Method for manufacturing resin filling plate, and resin filling plate

Abstract

To provide a method for manufacturing a large-sized resin filling plate which suppresses variation in in-plane resin impregnation.SOLUTION: A method for manufacturing a resin filling plate includes a step of laminating a first resin sheet, a porous nitride sinter plate having an area of a main surface of 2,500 mm2 or more and a second resin sheet in this order so as to be brought into contact with each other, heating them, thereby melting the first resin sheet and the second resin sheet, impregnating a pore possessed by the nitride sinter plate with a molten resin, and obtaining a resin filling plate, wherein the first resin sheet and the second resin sheet are moldings of semi-cured products of a thermosetting composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a resin-filled plate and a resin-filled plate.

Background Art

[0002] In components such as power devices, transistors, thyristors, and CPUs, it is required to efficiently dissipate the heat generated during use. In response to such requirements, conventionally, attempts have been made to increase the thermal conductivity of the insulating layer of a printed wiring board on which electronic components are mounted, or to attach an electronic component or a printed wiring board to a heat sink via a thermal interface material having electrical insulation properties. As such an insulating layer and thermal interface material, a composite sheet composed of a resin and a ceramic such as boron nitride is used as a heat dissipation member.

[0003] As such a composite sheet, a composite sheet in which a porous ceramic plate (for example, a boron nitride sintered plate) is impregnated with a resin has been studied (for example, see Patent Document 1). Further, in a laminate having a circuit board and a resin-impregnated boron nitride sintered body, it has also been studied to directly contact the primary particles constituting the boron nitride sintered body with the circuit board to reduce the thermal resistance of the laminate and improve the heat dissipation performance (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a method for manufacturing a large-sized resin-filled plate in which in-plane resin impregnation unevenness is suppressed. Another object of the present disclosure is to provide a large-sized resin-filled plate in which in-plane resin impregnation unevenness is suppressed and which has excellent insulating properties.

Means for Solving the Problems

[0006] In a conventional method for manufacturing a resin-filled plate, a solution or melt of a thermosetting composition is dropped onto a nitride sintered plate that has been previously formed thinly, spread by a squeegee or the like, and then semi-cured while impregnating the pores of the nitride sintered plate using capillary action. As a result of the study by the present inventors, in this case, it has been found that there is a problem that the curing behavior varies greatly due to a slight difference in the environment when semi-curing the thermosetting composition in the nitride sintered plate. As a countermeasure, when examining the step of impregnating a pre-semi-cured thermosetting composition, due to the balance between the impregnation rate and the cohesive force of the melt of the semi-cured product of the thermosetting composition, an imbalance such as liquid pooling occurs on the main surface of the nitride sintered plate, and impregnation unevenness occurs in the resulting resin-filled plate. Although this was not a major problem when the area of the main surface of the nitride sintered plate was sufficiently small, when using a large-sized nitride sintered plate (for example, the area of the main surface is 2500 mm 2 or more, etc.), a new problem occurs in that the problem of uneven resin impregnation becomes apparent in the resulting resin-filled plate, and by a method in which the curing of the thermosetting composition is advanced to such an extent that it can be formed into a sheet in advance and laminated so as to cover the main surface of the nitride sintered plate, the impregnation environment of the semi-cured product is made uniform on the nitride sintered plate, and it has been found that the above problems can be reduced by reducing the occurrence of liquid pooling when impregnating the nitride sintered plate. The present disclosure has been made based on the above findings. It has also been confirmed that when trying to use a resin-filled plate with uneven resin impregnation by adhering it to a metal plate or the like and using it as an insulating plate, the insulating properties are not exhibited as expected.

[0007] The present disclosure provides the following [1].

[0008] [1] The first resin sheet, a porous nitride sintered plate having a main surface area of 2500 mm 2 or more, and a second resin sheet are laminated in this order so as to be in contact with each other, and by heating, the first resin sheet and the second resin sheet are melted, and the molten resin is impregnated into the pores of the nitride sintered plate to obtain a resin-filled plate. The manufacturing method of the resin-filled plate, wherein the first resin sheet and the second resin sheet are molded bodies of semi-cured products of a thermosetting composition.

[0009] In the manufacturing method of the resin-filled plate described above, a means of impregnating resin from both sides of the nitride sintered plate using a resin sheet which is a molded body of a semi-cured product of a thermosetting composition prepared in advance is adopted. By adopting such a method, even when using a large-sized nitride sintered plate, when impregnating the resin into the pores of the nitride sintered plate, the environment of resin impregnation on the main surface of the nitride sintered plate can be made uniform, the generation of liquid pooling can be suppressed, and the generation of variation in resin impregnation can be suppressed.

[0010] The present disclosure also provides the following [2] to [7].

[0011] [2] The manufacturing method according to [1], wherein the ratio of the volume of the first resin sheet to the volume of the second resin sheet is 1 to 5. [3] The manufacturing method according to [1] or [2], wherein the volume of the first resin sheet is 0.5 times or more based on the total volume of the open pores of the nitride sintered plate. [4] The manufacturing method according to any one of [1] to [3], wherein the median pore diameter of the pores of the nitride sintered plate is 0.3 to 6.0 μm. [5] The manufacturing method according to any one of [1] to [4], wherein the shear viscosity at 120°C of the semi-cured product constituting the first resin sheet and the second resin sheet is 100 to 2500 mPa·s. [6] A step of further laminating a first setter, a ceramic green sheet containing a nitride, and a second setter in this order, and firing the ceramic green sheet to obtain the nitride sintered plate is further included. The area of the main surface of the ceramic green sheet is 2500 mm 2 or more, The manufacturing method according to any one of [1] to [5], wherein the area of the main surfaces of the first setter and the second setter is equal to or larger than the area of the main surface of the ceramic green sheet. [7] A resin-filled plate having a porous nitride sintered plate and a semi-cured product of a thermosetting composition filled in pores of the nitride sintered plate, The area of the main surface of the resin-filled plate is 2500 mm 2 or more, A resin-filled plate, wherein when an observation image is obtained from one main surface side of the resin-filled plate and a light-colored region is specified by binarizing the observation image, the ratio of the area of the light-colored region is less than 3 area%.

Advantages of the Invention

[0012] According to the present disclosure, a method for manufacturing a large-sized resin-filled plate with suppressed variation in resin impregnation in the plane can be provided. According to the present disclosure, a large-sized resin-filled plate with suppressed variation in resin impregnation in the plane and excellent insulation can also be provided.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as appropriate. However, the following embodiments are examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant descriptions are omitted as appropriate. Also, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0015] Unless otherwise specified, the materials exemplified in this specification can be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified.

[0016] In this specification, the resin-filled plate means a sheet-like composite having a porous nitride sintered plate and a semi-cured resin portion impregnated in the pores of the nitride sintered plate. The semi-cured resin portion is a semi-cured product of a thermosetting composition. In this specification, the semi-cured product means that the resin constituting the semi-cured product is in a state where it can be further cured, and is also referred to as a B-stage state. The resin-filled plate in this specification is provided with a semi-cured resin portion, so that when heated, the semi-cured resin portion melts and further curing can proceed, and by utilizing this state, it is possible to adhere to other members.

[0017] One embodiment of the method for manufacturing a resin-filled plate is to stack a first setter, a ceramic green sheet containing nitride, and a second setter in this order, and fire the ceramic green sheet to obtain the nitride sintered plate (hereinafter, also referred to as the sintered plate preparation step), and a first resin sheet, the area of the main surface is 2500 mm 2The porous nitride sintered plate and the second resin sheet are laminated in this order so as to be in contact with each other, and by heating, the first resin sheet and the second resin sheet are melted, and the molten resin is impregnated into the pores of the nitride sintered plate to obtain a resin-filled plate (hereinafter, also referred to as a filling plate preparation step). As the nitride sintered plate, those prepared separately can also be used. In other words, if the predetermined nitride sintered plate of the present disclosure can be obtained, the above-described sintered plate preparation step is an optional step and can be omitted.

[0018] FIG. 1 is a schematic diagram for explaining a method of manufacturing a resin-filled plate. FIGS. 1(a) and 1(b) show a sintered plate preparation step of obtaining a nitride sintered plate 9 by laminating a ceramics green sheet 1 between a first setter 2a and a second setter 2b and firing. FIGS. 1(c) and 1(d) show a filling plate preparation step of preparing a resin-filled plate 10 by laminating a first resin sheet 6a and a second resin sheet 6b in contact with both main surfaces of the nitride sintered plate 9 and impregnating the molten resin into the pores of the nitride sintered plate 9.

[0019] The porous nitride sintered plate has nitride particles and pores formed by sintering primary nitride particles together, and is a porous nitride sintered plate. Examples of the nitride sintered plate include a boron nitride sintered plate, a silicon nitride sintered plate, and an aluminum nitride sintered plate. The nitride sintered plate is preferably a boron nitride sintered plate because it is easier to form pores for resin filling and is also excellent in elastic modulus and the like for long-term reliability.

[0020] The shape of the nitride sintered plate as viewed from above is not particularly limited, but from the viewpoint of cutting and using the resin-filled plate, it may be, for example, square or rectangular.

[0021] The nitride sintered plate has a main surface area of 2500 mm 2 or more, and is a large-sized sintered plate. The lower limit value of the main surface area is, for example, 4000 mm 2 or more, 6000 mm 2 or more, 8000 mm 2 or more, or 10000 mm2 This may be the case. According to the method for manufacturing the resin-impregnated plate described above, since it is possible to suppress variations in resin impregnation, even if a nitride sintered plate having a large main surface area is adopted, the resin-impregnated plate desired by the present disclosure can be manufactured. The upper limit value of the area of the main surface is, for example, 250,000 mm 2 or less, 200,000 mm 2 or less, 150,000 mm 2 or less, or 100,000 mm 2 or less. Note that the area of the main surface of the nitride sintered plate means the area of the region surrounded by the outer periphery when the nitride sintered plate is viewed from above, and is not affected by the unevenness of the surface or the presence or absence of pores.

[0022] The upper limit value of the thickness of the nitride sintered plate may be, for example, 0.5 mm or less, 1.0 mm or less, 1.5 mm or less, or 2.0 mm or less. When the upper limit value of the thickness is within the above range, the filling of the resin becomes easier, so that variations in resin impregnation in the obtained resin-impregnated plate can be further suppressed. The lower limit value of the thickness of the nitride sintered plate may be, for example, 0.05 mm or more, 0.1 mm or more, 0.2 mm or more, or 0.3 mm or more. The thickness of the nitride sintered plate is measured along the direction perpendicular to the main surface. When the thickness is not constant, any 10 points are selected for thickness measurement, and it is sufficient if the average value is within the above range. Note that the thickness of the resin-impregnated plate corresponds to the thickness of the nitride sintered plate.

[0023] The upper limit value of the median pore diameter of the pores in the nitride sintered plate may be, for example, 6.0 μm or less, 5.5 μm or less, 5.0 μm or less, 4.0 μm or less, 3.8 μm or less, 3.6 μm or less, 3.4 μm or less, 3.2 μm or less, or 3.0 μm or less. Since such a nitride sintered plate has small pore sizes, the contact area between nitride particles can be made sufficiently large, and the thermal conductivity can be increased. The lower limit value of the median pore diameter of the pores in the nitride sintered plate may be, for example, 0.3 μm or more, 0.5 μm or more, 1.0 μm or more, 1.5 μm or more, 1.6 μm or more, 1.7 μm or more, 1.8 μm or more, 1.9 μm or more, or 2.0 μm or more. When the lower limit value of the median pore diameter is within the above range, the melt of the resin sheet can penetrate more easily. The median pore diameter of the pores in the nitride sintered plate may be adjusted within the above range, for example, 0.3 to 6.0 μm, 1.5 to 4.0 μm, or 2.0 to 3.0 μm.

[0024] The median pore diameter and the total pore volume (total volume of open pores) of the pores in the nitride sintered plate can be measured by the following procedure. First, for the nitride sintered plate to be measured, using a mercury porosimeter, while increasing the pressure from 0.0042 MPa to 206.8 MPa, the pore size distribution when the nitride sintered plate is pressurized is determined. 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. In the case where a resin-filled plate is the measurement target, first, the resin-filled plate is heated to remove the semi-cured product of the thermosetting composition to obtain a nitride sintered plate, and then the measurement is performed.

[0025] The upper limit of the porosity of the nitride sintered plate, that is, the ratio of the volume of pores in the nitride sintered plate, may be, for example, 65% by volume or less, 60% by volume or less, or 58% by volume or less. By setting the upper limit of the porosity of the nitride sintered plate within the above range, a decrease in the mechanical strength of the nitride sintered plate can be more sufficiently suppressed, and a resin-filled plate with better handleability can be provided. The lower limit of the porosity of the nitride sintered plate may be, for example, 40% by volume or more, 42% by volume or more, 44% by volume or more, or 45% by volume or more. By setting the upper limit of the porosity of the nitride sintered body within the above range, the content of the semi-cured product of the thermosetting composition can be improved, and the adhesiveness with an adherend such as a metal plate can be further improved. The porosity of the nitride sintered plate may be adjusted within the above range, for example, 40 to 65% by volume, or 40 to 60% by volume.

[0026] The porosity of the nitride sintered plate can be determined from the volume and mass of the nitride sintered plate by calculating the bulk density [Y (kg / m 3 )], and using this bulk density and the theoretical density [X (kg / m 3 )] of the nitride, it 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. In the case of boron nitride, the theoretical density X is 2280 kg / m 3 . In the case of aluminum nitride, the theoretical density X is 3260 kg / m 3 . In the case of silicon nitride, the theoretical density X is 3170 kg / m 3 . Porosity (% by volume) = [1 - (Y / X)] × 100... Formula (1)

[0027] When the nitride sintered plate is a boron nitride sintered body, the bulk density may be 800 to 1500 kg / m 3 , or 1000 to 1400 kg / m 3 . If the bulk density becomes too small, the strength of the nitride sintered plate tends to decrease. Also, by setting the upper limit of the bulk density within the above range, the filling amount of the cured resin can be made more sufficient, and the adhesiveness between the resin-filled plate and an adherend such as a metal plate can be made better.

[0028] The sintered plate preparation process in the case of preparing the above nitride sintered plate will be described.

[0029] The ceramic green sheet in the sintered plate preparation process may be a sheet formed by preparing a formulation containing a nitride as a ceramic raw material and shaping the formulation into a sheet. The shaping method is not particularly limited. For example, it may be performed by uniaxial pressing or may be performed by the cold isostatic pressing (CIP) method. The shaping pressure may be, for example, 5 to 350 MPa. By adjusting the shaping method and its shaping pressure, or the composition of the formulation described later, etc., the pore diameter, porosity, bulk density, etc. of the nitride sintered plate can be adjusted.

[0030] In addition to the nitride, the above formulation may contain, for example, a sintering aid, a binder resin, a solvent, and the like.

[0031] Examples of the nitride include boron carbonitride, boron nitride, silicon nitride, and aluminum nitride. Examples of the sintering aid include metal oxides such as yttrium oxide, aluminum oxide, and magnesium oxide, carbonates of alkali metals such as lithium carbonate and sodium carbonate, carbonates of alkaline earth metals such as calcium carbonate, and boric acid. By using a sintering aid, the sintering of the above nitride can be promoted.

[0032] When blending a sintering aid, the blending amount of the sintering aid may be, for example, 0.01 parts by mass or more, or 0.1 parts by mass or more, based on 100 parts by mass in total of the nitride and the sintering aid. The blending amount of the sintering aid may be, for example, 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less, based on 100 parts by mass in total of the nitride and the sintering aid. By setting the addition amount of the sintering aid within the above range, it becomes easier to adjust the median pore diameter of the nitride sintered body to the range described later. The blending amount of the sintering aid may be adjusted within the above range and may be, for example, 0.01 to 20 parts by mass, or 0.01 to 10 parts by mass, based on 100 parts by mass in total of the nitride and the sintering aid.

[0033] Examples of the binder resin include methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyvinyl butyral, and (meth)acrylic resins. By using the binder resin, the molding of the composition containing the nitride becomes easier, and it can be molded into various shapes such as a sheet shape. Examples of the solvent include organic solvents such as ethanol and toluene. By using the binder resin and the solvent, the above-mentioned composition becomes slurry-like, and the viscosity can be easily adjusted.

[0034] The area of the main surface of the ceramic green sheet may be adjusted according to the area of the main surface of the nitride sintered body. For example, it may be 2500 mm 2 or more, 4000 mm 2 or more, 6000 mm 2 or more, 8000 mm 2 or more, or 10000 mm 2 or more. The upper limit value of the area of the main surface of the ceramic green sheet may be, for example, 250000 mm 2 or less, 200000 mm 2 or less, 150000 mm 2 or less, or 100000 mm 2 or less.

[0035] In the sintered plate preparation step, the areas of the main surfaces of the first setter and the second setter are adjusted so that the main surface of the ceramic green sheet fits within the regions of the main surfaces of the first setter and the second setter. The areas of the main surfaces of the first setter and the second setter may be equal to or larger than the area of the main surface of the ceramic green sheet. By setting the areas of the main surfaces of the first setter and the second setter as described above, the occurrence of warping of the obtained nitride sintered plate can be more suppressed.

[0036] As the first setter and the second setter, a nitride ceramic sintered body or the like can be used. Examples of the nitride ceramic sintered body include a boron nitride sintered body and an aluminum nitride sintered body.

[0037] The heat treatment of the ceramic green sheet in the sintered plate preparation process is carried out by a plurality of heat treatments. For example, it may have a degreasing process of performing heat treatment at a heating temperature of 800 °C or lower, and a sintering process of performing heat treatment at a temperature higher than the heating temperature in the degreasing process. In the degreasing process, mainly, a binder resin or the like is burned to degrease the green sheet. Then, in the sintering process, a raw material containing a nitride and a sintering aid is sintered to obtain a nitride sintered plate.

[0038] The heating temperature in the degreasing process may be, for example, 400 - 750 °C, 500 - 700 °C, or 600 - 650 °C. By setting the upper limit value of the heating temperature within the above range, organic substances such as binder resin can be sufficiently removed before the sintering of the nitride, making the system more homogeneous, and then sintering can be carried out in the subsequent second heat treatment. The heating time in the degreasing process may be, for example, 0.5 - 20 hours.

[0039] The heating temperature in the sintering process is higher than the heating temperature in the degreasing process. The heating temperature in the sintering process may be, for example, 1600 - 2050 °C, 1700 - 1950 °C, or 1800 - 1900 °C. The heating time in the sintering process may be, for example, 5 - 15 hours. The sintering process may be carried out, for example, in a non-oxidizing gas atmosphere such as nitrogen, argon, ammonia, and hydrogen.

[0040] The first resin sheet and the second resin sheet used in the filling plate preparation process are molded bodies obtained by molding a semi-cured product of a thermosetting composition. The thermosetting composition may be a resin composition containing a main agent and a curing agent. The curing rate of the above semi-cured product may be, for example, 10% or more, 20% or more, 25% or more, or 30% or more. The curing rate of the above semi-cured product may be, for example, 80% or less, 70% or less, or 65% or less.

[0041] The above curing rate can be determined by measurement using a differential scanning calorimeter. The curing rate of the semi-cured product 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, 10 mg of a sample taken from the resin included in the composite sheet is heated in the same manner to determine the calorific value R per unit mass generated when it is completely cured. Assuming that the resin contains c (mass%) of a component having thermosetting properties, the curing rate of the semi-cured product impregnated in the resin filling plate can be determined by the following formula (2). Whether the resin is completely cured or not can be confirmed by the end of heat generation in the heat generation curve obtained by differential scanning calorimetry. Curing rate of semi-cured product (%) = {1 - [(R / c) × 100] / Q} × 100... Formula (2)

[0042] The semi-cured products constituting the first resin sheet and the second resin sheet may contain, for example, at least one selected from the group consisting of epoxy resin, cyanate resin, phenol resin, melamine resin, urea resin, bismaleimide resin, thermosetting polyimide, maleimide resin, maleimide-modified resin, silicone resin, silicone rubber, unsaturated polyester, polyurethane, and alkyd resin. The semi-cured product constituting the first resin sheet and the semi-cured product constituting the second resin sheet may be the same or different.

[0043] The shapes of the first resin sheet and the second resin sheet may be the same as or different from each other, and may be the same as the shape of the nitride sintered plate. From the viewpoint of making the production of the resin filling plate easier, the shapes of the first resin sheet and the second resin sheet are the same and are the same as the shape of the silicon nitride sintered plate.

[0044] The areas of the main surfaces of the first resin sheet and the second resin sheet may be adjusted so that when the first resin sheet, the nitride sintered plate, and the second resin sheet are laminated, the main surface of the nitride sintered plate is within the regions of the main surfaces of the first resin sheet and the second resin sheet.

[0045] The volumes of the first resin sheet and the second resin sheet may be prepared from the viewpoint of more sufficiently impregnating the open pores of the nitride sintered plate with the semi-cured product of the thermosetting composition. The lower limit value of the volume of the first resin sheet may be, for example, 0.5 times or more, 0.6 times or more, 0.7 times or more, 0.8 times or more, 0.9 times or more, 1.0 times or more, 1.1 times or more, 1.2 times or more, or 1.3 times or more based on the total volume of the open pores of the nitride sintered plate. The upper limit value of the volume of the first resin sheet may be, for example, 3.5 times or less, 3.0 times or less, 2.5 times or less, or 2.0 times or less based on the total volume of the open pores of the nitride sintered plate. By setting the lower limit value of the volume within the above range, an excessive increase in the manufacturing cost of the resin-filled plate can be suppressed. The description of the volume of the first resin sheet described above can be applied to the volume of the second resin sheet.

[0046] The volumes of the first resin sheet and the second resin sheet may be the same or different. However, by making the volume of one resin sheet larger than the volume of the other resin sheet, the supply amount of the molten resin from one surface of the nitride sintered plate in the manufacturing process of the resin-filled plate can be increased. Even if resin aggregation occurs prior to impregnation, since there is a sufficient volume of resin, the influence of aggregation can be further reduced, and the variation in resin impregnation in the resulting resin-filled plate can be further suppressed. For example, by making the volume of the first resin sheet larger than the volume of the second resin sheet, the supply amount of the molten resin from the surface (the upper surface in the vertical direction) of the nitride sintered plate in the manufacturing process of the resin-filled plate can be increased. Even when resin aggregation of the resin sheet occurs, since a sufficient volume of the semi-cured product of the thermosetting composition exists on the surface of the nitride sintered body, the imbalance in the impregnation environment is further suppressed, and the variation in resin impregnation in the resulting resin-filled plate can be further suppressed.

[0047] The ratio of the volume of the first resin sheet to the volume of the second resin sheet may be, for example, 1 to 5, 1.5 to 4.5, 2 to 4, 2.5 to 3.5, or 2.5 to 3.0. When the resin sheet laminated on the surface of the nitride sintered plate (the upper surface facing the vertical direction) in the manufacturing process of the resin-filled plate is defined as the first resin sheet, it is desirable that the volume of the first resin sheet is larger than the volume of the second resin sheet, and the ratio of the volume of the first resin sheet to the volume of the second resin sheet may be, for example, 1.5 to 4.5, 2 to 4, 2.5 to 3.5, or 2.5 to 3.0.

[0048] The shear viscosity at 120°C of the above-mentioned semi-cured product constituting the first resin sheet and the second resin sheet can be adjusted according to maintaining the resin sheet in a sheet form and the pore diameter of the nitride sintered plate, etc. The lower limit value of the shear viscosity at 120°C of the above-mentioned semi-cured product constituting the first resin sheet may be, for example, 100 mPa·s or more, 130 mPa·s or more, 160 mPa·s or more, or 200 mPa·s or more. By the lower limit value of the shear viscosity being within the above range, the handleability of the resin sheet can be further improved. The upper limit value of the shear viscosity at 120°C of the above-mentioned semi-cured product constituting the first resin sheet may be, for example, 2500 mPa·s or less, 2000 mPa·s or less, 1500 mPa·s or less, or 1000 mPa·s or less. By the upper limit value of the shear viscosity being within the above range, the impregnation into the pores of the nitride sintered plate becomes easier, and the uneven impregnation in the obtained resin-filled plate can be further suppressed. The shear viscosity of the second resin sheet can apply the description of the shear viscosity of the above-mentioned first resin sheet. The shear viscosity of the above-mentioned semi-cured product constituting the first resin sheet and the shear viscosity of the above-mentioned semi-cured product constituting the second resin sheet may be the same or different. The shear viscosity at 120°C of the above-mentioned semi-cured product constituting the first resin sheet and the second resin sheet may be, for example, 100 to 2500 mPa·s, or 200 to 1000 mPa·s.

[0049] The shear viscosity at 120°C of the above-mentioned semi-cured product constituting the first resin sheet and the second resin sheet means the value measured using a rheometer. The measurement shall be performed by collecting 2 g of the resin from the above-mentioned resin sheet and using this as the measurement sample. The measurement shall first heat the stage to 120°C, place the above-mentioned measurement sample to be measured between the parallel plate and the stage, and rotate the parallel plate at a shear rate of 1 / 10 s. As the rheometer, for example, a modular compact rheometer "MCR92" (trade name) manufactured by Anton Paar can be used.

[0050] One embodiment of the resin-filled plate is a resin-filled plate having a porous nitride sintered plate and a semi-cured product (semi-cured resin part) of a thermosetting composition filled in the pores of the nitride sintered plate.

[0051] The shape of the main surface of the above-mentioned resin-filled plate is not particularly limited, but from the viewpoint of cutting and using the resin-filled plate, it is preferably square or rectangular.

[0052] The area of the main surface of the above-mentioned resin-filled plate may be 2500 mm 2 or more. The area of the main surface may be, for example, 2500 to 250000 mm 2 , 6000 to 200000 mm 2 , 8000 to 150000 mm 2 , or 10000 to 100000 mm 2 . It is possible to cut out a plurality of resin-filled plates from the obtained resin-filled plate, and it is useful because a resin-filled plate with stable quality can be stably provided.

[0053] When an observation image is obtained from one main surface side of the above-mentioned resin-filled plate and the thin color region is specified by binarizing the observation image, the ratio of the area of the thin color region may be 5 area% or less. Since the thin color region corresponds to a region where the impregnation of the resin is insufficient, the small area of the thin color region corresponds to the suppression of the variation in resin impregnation.

[0054] The upper limit value of the area ratio of the light-colored region may be, for example, less than 3 area%, less than 2 area%, less than 1.5 area%, less than 1.3 area%, less than or equal to 1.2 area%, or less than 1 area%. By the upper limit value of the area ratio of the light-colored region being within the above range, the insulation property of the resin-filled plate itself and the laminated substrate including the resin-filled plate as an insulating sheet can be further improved. The lower limit value of the area ratio of the light-colored region is not particularly limited, and the entire main surface of the resin-filled plate may be uniform, but may be, for example, 0.1 area% or more, 0.3 area% or more, or 0.5 area% or more.

[0055] In this specification, the area of the light-colored region means a value determined in accordance with the method described below. First, place the measurement sample on a flat workbench in a room of 300 to 900 lux. Next, acquire an image from the upper surface of the measurement sample. Import the acquired image into image analysis software, perform grayscale conversion, check the brightness threshold value in 255 steps, and use the 216th step from black to white as the threshold value to perform binarization processing to create a binarized image. In the obtained binarized image, the white region is defined as the light-colored region, and the area ratio of the light-colored region is determined by the above image analysis software. As the image analysis software, for example, "GIMP" (product name) manufactured by GNU General Public License can be used.

[0056] The volume ratio of the nitride sintered plate in the resin-filled plate may be, for example, 40 to 70 volume% or 45 to 65 volume% based on the total volume of the resin-filled plate. The volume ratio of the cured resin in the resin-filled plate may be, for example, 30 to 60 volume% or 35 to 55 volume% based on the total volume of the resin-filled plate. Since a resin-filled plate with such a volume ratio can exhibit more excellent mechanical strength, it is possible to further suppress the occurrence of cracks or the like in the resin-filled plate when manufacturing a composite substrate.

[0057] The semi-cured product may contain at least one selected from the group consisting of, for example, epoxy resins, cyanate resins, phenol resins, melamine resins, urea resins, bismaleimide resins, thermosetting polyimides, maleimide resins, maleimide-modified resins, silicone resins, silicone rubbers, unsaturated polyesters, polyurethanes, and alkyd resins.

[0058] The above resin-filled plate contains a semi-cured product of a thermosetting composition and is excellent in adhesiveness to an adherend such as a metal layer, and thus is useful as an adhesive member for applications where thermal conductivity and insulation are required. Specifically, the above resin-filled plate can be used as an adhesive member for bonding a metal circuit and other layers in a power module structure, an LED light-emitting device, etc. That is, the above resin-filled plate is suitable for manufacturing a laminated substrate.

[0059] One embodiment of the laminated substrate includes the above resin-filled plate and a metal layer provided on the resin-filled plate. FIG. 2 is a cross-sectional view when an example of the laminated substrate is cut in the thickness direction. The laminated substrate 100 includes a resin-filled plate 10, a metal layer 30 adhered to the main surface 10a of the resin-filled plate 10, and a metal layer 40 adhered to the main surface 10b of the resin-filled plate 10. In a modified example of the laminated substrate 100, it is not essential to include both of the metal layers 30 and 40, and only one of the metal layers 30 and 40 may be included.

[0060] The metal layers 30 and 40 may be, for example, metal plates or metal foils. Further, the metal layers 30 and 40 may have a pattern such as a circuit, for example. Examples of the material of the metal layers 30 and 40 include aluminum and copper. The material, thickness, and presence or absence of a pattern of the metal layers 30 and 40 may be the same as or different from each other. The thickness of the metal layers 30 and 40 may be, independently of each other, for example, 0.035 mm or more, or 10 mm or less.

[0061] The laminated substrate 100 is thin and has excellent adhesiveness and heat dissipation between members. Therefore, for example, as a heat dissipation member, it can be suitably used for semiconductor devices and the like. The laminated substrate 100 can also be said to be a temporarily crimped body. In a modified example of the laminated substrate 100, the semi-cured product constituting the resin-filled plate 10 may be heated and melted, and pressure may be applied as necessary to further improve the adhesive force with the metal layers 30 and 40. The modified example of the laminated substrate includes an insulating sheet and a metal layer provided on the insulating sheet, and the insulating sheet is a cured product of the resin-filled plate described above.

[0062] As described above, several embodiments have been described, but the present disclosure is not limited to the above embodiments at all. Also, the description contents of the above-described embodiments can be applied to each other.

Example

[0063] Hereinafter, the content of the present disclosure will be described in more detail with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples.

[0064] (Example 1) [Production of nitride sintered plate] 100 parts by mass of orthoboric acid manufactured by Shin Nippon Chemical 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 into a graphite crucible and heated at 2200 ° C for 5 hours in an argon atmosphere in an arc furnace to obtain a massive boron carbide (B4C). The obtained massive material was roughly pulverized with a jaw crusher to obtain a coarse powder. This coarse powder was further pulverized by a ball mill having silicon carbide balls (φ10 mm) to obtain a pulverized powder.

[0065] The prepared pulverized powder was filled into a boron nitride crucible. Then, using a resistance heating furnace, it was heated at 2000 ° C and 0.85 MPa for 10 hours in a nitrogen gas atmosphere. In this way, a fired product containing boron carbonitride (B4CN4) was obtained.

[0066] A sintering aid was prepared by blending powdery boric acid and calcium carbonate. In the preparation, 50.0 parts by mass of calcium carbonate was blended with respect to 100 parts by mass of boric acid. At this time, the atomic ratio of boron to calcium was 17.5 atomic % of calcium with respect to 100 atomic % of boron. 20 parts by mass of the sintering aid was blended with respect to 100 parts by mass of the fired product containing the above-mentioned short boron nitride, and mixed using a Henschel mixer to prepare a powdery blend.

[0067] The blend was pressed at 150 MPa for 30 seconds using a powder press machine to form a sheet shape (length × width × thickness = 100 mm × 200 mm × 0.3 mm), and a ceramic green sheet was obtained.

[0068] Two boron nitride setters (length × width × thickness = 100 mm × 200 mm × 2.0 mm) were prepared and laminated so as to sandwich the above-mentioned ceramic green sheet to prepare a laminate. The obtained laminate was put into a boron nitride container and introduced into a batch type high-frequency furnace. In the batch type high-frequency furnace, it was heated for 5 hours under the conditions of normal pressure, a nitrogen flow rate of 5 L / min, and 2000 °C. Then, a boron nitride sintered plate (nitride sintered plate) was taken out from the boron nitride container. In this way, a square columnar boron nitride sintered plate was obtained. The area of the main surface of the boron nitride sintered plate was 20000 mm 2 and the thickness was 0.3 mm, and the median pore diameter was 2.4 μm.

[0069] [Preparation of Resin Composition] Into a container, 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 measured, and 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 with respect to a total of 100 parts by mass of the above three compounds. Since the epoxy resin was in a solid state at room temperature, it was mixed in a heated state at about 80 °C. The viscosity of the obtained thermosetting resin composition at 100 °C was 10 mPa·s.

[0070] The following compounds were used for the preparation of the thermosetting resin composition.

[0071] Compound having a cyanate group: Dimethyl methylene bis(1,4-phenylene) biscyanate (manufactured by 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 Kayaku Kasei Co., Ltd., trade name: BMI-80) Compound having an epoxy group: 1,6-bis(2,3-epoxypropane-1-yloxy)naphthalene (manufactured by DIC Corporation, trade name: HP-4032D)

[0072] Phosphine-based curing agent: Tetraphenylphosphonium tetra-p-tolylborate (manufactured by Kasei Chemical Co., Ltd., trade name: TPP-MK) Imidazole-based curing agent: 1-(1-cyanomethyl)-2-ethyl-4-methyl-1H-imidazole (manufactured by Shikoku Chemicals Corporation, trade name: 2E4MZ-CN)

[0073] [Preparation of the first and second resin sheets] After heating the prepared resin composition at 120°C for 240 minutes, it was molded into a sheet shape by press molding and cooled to prepare two resin sheets (length × width × thickness = 110 mm × 210 mm × 0.13 mm) made of a semi-cured product of the thermosetting composition. The shear viscosity of the above semi-cured product constituting the resin sheet at 120°C was 450 mPa·s.

[0074] [Preparation of the resin-filled plate] The above-prepared resin sheets were laminated on both main surfaces of the boron nitride sintered plate so as to be in contact therewith, and heated in two steps: heating on a heating plate such as a hot plate and heating in a vacuum dryer. The former was to leave the resin sheet on a hot plate heated to 120°C for 3 minutes to melt the resin sheet, and utilize the capillary phenomenon to impregnate the semi-cured product of the thermosetting composition into the pores of the nitride sintered plate. The latter was to heat while evacuating to 2 kPa in a vacuum dryer heated to 130°C, and perform heating for a total of 5 minutes to melt the resin sheet, and utilize the capillary phenomenon to impregnate the semi-cured product of the thermosetting composition into the pores of the nitride sintered plate. After impregnation, a tabletop hot roll press (manufactured by Takizawa Co., Ltd., product name: HSRP-60150H) was used to smooth the boron nitride sintered body while removing the excess melt remaining on both main surfaces under atmospheric pressure. In this way, a resin-filled plate (composite sheet) with smooth main surfaces was obtained.

[0075] <Evaluation of Resin-Filled Plate: Determination of the Ratio of the Area of the Light Color Region> The measurement sample was placed on a flat workbench in a room of 500 lux, and an image was acquired from the upper surface of the measurement sample. The acquired image was imported into image analysis software (manufactured by GNU General Public License, "GIMP" (product name)), grayscale conversion was performed, the brightness threshold was confirmed in 255 steps, and the 216th step from black to white was used as the threshold for binarization processing to create a binarized image. In the obtained binarized image, the white region was defined as the light color region, and the area ratio of the light color region was determined by the above image analysis software. For reference, photographs showing the upper surfaces of the resin-filled plates of Example 1 are shown in FIG. 3, and the binarized images of the resin-filled plates of Example 1 are shown in FIG. 4.

[0076] <Evaluation of Resin-Filled Plate: Variation in Resin Impregnation> The obtained resin-filled plates were evaluated according to the following criteria based on the area ratio of the above light color region. A: The light color region is less than 1 area%. B: The light color region is 1 area% or more and less than 2 area%. C: The light color region is 2 area% or more and less than 3 area%. D: The light-colored area is 3% or more and less than 5% of the area. E: The light-colored area is 5% or more of the area.

[0077] <Evaluation of Resin-Filled Plate: Insulation> The insulation of the above resin-filled plate was evaluated by the method described below.

[0078] [Evaluation of Insulation] The obtained resin-filled plate was cut out into a 50 mm□ shape from the end using a cutter to obtain measurement samples. In Example 1, a total of 8 samples were cut out. One of the cut measurement samples was placed on a copper plate inside a measurement jig (manufactured by Onishi Electronics Co., Ltd.), and a 40 mm□×1 mmt copper plate was placed on its center part, and the measurement sample was filled with insulating oil (manufactured by 3M, product name: Novec 7200) so that the measurement sample was sufficiently immersed. Next, an electrode was lowered from above the measurement sample to create a situation where electricity could be conducted between the device and the measurement sample, and in accordance with JIS C 2110-1:2016, using a high-voltage withstand tester (manufactured by Measurement Technology Research Laboratory Co., Ltd.), the breakdown voltage was measured. For each of the 8 measurement samples cut out from one resin-filled plate (large size), the same measurement was performed, and among the obtained measurement values, the lowest value was adopted as the breakdown voltage value of the resin-filled plate. Then, the results of the measured breakdown voltage were evaluated according to the following criteria. The results are shown in Table 1. A: The breakdown voltage is 10 kV or more. B: The breakdown voltage is 8 kV or more and less than 10 kV. C: The breakdown voltage is 6 kV or more and less than 8 kV. D: The breakdown voltage is 4 kV or more and less than 6 kV. E: The breakdown voltage is less than 4 kV.

[0079] (Example 2) Among the two resin sheets, except that the thickness of one sheet was changed to 0.2 mm so that the ratio of the volume of the first resin sheet to the volume of the second resin sheet became 1.5 times, a resin-filled plate was obtained in the same manner as in Example 1. The obtained resin-filled plate was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0080] (Comparative Example 1) Instead of laminating the above resin sheets so as to contact both main surfaces of the boron nitride sintered plate, the resin sheet was laminated only on one main surface and not on the other main surface, and a resin-filled plate was obtained in the same manner as in Example 1 except for this. The obtained resin-filled plate was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0081] (Comparative Example 2) [Preparation of Resin-Filled Plate] A resin composition was prepared in the same manner as in Example 1. After heating the prepared resin composition at 120 °C for 15 minutes, while maintaining the temperature, it was dropped onto the upper main surface of the boron nitride sintered plate prepared in the same manner as in Example 1 using a dispenser to impregnate the resin composition. The dropping amount of the resin composition was set to 1.5 times the total volume of the pores of the boron nitride sintered body. A part of the resin composition did not impregnate the boron nitride sintered body and remained on the main surface.

[0082] 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 Narbee Co., Ltd.). The excess resin composition was removed to obtain a resin-impregnated body having a smooth main surface.

[0083] The resin-impregnated body was heated at 160 °C for 60 minutes under atmospheric pressure to semi-cure the resin composition. In this way, a rectangular prism-shaped resin-filled plate (length × width × thickness = 50 mm × 50 mm × 0.36 mm) was prepared. A part of the main surface of the resin-filled plate had the boron nitride sintered body exposed. The resin-filled plate thus obtained was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0084]

Table 1

Industrial Applicability

[0085] According to the present disclosure, it is possible to provide a method for manufacturing a large-sized resin-filled plate in which the variation in in-plane resin impregnation is suppressed. Therefore, a plurality of resin-filled plates can be cut out from the obtained resin-filled plate, and resin-filled plates with stable quality can be stably provided. According to the present disclosure, it is also possible to provide a large-sized resin-filled plate in which the variation in in-plane resin impregnation is suppressed and which has excellent insulation properties.

Description of reference numerals

[0086] 1... ceramic green sheet, 2a... first setter, 2b... second setter, 6a... first resin sheet, 6b... second resin sheet, 9... nitride sintered plate, 10... resin-filled plate, 10a, 10b... main surfaces, 30, 40... metal layers, 100... laminated substrate.

Claims

1. A first resin sheet, a porous nitride sintered plate having a main surface area of 2500 mm ２ or more, and a second resin sheet are laminated in this order so as to be in contact with each other, and by heating, the first resin sheet and the second resin sheet are melted, and the pores of the nitride sintered plate are impregnated with the molten resin to obtain a resin-filled plate. A method for manufacturing a resin-filled plate, wherein the first resin sheet and the second resin sheet are molded articles of semi-cured products of a thermosetting composition.

2. The manufacturing method according to Claim 1, wherein the ratio of the volume of the first resin sheet to the volume of the second resin sheet is 1 to 5.

3. The manufacturing method according to Claim 1 or 2, wherein the volume of the first resin sheet is 0.5 times or more based on the total volume of the open pores of the nitride sintered plate.

4. The manufacturing method according to Claim 1 or 2, wherein the median pore diameter of the pores of the nitride sintered plate is 0.3 to 6.0 μm.

5. The manufacturing method according to Claim 1 or 2, wherein the shear viscosity at 120°C of the semi-cured product constituting the first resin sheet and the second resin sheet is 100 to 2500 mPa·s.

6. Further comprising a step of laminating a first setter, a ceramic green sheet containing nitride, and a second setter in this order, and firing the ceramic green sheet to obtain the nitride sintered plate, The area of the main surface of the ceramic green sheet is 2500 mm ２ or more, The manufacturing method according to Claim 1 or 2, wherein the area of the main surfaces of the first setter and the second setter is equal to or larger than the area of the main surface of the ceramic green sheet.

7. A resin-filled plate having a porous nitride sintered plate and a semi-cured product of a thermosetting composition filled in the pores of the nitride sintered plate, The area of the main surface of the resin filling plate is 2500 mm ２ or more, A resin-filled plate, wherein when an observation image is obtained from one main surface side of the resin-filled plate and a light-colored region is specified by binarizing the observation image, the ratio of the area of the light-colored region is less than 3 area%.

Images