Method for manufacturing a laminate

Abstract

A method for manufacturing a laminate that can prevent defects that may occur in the insulating layer for a laminate using a circuit pattern with a thickness of 0.8 mm or more is proposed. A method for manufacturing a laminate (1) having a metal base substrate (2), an insulating layer (3) formed by curing a resin composition, and a circuit pattern (4) having a thickness of 1 mm or more, comprising: a process of preparing a pre-compressed laminate (1A) in which a semi-cured resin composition (3A) is interposed between the metal base substrate (2) and the circuit pattern (4); a process of covering the pre-compressed laminate (1A) with a film (11) and placing it inside an autoclave (10); and a process of curing the semi-cured resin composition (3A) by increasing the temperature and pressure inside the autoclave (10) while exhausting the inside of the film (11).

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a laminate. Background Technology

[0002] A laminate has been known for some time as a circuit board on which electronic components such as semiconductor chips are mounted, comprising a metal base substrate, an insulating layer, and a circuit pattern (e.g., see Patent Document 1). This type of laminate is manufactured, for example, by preparing a resin composition by mixing a resin and a filler, applying the resin composition to a metal base substrate and pre-curing it, then placing a circuit pattern on the resin composition and performing a heat press.

[0003] Recently, there has been an increasing number of opportunities to use electronic components that carry high currents, such as high-brightness LEDs or power modules. In order to obtain a laminate capable of handling high currents that can use such electronic components, it is effective to lower the resistance value and, at the same time, increase the thickness of the circuit pattern so that sufficient heat dissipation is ensured when high currents are flowed. Prior art literature

[0004] Japanese Patent Publication No. JP 2002-012653 Japanese Patent Publication No. JP 2009-206225 The problem to be solved

[0005] However, when a heat press is performed during the manufacturing of a laminate, the resin composition in contact with the conductive parts (metal parts) constituting the circuit pattern is pressurized, but the gap parts located between adjacent conductive parts do not come into contact with the resin composition; consequently, the pressure applied to the resin composition in these gap parts becomes insufficient. In other words, when a heat press is performed, the pressure received by the resin composition becomes uneven depending on whether or not it is in contact with the conductive parts. In the areas where the gap parts are located, the insufficient pressure prevents the release of gases contained within the resin composition, resulting in the formation of numerous voids, which raises concerns that insulation performance may not be ensured. Particularly when the circuit pattern is made thick, the depth of these gap parts increases, making the insufficient pressure more pronounced and prone to such defects. Additionally, in the areas where the conductive parts are located, the resin composition is strongly pressed by the ends of the conductive parts (or a sudden pressure change occurs between the gap parts and the conductive parts with the ends of the conductive parts as the boundary), which may cause cracks to form when the insulating layer is formed.

[0006] In addition, when heat-pressing an object with surface irregularities, cushioning materials are sometimes used to fill the irregularities (e.g., see Patent Document 2). However, as mentioned earlier, when the depth of the gap increases, it becomes difficult to sufficiently fill the gap to the inner end even with such cushioning materials, and there were cases where the lack of pressure could not be resolved. In particular, when the thickness of the circuit pattern was 0.8 mm or more, the frequency of such defects increased.

[0007] In light of these problems, the present invention aims to provide a method for manufacturing a laminate that can prevent defects occurring in the insulating layer for a laminate using a circuit pattern with a thickness of 0.8 mm or more. means of solving the problem

[0008] The present invention is a method for manufacturing a laminate having a metal base substrate, an insulating layer formed by curing a resin composition, and a circuit pattern having a thickness of 0.8 mm or more, comprising the steps of: preparing a pre-compressing laminate having a semi-cured resin composition interposed between the metal base substrate and the circuit pattern; covering the pre-compressing laminate with a film and placing it inside an autoclave; and curing the semi-cured resin composition by increasing the temperature and pressure inside the autoclave while exhausting the inside of the film.

[0009] The above-described manufacturing method preferably includes a process of applying compressive force to the resin composition in a semi-cured state, which is performed before carrying out the process of preparing the laminate prior to compression.

[0010] In addition, in the manufacturing method described above, it is preferable that the weight average molecular weight increase rate of the resin composition in a semi-cured state be 30% or less after the process of applying the compressive force, based on the time before the process of applying the compressive force.

[0011] In addition, in the manufacturing method described above, it is preferable that the density of the resin composition in a semi-cured state be 85% or more after the process of applying the compressive force based on the actual density of the insulating layer. Effects of the invention

[0012] According to the method for manufacturing a laminate according to the present invention, defects that may occur in the insulating layer can be prevented in a laminate using a circuit pattern with a thickness of 0.8 mm or more. Brief explanation of the drawing

[0013] FIG. 1 is a drawing showing a laminate manufactured by a method for manufacturing a laminate according to one embodiment of the present invention. FIG. 2 is a diagram showing the flow of a method for manufacturing a laminate according to one embodiment of the present invention. FIG. 3 is a drawing showing an example of an autoclave used in a method for manufacturing a laminate according to one embodiment of the present invention. Specific details for implementing the invention

[0014] Hereinafter, an embodiment of a method for manufacturing a laminate according to the present invention will be described with reference to the attached drawings. However, the drawings shown in the attached drawings are schematic, and the thickness, width, and ratios between parts of each part may differ from the actual implementation.

[0015] FIG. 1 is a drawing illustrating a laminate (1) manufactured by the manufacturing method of the present embodiment. The laminate (1) comprises a metal base substrate (2), an insulating layer (3), and a circuit pattern (4).

[0016] The metal base substrate (2) is formed from a metal (which may be a single metal or an alloy), such as copper, aluminum, or iron. The metal base substrate (2) may have a single-layer structure or a multi-layer structure, and may be composed of a single component or composed of a combination of multiple components. The metal base substrate (2) of the present embodiment is plate-shaped, but it may also be a heat sink equipped with grill-shaped fins. Additionally, the metal base substrate (2) may include a configuration that enhances the effect of releasing heat to the outside, and, for example, may have a vapor chamber or a heat pipe embedded in the metal plate.

[0017] The insulating layer (3) is formed of an insulating material and is installed to cover the surface of the metal base substrate (2). The insulating layer (3) may cover the entire surface of the metal base substrate (2) or may cover only a part of the surface.

[0018] The insulating layer (3) is formed from a resin composition including a thermosetting resin. Examples of thermosetting resins include epoxy resin, phenolic resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, cyanate resin, etc. One type of thermosetting resin may be used alone, or two or more types may be used in combination.

[0019] As for the epoxy resin, monomers, oligomers, and polymers having two or more epoxy groups within one molecule may be used, regardless of their molecular weight and molecular structure. Specific examples of such epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol E-type epoxy resin, bisphenol S-type epoxy resin, hydrogenated bisphenol A-type epoxy resin, bisphenol M-type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol-type epoxy resin), bisphenol P-type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol-type epoxy resin), and bisphenol Z-type epoxy resin (4,4'-cyclohexidenebisphenol-type epoxy resin); Novolak-type epoxy resins such as phenol novolak-type epoxy resin, brominated phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, tetraphenol group ethane-type novolak-type epoxy resin, and novolak-type epoxy resin having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resin; aralkyl-type epoxy resins such as xylylene-type epoxy resin and biphenyl-aralkyl-type epoxy resin; epoxy resins having a naphthalene backbone such as naphthylene ether-type epoxy resin, naphthol-type epoxy resin, naphthalene-type epoxy resin, naphthalenediol-type epoxy resin, difunctional to tetrafunctional epoxy-type naphthalene resin, non-naphthyl-type epoxy resin, and naphthalene-aralkyl-type epoxy resin; anthracene-type epoxy resin; phenoxy-type epoxy resin; dicyclopentadiene-type epoxy resin; norbornene-type epoxy resin; and adamantane-type epoxy resin; Fluorene-type epoxy resin, phosphorus-containing epoxy resin, alicyclic epoxy resin, aliphatic chain-type epoxy resin, bisphenol A novolak-type epoxy resin, bixylenol-type epoxy resin, triphenol methane-type epoxy resin, trihydroxyphenylmethane-type epoxy resin, tetraphenyloletan epoxy resin, heterocyclic epoxy resin such as triglycidyl isocyanurate;Examples include glycidylamines such as N,N,N',N'-tetraglycidylmethoxylenediamine, N,N,N',N'-tetraglycidylbisaminomethylcyclohexane, and N,N-diglycidylaniline; copolymers of glycidyl (meth)acrylate and compounds having ethylenically unsaturated double bonds; epoxy resins having a butadiene structure; diglycidyl etherides of bisphenol; diglycidyl etherides of naphthalenediol; and glycidyl etherides of phenols. As an epoxy resin, one type may be used alone, or two or more types may be used in combination.

[0020] A curing agent is incorporated into the resin composition of the present embodiment. The curing agent is selected according to the type of thermosetting resin and is not particularly limited as long as it reacts with it. For example, when using epoxy resin, amine-based curing agents, imidazole-based curing agents, phenol-based curing agents, etc. may be used as curing agents.

[0021] In addition, a filler (inorganic filler) is incorporated into the resin composition of the present embodiment. The filler is preferably one that has excellent insulating properties and high thermal conductivity, and examples include aluminum oxide, silica, aluminum nitride, boron nitride, silicon nitride, magnesium oxide, etc. One type of filler may be used alone, or two or more types may be used in combination.

[0022] In addition, a curing accelerator is incorporated into the resin composition of the present embodiment. The curing accelerator is not particularly limited and may include, for example, organometallic salts such as benzoxazine compounds, borate complexes, zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, cobalt bisacetylacetonate (II), cobalt triacetylacetonate (III), phenol compounds such as phenol, bisphenol A, and nonylphenol, tertiary amines, tertiary amine salts, phosphine, and phosphonium salts.

[0023] In addition, a solvent is incorporated into the resin composition of the present embodiment. The solvent is not particularly limited and may include, for example, N-methylpyrrolidone, dimethylacetamide, tetrafluoroisopropanol, methyl ethyl ketone, ethylene diglycol acetate, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, ethylene glycol monomethyl ether, tetrahydrofuran, chloroform, toluene, xylene, acetone, dioxane, dimethyl sulfoxide, etc.

[0024] The resin composition may include additives. Examples of additives include stabilizers, ion capture agents, and flexibility enhancers.

[0025] The circuit pattern (4) is obtained by forming a predetermined pattern using a conductive material. Examples of such materials include metal plates of copper or aluminum. The thickness of the metal plate (thickness of the circuit pattern (4)) is 0.8 mm or more. Additionally, there is no special limit on the upper limit of the thickness of the metal plate (thickness of the circuit pattern (4)), but for example, it is 2.0 mm or less. Methods for forming a predetermined pattern using a metal plate include, for example, forming a mask pattern on the metal plate and etching away the exposed portion of the metal plate, or using a mold to perforate the metal plate.

[0026] Next, a method for manufacturing a laminate (1) will be explained with reference to FIGS. 2 and FIGS. 3.

[0027] First, the first process shown in FIG. 2 is carried out. In the first process, a thermosetting resin and a curing agent are placed in a container and stirred at a predetermined temperature for a predetermined time. Through this, the thermosetting resin and the curing agent can be reacted. Additionally, depending on the temperature and stirring time during stirring, the thermosetting resin and the curing agent reacting in the first process can be made into a prepolymer state, but this can be appropriately selected according to the degree of curing of the thermosetting resin in the process described later, and it is not necessary to make the thermosetting resin and the curing agent into a prepolymer state in the first process.

[0028] In the second process, the stirred thermosetting resin is mixed with a curing agent, a filler, a curing accelerator, and a solvent to produce a resin composition. Additionally, the resin composition in the second process is in a semi-cured state.

[0029] In the third process, the generated resin composition is applied to the surface of a thin substrate and dried to volatilize the solvent. There are no particular restrictions on the substrate as long as it can be peeled off from the resin composition in the process described later, but for example, a long PET sheet may be used. Additionally, although there are no particular restrictions on carrying out the third process, using a device equipped with a supply section for supplying the long substrate, a coating section installed downstream of the supply direction for applying the resin composition to the surface of the substrate, and a heating section installed upstream of the supply direction for heating the passing resin composition to a predetermined temperature is superior in that the application and drying of the resin composition can be performed continuously, thereby enabling the third process to be carried out efficiently.

[0030] In the fourth step, a long substrate coated with a resin composition is cut to a predetermined size to form a single-sheet material in which the resin composition and the substrate are laminated. Additionally, if a substrate that has been pre-cut to a predetermined size in the third step is used, the fourth step may be omitted.

[0031] In the fifth process, the resin composition applied to the substrate is heated at a predetermined temperature for a predetermined time. This allows the molecular weight (weight average molecular weight) of the semi-cured resin composition to be increased. Furthermore, although the molecular weight of the resin composition continues to increase in processes after the fifth process, increasing the molecular weight of the resin composition in advance during the fifth process can shorten the total time required to manufacture the laminate (1). Additionally, if the required molecular weight of the resin composition is already secured in a process prior to the fifth process, the fifth process may be omitted. As a specific example for performing the fifth process, a method may be provided in which several sheets of laminated resin composition and substrate are prepared and heated together in a heating furnace.

[0032] In the sixth process, a compressive force is applied to the resin composition in a semi-cured state. Before performing the sixth process, the resin composition contains many internal voids due to drying in the third process; however, by performing the sixth process, the density can be increased and the voids reduced, and furthermore, high insulation properties can be obtained when it is formed into an insulating layer through the process described later. One specific example for performing the sixth process is to place the sheet material described above onto the metal base substrate (2) shown in FIG. 1 in a state where the resin composition is in contact with the metal base substrate (2), and then place it inside, for example, a vacuum press device, and then, while the inside of the device is in a vacuum atmosphere and at a predetermined temperature, compress the overlapping metal base substrate (2) and the sheet material. Through this, the resin composition in a semi-cured state can be transferred to the metal base substrate (2) and a compressive force can be applied to the resin composition. In addition, a metal base substrate (2) is not strictly necessary for performing the sixth process; for example, a separately prepared substrate and the aforementioned sheet material may be overlapped and compressed, or a single sheet material may be compressed.

[0033] Meanwhile, gas can be discharged from the resin composition in a semi-cured state by carrying out the process using an autoclave (Process 8) described below. However, as a result of the inventors' investigation, there were cases where gas could not be sufficiently discharged from the resin composition even if Process 8 was carried out when the curing of the resin composition had progressed too far. Furthermore, even if Process 8 was carried out when the density of the resin composition was low and contained many internal voids, there were cases where it was difficult to reduce the voids to the extent that sufficient withstand voltage could be obtained. In light of these points, repeated investigations were conducted on the optimal range of molecular weight (weight average molecular weight) and density of the resin composition. Regarding the growth rate of the weight average molecular weight of the resin composition, the results were favorable when it was 30% or less after Process 6 (after applying compressive force) compared to before Process 6 (before applying compressive force). Additionally, as a result of further repeated investigations on the growth rate of the weight average molecular weight of the resin composition, more desirable results were obtained when it was 25% or less, and even more desirable results were obtained when it was 20% or less. In addition, the density of the resin composition was 85% or higher after the 6th process (after applying compressive force) based on the actual density of the insulation layer finally formed, and the results were satisfactory. Furthermore, as a result of repeated additional examinations regarding the density of the weight-average molecular weight of the resin composition, more desirable results were obtained when it was 90% or lower, and even more desirable results were obtained when it was 95% or lower. In addition, the weight-average molecular weight is a polystyrene equivalent value measured by the GPC (gel permeation chromatography) method.

[0034] In the seventh step, the substrate is peeled off from the semi-cured resin composition transferred onto the metal base substrate (2), or, if the resin composition is not transferred onto the metal base substrate (2), the substrate is peeled off from the resin composition after transferring it. Then, the circuit pattern (4) shown in FIG. 1 is superimposed on the resin composition to form a pre-press laminate (1A) (see FIG. 3). In this process, the circuit pattern superimposed on the resin composition may be pressed with a heat press to temporarily adhere the circuit pattern to the resin composition. Also, the reference numeral 3A shown in FIG. 3 indicates a semi-cured resin composition.

[0035] In the eighth process, an autoclave (10) having a configuration as shown in FIG. 3 and a film (bagging film) (11) are used to cure a semi-cured resin composition (3A) laminated on a laminate (1A) before compression. The autoclave (10) of this embodiment is equipped with a main body (10a) and a cover (10b). An exhaust passage (10c) is installed in the main body (10a), and a pressurizing passage (10d) is installed in the cover (10b). Additionally, a heater or the like is installed on both or one of the main body (10a) and the cover (10b) to raise the temperature inside the autoclave (10). The film (11) is preferably a fluorine resin film that is flexible and has excellent peelability. Furthermore, in carrying out this process, the use of only the film (11) is not limited to using only the film (11), and a cushion material or a breather cloth may be used in combination with the film (11).

[0036] In the eighth process, the laminate (1A) before compression is placed on the main body (10a) and covered with a film (11), and the cover (10b) is closed to clamp the film (11) between the main body (10a) and the cover (10b). Then, suction is performed from the exhaust passage (10c) to exhaust the inside of the film (11), and a pressurized gas (air or nitrogen, etc.) is injected from the pressurizing passage (10d) to increase the pressure inside the autoclave (10), and further, the temperature inside the autoclave (10) is increased by a heater. By maintaining this state for a predetermined time, the resin composition (3A) in a semi-cured state can be cured.

[0037] When performing the eighth process, it is preferable that the pressure inside the autoclave (10) be 0.8 MPa or higher and 3.0 MPa or lower, and the temperature inside the autoclave (10) be 100°C or higher and 350°C or lower, and the time for maintaining the increased pressure and temperature is 1 minute or higher and 90 minutes or lower. In addition, the pressure and temperature inside the autoclave (10) can be changed to ensure that the curing of the resin composition (3A) proceeds properly, and can be set to be maintained constant during the above time, or can be set to change over time.

[0038] By performing the eighth process, the film (11) not only adheres to the surface of the conductive portion (metal portion) constituting the circuit pattern (4), but also penetrates into the gap portion located between adjacent conductive portions and adheres to the resin composition (3A) exposed in the gap portion. That is, since the pressure inside the autoclave (10) is applied over the entire area of ​​the resin composition (3A), gas (gas contained in the voids or residual solvent, volatile low molecular weight components, gas generated according to the effect reaction, etc.) can be discharged from the entire area of ​​the resin composition (3A).

[0039] In the ninth process, the laminate (1) removed from the autoclave (10) is fully cured. As a specific example for carrying out the ninth process, the laminate (1) removed from the autoclave (10) may be placed in a heating furnace and heated at a predetermined temperature for a predetermined time. Through this, the resin composition (3A) in a semi-cured state can be fully cured. Additionally, the ninth process is performed when the main curing of the resin composition (3A) is not completed in the eighth process, and the ninth process is omitted when the main curing of the resin composition (3A) is completed in the eighth process.

[0040] In the 10th process, the resin composition (3A) is cured to a solid state, and the laminate (1) with the insulating layer (3) formed is washed and various inspections are performed.

[0041] As a result of examining the laminate (1) manufactured through the first to tenth processes described above, it was confirmed that it has sufficient withstand voltage as described in the following examples. In addition, even when the laminate (1) was heated repeatedly, no delamination occurred between the insulating layer (3) and the circuit pattern (4), and the result was satisfactory.

[0042] The following describes embodiments of the present invention. However, the present invention is not limited to these embodiments.

[0043] <Example>

[0044] Bisphenol A type epoxy resin (product of DIC) was prepared as the thermosetting resin, diethyltoluenediamine (product of Lonza) was prepared as the curing agent, aluminum oxide, boron nitride aggregates, and boron nitride fine powders were prepared as fillers, triphenylphosphine (product of Hokkoh Chemical Industry) was prepared as the curing accelerator, and ethyl 3-ethoxypropionate was prepared as the solvent.

[0045] Then, the thermosetting resin and the curing agent were stirred at 70°C for 11 hours to form a prepolymer (Process 1). Subsequently, the aforementioned filler, curing accelerator, and solvent were blended with the thermosetting resin in the prepolymer state and mixed with a mixer to produce a semi-cured resin composition (Process 2).

[0046] Here, the weight-average molecular weight of the resin composition after the second process was measured. The measured weight-average molecular weight is the polystyrene equivalent value measured by the GPC (gel permeation chromatography) method. In addition, the measurement was performed using tetrahydrofuran (THF) as the mobile phase.

[0047] Measuring device: Waters e2695 separation module

[0048] Differential Refractive Index (RI) Detector: Waters 2414 RI Detector

[0049] Column: TSKgel guardcolumn H

[0050] Column: TSKgel G1000H

[0051] Column: TSKgel G2000H

[0052] Column: TSKgel G3000H

[0053] In addition, the weight average molecular weight of the resin composition after the second process was 487.

[0054] Then, the generated resin composition was applied to a long PET sheet and heated at 80°C for 40 minutes (Process 3). After that, the PET sheet coated with the resin composition was cut to a predetermined size (Process 4). Then, the cut sheet material was heated at 80°C for 20 minutes (Process 5).

[0055] Here, the weight-average molecular weight and density of the resin composition after the fifth process were measured. The method for measuring the weight-average molecular weight is the same as the method used after the second process. Density was measured by the Archimedes method using the HR-250AZ electronic balance manufactured by A&D and the AD-1653 specific gravity measurement kit. At this time, the weight-average molecular weight of the resin composition was 1700, and the density was 1.87 g / cm³. In addition, the actual density of the insulating layer when the resin composition was fully cured through the tenth process was 2.10 g / cm³ as a result of being measured by the above Archimedes method.

[0056] Then, the sheet material after the fifth process was placed over the metal base substrate (2) in a state where the resin composition was in contact with the metal base substrate (2), and placed inside a vacuum press device. Subsequently, while maintaining the inside of the device in a vacuum atmosphere and at 90°C, the overlapping metal base substrate and the sheet material were pressed at 23 MPa for 30 seconds (sixth process).

[0057] Here, the weight-average molecular weight and density of the resin composition after the 6th process were measured. The method for measuring the weight-average molecular weight and density is the same as the method used after the 5th process. At this time, the weight-average molecular weight of the resin composition was 1900, and the density was 2.00 g / cm³. That is, in this embodiment, the increase rate of the weight-average molecular weight of the resin composition is calculated as ((1900 - 1700) / 1700) × 100% based on the time before the process of applying compressive force, and is 11.8% after the process of applying compressive force. In addition, in this embodiment, the density of the resin composition is calculated as (2.00 / 2.10) × 100% based on the actual density of the insulating layer, and is 95.2% after the process of applying compressive force.

[0058] Next, a PET sheet was peeled off from a semi-cured resin composition transferred onto a metal base substrate (2), and a circuit pattern (4) (thickness 1 mm) was overlapped to form a laminate before compression (7th process).

[0059] Then, as shown in FIG. 3, the laminated body before compression was placed in the main body of the autoclave and covered with a film. After closing the lid of the autoclave, the inside of the film was evacuated and the pressure and temperature inside the autoclave were increased (Process 8).

[0060] Process 8 was carried out under the following two conditions, A and B. The results will be described later.

[0061] <Condition A>

[0062] Maintain the internal temperature of the autoclave at 160°C for 18 minutes. The internal pressure is set to 0 MPa until 5 minutes have elapsed since the start, and then pressurized to 3 MPa from 5 minutes until 18 minutes (13 minutes).

[0063] <Condition B>

[0064] Maintain the internal temperature of the autoclave at 180°C for 11.5 minutes. The internal pressure is set to 0 MPa until 5 minutes have elapsed since the start, and then pressurized to 3 MPa from 5 minutes until 11.5 minutes (6.5 minutes).

[0065] Next, the laminate removed from the autoclave was heated at 185°C under no pressure (atmospheric pressure) for 1 hour (Process 9). Afterward, a cleaning was performed along with a prescribed inspection (Process 10).

[0066] Then, a dielectric strength test was performed on the laminates manufactured through the first to tenth processes. Both the laminates manufactured under condition A and the laminates manufactured under condition B showed no abnormalities even when a voltage of 5 to 8 kV was applied, and the results were satisfactory. In addition, regarding the laminates manufactured under condition A and condition B, after heating at 300°C for 5 minutes (after the first heating), internal inspection was performed using an ultrasonic testing device (SAT), and no delamination between the insulating layer and the circuit pattern was observed in either laminate. Furthermore, even after heating at 300°C for 5 minutes (after the second heating) and after heating at 300°C for an additional 5 minutes (after the third heating), no delamination between the insulating layer and the circuit pattern was observed in the laminates manufactured under conditions A and B, and the results were satisfactory.

[0067] Although an embodiment of the present invention has been described above, the present invention is not limited to specific embodiments, and various modifications and changes are possible within the scope of the intent of the invention as described in the claims, unless specifically limited in the above description. Furthermore, the effects in the above embodiments are merely illustrative of the effects resulting from the present invention, and do not imply that the effects according to the present invention are limited to the effects described above. Explanation of the symbols

[0068] 1: Laminate 1A: Laminate before compression 2: Metal base substrate 3: Insulating layer 3A: Resin composition in a semi-cured state 4: Circuit pattern 10: Autoclave 11: Film

Claims

Claim 1 A method for manufacturing a laminate having a metal base substrate, an insulating layer formed by curing a resin composition, and a circuit pattern having a thickness of 0.8 mm or more, comprising: a step of preparing a pre-compressed laminate in which a resin composition in a semi-cured state is interposed between the metal base substrate and the circuit pattern; a step of applying a compressive force to the resin composition in a semi-cured state, performed before the step of preparing the pre-compressed laminate; a step of covering the pre-compressed laminate with a film and placing it inside an autoclave; and a step of curing the resin composition in a semi-cured state by increasing the temperature and pressure inside the autoclave while exhausting the inside of the film, wherein the weight average molecular weight growth rate of the resin composition in a semi-cured state is 30% or less after the step of applying the compressive force, based on the standard before the step of applying the compressive force. Claim 2 A method for manufacturing a laminate according to claim 1, wherein the density of the resin composition in a semi-cured state is 85% or more after the process of applying the compressive force based on the actual density of the insulating layer. Claim 3 delete Claim 4 delete

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