WO2022209325A1

WO2022209325A1 - Composite, method for manufacturing same, resin-filled plate, laminate, and method for manufacturing same

Info

Publication number: WO2022209325A1
Application number: PCT/JP2022/005063
Authority: WO
Inventors: 仁孝南方; 政秀金子; 亮吉松; 真也坂口
Original assignee: デンカ株式会社
Priority date: 2021-03-31
Filing date: 2022-02-09
Publication date: 2022-10-06
Also published as: JP7217391B1; JPWO2022209325A1

Abstract

One aspect of the present disclosure provides a composite having: a resin-filled plate that includes a porous nitride sintered plate, and a first resin with which pores in the nitride sintered plate are filled; and a semi-cured resin layer that includes a second resin and that is provided on at least part of the principal surface of the resin-filled plate, the curing rate of the first resin being 70% or greater, and the semi-cured resin layer containing a thermosetting resin.

Description

Composite and its manufacturing method, resin-filled plate, and laminate and its manufacturing method

The present disclosure relates to a composite and its manufacturing method, a resin-filled plate, and a laminate and its manufacturing method.

Components such as power devices, transistors, thyristors, and CPUs are required to efficiently dissipate the heat generated during use. In response to such demands, it has been conventional practice to increase the thermal conductivity of the insulating layer of the printed wiring board on which electronic components are mounted, or to place the electronic components or the printed wiring board through a thermal interface material having electrical insulation. It has been practiced to attach it to a heat sink. For such an insulating layer and thermal interface material, a composite composed of a resin and a ceramic such as boron nitride is used as a heat dissipation member.

As such a composite, a composite obtained by impregnating a porous ceramic sintered body (for example, a boron nitride sintered body) with a resin has been studied (see, for example, Patent Document 1). In addition, in a laminate having a circuit board and a resin-impregnated boron nitride sintered body, the primary particles constituting the boron nitride sintered body are brought into direct contact with the circuit board to reduce the thermal resistance of the laminate and improve heat dissipation. is also being studied (see Patent Document 2, for example).

WO2014/196496 JP 2016-103611 A

Composites that are used together with circuit boards used under high voltage are required to have better insulation.

An object of the present disclosure is to provide a composite that can exhibit excellent insulation after bonding to an adherend, and a method for producing the same. Another object of the present disclosure is to provide a resin-filled plate suitable for preparing the composites described above. Another object of the present disclosure is to provide a laminate having excellent insulating properties and a method for manufacturing the same.

In the composite as described above, the resin part is maintained in a semi-cured state, and the adhesion is improved by further curing the resin when connecting to an adherend such as a metal sheet. The inventors of the present invention have found that the resin is in a semi-cured state and becomes fluid due to heating at the time of connection, so that part of the resin flows out from the side of the composite, reducing the amount of resin in the composite, voids, etc. It has been found that the insulation may not be exhibited to the extent expected. The present disclosure is made based on this finding.

One aspect of the present disclosure is a resin-filled plate including a porous nitride sintered plate and a first resin filled in the pores of the nitride sintered plate, and on a main surface of the resin-filled plate and a semi-cured resin layer containing a second resin provided on at least a part thereof, wherein the curing rate of the first resin is 70% or more, and the semi-cured resin layer contains a thermosetting resin. , providing a complex.

In the composite, the first resin filled in the resin-filled plate has a relatively high cure rate, so that the outflow of the resin when connecting to the adherend can be suppressed. Since the resin filled in the resin-filled plate has a high curing rate, the resin itself does not have sufficient adhesiveness. However, the above composite further has a semi-cured resin layer on at least part of the main surface of the resin-filled plate. As a result, the composite can exhibit excellent adhesion to adherends and excellent insulating properties.

The difference between the curing rate of the first resin and the curing rate of the second resin may be 30% or more. The hardening rate of the first resin is 30% or more advanced than the hardening rate of the second resin, so that the outflow of the resin when connecting to the adherend is further reduced and the adhesiveness is sufficiently secured. can do.

The curing rate of the first resin may be 90% or less. When the curing rate of the first resin is 90% or less, it is possible to ensure appropriate flexibility, and further suppress damage to the composite during distribution, pressure bonding to the adherend, etc. can.

The thickness of the semi-cured resin layer may be 0.5 to 25.0% of the thickness of the nitride sintered plate. By setting the thickness of the semi-cured resin layer within the above range, it is possible to prepare a laminate that achieves a higher level of both adhesiveness and heat dissipation.

The main surface of the resin-filled plate may have a surface roughness Rz of 3 to 25 μm. When the surface roughness Rz of the main surface of the resin-filled plate is within the above range, the adhesive force between the resin-filled plate and the semi-cured resin layer can be further improved, and the adhesion between the resin-filled plate and the semi-cured resin layer can be improved. It is possible to suppress the formation of voids and the like at the interface, and further suppress the decrease in heat dissipation inside the composite. Due to such action, the resin-filled plate can be suitably used to prepare a laminate having both adhesiveness and heat dissipation at a higher level.

The median pore diameter of the nitride sintered plate may be 0.3 to 6.0 μm. When the median pore diameter of the nitride sintered plate is within the above range, it is possible to improve the filling property of the first resin and improve the thermal conductivity of the nitride sintered plate. In addition, by ensuring the filling property, the wettability with the second resin can be improved, and the adhesiveness between the resin-filled plate and the semi-cured resin layer can be further improved.

One aspect of the present disclosure provides a laminate comprising the composite described above and a metal sheet provided on the composite.

Since the laminate includes the composite described above, it can exhibit excellent insulating properties.

One aspect of the present disclosure is a resin-filled plate including a porous nitride sintered plate and a resin filled in the pores of the nitride sintered plate, wherein the curing rate of the resin is 70% or more. I will provide a.

The above resin-filled plate has a high cure rate of the filled resin, and even when heated, the resin is suppressed from flowing out of the nitride sintered plate. Therefore, the resin-filled plate can be suitably used for producing the above composite.

In the resin-filled plate, the curing rate of the resin may be 90% or less. When the curing rate of the resin is 90% or less, it is possible to ensure appropriate flexibility, and it is possible to further suppress breakage during distribution.

In the above resin-filled plate, the main surface may have a surface roughness Rz of 3 to 25 μm. When the surface roughness Rz of the main surface of the resin-filled plate is within the above range, the semi-cured resin layer can be more easily formed on the resin-filled plate.

One aspect of the present disclosure includes an impregnation step of impregnating a porous nitride sintered plate with a first resin composition to obtain a resin-impregnated body, and heating the resin-impregnated body to fill the pores with the resin composition. a curing step of curing or semi-curing an object to obtain a resin-filled board containing a first resin; a coating step of providing a semi-cured resin layer containing a second resin on at least a portion of the main surface of the resin-filled board; and the curing rate of the first resin is 70% or more.

In the above manufacturing method, in the curing step, curing proceeds so that the curing rate of the first resin reaches a predetermined value or more, the first resin is sufficiently fixed in the resin-filled plate, and the first resin flows out by reheating. By providing a semi-cured resin layer in a semi-cured state containing the second resin in the coating step, the adhesiveness of the composite to the adherend can be imparted. Such a manufacturing method can provide a composite that can exhibit excellent insulating properties after being adhered to an adherend.

The coating step may be a step of providing the semi-cured resin layer on at least a portion of the main surface of the resin-filled plate by applying a second resin composition to the resin-filled plate and heating the second resin composition. Since the coating step is a step as described above, the hardening rate of the second resin can be freely adjusted, and the resin hardening rate can be set to suit the application of the composite.

The coating step may be a step of providing the semi-cured resin layer on at least part of the main surface of the resin-filled plate by bonding a semi-cured material of the second resin composition to the resin-filled plate. . By using the coating step as described above, the resin thickness of the second resin can be made uniform, and the resulting composite can exhibit more stable adhesive strength with the adherend.

One aspect of the present disclosure provides a method for manufacturing a laminate, which includes a lamination step of laminating the composite obtained by the above-described manufacturing method and a metal sheet, and heating and pressurizing them.

The manufacturing method of the laminate can provide a laminate capable of exhibiting excellent insulation properties because the above-described composite is used.

According to the present disclosure, it is possible to provide a composite that can exhibit excellent insulation after bonding to an adherend, and a method for producing the same. The present disclosure can also provide resin-filled plates suitable for preparing the composites described above. According to the present disclosure, it is also possible to provide a laminate having excellent insulating properties and a method for manufacturing the same.

FIG. 1 is a perspective view showing an example of a composite. FIG. 2 is a schematic diagram showing a cross section along line II-II in FIG. FIG. 3 is a cross-sectional view showing an example of a laminate.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same functions, and duplicate descriptions are omitted depending on the case. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratio of each element is not limited to the illustrated ratio.

The materials exemplified in this specification can be used singly or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the multiple substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. .

One embodiment of the composite includes a resin-filled plate containing a porous nitride sintered plate, a first resin filled in the pores of the nitride sintered plate, and a main surface of the resin-filled plate and a semi-cured resin layer containing a second resin provided on at least a part of the. The curing rate of the first resin is 70% or more. Further, the semi-cured resin layer contains a thermosetting resin. The shape of the composite is not particularly limited, and may be, for example, a sheet shape.

FIG. 1 is a perspective view showing an example of a complex. FIG. 2 is a schematic diagram showing a cross section along line II-II in FIG. The composite 10 has a resin-filled plate 12 and semi-cured resin layers 14 on both main surfaces of a pair of main surfaces 12 a of the resin-filled plate 12 . In FIG. 1, the composite 10 is shown as an example in which the semi-cured resin layer 14 is provided so as to cover the entire main surface 12a of both resin-filled plates 12, but the adhesiveness to the adherend is ensured. It is sufficient if the semi-cured resin layer 14 is provided on at least a part of the resin-filled plate 12 . However, when the semi-cured resin layer 14 is partially provided, it is desirable to provide it in the center so as not to entrap gas or the like when it comes into contact with the adherend, reducing the effect of the semi-cured resin layer 14 melting and spreading. In view of this, the semi-cured resin layer 14 may be provided so as to be smaller than the area of the main surface 12 a of the resin-filled plate 12 . In addition, although the composite 10 is shown as an example in which the semi-cured resin layer 14 is provided on both main surfaces 12a of the resin-filled plate 12, depending on the adhesiveness of the resin-filled plate 12, only one main surface may be provided. may Moreover, the composite 10 may further have a semi-cured resin layer on the side surface of the resin-filled plate 12 . However, in the composite according to the present disclosure, the outflow of the first resin from the resin-filled plate 12 is sufficiently suppressed, and the semi-cured resin layer does not have to be provided on the side surface of the resin-filled plate 12 .

The thickness of the composite 10 may be, for example, less than 10.0 mm, less than 5.0 mm, or less than 2.0 mm. The lower limit of the thickness of the composite 10 may be, for example, 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, or 0.5 mm or more. This allows the composite 10 to be sufficiently miniaturized. Such a composite 10 is suitably used, for example, as a component of a semiconductor device. The thickness of composite 10 may be adjusted within the ranges described above, and may be from 0.1 mm to less than 10.0 mm, or from 0.2 mm to less than 2.0 mm.

The thickness of the composite 10 is measured along the direction perpendicular to the main surface. When the thickness of the composite 10 is not constant, the thickness is measured at 10 arbitrary points, and the arithmetic mean value thereof should be within the above range.

The size of the main surface 12a of the resin-filled plate 12 is not particularly limited, and may be, for example, 50 mm ² or more, 200 mm ² or more, 500 mm ² or more, 800 mm ² or more, or 1000 mm ² or more. The sizes of the main surfaces 12a of the resin-filled plates 12 are generally the same, but they do not need to be exactly the same, and may be different from each other.

The upper limit of the surface roughness Rz of the main surface 12a of the resin-filled plate 12 may be, for example, 25 μm or less, 23 μm or less, or 20 μm or less. When the upper limit of the surface roughness Rz is within the above range, formation of voids at the interface between the resin-filled plate and the semi-cured resin layer can be suppressed, thereby further suppressing deterioration of heat dissipation inside the composite. The lower limit of the surface roughness Rz of the main surface 12a of the resin-filled plate 12 may be, for example, 3 μm or more, 5 μm or more, or 7 μm or more. When the lower limit of the surface roughness Rz is within the above range, the adhesion between the resin-filled plate and the semi-cured resin layer can be further improved. The surface roughness Rz of the main surface 12a of the resin-filled plate 12 may be adjusted within the range described above, and may be, for example, 3-25 μm, or 7-20 μm. The surface roughnesses Rz of both main surfaces 12a of the resin-filled plate 12 may be the same or different, but even if they are different, it is desirable that both main surfaces 12a are within the above range. .

The surface roughness Rz in this specification is the maximum height roughness specified in JIS B 0601: 2013 "Use of geometric properties of products (GPS) - surface texture: contour curve method - terms, definitions and surface texture parameters" means. The surface roughness Rz is a value measured according to JIS B 0601:2013.

The volume ratio of the first resin in the resin-filled plate 12 may be, for example, 30-60% by volume, or 35-55% by volume, based on the total volume of the resin-filled plate 12 . The volume ratio of the nitride particles constituting the porous nitride sintered plate in the resin-filled plate 12 is, for example, 40 to 70% by volume, or 45 to 65% by volume, based on the total volume of the resin-filled plate 12. It's okay. The resin-filled plate 12 having such a volume ratio can exhibit excellent strength.

Examples of porous nitride sintered plates include boron nitride sintered plates. The nitride sintered plate contains nitride particles and pores formed by sintering nitride primary particles. The median pore size of the pores of the nitride sintered plate may be, for example, 6.0 μm or less, 5.0 μm or less, 4.0 μm or less, or 3.5 μm or less. Since such a nitride sintered plate has a small pore size, it is possible to sufficiently increase the contact area between the nitride particles. Therefore, thermal conductivity can be increased. The median pore diameter of the pores of the nitride sintered plate may be, for example, 0.3 μm or more, 0.5 μm or more, 1.0 μm or more, or 1.5 μm or more. Since such a nitride sintered plate can be sufficiently deformed by pressurization during bonding, it has excellent adhesion to other members (adherends). The median pore size of the pores of the nitride sintered plate may be adjusted within the above range, and may be, for example, 0.3-6.0 μm, or 1.5-3.5 μm.

The median pore diameter of the pores of the nitride sintered plate can be measured by the following procedure. First, the composite is heated to remove the semi-cured resin layer and the first resin. Then, using a mercury porosimeter, the pore size distribution is determined when the nitride sintered plate is pressed while increasing the pressure from 0.0042 MPa to 206.8 MPa. When the horizontal axis is the pore diameter and the vertical axis is the cumulative pore volume, the pore diameter when the cumulative pore volume reaches 50% of the total pore volume is the median pore diameter. As the mercury porosimeter, for example, one manufactured by Shimadzu Corporation can be used.

The porosity of the nitride sintered plate, that is, the ratio of the pore volume (V1) in the nitride sintered plate may be 30 to 65% by volume, and may be 40 to 60% by volume. If the porosity becomes too large, the strength of the nitride sintered plate tends to decrease. On the other hand, if the porosity is too small, less resin tends to ooze out when the composite is adhered to another member.

The porosity is obtained by calculating the bulk density [B (kg/m ³ )] from the volume and mass of the nitride sintered plate, and using this bulk density and the theoretical density [A (kg/m ³ )] of the nitride. , can be obtained by the following formula (1). The nitride sintered plate may contain at least one selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride. For boron nitride, the theoretical density A is 2280 kg/m ³ . For aluminum nitride, the theoretical density A is 3260 kg/m ³ . For silicon nitride, the theoretical density A is 3170 kg/m ³ .
Porosity (volume%) = [1-(B/A)] x 100 (1)

When the nitride sintered plate is a boron nitride sintered body, the bulk density B may be 800 to 1500 kg/m ³ or 1000 to 1400 kg/m ³ . If the bulk density B becomes too small, the strength of the nitride sintered plate tends to decrease. On the other hand, if the bulk density B is too high, the amount of resin filled in the composite may decrease, resulting in a loss of good adhesion of the composite.

The thickness of the nitride sintered plate may be, for example, 10.0 mm or less, 5.0 mm or less, or 2.0 mm or less. The lower limit of the thickness of the nitride sintered plate may be, for example, 0.1 mm or more, or 0.5 mm or more. The thickness of the nitride sintered plate is measured along the direction perpendicular to the main surface, and if the thickness is not constant, select 10 arbitrary locations to measure the thickness, and the average value is the above may be within the range of The thickness of the nitride sintered plate may be adjusted within the above range, and may be, for example, 0.1-10.0 mm, or 0.5-2.0 mm.

The first resin contained in the resin-filled plate 12 is a cured product (C stage) or semi-cured product (B stage) of a resin composition containing a main agent and a curing agent. The cured product is obtained by completing the curing reaction of the resin composition. The semi-cured product is obtained by partially progressing the curing reaction of the resin composition. The semi-cured product can be further cured by a subsequent curing treatment.

The first resin may contain a thermosetting resin or the like generated by the reaction of the main agent and curing agent in the resin composition. The semi-cured product may contain monomers such as a main agent and a curing agent in addition to the thermosetting resin as a resin component. It can be confirmed by, for example, a differential scanning calorimeter that the resin contained in the composite is a semi-cured product (B stage) before becoming a cured product (C stage).

The first resin contained in the resin-filled plate 12 has a cured rate higher than that of the conventional resin-filled plate. The curing rate of the first resin is 70% or more, and may be, for example, 72% or more, 75% or more, or 80% or more. When the curing rate of the first resin is within the above range, the outflow of the first resin during adhesion to the adherend is further suppressed, and the insulation properties of the obtained laminate can be further improved. The upper limit of the cure rate of the first resin is not particularly limited, but may be, for example, 90% or less, 88% or less, or 85% or less. When the upper limit of the curing rate of the first resin is within the above range, it is possible to ensure appropriate flexibility, and the composite will not be damaged during distribution, pressure bonding to an adherend, etc. can be further suppressed. The cure rate of the first resin may be adjusted within the above range, and may be, for example, 70-90%, or 72-85%.

The cure rate of the first resin can be determined by measurement using a differential scanning calorimeter. First, the calorific value Q per unit mass generated when 2 mg of the uncured resin composition is completely cured is measured. Then, a 10 mg sample taken from the resin included in the composite sheet is heated in the same manner, and the calorific value R per unit mass generated when the sample is completely cured is determined. At this time, the mass of the sample used for the measurement with the differential scanning calorimeter is the same as that of the resin composition used for the measurement of the calorific value Q. Assuming that c (% by mass) of a thermosetting component is contained in the resin, the curing rate of the resin composition impregnated in the composite sheet is obtained by the following formula (A). Whether or not the resin is completely cured can be confirmed by the end of heat generation in the heat generation curve obtained by differential scanning calorimetry.
Curing rate (%) of impregnated resin composition={1-[(R/c)×100]/Q}×100 (A)

Examples of the first resin include epoxy resin, silicone resin, cyanate resin, silicone rubber, acrylic resin, phenol resin, melamine resin, urea resin, bismaleimide resin, unsaturated polyester, fluorine resin, polyimide, polyamideimide, and polyetherimide. , polybutylene terephthalate, polyethylene terephthalate, polyphenylene ether, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyethersulfone, polycarbonate, maleimide resin, maleimide-modified resin, ABS (acrylonitrile-butadiene-styrene) resin, AAS (acrylonitrile - acrylic rubber/styrene) resin, AES (acrylonitrile/ethylene/propylene/diene rubber-styrene) resin, polyglycolic acid resin, polyphthalamide, and polyacetal.

The semi-cured resin layer 14 contains the second resin and has a lower curing rate than the first resin. By having the semi-cured resin layer 14, the composite 10 has excellent adhesion to the adherend. The difference between the cure rate of the first resin and the cure rate of the second resin may be, for example, 30% or more, 35% or more, or 40% or more. The curing rate of the second resin can be measured using a sample taken from the semi-cured resin layer 14 in the same manner as measuring the curing rate of the first resin.

The components of the second resin may be the same as or different from those of the first resin. From the viewpoint of improving the insulation properties after the coating, it is desirable that they are made of the same resin.

The thickness of the semi-cured resin layer 14 may be adjusted from the viewpoint of achieving both adhesion and heat dissipation. The thickness of the semi-cured resin layer 14 may be, for example, 25.0% or less, 20.0% or less, or 15.0% or less based on the thickness of the nitride sintered plate. When the upper limit of the thickness of the semi-cured resin layer 14 is within the above range, it is possible to sufficiently suppress a decrease in heat dissipation. The thickness of the semi-cured resin layer 14 may be, for example, 0.5% or more, 1.0% or more, or 2.0% or more based on the thickness of the nitride sintered plate. When the lower limit of the thickness of the semi-cured resin layer 14 is within the above range, the semi-cured resin layer 14 is more firmly fixed to the resin-filled plate, and the adhesiveness to the adherend is further improved. can be made The thickness of the semi-cured resin layer 14 may be adjusted within the above range, and is, for example, 0.5 to 25.0%, or 2.0 to 15.0%, based on the thickness of the nitride sintered plate. %.

In the composite 10 described above, since the outflow of the first resin during heating is suppressed, even when laminated with a metal sheet or the like, the property change of the resin filling is sufficiently suppressed in practice, and the high degree of It is useful for forming a laminate that requires good insulation. One embodiment of a laminate includes the composite and a metal sheet provided on the composite. The composite and the metal sheet may be joined by a cured semi-cured resin layer of the composite. That is, in one aspect of the laminate, a resin-filled plate, a cured resin layer, and a metal sheet are provided in this order. In this case, the resin filling and the metal sheet are joined via the cured resin layer.

The metal sheet is not particularly limited as long as it is made of metal and has a sheet shape. The adherend (another member) mentioned in the description of the composite above may be a metal sheet. The metal sheet may be a metal plate or a metal foil. Examples of the material of the metal sheet include aluminum and copper.

FIG. 3 is a cross-sectional view showing an example of a laminate. FIG. 3 shows a cross section of the laminate 20 cut along the lamination direction. Laminate 20 comprises composite 10 of FIGS. 1 and 2 and metal sheets 22 laminated on both major surfaces of composite 10 . The material and thickness of the plurality of metal sheets 22 may be the same or different. Also, it is not essential to provide the metal sheets 22 on both major surfaces of the composite 10 . Alternatively, only one major surface of composite 10 may be provided with metal sheet 22 .

The metal sheet 22 in the laminate 20 is in contact with the semi-cured resin layer 14 . Thereby, the metal sheet 22 and the composite 10 are adhered with high adhesion. In order to fix this state, the semi-cured resin layer 14 may be cured to form a cured resin layer. Since the metal sheet 22 and the composite body 10 are adhered to each other with high adhesiveness, the laminated body 20 can be suitably used as a heat radiation member, for example, in a semiconductor device or the like.

The thickness of the laminate 20 may be, for example, less than 12.0 mm, less than 6.0 mm, or less than 3.0 mm. The lower limit of the thickness of the laminate 20 may be, for example, 0.6 mm or more. As a result, the laminated body 20 can be sufficiently miniaturized. Such a laminate 20 is suitably used as a component of a semiconductor device, for example. The thickness of the laminate 20 may be adjusted within the range described above, and may be, for example, 0.6 mm or more and less than 12.0 mm, or 0.6 mm or more and less than 6.0 mm.

Since the laminate 20 includes the composite 10, it is possible to achieve both high levels of thermal conductivity and insulation reliability. For example, by increasing the curing rate of the first resin in advance, the outflow of the first resin when forming the laminate is sufficiently suppressed, and the insulating properties expected of the resin-filled plate can be sufficiently exhibited. obtain.

The above composite can be produced, for example, by the following method. One embodiment of the method for producing a composite includes an impregnation step of impregnating a porous nitride sintered plate with a first resin composition to obtain a resin-impregnated body, and heating the resin-impregnated body to fill the pores. a curing step of curing or semi-curing the resin composition to obtain a resin-filled board containing a first resin; and providing a semi-cured resin layer containing a second resin on at least a portion of the main surface of the resin-filled board. and a coating step. Here, the curing rate of the first resin is 70% or more.

A nitride sintered plate prepared in advance may be used as the porous nitride sintered plate, or a nitride sintered plate prepared by the following sintering process may be used. When a previously prepared nitride sintered plate is used as the porous nitride sintered plate, the sintering step described later can be omitted.

When preparing a nitride sintered plate by a sintering process, first, a raw material powder containing nitride is prepared. The nitride contained in the raw material powder may contain, for example, at least one nitride selected from the group consisting of boron nitride, aluminum nitride, and silicon nitride. When boron nitride is contained, the boron nitride may be amorphous boron nitride or hexagonal boron nitride. When preparing a boron nitride sintered plate as a nitride sintered plate, the raw material powder is, for example, an amorphous boron nitride powder having an average particle size of 0.5 to 10.0 μm, or an average particle size of 3.0 to A 40.0 μm hexagonal boron nitride powder can be used.

In the sintering step, a compound containing nitride powder may be molded and sintered to obtain a nitride sintered body. The molding may be carried out, for example, by uniaxial pressing or cold isostatic pressing (CIP). A sintering aid may be blended into the formulation prior to molding. Examples of sintering aids include metal oxides such as yttrium oxide, aluminum oxide and magnesium oxide, alkali metal carbonates such as lithium carbonate and sodium carbonate, and boric acid. When a sintering aid is blended, the amount of the sintering aid is, for example, 0.01 parts by mass or more, or 0.10 parts by mass with respect to a total of 100 parts by mass of the nitride and the sintering aid. or more. The amount of the sintering aid compounded is, for example, 20.00 parts by mass or less, 15.00 parts by mass or less, or 10.00 parts by mass or less with respect to a total of 100 parts by mass of the nitride and the sintering aid. good. By setting the amount of the sintering aid to be added within the above range, it becomes easier to adjust the median pore diameter of the nitride sintered body within the range described below. The amount of the sintering aid may be adjusted within the above range, for example, 0.01 to 20.00 parts by mass, or 0.10 parts per 100 parts by mass of the total of the nitride and the sintering aid. It may be up to 10.00 parts by mass.

The compound may be formed into a sheet-like molded body by, for example, a doctor blade method. The molding method is not particularly limited, and press molding may be performed using a mold to form a molded body. The molding pressure may be, for example, 5-350 MPa. The shape of the compact may be a sheet with a thickness of less than 2 mm. If a nitride sintered plate is produced using such a sheet-like compact, a sheet-like composite having a thickness of less than 2 mm can be produced without cutting the nitride sintered plate. In addition, compared to the case where a block-shaped nitride sintered body is cut to form a sheet, the material loss due to processing can be reduced by forming the block into a sheet from the compact stage. Therefore, the composite can be manufactured with high yield.

The sintering temperature in the sintering step may be, for example, 1600°C or higher, or 1700°C or higher. The sintering temperature may be, for example, 2200° C. or lower, or 2000° C. or lower. The sintering time may be, for example, 1 hour or more and may be 30 hours or less. The atmosphere during sintering may be, for example, an inert gas atmosphere such as nitrogen, helium, and argon.

For sintering, for example, a batch type furnace and a continuous type furnace can be used. Batch type furnaces include, for example, muffle furnaces, tubular furnaces, atmosphere furnaces, and the like. Examples of continuous furnaces include rotary kilns, screw conveyor furnaces, tunnel furnaces, belt furnaces, pusher furnaces, and large continuous furnaces. Thus, a nitride sintered body or a nitride sintered plate can be obtained. The nitride sintered body may be block-shaped.

When the nitride sintered body is block-shaped, a cutting step may be performed to process it so that it has a thickness of less than 2 mm. In the cutting step, the nitride sintered body is cut using, for example, a wire saw. The wire saw may be, for example, a multi-cut wire saw or the like. A sheet-like nitride sintered plate having a thickness of less than 2 mm, for example, can be obtained by such a cutting process. Thereby, the nitride sintered body can be smoothly impregnated with the first resin composition in the next impregnation step.

In the impregnation step, the pores of the nitride sintered body are impregnated with the first resin composition having a viscosity of 10 to 500 mPa·s to obtain a resin-impregnated body. By reducing the thickness of the nitride sintered body, the impregnation of the first resin composition can be facilitated. Also, by setting the viscosity of the first resin composition to a range suitable for impregnation, the filling rate of the resin filler can be sufficiently increased.

The viscosity of the first resin composition when the nitride sintered plate is impregnated with the first resin composition may be, for example, 440 mPa·s or less, 390 mPa·s or less, or 340 mPa·s or less. By reducing the viscosity of the first resin composition in this manner, the impregnation of the first resin composition can be sufficiently promoted. The viscosity of the first resin composition when the nitride sintered plate is impregnated with the first resin composition may be, for example, 15 mPa·s or more, or 20 mPa·s or more. By thus setting a lower limit for the viscosity of the first resin composition, it is possible to further suppress the first resin composition once impregnated in the pores from flowing out from the pores. The viscosity of the first resin composition may be adjusted within the range described above, and may be, for example, 15 to 440 mPa·s, or 20 to 340 mPa·s. The viscosity of the first resin composition may be adjusted by partially polymerizing the monomer component, or may be adjusted by adding a solvent.

The above viscosity of the first resin composition is the viscosity at the temperature (T1) of the first resin composition when impregnating the nitride sintered plate with the first resin composition. This viscosity is a value measured using a rotational viscometer at a shear rate of 10 (1/sec) and a temperature (T1). Therefore, by changing the temperature T1, the viscosity when the nitride sintered plate is impregnated with the first resin composition may be adjusted.

The temperature (T1) at which the nitride sintered plate is impregnated with the first resin composition is, for example, the temperature (T2) at which the first resin composition is semi-cured or higher and less than the temperature T3 (=T2 + 20 ° C.). you can The temperature (T2) may be, for example, 80-140°C. Impregnation of the nitride sintered plate with the first resin composition may be performed under pressure or under reduced pressure. The impregnation method is not particularly limited, and the nitride sintered plate may be immersed in the first resin composition, or the surface of the nitride sintered plate may be coated with the first resin composition. good.

The impregnation step may be performed under either reduced pressure or increased pressure, or a combination of impregnation under reduced pressure and increased pressure. The pressure in the impregnation device when the impregnation step is performed under reduced pressure conditions may be, for example, 1000 Pa or less, 500 Pa or less, 100 Pa or less, 50 Pa or less, or 20 Pa or less. The pressure in the impregnation device when the impregnation step is performed under pressurized conditions may be, for example, 1 MPa or higher, 3 MPa or higher, 10 MPa or higher, or 30 MPa or higher.

By adjusting the pore size of the pores in the nitride sintered plate, the impregnation of the resin composition by capillary action may be promoted, and the filling rate of the resin in the resin filling body may be adjusted. From this point of view, the median pore diameter of the nitride sintered plate may be, for example, 0.3-6.0 μm, 0.5-5.0 μm, or 1.0-4.0 μm.

For the first resin composition, it is possible to use, for example, one that becomes the resin mentioned in the above description of the composite by curing or semi-curing reaction.

The first resin composition may contain a solvent. Solvents include, for example, ethanol and aliphatic alcohols such as isopropanol, 2-methoxyethanol, 1-methoxyethanol, 2-ethoxyethanol, 1-ethoxy-2-propanol, 2-butoxyethanol, 2-(2-methoxy Ether alcohols such as ethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, and 2-(2-butoxyethoxy)ethanol, glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monobutyl ether, acetone, methyl ethyl ketone, methyl isobutyl Examples include ketones, ketones such as diisobutyl ketone, and aromatic hydrocarbons such as toluene and xylene.

The first resin composition is thermosetting, for example, at least one compound selected from the group consisting of a compound having a cyanate group, a compound having a bismaleimide group, and a compound having an epoxy group, and a curing agent. , may contain.

Examples of compounds having a cyanate group include dimethylmethylenebis(1,4-phenylene)biscyanate and bis(4-cyanatophenyl)methane. Dimethylmethylenebis(1,4-phenylene)biscyanate is commercially available, for example, as TACN (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name).

Examples of compounds having a bismaleimide group include N,N'-[(1-methylethylidene)bis[(p-phenylene)oxy(p-phenylene)]]bismaleimide and 4,4'-diphenylmethanebismaleimide. etc. N,N'-[(1-methylethylidene)bis[(p-phenylene)oxy(p-phenylene)]]bismaleimide is commercially available as BMI-80 (manufactured by K.I. Kasei Co., Ltd., trade name), for example. readily available.

Examples of compounds having epoxy groups include bisphenol F type epoxy resins, bisphenol A type epoxy resins, biphenyl type epoxy resins, and polyfunctional epoxy resins. For example, it may be 1,6-bis(2,3-epoxypropan-1-yloxy)naphthalene, which is commercially available as HP-4032D (manufactured by DIC Corporation, trade name).

The curing agent may contain a phosphine-based curing agent and an imidazole-based curing agent. A phosphine-based curing agent can promote a triazine formation reaction by trimerization of a compound having a cyanate group or a cyanate resin. Phosphine-based curing agents include, for example, tetraphenylphosphonium tetra-p-tolylborate and tetraphenylphosphonium tetraphenylborate. Tetraphenylphosphonium tetra-p-tolylborate is commercially available, for example, as TPP-MK (manufactured by Hokko Chemical Industry Co., Ltd., trade name).

The imidazole-based curing agent generates oxazoline and accelerates the curing reaction of the epoxy group-containing compound or epoxy resin. Examples of imidazole curing agents include 1-(1-cyanomethyl)-2-ethyl-4-methyl-1H-imidazole and 2-ethyl-4-methylimidazole. 1-(1-Cyanomethyl)-2-ethyl-4-methyl-1H-imidazole is commercially available, for example, as 2E4MZ-CN (manufactured by Shikoku Kasei Co., Ltd., trade name).

The content of the phosphine-based curing agent is, for example, 5 parts by mass or less, 4 parts by mass or less, or It may be 3 parts by mass or less. The content of the phosphine-based curing agent is, for example, 0.1 parts by mass or more, or 0.5 parts by mass, with respect to 100 parts by mass of the total amount of the compound having a cyanate group, the compound having a bismaleimide group, and the compound having an epoxy group. It may be at least parts by mass. When the content of the phosphine-based curing agent is within the above range, it is easy to prepare the resin-impregnated body. The content of the phosphine-based curing agent may be adjusted within the above-mentioned range, and for example, 0.5 parts per 100 parts by mass of the total amount of the compound having a cyanate group, the compound having a bismaleimide group and the compound having an epoxy group. It may be 1 to 5 parts by mass.

The content of the imidazole-based curing agent is, for example, 0.1 parts by mass or less, 0.05 parts by mass with respect to 100 parts by mass of the total amount of the compound having a cyanate group, the compound having a bismaleimide group, and the compound having an epoxy group. parts or less, or 0.03 parts by mass or less. The content of the imidazole-based curing agent is, for example, 0.001 parts by mass or more, or 0.005 parts by mass with respect to 100 parts by mass of the total amount of the compound having a cyanate group, the compound having a bismaleimide group, and the compound having an epoxy group. It may be at least parts by mass. When the content of the imidazole-based curing agent is within the above range, preparation of the resin-impregnated body is easy. The content of the imidazole-based curing agent may be adjusted within the range described above. 001 to 0.1 parts by mass.

The first resin composition may contain components other than the main agent and the curing agent. Other components further include, for example, other resins such as phenolic resins, melamine resins, urea resins, and alkyd resins, silane coupling agents, leveling agents, antifoaming agents, surface control agents, and wetting and dispersing agents. It's okay. The content of these other components may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less based on the total amount of the first resin composition.

In the curing step, by curing or semi-curing the first resin composition in the resin-impregnated body obtained in the impregnation step, a resin-filled plate containing the first resin having a curing rate of 70% or more is prepared. In the curing step, the first resin composition is cured or semi-cured by heating and/or light irradiation depending on the type of the first resin composition (or curing agent added as necessary).

In the curing step, the heating temperature for curing or semi-curing the first resin composition by heating may be, for example, 80 to 130°C. The first resin obtained by semi-curing or curing the first resin composition contains, as a resin component, at least one thermosetting resin selected from the group consisting of cyanate resins, bismaleimide resins, and epoxy resins. you can The first resin may also contain a curing agent. In addition to these components, the first resin includes other resins such as phenolic resins, melamine resins, urea resins, and alkyd resins, as well as silane coupling agents, leveling agents, antifoaming agents, surface control agents, and components derived from wetting and dispersing agents.

The curing step is preferably performed in a situation where the first resin composition exists around the resin-impregnated body. By doing so, even when the volume is reduced due to curing shrinkage of the first resin composition, the first resin composition is supplied from the periphery of the resin-impregnated body, and the formation of voids can be further suppressed. Moreover, even when the volume is reduced due to solidification shrinkage of the first resin that occurs when the curing reaction is stopped and cooled, the presence of the similar resin in the surroundings can also suppress the formation of voids.

In the coating step, a composite is prepared by providing a semi-cured resin layer containing the second resin on at least part of the main surface of the resin-filled plate. The coating step is, for example, a step of applying a second resin composition to the resin-filled plate obtained in the curing step and heating it to provide a semi-cured resin layer on at least a portion of the main surface of the resin-filled plate. Alternatively, the step may include providing a semi-cured resin layer on at least a portion of the main surface of the resin-filled plate by adhering a pre-prepared semi-cured second resin composition.

The coating method in the coating step is not particularly limited, and the resin-filled plate may be immersed in the second resin composition, or the surface of the resin-filled plate may be coated with the second resin composition. Alternatively, a separately prepared semi-cured resin layer may be adhered. The means for bonding the separately prepared semi-cured resin layer may be a method of transferring the semi-cured resin layer separately provided on the support. The amount of the second resin composition adhering to the resin filler may be adjusted by the viscosity of the second resin composition.

The viscosity of the second resin composition when adhered to the resin-filled plate may be, for example, 10 to 500 mPa·s, or 15 to 400 mPa·s.

The viscosity of the second resin composition is the viscosity at the temperature (T4) of the second resin composition when the second resin composition adheres to the resin filling. The viscosity is measured using a rotational viscometer at a shear rate of 10 (1/sec) and under temperature (T4). By changing the temperature (T4), the viscosity at which the second resin composition adheres to the resin filling may be adjusted. This viscosity may be adjusted by changing the temperature (T4) of the second resin composition, or may be adjusted by changing the blending amount of the solvent as in the case of the first resin composition.

The components contained in the second resin composition may be the same as those exemplified for the first resin composition. The compositions of the second resin composition and the first resin composition may be the same or different. After adhering the second resin composition to the resin-filled plate, the second resin composition is cured or semi-cured to obtain the second resin. The second resin composition is cured or semi-cured by heating and/or light irradiation depending on the type of the second resin composition (or curing agent added as necessary).

The heating temperature for curing or semi-curing the second resin composition by heating may be, for example, 80 to 130°C. When the compositions of the first resin composition and the second resin composition are the same, the first The hardening rate of the second resin can be made lower than the hardening rate of the resin.

The second resin obtained by semi-curing or curing the second resin composition contains, as a resin component, at least one thermosetting resin selected from the group consisting of cyanate resins, bismaleimide resins and epoxy resins, and a curing agent. may contain In addition to these components, the second resin includes other resins such as phenolic resins, melamine resins, urea resins, and alkyd resins, as well as silane coupling agents, leveling agents, antifoaming agents, surface control agents, and components derived from wetting and dispersing agents.

The manufacturing method described above may have other steps such as a sintering step, an impregnation step, a curing step, and a coating step. Other steps include, for example, a step of adjusting the surface roughness Rz of the main surface of the resin-filled plate. The surface roughness Rz can be adjusted by, for example, polishing and removing surface particles.

An embodiment of a method for manufacturing a laminate has a lamination step of laminating the above-described composite and metal sheets, followed by heating and pressing. As the composite, a composite obtained by any of the above-described production methods can be used. That is, the manufacturing method of the laminate may be a manufacturing method including the above-described lamination step in addition to the manufacturing method described above. The metal sheet may be a metal plate or a metal foil.

In the lamination process, a metal sheet is placed on the main surface of the composite. With the main surfaces of the composite and the metal sheet in contact with each other, pressure is applied in the direction in which the main surfaces face each other, and heating is applied. Note that the pressurization and heating need not necessarily be performed at the same time, and the heating may be performed after pressurization and crimping.

The laminate thus obtained can be used for manufacturing semiconductor devices and the like. A semiconductor element may be provided on one of the metal sheets. The other metal sheet may be joined with cooling fins.

Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Also, the descriptions of the above-described embodiments can be applied to each other.

Hereinafter, the present disclosure will be described in more detail using examples and comparative examples. It should be noted that the present disclosure is not limited to the following examples.

(Example 1)
[Production of nitride sintered plate]
100 parts by mass of orthoboric acid manufactured by Shin Nippon Denko Co., Ltd. and 35 parts by mass of acetylene black (trade name: HS100) manufactured by Denka Co., Ltd. were mixed using a Henschel mixer. The obtained mixture was filled in a graphite crucible and heated at 2200° C. for 5 hours in an argon atmosphere in an arc furnace to obtain massive boron carbide (B ₄ C). The resulting mass was coarsely pulverized with a jaw crusher to obtain coarse powder. This coarse powder was further pulverized by a ball mill having silicon carbide balls (φ10 mm) to obtain pulverized powder.

The prepared pulverized powder was filled in a crucible made of boron nitride. After that, using a resistance heating furnace, heating was performed for 10 hours under conditions of 2000° C. and 0.85 MPa in a nitrogen gas atmosphere. Thus, a fired product containing boron carbonitride (B ₄ CN ₄ ) was obtained.

A sintering aid was prepared by blending powdered boric acid and calcium carbonate. In preparation, 50.0 parts by mass of calcium carbonate was blended with 100 parts by mass of boric acid. At this time, the atomic ratio of boron to calcium was 17.5 atomic % of calcium to 100 atomic % of boron. 20 parts by mass of a sintering aid was blended with 100 parts by mass of the fired product, and mixed using a Henschel mixer to prepare a powdery compound.

Using a powder press, the compound was pressed at 150 MPa for 30 seconds to obtain a sheet-like molded body (length x width x thickness = 50 mm x 50 mm x 0.35 mm). The compact was placed in a boron nitride container and introduced into a batch-type high-frequency furnace. In a batch-type high-frequency furnace, heating was performed for 5 hours under the conditions of atmospheric pressure, nitrogen flow rate of 5 L/min, and 2000°C. After that, the boron nitride sintered body was taken out from the boron nitride container. Thus, a sheet-like (square prism-like) boron nitride sintered body was obtained. The thickness of the boron nitride sintered plate was 0.36 mm.

<Measurement of median pore size>
The pore volume distribution of the resulting boron nitride sintered body was measured using a mercury porosimeter (device name: Autopore IV9500) manufactured by Shimadzu Corporation while increasing the pressure from 0.0042 MPa to 206.8 MPa. The pore diameter at which the accumulated pore volume reached 50% of the total pore volume was defined as the "median pore diameter". Table 1 shows the results.

[Preparation of resin-filled plate]
10 parts by mass of a commercially available curing agent (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name: Akmex H-8) was blended with 100 parts by mass of a commercially available epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: Epicoat 807). After heating the prepared resin composition at 120 ° C. for 15 minutes, using a dispenser while maintaining the temperature, drop it onto the upper main surface of the boron nitride sintered body. It was impregnated with a resin composition.The amount of the resin composition dropped was 1.5 times the total volume of the pores of the boron nitride sintered body.A part of the resin composition was not impregnated into the boron nitride sintered body. , remained on the main surface.

Under atmospheric pressure, the resin composition remaining on the upper main surface of the boron nitride sintered body was smoothed using a stainless steel scraper (manufactured by Narby Co., Ltd.). An excess resin composition was removed to obtain a resin-impregnated body having a smooth main surface.

The resin-impregnated body was heated at 160°C for 60 minutes under atmospheric pressure to semi-cure the resin composition. Thus, a quadrangular prism-shaped composite sheet (length x width x thickness = 50 mm x 50 mm x 0.36 mm) was produced. The boron nitride sintered body was exposed on part of the main surface of the composite sheet.

<Measurement of Curing Rate of First Resin>
The curing rate of the resin composition contained in the semi-cured product was determined by measurement using a differential scanning calorimeter. First, the calorific value Q per unit mass generated when 2 mg of the uncured resin composition was completely cured was measured. Then, a 10 mg sample taken from the semi-cured material of the composite was heated in the same manner, and the amount of heat generated per unit mass R generated when completely cured was determined. At this time, the mass of the sample used for the measurement with the differential scanning calorimeter was the same as that of the resin composition used for the measurement of the calorific value Q. Assuming that c (% by mass) of a thermosetting component is contained in the semi-cured product, the curing rate of the resin composition impregnated in the composite was obtained by the following formula (A). The curing rate of the first resin was 85%.
Curing rate (%) of impregnated resin composition={1-[(R/c)×100]/Q}×100 (A)

<Measurement of filling rate of first resin>
The filling rate of the first resin contained in the resin-filled plate was obtained by the following formula (3). The results were as shown in Table 1.
Filling rate (% by volume) of the first resin in the resin-filled plate = {(Bulk density of the resin-filled plate-Bulk density of the boron nitride sintered plate)/(Theoretical density of the resin-filled plate-Bulk density of the boron nitride sintered plate )}×100 (3)

The bulk density of the boron nitride sintered plate and the resin-filled plate conforms to JIS Z 8807:2012 "Method for measuring density and specific gravity by geometric measurement", and It was determined based on the volume calculated from the length (measured with a vernier caliper) and the mass of the boron nitride sintered plate or resin-filled plate measured with an electronic balance (see JIS Z 8807:2012, Item 9). The theoretical density of the resin-filled plate was determined by the following formula (4).
Theoretical density of resin-filled plate = bulk density of boron nitride sintered plate + true density of resin × (1-bulk density of boron nitride sintered plate/true density of boron nitride) (4)

The boron nitride sintered plate and the true density of the resin were measured using a dry automatic densitometer in accordance with JIS Z 8807:2012 "Method for measuring density and specific gravity by gas replacement method". 1 determined from the volume and mass of the resin (see formulas (14) to (17) in item 11 of JIS Z 8807:2012).

[Preparation of complex]
The resin-filled plate obtained as described above had a surface roughness Rz of 18 μm.

Next, a resin composition was prepared by the same method as in preparing the resin-filled plate, and the resin composition was heated at 160° C. for 30 minutes to adjust the curing rate to 38%. composition. The second resin composition was dripped onto the main surface of the resin-filled plate while maintaining its temperature. Under atmospheric pressure, the second resin composition dropped onto the main surface of the resin-filled plate is spread using a spatula made of silicone rubber, the resin composition is spread over the entire main surface, and then cooled to room temperature. A composite having a semi-cured resin layer containing the second resin was obtained. The thickness of the semi-cured resin layer was 0.03 mm.

<Measurement of Hardening Rate of Second Resin>
The cure rate of the second resin was measured by the same method as for the first resin. The curing rate of the second resin was 38%.

<Evaluation of outflow amount during laminate production>
A copper plate (length x width x thickness = 20 mm x 20 mm x 1 mm) is sandwiched on one side and a Teflon sheet on the other side, and the above composite (length x width x thickness = 20 mm x 20 mm x 0.36 mm) is placed. Thus, a laminate of the composite and the copper plate was produced. The laminate was heated and pressurized under conditions of 200° C. and 5 MPa for 5 minutes, and then heat-treated under conditions of 200° C. and atmospheric pressure for 2 hours. A laminate was thus obtained. With respect to this laminate, the outflow amount when producing the laminate was evaluated by the following procedure. After the heat treatment for obtaining the laminate, an image of the laminate viewed from above in a direction perpendicular to the lamination direction is acquired, and the acquired image is analyzed using image analysis software (manufactured by GNU General Public License, GIMP). A quantification process was performed to distinguish between a region derived from the first resin and the second resin that flowed out and a region other than that. From the binarized image, the area Y of the region derived from the first resin and the second resin was determined, and the ratio (value of Y/X) to the area of the copper plate was calculated. Table 1 shows the results.

<Measurement of Dielectric Breakdown Voltage of Laminate>
The obtained composite was placed between two copper plates, heated and pressed under conditions of 200° C. and 5 MPa for 5 minutes, and further heated under conditions of 200° C. and atmospheric pressure for 2 hours. A laminate obtained by the above was prepared. The dielectric breakdown voltage was measured using the laminate described above. First, an etching resist agent was screen-printed on one surface of the laminate so as to form a circular shape with a diameter of 20 mm, and the entire surface of the laminate structure was screen-printed with an etching resist agent. After printing, the etching resist agent was irradiated with ultraviolet rays to be cured to form a resist. Next, the copper plate on which the circular resist was formed was etched with a cupric chloride solution to form a circular copper circuit with a diameter of 20 mm on one surface of the laminate. In this way, the laminated structure having a circular copper circuit formed thereon was obtained, which was the object to be measured. The dielectric breakdown voltage of the obtained laminated structure was measured according to JIS C2110-1:2016 using a withstand voltage tester (manufactured by Kikusui Denshi Kogyo Co., Ltd., device name: TOS-8700).

(Example 2)
[Preparation of resin-filled plate]
80 parts by mass of a compound having a cyanate group, 20 parts by mass of a compound having a bismaleimide group, and 50 parts by mass of a compound having an epoxy group were weighed into a container, and the total amount of the above three compounds was 100 parts by mass. 1 part by mass of a phosphine-based curing agent and 0.01 part by mass of an imidazole-based curing agent were added and mixed. Since the epoxy resin was in a solid state at room temperature, it was mixed while being heated to about 80°C. The resulting thermosetting composition had a viscosity of 10 mPa·sec at 100°C. After the prepared resin composition was heated to 100° C., it was dropped onto the upper main surface of the boron nitride sintered body using a dispenser while maintaining the temperature to impregnate the resin composition. The amount of the resin composition dropped was 1.5 times the total volume of the pores of the boron nitride sintered body. Part of the resin composition remained on the main surface without impregnating the boron nitride sintered body.

The following compounds were used to prepare the thermosetting composition.

Compound having a cyanate group: dimethylmethylenebis(1,4-phenylene)biscyanate (Mitsubishi Gas Chemical Company, Inc., trade name: TA-CN)
Compound having a bismaleimide group: N,N'-[(1-methylethylidene)bis[(p-phenylene)oxy(p-phenylene)]]bismaleimide (manufactured by K.I. Kasei Co., Ltd., trade name: BMI- 80)
Compound having an epoxy group: 1,6-bis(2,3-epoxypropan-1-yloxy)naphthalene (manufactured by DIC Corporation, trade name: HP-4032D)

Phosphine-based curing agent: tetraphenylphosphonium tetra-p-tolylborate (manufactured by Chemical Co., Ltd., trade name: TPP-MK)
Imidazole-based curing agent: 1-(1-cyanomethyl)-2-ethyl-4-methyl-1H-imidazole (manufactured by Shikoku Chemical Industry Co., Ltd., trade name: 2E4MZ-CN)

Next, under atmospheric pressure, the resin composition remaining on the upper main surface of the boron nitride sintered body was smoothed using a stainless steel scraper (manufactured by Narby Co., Ltd.). An excess resin composition was removed to obtain a resin-impregnated body having a smooth main surface.

The resin-impregnated body was heated at 80°C for 60 hours under atmospheric pressure to semi-cure the resin composition. Thus, a quadrangular prism-shaped composite sheet (length x width x thickness = 50 mm x 50 mm x 0.38 mm) was produced. The boron nitride sintered body was exposed on part of the main surface of the composite sheet.

Next, a resin composition was prepared by the same method as in preparing the resin-filled plate, and the resin composition was heated at 120° C. for 7 hours to adjust the curing rate to 32%. composition. The second resin composition was dripped onto the main surface of the resin-filled plate while maintaining its temperature. Under atmospheric pressure, the second resin composition dropped onto the main surface of the resin-filled plate is spread using a spatula made of silicone rubber, the resin composition is spread over the entire main surface, and then cooled to room temperature. A composite having a semi-cured resin layer containing the second resin was obtained. The thickness of the semi-cured resin layer was 0.03 mm.

(Comparative example 1)
The thickness of the nitride sintered plate was set to 0.40 mm, the hardening rate of the first resin was set to 29%, the hardening rate of the second resin was set to 35%, and the thickness of the second resin was set to 0. Composites and laminates were prepared by the same procedure as in Example 1, except that the thickness was 0.01 mm.

(Comparative example 2)
The thickness of the nitride sintered plate was set to 0.37 mm, the hardening rate of the first resin was set to 48%, the hardening rate of the second resin was set to 40%, and the thickness of the second resin was set to 0. Composites and laminates were prepared by the same procedure as in Example 2, except that the thickness was 0.05 mm.

Regarding the composites and laminates prepared in Example 2 and Comparative Examples 1 and 2, the filling rate and curing rate of the first resin, the surface roughness Rz, the curing rate of the second resin, and the semi-cured resin layer were measured. Measured as in 1. Regarding the production of the laminates prepared in Example 2 and Comparative Examples 1 and 2, the outflow amount and dielectric breakdown voltage were evaluated. Table 1 shows the results.

DESCRIPTION OF SYMBOLS 10... Composite, 12... Resin-filled board, 12a... Main surface, 14... Semi-hardened resin layer, 20... Laminated body, 22... Metal sheet.

Claims

a resin-filled plate including a porous nitride sintered plate and a first resin filled in the pores of the nitride sintered plate;
a semi-cured resin layer containing a second resin provided on at least a portion of the main surface of the resin-filled plate;
The curing rate of the first resin is 70% or more,
A composite, wherein the semi-cured resin layer contains a thermosetting resin.
The composite according to claim 1, wherein the difference between the curing rate of the first resin and the curing rate of the second resin is 30% or more.
The composite according to claim 1 or 2, wherein the curing rate of the first resin is 90% or less.
The composite according to any one of claims 1 to 3, wherein the semi-cured resin layer has a thickness of 0.5 to 25.0% of the thickness of the nitride sintered plate.
The composite according to any one of claims 1 to 4, wherein the main surface of the resin-filled plate has a surface roughness Rz of 3 to 25 µm.
The composite according to any one of claims 1 to 5, wherein the nitride sintered plate has a median pore diameter of 0.3 to 6.0 µm.
A laminate comprising the composite according to any one of claims 1 to 6 and a metal sheet provided on the composite.
including a porous nitride sintered plate and a resin filled in the pores of the nitride sintered plate,
A resin-filled plate, wherein the curing rate of the resin is 70% or more.
The resin-filled plate according to claim 8, wherein the curing rate of the resin is 90% or less.
The resin-filled plate according to claim 8 or 9, wherein the main surface has a surface roughness Rz of 3 to 25 μm.
an impregnation step of impregnating a porous nitride sintered plate with the first resin composition to obtain a resin-impregnated body;
a curing step of heating the resin-impregnated body to cure or semi-cure the resin composition filled in the pores to obtain a resin-filled plate containing a first resin;
a coating step of providing a semi-cured resin layer containing a second resin on at least part of the main surface of the resin-filled plate;
A method for producing a composite, wherein the curing rate of the first resin is 70% or more.
12. The semi-cured resin layer according to claim 11, wherein in the covering step, the second resin composition is applied to the resin-filled plate and heated to form the semi-cured resin layer on at least a portion of the main surface of the resin-filled plate. A method for producing a composite of
12. The method according to claim 11, wherein in the covering step, the semi-cured resin layer is provided on at least part of the main surface of the resin-filled plate by bonding a semi-cured material of the second resin composition to the resin-filled plate. A method of making the described composite.
A method for producing a laminate, comprising a step of laminating the composite obtained by the production method according to any one of claims 11 to 13 and a metal sheet, followed by heating and pressing.