal substrate 101.
The insulating resin layer 102 includes a thermosetting resin (A) and an inorganic filler (B) dispersed in the thermosetting resin (A).
When the pore size distribution measurement by mercury intrusion method was performed on the inorganic filler (B) contained in the ashing residue after the insulating resin layer 102 was ashed by heat treatment at 700 ° C. for 4 hours, the mercury The pore diameter distribution curve of the inorganic filler (B) measured by the press-fitting method when the pore diameter R is the horizontal axis and the logarithmic differential pore volume (dV / dlogR) is the vertical axis is the pore diameter R Having a first maximum value in the range of 0.1 μm to 5.0 μm, preferably 0.2 μm to 1.5 μm, more preferably 0.2 μm to 1.0 μm,
The pore diameter R has a second maximum value in the range of 10 μm to 30 μm, preferably 11 μm to 25 μm, more preferably 12 μm to 20 μm,
The difference between the second pore diameter at the second maximum value and the first pore diameter at the first maximum value is 9.9 to 25 μm, preferably 11 to 23 μm, more preferably 12 to 20 μm. It is as follows.
Here, when there are two or more maximum values in each of the above ranges, the largest value is set as the first maximum value or the second maximum value.

  The pore diameter R of the inorganic filler (B) can be measured, for example, with a mercury intrusion porosimeter. Here, when there are two or more peaks in the pore diameter distribution curve of the inorganic filler (B) in the range of the pore diameter of 0.03 μm or more and 100 μm or less, usually the pore diameter is in the range of 0.03 μm or more and 3.0 μm or less Indicates a void volume in the particle, and a peak having a pore diameter in the range of 3.0 μm to 100 μm indicates the interparticle void volume. Therefore, the first pore diameter indicates the pore diameter in the particles, and the second pore diameter indicates the pore diameter between the particles. Here, that the pore diameter R has a peak in the above range means that the maximum value of the peak is in the above range. Moreover, in this embodiment, a pore diameter shows the diameter of a pore. The first pore diameter and the second pore diameter are mode diameters.

According to this embodiment, when the difference between the second pore diameter and the first pore diameter is equal to or greater than the lower limit, the strength of the inorganic filler (B) (aggregation in the case of secondary agglomerated particles) As a result, the shape and orientation of the inorganic filler (B) (or the orientation of primary particles in the case of secondary agglomerated particles) can be maintained to some extent before and after the production of the power module substrate 100. it can. Thereby, since the heat conductivity of the board | substrate 100 for power modules can be improved, the heat dissipation of the power module obtained can be improved. Especially when the inorganic filler (B) is secondary agglomerated particles, the shape of the secondary agglomerated particles is maintained to some extent, so that the contact between the primary particles is maintained and the random orientation of the primary particles is maintained. The thermal conductivity of the module substrate 100 can be further improved.
Further, if the difference between the second pore diameter and the first pore diameter is not more than the upper limit value, the thermosetting resin (A) sufficiently enters the inside of the inorganic filler (B). There is little generation of voids in the insulating resin layer 102. Thereby, since the insulation of the board | substrate 100 for power modules can be improved, the insulation reliability of the power module obtained can be improved.
Further, when the difference between the second pore diameter and the first pore diameter is not more than the upper limit value, the filling property of the inorganic filler (B) in the insulating resin layer 102 is high, and the inorganic filler (B ) The contact area between each other is large. Thereby, the thermal conductivity of the power module substrate 100 can be improved.
From the above, according to the present embodiment, by controlling the difference between the second pore diameter and the first pore diameter of the inorganic filler (B) in the insulating resin layer 102 within the above range, It is presumed that the power module substrate 100 having excellent conductivity and heat dissipation can be obtained. By applying the power module substrate 100 to the power module, a highly durable power module can be realized.

By using the power module substrate 100 according to the present embodiment, a highly durable power module can be realized. Although this reason is not necessarily clear, the following reasons can be considered.
According to the inventor's study, when a power module using a conventional power module substrate is placed in an environment where the temperature change is severe, such as in an automobile engine room, for a long time, the heat dissipation of the power module substrate It has been clarified that the durability of the power module is lowered due to a decrease in insulation or the like. Therefore, the conventional power module is inferior in durability.
On the other hand, the power module using the power module substrate 100 according to the present embodiment is excellent in durability even in an environment where the temperature change is severe. This is because the insulating resin layer 102 has a structure in which voids are unlikely to occur, and the inorganic filler (B) in the insulating resin layer 102 maintains the shape before the power module substrate 100 is manufactured to some extent. Furthermore, it is considered that the filling property of the inorganic filler (B) in the insulating resin layer 102 is high and the contact area between the inorganic fillers (B) is large.
Since the generation of voids in the insulating resin layer 102 is small, the insulation of the power module substrate 100 can be improved, and the shape and orientation of the inorganic filler (B) are maintained to some extent before and after the power module substrate 100 is manufactured. The thermal conductivity of the power module substrate 100 can be improved by improving the contact area between the inorganic fillers (B).
For the above reasons, the power module substrate 100 according to this embodiment has a well-balanced structure from the viewpoints of thermal conductivity and insulation. Therefore, it is speculated that when the power module substrate 100 is used, a power module having excellent durability can be obtained.

In the power module substrate 100, the cumulative pore volume V1 in the range where the pore diameter R is more than 5.0 μm and 180 μm or less is preferably 0.4 mL / g or more and 1.0 mL / g or less, more preferably 0.5 mL. / G to 0.9 mL / g,
The cumulative pore volume V2 in the range where the pore diameter R is 0.01 μm or more and 180 μm or less is preferably 0.8 mL / g or more and 1.7 mL / g or less, more preferably 0.9 mL / g or more and 1.6 mL / g or less. It is.
Here, the cumulative pore volume V1 indicates the pore volume between the particles, and (V2-V1) indicates the pore volume in the particle.
When the cumulative pore volume V1 and the cumulative pore volume V2 are within the above ranges, the power module substrate 100 that is more excellent in terms of the balance between heat dissipation and insulation can be obtained.

The first pore diameter and the second pore diameter of the inorganic filler (B) in the insulating resin layer 102 are the types and blending ratios of the components constituting the insulating resin layer 102, and the production of the insulating resin layer 102. It can be controlled by adjusting the method appropriately.
In the present embodiment, in particular, the type of the thermosetting resin (A) is appropriately selected, the solvent constituting the resin varnish for forming the insulating resin layer 102 is appropriately selected, and the insulating resin layer 102 is selected. Including a step of applying a compression pressure to the resin, aging the resin varnish to which the thermosetting resin (A) and the inorganic filler (B) are added, heating / pressurizing conditions in the aging, inorganic filling The firing conditions and the like of the material (B) can be cited as factors for controlling the first pore diameter and the second pore diameter.

  The insulating resin layer 102 is provided between the metal substrate 101 and the metal layer 103, and promotes heat conduction from the heat generating element to the heat radiating element in the power module. As a result, failures due to characteristic fluctuations in a semiconductor chip or the like are suppressed, and stability of the power module is improved.

In the power module substrate 100, the glass transition temperature of the insulating resin layer 102 measured by dynamic viscoelasticity measurement under conditions of a temperature rising rate of 5 ° C./min and a frequency of 1 Hz is preferably 175 ° C. or more, more preferably. 190 ° C. or higher. Although the upper limit of the said glass transition temperature is not specifically limited, For example, it is 300 degrees C or less.
Here, the glass transition temperature (Tg) of the insulating resin layer 102 is determined under the conditions of a temperature rising rate of 5 ° C./min and a frequency of 1 Hz by DMA (dynamic viscoelasticity measurement) after removing the metal substrate 101 and the metal layer 103. taking measurement.
When the glass transition temperature is equal to or higher than the above lower limit value, it is possible to further suppress the movement release of the conductive component, and thus it is possible to further suppress the decrease in the insulating property of the insulating resin layer 102 due to the temperature rise. As a result, a power module with even better insulation reliability can be realized.
The glass transition temperature can be controlled by appropriately adjusting the type and blending ratio of each component constituting the insulating resin layer 102 and the method for manufacturing the insulating resin layer 102.

Although the thickness of the insulating resin layer 102 is appropriately set according to the purpose, it is possible to transmit heat from the electronic component to the metal substrate 101 more effectively while improving the mechanical strength and heat resistance. The thickness of the insulating resin layer 102 is preferably 40 μm or more and 400 μm or less, and the thickness of the insulating resin layer 102 is set to 100 μm or more and 300 μm or less from the viewpoint of further improving the balance between heat dissipation and insulation in the power module substrate 100 as a whole. It is more preferable.
By setting the thickness of the insulating resin layer 102 to be equal to or less than the above upper limit value, heat from the electronic component can be easily transmitted to the metal substrate 101.
Further, by setting the thickness of the insulating resin layer 102 to be equal to or greater than the above lower limit, it is possible to sufficiently reduce the generation of thermal stress due to the difference in thermal expansion coefficient between the metal substrate 101 and the insulating resin layer 102 with the insulating resin layer 102. . Furthermore, the insulation of the power module substrate 100 is improved.

  The insulating resin layer 102 includes a thermosetting resin (A) and an inorganic filler (B) dispersed in the thermosetting resin (A). Hereinafter, each material constituting the insulating resin layer 102 will be described.

(Thermosetting resin (A))
Examples of the thermosetting resin (A) include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenol resins, melamine resins, silicone resins, bismaleimide resins, acrylic resins, and the like. As the thermosetting resin (A), one of these may be used alone, or two or more may be used in combination.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4 ′-(1,3-phenylenediiso Pridiene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4 ′-(1,4-phenylenediisopridiene) bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4′-cyclohexyl) Diene bisphenol type epoxy resin), etc .; phenol novolac type epoxy resin, cresol novolac type epoxy resin, tetraphenol group ethane type novolac type epoxy resin, novolak having condensed ring aromatic hydrocarbon structure Type epoxy resins and other novolak type epoxy resins; biphenyl skeleton epoxy resins; xylylene type epoxy resins and biphenyl aralkyl epoxides and other aryl alkylene type epoxy resins; naphthylene ether type epoxy resins, naphthol type epoxy resins, naphthalene Diol type epoxy resin, bifunctional or tetrafunctional epoxy type naphthalene resin, binaphthyl type epoxy resin, naphthalene type epoxy resin such as epoxy resin having naphthalene aralkyl skeleton; anthracene type epoxy resin; phenoxy type epoxy resin; having dicyclopentadiene skeleton Epoxy resin; Norbornene type epoxy resin; Epoxy resin having adamantane skeleton; Fluorene type epoxy resin; Epoxy resin having phenol aralkyl skeleton, etc. And the like.

Among these, the thermosetting resin (A) has an epoxy resin having a dicyclopentadiene skeleton, an epoxy resin having a biphenyl skeleton, an epoxy resin having an adamantane skeleton, an epoxy resin having a phenol aralkyl skeleton, and a biphenyl aralkyl skeleton. Epoxy resins, epoxy resins having a naphthalene aralkyl skeleton, cyanate resins and the like are preferable.
By using such a thermosetting resin (A), it is possible to increase the glass transition temperature of the insulating resin layer 102 and improve the heat dissipation and insulation of the power module substrate 100.

  The content of the thermosetting resin (A) contained in the insulating resin layer 102 is preferably 1% by mass to 30% by mass, and preferably 5% by mass to 28% by mass with respect to 100% by mass of the insulating resin layer (102). The following is more preferable. When the content of the thermosetting resin (A) is not less than the above lower limit value, the handling property is improved and the insulating resin layer 102 can be easily formed. When the content of the thermosetting resin (A) is not more than the above upper limit, the strength and flame retardancy of the insulating resin layer 102 are further improved, or the thermal conductivity of the insulating resin layer 102 is further improved. To do.

(Inorganic filler (B))
Examples of the inorganic filler (B) include silica, alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide and the like. These may be used alone or in combination of two or more.

  The shape of the inorganic filler (B) is not particularly limited, but is usually spherical.

  The inorganic filler (B) is preferably secondary agglomerated particles formed by agglomerating primary particles of scaly boron nitride from the viewpoint of further improving the thermal conductivity of the insulating resin layer 102.

Secondary agglomerated particles formed by agglomerating the primary particles of flaky boron nitride are prepared by, for example, preparing a slurry by mixing a binder with flaky boron nitride and aggregating it using a spray drying method or the like. Can be formed by firing. The firing temperature is, for example, 1200 to 2500 ° C. The firing time is, for example, 2 to 24 hours.
Usually, as the firing temperature is increased or the firing time is increased, the first pore diameter can be increased and the second pore diameter can be decreased. As a result, the difference between the second pore diameter and the first pore diameter can be reduced.
Thus, when using secondary agglomerated particles obtained by sintering primary particles of flaky boron nitride as the inorganic filler (B), the inorganic filler (B) in the thermosetting resin (A) ) Is particularly preferred as the thermosetting resin (A) is an epoxy resin having a dicyclopentadiene skeleton.

The average particle diameter of the inorganic filler (B) is, for example, preferably from 5 μm to 180 μm, and more preferably from 10 μm to 100 μm. Thereby, the more excellent insulating resin layer 102 can be realized by the balance between thermal conductivity and insulating properties.
Here, the average particle diameter of the inorganic filler (B) is the median diameter (D ₅₀ ) when the particle size distribution of the particles is measured on a volume basis by a laser diffraction particle size distribution measuring device.

The average major axis of the primary particles of the scaly boron nitride constituting the secondary agglomerated particles is preferably 0.01 μm or more and 20 μm or less, more preferably 0.1 μm or more and 15 μm or less. Thereby, the more excellent insulating resin layer 102 can be realized by the balance between thermal conductivity and insulating properties.
The average major axis can be measured by an electron micrograph. For example, the measurement is performed according to the following procedure. First, secondary agglomerated particles are cut with a microtome or the like to prepare a sample. Subsequently, several cross-sectional photographs of the secondary aggregated particles magnified several thousand times are taken with a scanning electron microscope. Next, arbitrary secondary agglomerated particles are selected, and the major axis of the primary particles of scaly boron nitride is measured from the photograph. At this time, the major axis is measured for 10 or more primary particles, and the average value thereof is taken as the average major axis.

The content of the inorganic filler (B) contained in the insulating resin layer 102 is preferably 50% by mass or more and 95% by mass or less, and 55% by mass or more and 88% by mass with respect to 100% by mass of the insulating resin layer (102). More preferably, it is at most 60 mass%, particularly preferably at least 60 mass% but at most 80 mass%.
By making content of an inorganic filler (B) more than the said lower limit, the thermal conductivity in the insulating resin layer 102 and the improvement of mechanical strength can be aimed at more effectively. On the other hand, by making content of an inorganic filler (B) below the said upper limit, the film formability and workability | operativity of a thermosetting resin composition (P) are improved, and the film thickness of the insulating resin layer 102 is improved. The uniformity can be further improved.

From the viewpoint of further improving the thermal conductivity of the insulating resin layer 102, the inorganic filler (B) according to the present embodiment is composed of the scaly boron nitride constituting the secondary aggregated particles in addition to the secondary aggregated particles. It is preferable to further include primary particles of flaky boron nitride different from the primary particles. The average major axis of the primary particles of the scaly boron nitride is preferably 0.01 μm or more and 20 μm or less, more preferably 0.1 μm or more and 15 μm or less.
Thereby, the more excellent insulating resin layer 102 can be realized by the balance between thermal conductivity and insulating properties.

(Curing agent (C))
When using an epoxy resin as the thermosetting resin (A), the insulating resin layer 102 preferably further contains a curing agent (C).
As a hardening | curing agent (C), 1 or more types selected from a hardening catalyst (C-1) and a phenol type hardening | curing agent (C-2) can be used.
Examples of the curing catalyst (C-1) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III). Tertiary amines such as triethylamine, tributylamine, 1,4-diazabicyclo [2.2.2] octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole Imidazoles such as 2-phenyl-4-methyl-5-hydroxyimidazole and 2-phenyl-4,5-dihydroxymethylimidazole; triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenyl Phenylphosphine Organic phosphorus compounds such as rephenylborane and 1,2-bis- (diphenylphosphino) ethane; phenolic compounds such as phenol, bisphenol A and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid and p-toluenesulfonic acid; Etc., or mixtures thereof. As the curing catalyst (C-1), one kind including these derivatives can be used alone, or two or more kinds including these derivatives can be used in combination.
Although content of the curing catalyst (C-1) contained in the insulating resin layer 102 is not specifically limited, 0.001 mass% or more and 1 mass% or less are preferable with respect to 100 mass% of the insulating resin layer (102).

Examples of the phenolic curing agent (C-2) include phenol novolak resins, cresol novolak resins, naphthol novolak resins, aminotriazine novolak resins, novolak resins, and novolak phenol resins such as trisphenylmethane type phenol novolak resins; Modified phenol resins such as modified phenol resins and dicyclopentadiene modified phenol resins; aralkyl type resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton, naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; Examples thereof include bisphenol compounds such as bisphenol F; resol type phenol resins and the like, and these may be used alone or in combination of two or more.
Among these, it is preferable that a phenol type hardening | curing agent (C-2) is a novolak type phenol resin or a resol type phenol resin from a viewpoint of the improvement of a glass transition temperature, and the reduction of a linear expansion coefficient.
Although content of a phenol type hardening | curing agent (C-2) is not specifically limited, 1 to 30 mass% is preferable with respect to 100 mass% of insulating resin layers (102), and 5 to 15 mass% is preferable. Is more preferable.

(Coupling agent (D))
Furthermore, the insulating resin layer 102 may contain a coupling agent (D).
The coupling agent (D) can improve the wettability of the interface between the thermosetting resin (A) and the inorganic filler (B).

As the coupling agent (D), any commonly used one can be used. Specifically, an epoxy silane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, a titanate coupling agent, and a silicone oil type. It is preferable to use one or more coupling agents selected from coupling agents.
The addition amount of the coupling agent (D) depends on the specific surface area of the inorganic filler (B) and is not particularly limited, but is 0.1 parts by mass or more and 10 parts by mass with respect to 100 parts by mass of the inorganic filler (B). The following is preferable, and 0.5 to 7 parts by mass is particularly preferable.

(Phenoxy resin (E))
The insulating resin layer 102 may further contain a phenoxy resin (E). By including the phenoxy resin (E), the bending resistance of the power module substrate 100 can be further improved.
Further, by including the phenoxy resin (E), the elastic modulus of the insulating resin layer 102 can be reduced, and the stress relaxation force of the power module substrate 100 can be improved.
Moreover, when phenoxy resin (E) is included, fluidity | liquidity will reduce by a viscosity raise and it can suppress that a void etc. generate | occur | produce. In addition, adhesion between the insulating resin layer 102 and the metal substrate 101 or the metal layer 103 can be improved. These synergistic effects can further increase the insulation reliability of the power module.

  Examples of the phenoxy resin (E) include a phenoxy resin having a bisphenol skeleton, a phenoxy resin having a naphthalene skeleton, a phenoxy resin having an anthracene skeleton, and a phenoxy resin having a biphenyl skeleton. A phenoxy resin having a structure having a plurality of these skeletons can also be used.

  Content of a phenoxy resin (E) is 3 to 10 mass% with respect to 100 mass% of insulating resin layers (102), for example.

(Other ingredients)
The insulating resin layer 102 can contain an antioxidant, a leveling agent and the like as long as the effects of the present invention are not impaired.

The insulating resin layer 102 can be manufactured as follows, for example.
First, each above-mentioned component is added to a solvent, and a varnish-like thermosetting resin composition (P) is obtained. In this embodiment, for example, a thermosetting resin (A) or the like is added to a solvent to prepare a resin varnish, and then an inorganic filler (B) is put into the resin varnish and a three-roll or the like is used. A thermosetting resin composition (P) can be obtained by kneading. Thereby, an inorganic filler (B) can be disperse | distributed more uniformly in a thermosetting resin (A).
Although it does not specifically limit as said solvent, Methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, cyclohexanone, etc. are mentioned.

Next, aging is performed on the thermosetting resin composition (P). Thereby, about the obtained power module substrate 100, the said 1st pore diameter of the inorganic filler (B) in the insulating resin layer 102 can be enlarged, and the said 2nd pore diameter can be made small. As a result, the difference between the second pore diameter and the first pore diameter can be reduced.
This is because the affinity of the thermosetting resin (A) to the inorganic filler (B) is increased by aging, so that the thermosetting resin (A) sufficiently penetrates into the inorganic filler (B), and as a result Since the voids in the particles of the inorganic filler (B) can be retained before and after the power module substrate 100 is manufactured, it is estimated that the first pore diameter can be increased.
Moreover, the affinity with respect to the inorganic filler (B) of a thermosetting resin (A) rises by aging, and the dispersibility of the inorganic filler (B) in a thermosetting resin (A) improves. Thereby, since the filling property of the inorganic filler (B) is improved, it is presumed that the second pore diameter can be reduced.
Aging can be performed, for example, under conditions of 30 to 80 ° C., 8 to 25 hours, preferably 12 to 24 hours, and 0.1 to 1.0 MPa. Usually, as the aging temperature is increased or the aging time is increased, the first pore diameter can be increased and the second pore diameter can be decreased.

  Next, the thermosetting resin composition (P) is formed into a sheet shape to form the insulating resin layer 102. In the present embodiment, for example, the insulating resin layer 102 can be obtained by applying a varnish-like thermosetting resin composition (P) on a substrate and then heat-treating it and drying it. As a base material, the metal foil which comprises the metal substrate 101, the metal layer 103, the peelable carrier material etc. is mentioned, for example. Moreover, the heat processing for drying thermosetting resin composition (P) is performed on the conditions of 80-150 degreeC and 5 minutes-1 hour, for example.

Next, it is preferable to remove bubbles in the insulating resin layer 102 by compressing the insulating resin layer 102 through two rolls.
In this embodiment, the inorganic filler (B) is deformed due to the compression pressure and includes the inorganic filling in the insulating resin layer 102 by including the step of removing bubbles by applying the compression pressure by the roll in this way. The difference between the second pore diameter of the material (B) and the first pore diameter can be reduced.

<Metal substrate>
The metal substrate 101 has a role of radiating heat accumulated in the power module substrate 100. The metal substrate 101 is not particularly limited as long as it is a heat-dissipating metal substrate, and is, for example, a copper substrate, a copper alloy substrate, an aluminum substrate, or an aluminum alloy substrate, preferably a copper substrate or an aluminum substrate, and more preferably a copper substrate. By using a copper substrate or an aluminum substrate, the heat dissipation of the metal substrate 101 can be improved.

The thickness of the metal substrate 101 can be appropriately set as long as the object of the present invention is not impaired.
The upper limit value of the thickness of the metal substrate 101 is, for example, 20.0 mm or less, preferably 5.0 mm or less. By using the metal substrate 101 having a thickness equal to or less than this value, the power module substrate 100 as a whole can be thinned. Moreover, the workability in the outer shape processing, the cutting processing, etc. of the power module substrate 100 can be improved.
Moreover, the lower limit of the thickness of the metal substrate 101 is, for example, 0.1 mm or more, preferably 1.0 mm or more, and more preferably 2.0 mm or more. By using the metal substrate 101 having a value equal to or higher than this value, the heat dissipation property of the power module substrate 100 as a whole can be improved.

<Metal layer>
The metal layer 103 is provided on the insulating resin layer 102 and is subjected to circuit processing.
Examples of the metal constituting the metal layer 103 include one or more selected from copper, copper alloy, aluminum, aluminum alloy, nickel, iron, tin, and the like. Among these, as a metal which comprises the metal layer 103, Preferably it is copper or aluminum, Most preferably, it is copper. By using copper or aluminum, the circuit workability of the metal layer 103 can be improved.

The lower limit of the thickness of the metal layer 103 is, for example, 0.01 mm or more, preferably 0.10 mm or more, and more preferably 0.25 mm or more. If it is more than such a numerical value, even if it is a use requiring a high current, the heat generation of the circuit pattern can be suppressed.
Moreover, the upper limit of the thickness of the metal layer 103 is 2.0 mm or less, for example, Preferably it is 1.5 mm or less, More preferably, it is 1.0 mm or less. If it is below such a numerical value, circuit workability can be improved and thickness reduction of the whole board | substrate can be achieved.

  The metal layer 103 may be a metal foil that can be obtained in a plate shape, or a metal foil that can be obtained in a roll shape.

<Manufacturing method of power module substrate>
The power module substrate 100 as described above can be manufactured, for example, as follows.

First, after applying a varnish-like thermosetting resin composition (P) on a carrier material, this is heat-processed and dried to form a resin layer, thereby obtaining a carrier material with a resin layer.
The carrier material is, for example, a resin film such as polyethylene terephthalate (PET); a metal foil such as a copper foil. The thickness of the carrier material is, for example, 10 to 500 μm.

  Next, the carrier material with a resin layer is laminated on the metal substrate 101 such that the surface on the resin layer side of the carrier material with the resin layer is in contact with the surface of the metal substrate 101. Thereafter, the resin layer is bonded in a B-stage state by pressing and heating using a press or the like.

Next, the carrier material is removed from the resin layer in the B-stage state, and the metal layer 103 is formed on the surface of the exposed resin layer to obtain a laminate.
In addition, when using metal foil as a carrier material, this carrier material can be used as the metal layer 103 as it is. That is, in this case, after obtaining the resin layer-attached metal layer 103, the resin layer-attached metal layer 103 is laminated on the metal substrate 101, whereby the target laminate is obtained.

  Next, by pressing and heating the laminate using a press or the like, the resin layer is heated and cured to form the insulating resin layer 102, and the power module substrate 100 is obtained.

In the above description, the manufacturing method for laminating the carrier material with the resin layer on the metal substrate 101 is described. However, in this embodiment, the metal layer 103 is laminated with the carrier material with the resin layer and the carrier material is removed. It can also be bonded to the substrate 101.
When a metal foil is used as the carrier material and the metal foil is used as it is as the metal layer 103, the metal layer 103 may be a metal foil extruded from a roll, preferably a copper foil or an aluminum foil extruded from a roll. it can.
By doing in this way, improvement in production efficiency can be aimed at.

[Power Module Circuit Board]
The obtained power module substrate 100 can be processed by etching the metal layer 103 into a predetermined pattern to obtain a power module circuit substrate.
Further, a solder resist 10 (see FIG. 2) may be formed on the outermost layer, and the connection electrode portion may be exposed so that electronic parts can be mounted by exposure and development.

[Power module]
Next, the power module 11 according to the present embodiment will be described. FIG. 2 is a cross-sectional view of the power module 11 according to an embodiment of the present invention.
The power module 11 can be obtained by providing an electronic component on the power module circuit board of the present embodiment.
In this embodiment, the power module 11 is a semiconductor device, for example, a power semiconductor device, LED lighting, or an inverter device.
Here, the inverter device electrically generates AC power from DC power (has a reverse conversion function). A power semiconductor device is characterized by higher withstand voltage, higher current, higher speed and higher frequency than ordinary semiconductor elements, and is generally called a power device. , A power MOSFET, an insulated gate bipolar transistor (IGBT), a thyristor, a gate turn-off thyristor (GTO), and a triac mounted electronic component.
Electronic components are semiconductor elements such as insulated gate bipolar transistors, diodes, and IC chips, and various heating elements such as resistors and capacitors. The power module substrate 100 functions as a heat spreader.

Here, an example of the power module 11 will be described with reference to FIG.
In the power module 11 of the present embodiment, the IC chip 2 is mounted on the metal layer 103a of the power module circuit board via the adhesive layer 3. The IC chip 2 is electrically connected to the metal layer 103b through the bonding wire 7.
Further, the IC chip 2, the bonding wire 7, and the metal layers 103 a and 103 b are sealed with a sealing material 6.

  In the power module 11, the chip capacitor 8 and the chip resistor 9 are mounted on the metal layer 103. Conventionally known chip capacitors 8 and chip resistors 9 can be used.

  Further, the metal substrate 101 of the power module 11 is connected to the heat radiating fins 5 through the heat conductive grease 4. That is, the heat generated by the IC chip 2 is conducted to the heat radiating fins 5 through the adhesive layer 3, the metal layer 103 a, the insulating resin layer 102, the metal substrate 101, and the heat conduction grease 4, thereby removing heat. it can.

  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these. In addition, in an Example, unless otherwise specified, a part represents a mass part. Moreover, each thickness is represented by the average film thickness.

(Preparation of secondary agglomerated particles composed of primary particles of scaly boron nitride)
A mixture obtained by mixing melamine borate (boric acid: melamine = 2: 1 (molar ratio)) and flaky boron nitride powder (average major axis: 15 μm) (melamine borate: flaky boron nitride powder = 10: 1 (mass ratio)) was added to a 0.2 mass% aqueous solution of ammonium polyacrylate, and mixed for 2 hours to prepare a slurry for spraying (aqueous solution of ammonium polyacrylate: mixture = 100: 30 (mass ratio)). ). Subsequently, this slurry was supplied to a spray granulator and sprayed under the conditions of an atomizer rotation speed of 15000 rpm, a temperature of 200 ° C., and a slurry supply amount of 5 ml / min, thereby producing composite particles. Next, the obtained composite particles were fired under a nitrogen atmosphere at 2000 ° C. for 10 hours to obtain aggregated boron nitride having an average particle size of 80 μm.
Here, the average particle diameter of the aggregated boron nitride was determined by measuring the particle size distribution of the particles on a volume basis with a laser diffraction particle size distribution measuring apparatus (LA-500, manufactured by HORIBA), and the median diameter (D ₅₀ ). .

(Production of power module substrate)
About Examples 1-7 and Comparative Examples 1-2, the board | substrate for power modules was produced as follows.
First, according to the composition shown in Table 1, a thermosetting resin and a curing agent were added to methyl ethyl ketone as a solvent, and this was stirred to obtain a solution of a thermosetting resin composition. Next, an inorganic filler was put into this solution and premixed, and then kneaded with three rolls to obtain a varnish-like thermosetting resin composition in which the inorganic filler was uniformly dispersed. Next, aging was performed on the obtained thermosetting resin composition under the conditions of 60 ° C., 0.6 MPa, and 15 hours. Next, the thermosetting resin composition was applied onto a copper foil (thickness 0.07 mm, manufactured by Furukawa Electric Co., Ltd., GTS-MP foil) using a doctor blade method, and then applied at 100 ° C. for 30 minutes. The copper foil with a resin layer was produced by drying by heat treatment.
Subsequently, air bubbles in the resin layer were removed by compressing the copper foil with the resin layer through two rolls.
Next, the obtained copper foil with a resin layer and a 3.0 mm thick copper plate (tough pitch copper) are bonded together, and are pressed with a vacuum press at a press pressure of 100 kg / cm ² at 180 ° C. for 40 minutes for a power module. A substrate (the thickness of the insulating resin layer 102: 200 μm) was obtained.

  For Example 8, a power module substrate was produced in the same manner as in Example 1 except that the thermosetting resin composition was aged under the conditions of 80 ° C., 0.6 MPa, and 20 hours.

  For Example 9, a power module substrate was produced in the same manner as in Example 1 except that the thermosetting resin composition was aged under the conditions of 40 ° C., 0.6 MPa, and 10 hours.

  For Example 10, a power module substrate was produced in the same manner as in Example 1 except that the thermosetting resin composition was aged under the conditions of 50 ° C., 0.6 MPa, and 15 hours.

  For Example 11, the thermosetting resin composition was aged under the conditions of 30 ° C., 0.6 MPa, and 15 hours, and the epoxy resin 7 was used instead of the epoxy resin 1. In the same manner as in Example 1, a power module substrate was produced.

  For Example 12, the thermosetting resin composition was aged under the conditions of 30 ° C., 0.6 MPa, and 20 hours, and the epoxy resin 8 was used instead of the epoxy resin 1. In the same manner as in Example 1, a power module substrate was produced.

For Comparative Example 3, a power module substrate was produced in the same manner as in Example 1 except that aging was not performed on the thermosetting resin composition.
The details of each component in Table 1 are as follows.

(Thermosetting resin (A))
Epoxy resin 1: Epoxy resin having a dicyclopentadiene skeleton (XD-1000, manufactured by Nippon Kayaku Co., Ltd.)
Epoxy resin 2: Epoxy resin having a biphenyl skeleton (YX-4000, manufactured by Mitsubishi Chemical Corporation)
Epoxy resin 3: Epoxy resin having an adamantane skeleton (E201, manufactured by Idemitsu Kosan Co., Ltd.)
Epoxy resin 4: Epoxy resin having a phenol aralkyl skeleton (NC-2000-L, manufactured by Nippon Kayaku Co., Ltd.)
Epoxy resin 5: epoxy resin having a biphenylaralkyl skeleton (NC-3000, manufactured by Nippon Kayaku Co., Ltd.)
Epoxy resin 6: epoxy resin having naphthalene aralkyl skeleton (NC-7000, manufactured by Nippon Kayaku Co., Ltd.)
Epoxy resin 7: Bisphenol F type epoxy resin (830S, manufactured by Dainippon Ink & Chemicals, Inc.)
Epoxy resin 8: bisphenol A type epoxy resin (828, manufactured by Mitsubishi Chemical Corporation)
Cyanate resin 1: phenol novolac type cyanate resin (PT-30, manufactured by Lonza Japan)

(Curing catalyst C-1)
Curing catalyst 1: 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW, manufactured by Shikoku Chemicals)
Curing catalyst 2: Triphenylphosphine (Hokuko Chemical Co., Ltd.)
(Curing agent C-2)
Phenol curing agent 1: Trisphenylmethane type phenol novolac resin (MEH-7500, manufactured by Meiwa Kasei Co., Ltd.)

(Inorganic filler (B))
Filler 1: Aggregated boron nitride produced by producing secondary agglomerated particles composed of the primary particles of the flaky boron nitride Filler 2: In the above production example, the firing temperature is 1500 ° C. and the firing time is 8 hours. Aggregated boron nitride with an average particle size of 80 μm, produced by the same method as in the above example of secondary aggregated particles, except for the change. Filler 3: In the above example of preparation, the firing temperature is 2100 ° C. and the firing time is 15 hours. Aggregated boron nitride having an average particle size of 80 μm, produced by the same method as in the above example of producing secondary agglomerated particles except that

(Measurement of pore size distribution curve)
First, the metal plate and the metal layer were peeled from the obtained power module substrate to obtain an insulating resin layer. Next, the insulating resin layer was ashed by heat treatment at 700 ° C. for 4 hours under atmospheric pressure. Subsequently, the pore diameter distribution curve of the inorganic filler (B) contained in the obtained ashing residue was measured with a mercury intrusion type porosimeter (Micromeritex pore distribution measuring device Autopore 9520 manufactured by Shimadzu Corporation).
Specifically, it is as follows. A measurement sample (inorganic filler (B)) was obtained by heating and drying the incineration residue at 100 ° C. for 1 hour under atmospheric pressure to evaporate water. Next, about 0.2 g of the obtained measurement sample was placed in a standard 5 cc powder cell (stem volume: 0.4 cc), and measured under conditions of an initial pressure of 7 kPa (about 1 psia, corresponding to a pore diameter of about 180 μm). Mercury parameters were set to a device default mercury contact angle of 130 degrees and a mercury surface tension of 485 dynes / cm.

From the obtained pore diameter distribution curve, the first pore diameter and the second pore diameter were determined. A pore diameter at a first maximum value of a peak having a pore diameter R in the range of 0.1 μm or more and 5.0 μm or less is defined as a first pore diameter, and the pore diameter R is in a range of 10 μm or more and 30 μm or less. The pore diameter at the maximum value was taken as the second pore diameter. The difference between the second pore diameter and the first pore diameter was calculated from the obtained first pore diameter and second pore diameter.
Further, from the obtained pore diameter distribution curve, the cumulative pore volume V1 in the range where the pore diameter R exceeds 5.0 μm and 180 μm or less and the cumulative pore volume V2 in the range where the pore diameter R is 0.01 μm or more and 180 μm or less are obtained. I asked for each.

(Measurement of Tg (glass transition temperature))
The glass transition temperature of the insulating resin layer was measured as follows. First, the metal plate and the metal layer were peeled from the obtained power module substrate to obtain an insulating resin layer.
Next, the glass transition temperature (Tg) of the obtained insulating resin layer was measured by DMA (dynamic viscoelasticity measurement) under conditions of a temperature rising rate of 5 ° C./min and a frequency of 1 Hz.

(Insulation reliability evaluation)
About each of Examples 1-12 and Comparative Examples 1-3, the insulation reliability of the power module was evaluated as follows. First, the power module shown in FIG. 2 was produced using the power module substrate. An IGBT chip was used as the IC chip. A bonding wire made of Cu was used. Next, using this power module, the insulation resistance in continuous humidity was evaluated under the conditions of a temperature of 85 ° C., a humidity of 85%, and an AC applied voltage of 1.5 kV. A resistance value of 10 ⁶ Ω or less was regarded as a failure. The evaluation criteria are as follows.
◎: No failure for 300 hours or more ◎: Failure for 200 hours to less than 300 hours ○: Failure for 150 hours to less than 200 hours △: Failure for 100 hours to less than 150 hours ×: Failure for less than 100 hours

(Heat cycle test)
About each of Examples 1-12 and Comparative Examples 1-3, the heat cycle property of the power module was evaluated as follows. First, the power module shown in FIG. 2 was produced using the power module substrate. An IGBT chip was used as the IC chip. A bonding wire made of Cu was used. Next, a heat cycle test was performed using the three power modules. The heat cycle test was performed 3000 times with one cycle of −40 ° C. for 5 minutes to + 125 ° C. for 5 minutes. The evaluation criteria are as follows.
Next, using an ultrasonic imaging device (manufactured by Hitachi Construction Machinery Finetech Co., Ltd., FS300), the IC chip and the conductive layer were observed for abnormalities.
A: No abnormality in both IC chip and conductive layer.
○: Cracks are seen in a part of the IC chip and / or conductive layer, but there is no practical problem.
(Triangle | delta): A crack is seen in a part of IC chip and / or a conductive layer, and there is a problem in practical use.
X: Both IC chip and conductive layer are cracked and cannot be used.

The power modules of Examples 1 to 12 using the power module substrate in which the difference between the second pore diameter and the first pore diameter is within the scope of the present invention were excellent in insulation reliability and heat cycle performance. .
On the other hand, the power modules of Comparative Examples 1 to 3 using the power module substrate whose difference between the second pore diameter and the first pore diameter is outside the scope of the present invention are inferior in insulation reliability and heat cycle performance. It was.
Therefore, it was found that a highly durable power module can be obtained by using the power module substrate according to the present invention.

2 IC chip 3 Adhesive layer 4 Thermal conductive grease 5 Radiation fin 6 Sealing material 7 Bonding wire 8 Chip capacitor 9 Chip resistor 10 Solder resist 11 Power module 100 Power module substrate 101 Metal substrate 102 Insulating resin layer 103 Metal layer 103a Metal layer 103b metal layer

Claims (14)

A power module substrate comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer,
The insulating resin layer includes a thermosetting resin and an inorganic filler dispersed in the thermosetting resin,
For the inorganic filler contained in the ashing residue after ashing by heat treatment of the insulating resin layer at 700 ° C. for 4 hours, when pore diameter distribution measurement was performed by mercury porosimetry,
The pore size distribution curve of the inorganic filler measured by the mercury intrusion method when the pore diameter R is the horizontal axis and the logarithmic differential pore volume (dV / dlogR) is the vertical axis,
The pore diameter R has a first maximum value in a range of 0.1 μm or more and 5.0 μm or less,
The pore diameter R has a second maximum value in the range of 10 μm or more and 30 μm or less,
A power module substrate, wherein a difference between a second pore diameter at the second maximum value and a first pore diameter at the first maximum value is 9.9 μm or more and 25 μm or less. The power module substrate according to claim 1,
The cumulative pore volume V1 in the range where the pore diameter R is more than 5.0 μm and 180 μm or less is 0.4 mL / g or more and 1.0 mL / g or less,
A power module substrate having a cumulative pore volume V2 of 0.8 mL / g or more and 1.7 mL / g or less in a range where the pore diameter R is 0.01 μm or more and 180 μm or less. The power module substrate according to claim 1 or 2,
The power module substrate, wherein the inorganic filler is secondary agglomerated particles composed of primary particles of scaly boron nitride. In the power module substrate according to claim 3,
The power module substrate, wherein an average major axis of the primary particles constituting the secondary agglomerated particles is 0.01 μm or more and 20 μm or less. In the board | substrate for power modules as described in any one of Claims 1 thru | or 4,
A power module substrate, wherein the inorganic filler has an average particle size of 5 μm or more and 180 μm or less. In the board | substrate for power modules as described in any one of Claims 1 thru | or 5,
The power module substrate, wherein the content of the inorganic filler is 50% by mass to 95% by mass with respect to 100% by mass of the insulating resin layer. In the board | substrate for power modules as described in any one of Claims 1 thru | or 6,
The thermosetting resin has an epoxy resin having a dicyclopentadiene skeleton, an epoxy resin having a biphenyl skeleton, an epoxy resin having an adamantane skeleton, an epoxy resin having a phenol aralkyl skeleton, an epoxy resin having a biphenyl aralkyl skeleton, and a naphthalene aralkyl skeleton. A power module substrate that is one or more selected from an epoxy resin and a cyanate resin. In the board | substrate for power modules as described in any one of Claims 1 thru | or 7,
A power module substrate having a glass transition temperature of 175 ° C. or higher measured by dynamic viscoelasticity measurement under conditions of a temperature rising rate of 5 ° C./min and a frequency of 1 Hz. In the power module substrate according to any one of claims 1 to 8,
A power module substrate, wherein the metal layer has a thickness of 0.25 mm to 1.0 mm. The power module substrate according to any one of claims 1 to 9,
The power module substrate in which the metal constituting the metal layer contains copper. In the power module substrate according to any one of claims 1 to 10,
A power module substrate, wherein the metal substrate has a thickness of 2.0 mm to 5.0 mm. In the board | substrate for power modules as described in any one of Claims 1 thru | or 11,
A power module substrate, wherein the metal substrate is a copper substrate.   A power module circuit board obtained by processing a circuit on the metal layer of the power module board according to claim 1. A circuit board for a power module according to claim 13,
An electronic component provided on the circuit board for the power module;
Power module comprising.

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