Method for manufacturing circuit board

Abstract

A method for manufacturing a circuit board using a core substrate in which a cavity is formed, a temporary fixing film, and a resin sheet provided with a support and a resin composition layer. The manufacturing method comprises the following steps in this order: a step (2) of placing a component in a cavity; a step (3) of pressing a supporting body with a rigid member to laminate a resin sheet and a core substrate; and a step (4) of curing a resin composition layer. A step (5) for pressing the support body with the elastic member such that the resin composition layer is bonded to the core substrate is included between the step (2) and the step (3), or the step (5) is not included; in the step (3), the product of the pressing force of the rigid member pressing the support body and the pressing time is within a specific range. In the step (5), the product of the pressing force of the elastic member pressing the support body and the pressing time satisfies a specific condition.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a circuit substrate. Background Art

[0002] Components such as bare chips and chip capacitors can be mounted on a circuit substrate provided in a semiconductor device. Such components are sometimes embedded in the interior of the circuit substrate in order to meet the requirements of further high functionality and miniaturization (Patent Document 1). For example, when manufacturing a high-performance CPU, it is ideal to embed the components in the core substrate.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2011-216636. Summary of the invention

[0004] Technical problem to be solved by the invention As a method for embedding components using a resin composition, it is preferred that a resin sheet having a resin composition layer including a resin composition is stacked on a core substrate having a cavity (cavity) in which components are accommodated. If this method is adopted, the takt time (takt time) can be shortened. However, in this method, after the components are embedded, a void may be generated in the cavity.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a circuit board capable of suppressing the generation of voids in a cavity accommodating a component.

[0006] Means of solving technical problems The present inventors have conducted intensive research to solve the above-mentioned problems. As a result, the present inventors have found that in the process of laminating a resin sheet having a support body and a resin composition layer with a core substrate, the above-mentioned problems can be solved when the pressing member for pressing the support body for lamination and the pressing conditions using the pressing member are appropriately adjusted, thereby completing the present invention.

[0007] That is, the present invention includes the following contents. <1> A method for manufacturing a circuit board, comprising: using a core substrate having a cavity formed therethrough, a temporary fixing film, and a resin sheet having a support and a resin composition layer, wherein the manufacturing method comprises: Step (1) of bonding a temporary fixing film to one side of the core substrate, Step (2) of placing a component in the cavity, a step (3) of laminating the resin sheet and the core substrate by pressing the support body with a rigid member so that the resin composition layer is bonded to the core substrate, and A step (4) of curing the resin composition layer; The manufacturing method includes, between step (2) and step (3), a step (5) of pressing the support body with an elastic member so that the resin composition layer is bonded to the core substrate, or does not include the step (5); In step (3), the pressing force F of the rigid member pressing the support body is R and pressing time T R The product of H R 200kgf·sec / cm 2 above; When the manufacturing method includes step (5), in the step (5), the pressing force F of the elastic member pressing the support body is E and pressing time T E The product of H E Satisfies the following formula (I): 2×H E <H R (I). <2> The method for producing a circuit board according to <1>, wherein the pressing temperature in the step (3) is 50° C. or higher and 140° C. or lower. <3> The method for producing a circuit board according to <1> or <2>, wherein the pressing temperature in the step (5) is 50° C. or higher and 140° C. or lower. <4> The method for producing a circuit board according to any one of <1> to <3>, wherein the resin composition layer contains (A) a curable resin and (B) an inorganic filler. <5> The method for producing a circuit board according to <4>, wherein the amount of the (B) inorganic filler contained in the resin composition layer is 65% by mass or more relative to 100% by mass of the nonvolatile component in the resin composition layer. <6> The method for producing a circuit board according to any one of <1> to <5>, wherein the average linear thermal expansion coefficient of a cured product obtained by curing the resin composition layer at 200°C for 90 minutes from 25°C to 150°C is less than 25 ppm / °C. <7> The method for manufacturing a circuit board according to any one of <1> to <6>, wherein a ratio of a volume of the component placed in the cavity to a volume of the cavity is 30 volume % or more.

[0008] Effects of the Invention According to the present invention, it is possible to provide a method for manufacturing a circuit board capable of suppressing the generation of voids in a cavity accommodating a component.

[0009] Brief description of the attached figure Figure 1This is a schematic cross-sectional view for explaining step (1) of the first embodiment of the present invention. Figure 2 This is a schematic cross-sectional view for explaining step (2) of the first embodiment of the present invention. Figure 3 This is a schematic cross-sectional view for explaining step (3) of the first embodiment of the present invention. Figure 4 This is a schematic cross-sectional view for explaining step (3) of the first embodiment of the present invention. Figure 5 This is a schematic cross-sectional view for explaining step (4) of the first embodiment of the present invention. Figure 6 This is a schematic cross-sectional view for explaining step (5) of the second embodiment of the present invention. Figure 7 This is a schematic plan view showing the state of the core substrate as viewed from the thickness direction, for explaining the position of the cavity formed in Example 1 of the present invention. DETAILED DESCRIPTION

[0010] Hereinafter, the present invention will be described with reference to the embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be implemented with arbitrary modifications within the scope of the claims and their equivalents.

[0011] In the following description, unless otherwise specified, the “in-plane direction” means a direction perpendicular to the thickness direction.

[0012] <Overview of the method for producing a circuit board> The manufacturing method of the circuit substrate of the present invention is a manufacturing method of the circuit substrate using a core substrate, a temporary fixing film and a resin sheet. The core substrate is formed with a cavity penetrating the core substrate. In addition, the resin sheet has a support and a resin composition layer. The resin composition layer contains a resin composition, preferably only contains a resin composition.

[0013] The manufacturing method sequentially comprises: Step (1) of bonding a temporary fixing film to one side of the core substrate, Step (2) of placing a component in the cavity, a step (3) of laminating the resin sheet and the core substrate by pressing the support body with a rigid member so that the resin composition layer is bonded to the core substrate, and A step (4) of curing the resin composition layer.

[0014] In addition, the manufacturing method may or may not include the following between step (2) and step (3): A step (5) of pressing the support body with an elastic member so that the resin composition layer is bonded to the core substrate.

[0015] Furthermore, in step (3), the pressing force F of the rigid member pressing the support body is R and pressing time T R The product of H R At 200kgf·sec / cm 2 Furthermore, when the manufacturing method includes step (5), in the step (5), the pressing force F of the elastic member pressing the support body is E and pressing time T E The product of H E , and the product H R The following formula (I) is satisfied: 2×H E <H R (I).

[0016] According to the method for manufacturing a circuit board, it is possible to manufacture a circuit board in which the generation of voids in the cavity in which the components are housed is suppressed.

[0017] The present inventors presume that the principle for obtaining the above-mentioned effects is as follows. However, the technical scope of the present invention is not limited to the principle described below.

[0018] In general, when a core substrate and a resin sheet are stacked to form a cavity, the filling of the resin composition into the cavity is realized by flowing the resin composition contained in the resin composition layer of the front part facing the cavity and the resin composition contained in the resin composition layer of the peripheral part around the cavity into the cavity. That is, from the front part of the resin composition layer facing the cavity to the cavity, the resin composition is pressed into the cavity along the thickness direction. In addition, at the same time, the resin composition moves from the part (peripheral part) of the resin composition layer around the cavity subjected to the pressing force to the cavity along the in-plane direction, and the resin composition is pressed into the cavity. Then, using these resin compositions, the cavity is filled with the resin composition.

[0019] In the past, in order to make the resin sheet fully conform to the concavo-convex surface of the core substrate, when the core substrate and the resin sheet are stacked, an elastic member is generally used to press the resin sheet. When pressing, the elastic member is deformed according to the shape of the core substrate while pressing the resin sheet. However, in the case of using a core substrate with a cavity, the elastic member subjected to pressure during pressing conforms to the cavity and deforms, narrowing the passage of the resin composition moving from the periphery of the cavity to the cavity. As a result, the resin composition supplied to the cavity is insufficient, resulting in holes.

[0020] Generally, the greater the pressure during pressing, the greater the degree of deformation of the elastic member. Therefore, when simply increasing the pressing force, the stress for moving the resin composition is further increased, but the passage of the resin composition is further narrowed due to the greatly deformed elastic member, so that the resin composition supplied to the cavity is insufficient. Therefore, even if the pressing force is simply increased, it is difficult to suppress the hole.

[0021] In this regard, in the method for manufacturing the circuit board of the present invention, a rigid member is used to fully press the resin sheet. The rigid member generally does not deform even when subjected to stress, and thus can uniformly press the resin composition without narrowing the passage of the resin composition. The resin composition that is fully pressed under uniform pressure without narrowing the passage can be smoothly filled into the cavity, so that voids can be suppressed.

[0022] The lamination of the core substrate and the resin sheet is preferably performed by a vacuum lamination method using a laminator. As the laminator, a commercially available product can be used, and for example, "CVP-700" manufactured by Nikko Materials Co., Ltd. can be mentioned.

[0023] <First embodiment: embodiment not including step (5)> The following is a diagrammatic description of a method for manufacturing a circuit board according to a first embodiment of the present invention. In the first embodiment described below, a method for manufacturing a circuit board does not include a step (5) of pressing a support body of a resin sheet with an elastic member between steps (2) and (3).

[0024] (Description of step (1)) Figure 1 Schematic cross-sectional view for explaining step (1) of the first embodiment of the present invention. Figure 1 As shown, the method for manufacturing a circuit board according to the present embodiment includes a step (1) of bonding a temporary fixing film 30 to one side 10D of a core substrate 10 having a cavity 20 formed thereon.

[0025] The core substrate 10 has a first surface 10U as a main surface and a second surface 10D located on the opposite side of the first surface 10U. The core substrate 10 is formed with a cavity 20 that penetrates the core substrate 10. Generally, the cavity 20 penetrates the core substrate 10 in the thickness direction and opens on both the first surface 10U and the second surface 10D.

[0026] As the core substrate 10, for example, a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, etc. can be cited, preferably a glass epoxy substrate. In addition, the core substrate 10 may have a conductor layer (not shown). The conductor layer may be patterned. The conductor layer can be used as circuit wiring such as through-hole wiring and surface wiring. The core substrate 10, for example, when manufacturing a semiconductor chip package or a printed wiring board, also includes an intermediate product that requires further formation of an insulating layer and / or a conductor layer.

[0027] The thickness of the core substrate 10 can be set according to the size of the circuit substrate to be manufactured. Usually, the thickness of the core substrate 10 is consistent with the depth of the cavity 20. In addition, generally speaking, the deeper the cavity 20 is, the easier it is to generate holes in the cavity 20. That is, holes are generally more likely to be generated as the component is larger, and are easily generated in a cavity deep enough to accommodate the large component, so there is a tendency for them to be easily generated in a thick core substrate having such a deep cavity. In this regard, if the manufacturing method involved in this embodiment is adopted, the generation of holes can be suppressed even under conditions such as this that are easy to generate holes in the past. From the viewpoint of utilizing the advantage of suppressing the generation of the holes, it is better to use a core substrate 10 having a deep cavity 20 that is easy to generate holes in the previous technology, so it is better that the thickness of the core substrate 10 is larger.

[0028] The specific thickness of the core substrate 10 can be, for example, more than 50 μm, more than 100 μm, or more than 200 μm. Among them, from the viewpoint of suppressing the hole even when using a thick core substrate 10 that is prone to generating holes in the past, the thickness of the core substrate 10 is preferably more than 400 μm, more preferably more than 500 μm, and further preferably more than 600 μm. In addition, from the viewpoint of thinning the circuit substrate, the upper limit of the thickness of the core substrate 10 is preferably less than 3 mm, more preferably less than 2.5 mm, and further preferably less than 2 mm. Usually, as mentioned above, the thickness of the core substrate 10 is consistent with the depth of the cavity 20, so the range of the depth of the cavity 20 can be the same as the range of the thickness of the core substrate 10.

[0029] Only one cavity 20 may be formed in the core substrate 10, or multiple cavities 20 may be formed with gaps. The pitch between the cavities 20 also varies depending on the opening size of the cavity 20 itself, but from the perspective of miniaturization of the circuit substrate, it is preferably less than 10 mm, more preferably less than 9 mm, and further preferably less than 8 mm. The lower limit is, for example, more than 1 mm, more than 2 mm, etc. The pitches between the cavities 20 may be the same or different throughout the core substrate 10.

[0030] The size of the cavity 20 is such that the component ( Figure 1The cavity 20 is set according to the conditions under which the core substrate 10 (not shown) is accommodated. Generally speaking, the smaller the openings 21 and 22 of the cavity 20 are, the more likely it is that a hole will be generated in the cavity 20. From the perspective of utilizing the advantage of suppressing the generation of holes, it is better to use a cavity 20 with a small opening diameter that is close to the size of the embedded component that is prone to generate holes under the previous technology. The size of the cavity 20 may be the same or different throughout the core substrate 10.

[0031] The opening shape of the cavity 20 is not particularly limited. The opening shape of the cavity 20 refers to the shape of the openings 21 and 22 of the cavity 20 when the core substrate 10 is viewed from the thickness direction. The opening shape of the cavity 20 can be, for example, rectangular, circular, approximately rectangular, approximately circular, etc. The opening shape of the cavity 20 can be the same or different throughout the core substrate 10.

[0032] The core substrate 10 may be manufactured by a method including forming the cavity 20 in the core substrate 10 before forming the cavity 20. The cavity 20 may be formed by using methods such as a drill, laser, plasma, or an etching medium according to the composition of the core substrate 10.

[0033] Step (1) includes bonding a temporary fixing film 30 to one side 10D of the core substrate 10. By bonding the temporary fixing film 30, the opening 22 on one side of the cavity 20 is blocked by the temporary fixing film 30. Therefore, the component placed in the cavity 20 can be stably held in the cavity 20.

[0034] The temporary fixing film 30 preferably has an adhesive surface 30U having sufficient adhesiveness to hold the component from the viewpoint of stably holding the component in the cavity 20. Examples of such a temporary fixing film 30 include "PFDKE-1525TT" (polyimide film with adhesive) manufactured by Arisawa Manufacturing Co., Ltd. and UC series (UV tape for wafer dicing) manufactured by Furukawa Electric Co., Ltd.

[0035] (Description of step (2)) Figure 2 Schematic cross-sectional view for explaining step (2) of the first embodiment of the present invention. Figure 2 As shown, the method for manufacturing a circuit board according to the present embodiment includes a step (2) of placing a component 40 in the cavity 20 after the step (1).

[0036] The component 40 is usually placed in the cavity 20 through the opening 21 opened in the first surface 10U and placed at the bottom of the cavity 20. When the temporary fixing member 30 having the adhesive surface 30U is provided, the component 40 is fixed by adhering to the adhesive surface 30U of the temporary fixing film 30 exposed through the cavity 20.

[0037] As the component 40, a suitable electronic component is usually selected according to the desired characteristics. As the component 40, for example, passive components such as capacitors, inductors, resistors, and active components such as semiconductor chips can be cited. The same component 40 can be installed in all cavities 20, and different components 40 can be installed in each cavity 20.

[0038] The ratio of the volume of the component 40 placed in the cavity 20 to the volume of the cavity 20 is preferably within a specific range. Hereinafter, the ratio is sometimes referred to as "occupancy ratio". Specifically, the occupancy ratio is preferably 15% by volume or more, more preferably 20% by volume or more, further preferably 25% by volume or more, preferably 60% by volume or less, more preferably 50% by volume or less, and further preferably 45% by volume or less. Generally speaking, if the component 40 is accommodated in the cavity 20, the passage through which the resin composition can flow in the cavity 20 becomes narrower corresponding to the volume of the component 40, thereby increasing the pressure loss on the passage. Therefore, corresponding to the volume of the component 40, it is difficult for the resin composition to enter the cavity 20, resulting in the easy generation of holes. In the past, when the occupancy ratio of the component 40 relative to the cavity 20 was large as described above, it was difficult to suppress the hole, but if the manufacturing method of this embodiment is adopted, the generation of the hole can be suppressed. From the viewpoint of utilizing the advantage of suppressing the generation of voids as described above, the proportion of the component 40 to the cavity 20 is preferably within the above range.

[0039] Typically, the thickness of the component 40 is the same as or smaller than the depth of the cavity 20. Unless otherwise specified, the "thickness of the component 40" refers to the size of the component 40 in the depth direction of the cavity 20, and thus refers to the size of the component 40 in the thickness direction of the core substrate 10. In one example, the ratio of the thickness of the component 40 to the depth of the cavity 20 (thickness of the component 40 / depth of the cavity 20) is preferably in the range of 0.01 or more, more preferably 0.1 or more, further preferably 0.2 or more, further preferably 0.3 or more, further preferably 0.4 or more, preferably 1.0 or less, more preferably less than 1.0, further preferably less than 0.8, and further preferably less than 0.6. Generally speaking, the depth of the cavity 20 is consistent with the thickness of the core substrate 10, so the range of the ratio of the thickness of the component 40 to the thickness of the core substrate 10 (thickness of the component 40 / thickness of the core substrate 10) can be the same as the range of the ratio of the thickness of the component 40 to the depth of the cavity 20 (thickness of the component 40 / depth of the cavity 20).

[0040] (Description of step (3)) Figure 3 and Figure 4 Schematic cross-sectional view for explaining step (3) of the first embodiment of the present invention. Figure 3 As shown, the manufacturing method of the circuit substrate involved in this embodiment includes a step (3) of laminating the resin sheet 50 having the support body 51 and the resin composition layer 52 with the core substrate 10 after the step (2). The lamination is performed by pressing the support body 51 with the rigid member 60 as shown by the arrow A1 in such a manner that the resin composition layer 52 is bonded to the core substrate 10. Through the lamination, a part of the resin composition contained in the resin composition layer 52 enters the cavity 20. Therefore, as Figure 4 As shown, the cavity 20 is filled with the resin composition, so a resin composition layer 52 is formed in the cavity 20. Therefore, the component 40 in the cavity 20 can be buried (embedded) with the resin composition layer 52. In addition, generally, another part of the resin composition contained in the resin composition layer 52 does not enter the cavity 20, so the resin composition layer 52 can also be formed on the first surface 10U of the core substrate 10. In the case where the core substrate 10 has a conductor layer (not shown) such as circuit wiring on the first surface 10U connected to the resin composition layer 52, these conductor layers can be buried through the resin composition layer 52.

[0041] The rigid member 60 is formed of a rigid material. As the rigid material, a material having a rigidity sufficient to fill the resin composition into the cavity 20 of the core substrate 10 can be used. As the rigid material, a material that does not deform when the support body 51 is pressed is preferred.

[0042] As a rigid material, a material with a large elastic modulus (Young's modulus) can be used. The elastic modulus of the rigid material is usually 1 GPa or more, preferably 10 GPa or more, more preferably 50 GPa or more, preferably 500 GPa or less, more preferably 400 GPa or less, and further preferably 300 GPa or less. The elastic modulus of the rigid material can be measured by a free resonance method at 23 ° C.

[0043] As the rigid material, a metal material is preferred. Examples of the metal material include iron, aluminum, and alloys thereof. Examples of the alloy include stainless steel. Among them, stainless steel is preferred due to its excellent rust resistance.

[0044] Typically, the rigid member 60 has a flat, planar pressing surface 60D. And, the pressing surface 60D is pressed in a manner that it is in direct contact with the support body 51 of the resin sheet 50. Unless otherwise specified, the "direct" contact of two components means that there is no other component between the two components. When the support body 51 is pressed with such a flat pressing surface 60D, pressure can be uniformly applied to the resin composition layer 52 in the in-plane direction. Therefore, not only the front part facing the opening 21 of the cavity 20, but also the wider peripheral part around the opening 21 can be uniformly pressured, so that the resin composition is effectively moved from the resin composition layer 52 of these parts to the cavity 20. In addition, by uniformly applying pressure, it is possible to suppress the local generation of a position with less pressure in the cavity 20. Therefore, holes can be particularly effectively suppressed. Furthermore, the flatness of the surface (the surface in contact with the support body 51) of the resin composition layer 52 can usually be improved.

[0045] Usually, the pressing surface 60D of the rigid member 60 is formed of a rigid material and thus has high rigidity. In one example, the Vickers hardness of the pressing surface 60D of the rigid member 60 is preferably 150 HV or more, more preferably 200 HV or more, further preferably 300 HV or more, preferably 1000 HV or less, and more preferably 700 HV or less. The Vickers hardness can be measured at 23° C. according to JIS Z 2244.

[0046] In step (3), the rigid member 60 is used to apply a pressing force F R and pressing time T R The product of H R The support body 51 is pressed under the conditions of a specific range. R The range is usually 200kgf·sec / cm 2 More than, preferably 500kgf·sec / cm 2 More than 1000kgf·sec / cm 2 Above, more preferably 1500kgf·sec / cm 2 More than 4000 kgf·sec / cm 2 The upper limit may be, for example, 100,000 kgf·sec / cm 2 Below, 8000kgf·sec / cm 2 Below, 6000kgf·sec / cm 2 The following etc. Rigid member 60 is H RWhen the support body 51 is pressed under the conditions within the above range, the generation of voids can be suppressed. In addition, if the pressing is performed under such conditions, when the first surface 10U of the core substrate 10 that is in contact with the resin composition layer 52 has a conductor layer such as circuit wiring (not shown), the conductor layer can be particularly well embedded in the resin composition layer 52.

[0047] In step (3), the pressing force F of the rigid member 60 pressing the support body 51 is R , according to the pressing force F R and pressing time T R The product of H R The conditions within the above range are set. From the perspective of smoothly filling the cavity 20, the pressure F R The range is preferably 2kgf / cm 2 Above, preferably 3kgf / cm 2 Above, further preferably 5kgf / cm 2 The upper limit may be, for example, 100 kgf / cm 2 Below, 40kgf / cm 2 Below, 20kgf / cm 2 The following etc.

[0048] In step (3), the pressing time T of the rigid member 60 pressing the support body 51 is R , according to the pressing force F R and pressing time T R The product of H R The conditions are set within the above range. From the perspective of smoothly filling the cavity 20, the pressing time T R The range of is preferably at least 10 seconds, more preferably at least 20 seconds, particularly preferably at least 30 seconds, preferably at most 30 minutes, more preferably at most 20 minutes, particularly preferably at most 10 minutes.

[0049] The pressing of the support body 51 using the rigid component 60 in step (3) is preferably performed at a pressing temperature higher than room temperature. By heating the resin composition layer 52 to an appropriate pressing temperature, the viscosity of the resin composition decreases and the fluidity increases, so that the resin composition can be smoothly filled into the cavity 20. Therefore, the generation of voids can be effectively suppressed. The pressing temperature is preferably above 50°C, more preferably above 60°C, and further preferably above 70°C, preferably below 140°C, more preferably below 130°C, and further preferably below 120°C. The specific pressing temperature is preferably set according to the composition of the resin composition contained in the resin composition layer 52, under conditions that can reduce the viscosity of the resin composition. Usually, the temperature of the rigid component 60 is adjusted to the pressing temperature.

[0050] The pressing of the support body 51 using the rigid member 60 in step (3) is preferably carried out under a reduced pressure environment. The vacuum degree of the reduced pressure environment is preferably below 20 hPa, more preferably below 15 hPa, further preferably below 10 hPa, and particularly preferably below 5 hPa. The lower limit is preferably above 0 hPa, but is usually above 0.1 hPa. When laminating under a high level of vacuum like this, the generation of holes can be effectively suppressed.

[0051] (Description of step (4)) Figure 5 Schematic cross-sectional view for explaining step (4) of the first embodiment of the present invention. The method for manufacturing a circuit substrate according to this embodiment includes, after step (3), a step (4) of curing the resin composition layer 52. By curing the resin composition layer 52, Figure 5 As shown, an insulating layer 70 can be obtained. Thus, a circuit board 100 including a core substrate 10, a component 40, and an insulating layer 70 can be manufactured. The insulating layer 70 is a cured layer obtained by curing the resin composition layer 52, and therefore includes a cured product of the resin composition, and preferably only includes a cured product of the resin composition.

[0052] The resin composition layer 52 can be cured by an appropriate method depending on the composition of the resin composition contained in the resin composition layer 52. For example, when a thermosetting resin composition is used, the resin composition can be cured by heating.

[0053] The curing conditions of the resin composition layer 52 will also vary depending on the composition of the resin composition. The curing temperature is preferably in the range of 120°C to 240°C, more preferably in the range of 150°C to 220°C, and particularly preferably in the range of 160°C to 210°C. The curing time is preferably in the range of 5 minutes to 180 minutes, more preferably in the range of 10 minutes to 150 minutes, and particularly preferably in the range of 15 minutes to 120 minutes.

[0054] Before curing, the resin composition layer 52 may be preheated at a temperature lower than the curing temperature. For example, before curing, the resin composition layer 52 may be preheated at a temperature of 50° C. or higher and lower than 120° C., preferably 60° C. or higher and lower than 110° C., more preferably 70° C. or higher and lower than 100° C., for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes.

[0055] (Description of any process) The method for producing a circuit board according to the first embodiment of the present invention may further include any steps in combination with the above-mentioned steps. For example, the method for producing a circuit board may include a step of peeling off the temporary fixing film after step (4).

[0056] The method for manufacturing a circuit board may include, for example, a step of peeling off the support of the resin sheet after step (3). The support may be peeled off before step (4) or after step (4). In addition, when the support includes a metal foil, the support may not be peeled off and may be used for forming a conductor layer as described later.

[0057] The method for manufacturing a circuit board may include, for example, a step of forming a conductor layer on an insulating layer. The method for forming the conductor layer is not limited. For example, when a resin sheet having a support body including a metal foil is used in step (4), the metal foil may be used to form a conductor layer as a circuit by a subtractive method or a modified semi-additive method.

[0058] In the subtractive method, usually, unnecessary parts (non-circuit forming parts) of the metal foil are selectively removed by a removal method such as etching to form a circuit. Circuit formation based on the subtractive method can be implemented by, for example, a method including the following steps in sequence: i) a step of providing an anti-etching layer on the surface of the metal foil (i.e., the surface opposite to the insulating layer); ii) a step of exposing and developing the anti-etching layer to form a wiring pattern; iii) a step of removing the exposed metal foil portion by etching; iv) a step of removing the anti-etching layer.

[0059] In the improved semi-additive method, the non-circuit forming part of the metal foil is usually protected by a plating resist, and after the metal such as copper is thickened in the circuit forming part by electrolytic plating, the plating resist is removed, and the metal foil other than the circuit forming part is removed by etching to form a circuit. Circuit formation based on the improved semi-additive method can be implemented by, for example, a method including the following steps in sequence: i) a step of providing a plating resist on the surface of the metal foil (i.e., the surface opposite to the insulating layer); ii) a step of exposing and developing the plating resist to form a wiring pattern; iii) a step of electrolytic plating through the plating resist; iv) a step of removing the plating resist; v) a step of removing the metal foil other than the circuit forming part by etching. In the case where the metal foil is relatively thick, the entire surface of the metal foil can be thinned by a removal method such as etching before the above i) so that the metal foil has a desired thickness.

[0060] The conductor layer may also be formed without using a metal foil. Examples of methods for forming such a conductor layer include plating, sputtering, and vapor deposition. For example, a conductor layer having a desired wiring pattern may be formed by plating the surface of the insulating layer using an appropriate method such as a semi-additive method or a full-additive method.

[0061] The manufacturing method of the circuit substrate may include, for example, a process of opening a hole in the insulating layer. Through this process, holes such as through holes and vias can be formed in the insulating layer. If a specific example is given, in the case where a hole is formed in the insulating layer that is connected from the surface of the insulating layer to the component, by forming a conductive layer in the hole, the conductive layer on the insulating layer can be electrically connected to the component, so that interlayer connection through the hole can be achieved. In addition, if another specific example is given, in the case where a hole is formed in the insulating layer that is connected from the surface of the insulating layer to the circuit wiring of the core substrate, by forming a conductive layer in the hole, the conductive layer on the insulating layer can be electrically connected to the circuit wiring of the core substrate, so that interlayer connection through the hole can be achieved. As a method for forming the hole, for example, laser irradiation, etching, mechanical drilling, etc. can be cited. The size and shape of the hole can be appropriately determined according to the design of the circuit substrate.

[0062] When a hole is formed in the insulating layer, contamination (resin residue) may be formed in the hole. Therefore, the method for manufacturing the circuit substrate may include, for example, a step of removing contamination in the hole after the hole is formed. This step is also called a decontamination treatment. The decontamination treatment may be, for example, a wet decontamination treatment using a swelling liquid, an oxidizing agent, and a neutralizing liquid, or a dry decontamination treatment such as a plasma treatment. The surface of the insulating layer may be roughened by the decontamination treatment.

[0063] The manufacturing method of the circuit board may, for example, roughen the insulating layer before forming the conductor layer on the insulating layer. Through the roughening treatment, the surface of the insulating layer including the inside of the hole is usually roughened. As the roughening treatment, any of the dry and wet roughening treatments may be performed. As an example of the dry roughening treatment, plasma treatment may be cited. In addition, as an example of the wet roughening treatment, a method of sequentially performing a swelling treatment using a swelling liquid, a roughening treatment using an oxidant, and a neutralization treatment using a neutralizing liquid may be cited.

[0064] The method for producing a circuit board can produce a circuit board having a multilayer structure such as a multilayer printed wiring board by, for example, repeatedly forming a conductor layer on an insulating layer and forming an arbitrary insulating layer.

[0065] The manufacturing method of the circuit substrate can form a conductor layer on the second surface 10D of the core substrate 10 on the opposite side of the first surface 10U laminated with the resin sheet 50. In addition, the formation of the conductor layer on the second surface 10D and the formation of any insulating layer can be repeated. At this time, any treatment such as opening holes, decontamination treatment, and roughening treatment can be performed on the insulating layer as needed.

[0066] In the first embodiment, a method for manufacturing a circuit substrate is described that does not include the step (5) of pressing the support of the resin sheet with an elastic member before the step (3), but the manufacturing method may include the step of pressing the support of the resin sheet with any pressing member other than the elastic member before the step (3). However, the method for manufacturing a circuit substrate according to the present embodiment preferably does not include the step of pressing the support of the resin sheet with any pressing member before the step (3) as described above. Therefore, the pressing of the support performed first after the step (2) is preferably the pressing described in the step (3) using a rigid member.

[0067] (Description of manufactured circuit board) If the manufacturing method involved in the first embodiment described above is adopted, a circuit substrate having a core substrate with a cavity formed therein, a component housed in the cavity, and an insulating layer filling the cavity can be manufactured. The insulating layer is not only in the cavity but can also be formed on the surface of the core substrate outside the cavity. In the circuit substrate, the component in the cavity is buried in the insulating layer filling the cavity.

[0068] In the cavity of the manufactured circuit board, the generation of holes, which are gaps without components and insulating layers, is suppressed. Therefore, for example, in the case where the circuit board has a plurality of cavities containing components, the number of cavities generating holes can be reduced, and preferably, the cavities generating holes can be eliminated.

[0069] The insulating layer of the circuit substrate preferably has a smaller average linear thermal expansion coefficient. The specific average linear thermal expansion coefficient of the insulating layer can usually be the same as the range of the average linear thermal expansion coefficient of the cured product obtained by curing the resin composition layer of the resin sheet at 200°C and 90 minutes described later. When the insulating layer has a smaller average linear thermal expansion coefficient like this, the warping of the circuit substrate can be suppressed. In addition, generally speaking, in order to obtain an insulating layer with a smaller average linear thermal expansion coefficient like this, the insulating layer is required to contain an inorganic filler, but the insulating layer containing an inorganic filler has a tendency to easily generate holes in the past. In contrast, if the manufacturing method involved in the present embodiment is adopted, even if an insulating layer with a smaller average linear thermal expansion coefficient like this is adopted, the generation of holes can be suppressed.

[0070] The average linear thermal expansion coefficient of the insulating layer can be measured by thermomechanical analysis using a thermomechanical analyzer with a tensile load method. The measurement can be performed under the measurement conditions of a load of 1 g and a heating rate of 5°C / min, and can be measured within a temperature range of 25°C to 150°C. The specific measurement operation can be the operation described in the <CTE measurement test> of the examples described later.

[0071] As circuit substrates, for example, printed wiring boards and semiconductor chip packages can be cited. As semiconductor chip packages, for example, FC-CSP, MIS-BGA packages, ETS-BGA packages, fan-out WLP (wafer level package, Wafer Level Package), fan-in WLP, fan-out PLP (panel level package, Panel Level Package), fan-in PLP can be cited. However, circuit substrates are not limited to the substrates exemplified here. In addition, in these circuit substrates, the insulating layer may include, for example, an interlayer insulating layer, a rewiring formation layer, a molded bottom filling layer, a solder resist layer, etc.

[0072] <Second embodiment: embodiment including step (5)> The following describes a method for manufacturing a circuit board according to a second embodiment of the present invention with reference to the accompanying drawings. In the second embodiment described below, a method for manufacturing a circuit board includes a step (5) of pressing a support body of a resin sheet with an elastic member between steps (2) and (3).

[0073] (Description of step (1)) The manufacturing method of the circuit substrate according to the second embodiment is as follows Figure 1 As shown, the process (1) includes bonding a temporary fixing film 30 to one side 10D of a core substrate 10 having a cavity 20. The process (1) of the second embodiment can be implemented in the same manner as the process (1) of the first embodiment, and the same advantages as described in the first embodiment can be obtained.

[0074] (Description of step (2)) The method for manufacturing a circuit substrate according to the second embodiment includes, after step (1), Figure 2 As shown, the process (2) includes placing the component 40 in the cavity 20. The process (2) of the second embodiment can be performed in the same manner as the process (2) of the first embodiment, and the same advantages as described in the first embodiment can be obtained.

[0075] (Description of step (5)) Figure 6 Schematic cross-sectional view for explaining step (5) of the second embodiment of the present invention. Figure 6As shown, the method for manufacturing a circuit substrate according to the present embodiment includes, after step (2) and before step (3), a step (5) of pressing the support 51 of the resin sheet 50 with an elastic member 80 as shown by arrow A2 in such a manner that the resin composition layer 52 of the resin sheet 50 is bonded to the core substrate 10. By this pressing, the resin composition layer 52 is in close contact with the first surface 10U of the core substrate 10, and a portion of the resin composition contained in the resin composition layer 52 enters the cavity 20. However, unlike the step (3) described in the first embodiment, the resin composition entering the cavity 20 fills a portion of the cavity 20, and usually does not fill the entire cavity 20. In the present embodiment, the portion of the cavity 20 that is not filled with the resin composition in step (5) is filled in the step (3) described later.

[0076] The elastic member 80 is formed of an elastic material. As the elastic material, a material having elasticity sufficient to press the support body 51 while being deformed by pressure when pressed can be used. As the elastic material, a material having a relatively small elastic modulus (Young's modulus) can be used. The elastic modulus of the elastic material is usually above 0.1 MPa, preferably above 1 MPa, and more preferably above 2 MPa, and is usually below 100 MPa, preferably below 90 MPa, and more preferably below 80 MPa. The elastic modulus E [MPa] of the elastic material can be obtained by measuring the durometer hardness A [Hs] at 23°C using the formula (M1) shown below. As the elastic material, for example, rubber can be cited.

[0077] [Mathematical formula 1]

[0078] As the elastic member 80, for example, a plate or sheet formed of an elastic material can be used. The elastic member 80 has a pressing surface 80D for pressing the support body 51 of the resin sheet 50. And, the pressing is performed in a manner that the pressing surface 80D is in direct contact with the support body 51 of the resin sheet 50. If such pressing is performed, the resin sheet 50 can fully conform to the surface shape of the first surface 10U of the core substrate 10, so the closeness between the first surface 10U of the core substrate 10 and the resin composition layer 52 can be improved. In addition, when the core substrate 10 has a conductor layer (not shown) such as circuit wiring on the first surface 10U, the conductor layer can be buried (buried) through the resin composition layer 52. At this time, the resin sheet 50 can fully conform to the surface shape of the core substrate 10, so good embedding can be achieved.

[0079] The pressing force F of the support body 51 by the elastic member 80 in step (5) is such that the pressing force F of the elastic member 80 pressing the support body 51 is satisfied. E and pressing time T E The product of H ESatisfy the following formula (I): 2×H E <H R (I) Here, H R As described above, the pressing force F of the rigid member pressing the support body in step (3) is represented by R and pressing time T R The product of H R .

[0080] In step (5), the pressing force F of the elastic member 80 pressing the support body 51 is E , according to the pressing force F E and pressing time T E The product of H E The pressing force F is set to satisfy the condition of the above formula (I). E The range is preferably 1kgf / cm 2 More than 2kgf / cm 2 Above, further preferably 3kgf / cm 2 Above, preferably 20kgf / cm 2 Below, preferably 18kgf / cm 2 Below, further preferably 15kgf / cm 2 the following.

[0081] The pressing time T of the elastic member 80 pressing the support body 51 in step (5) E , according to the pressing force F E and pressing time T E The product of H E The pressing time T is set to satisfy the condition of the above formula (I). From the viewpoint of improving the adhesion between the first surface 10U of the core substrate 10 and the resin composition layer 52, the pressing time T E The range of is preferably at least 1 second, more preferably at least 2 seconds, further preferably at least 5 seconds, preferably at most 60 seconds, more preferably at most 50 seconds, particularly preferably at most 40 seconds.

[0082] The pressing of the support body 51 using the elastic member 80 in the step (5) is preferably performed at a pressing temperature higher than room temperature. The range of the pressing temperature in the step (5) may be the same as the range of the pressing temperature in the step (3) described in the first embodiment. In this case, the pressing temperature in the step (5) may be the same as or different from the pressing temperature in the step (3). Usually, the temperature of the elastic member 80 is adjusted to the pressing temperature.

[0083] The pressing of the support body 51 using the elastic member 80 in the process (5) is preferably performed under a reduced pressure environment. The range of the vacuum degree of the reduced pressure environment in the process (5) may be the same as the range of the vacuum degree in the process (3) described in the first embodiment. In this case, the vacuum degree in the process (5) may be the same as or different from the vacuum degree in the process (3). When pressing under a high level of vacuum like this, the generation of holes can be effectively suppressed.

[0084] (Description of step (3)) The method for manufacturing a circuit board according to the second embodiment includes, after step (5), step (3) of laminating the resin sheet and the core substrate by pressing the support body 51 with the rigid member 60 so that the resin composition layer 52 of the resin sheet 50 is bonded to the core substrate 10. By laminating in step (3), the portion of the cavity 20 that was not filled with the resin composition in step (5) is filled with the resin composition. Figure 4 As shown, a resin composition layer 52 is formed in the cavity 20. Therefore, the component 40 in the cavity 20 can be buried (embedded) by the resin composition layer 52. In addition, the resin composition layer 52 can also be formed on the first surface 10U of the core substrate 10, usually similarly to the first embodiment.

[0085] The step (3) of the second embodiment can be performed in the same manner as the step (3) of the first embodiment, and the same advantages as described in the first embodiment can be obtained. R , pressing time T R , their product R , pressing temperature, and the degree of vacuum in the pressing environment may be the same as those in step (3) of the first embodiment.

[0086] In this embodiment, the support 51 of the resin sheet 50 is pressed by the elastic member 80 in the step (5) before the step (3), so the filling of the resin composition into the cavity 20 is usually carried out halfway. Therefore, even if the pressing with the rigid member is performed under milder conditions than the step (3) involved in the first embodiment, the void can be suppressed.

[0087] Therefore, in the step (3) according to the second embodiment, the pressing force F R and pressing time T R The product of H R The range of may be the same as that of step (3) in the first embodiment, but may be, for example, 200 kgf·sec / cm 2 Above, 210kgf·sec / cm 2 Above, 220kgf·sec / cm 2 Above, or 230kgf·sec / cm2 Above, and can be 1000kgf·sec / cm 2 Below, 800kgf·sec / cm 2 Below, or 600kgf·sec / cm 2 Below. R When the content falls within the above range, the cavity 20 can be filled with less energy and time while suppressing the generation of voids.

[0088] In the step (3) according to the second embodiment, the pressing force F of the rigid member 60 pressing the support body 51 is R The process may be the same as step (3) in the first embodiment, but may be, for example, 1 kgf / cm 2 Above, 2kgf / cm 2 Above, or 3kgf / cm 2 Above, and can be 50kgf / cm 2 Below, 30kgf / cm 2 Below, or 10kgf / cm 2 Below. Pressing force F R When the content falls within the above range, the cavity 20 can be filled with less energy while suppressing the generation of voids.

[0089] Furthermore, in the step (3) according to the second embodiment, the pressing time T during which the rigid member 60 presses the support body 51 is R The pressing time T may be the same as step (3) of the first embodiment, but may be, for example, 5 seconds or more, 10 seconds or more, or 20 seconds or more, and may be 5 minutes or less, 3 minutes or less, or 2 minutes or less. R When the content is within the above range, the cavity 20 can be filled in a short time while suppressing the generation of voids.

[0090] (Description of step (4)) The method for manufacturing a circuit board according to the second embodiment includes, after step (3), a step (4) of curing the resin composition layer 52. By curing the resin composition layer 52, Figure 5 As shown, the insulating layer 70 can be obtained. Therefore, the circuit substrate 100 including the core substrate 10, the component 40 and the insulating layer 70 can be manufactured. The step (4) involved in the second embodiment can be implemented in the same manner as the step (4) involved in the first embodiment, and the same advantages as described in the first embodiment can be obtained.

[0091] (Description of any process) The manufacturing method of the circuit substrate involved in the second embodiment of the present invention can be combined with the above-mentioned steps to further include any steps. As the arbitrary steps that can be included in the manufacturing method of the circuit substrate involved in the second embodiment, for example, the same steps as the arbitrary steps that can be included in the manufacturing method of the circuit substrate involved in the first embodiment can be cited.

[0092] (Description of manufactured circuit board) If the manufacturing method of the second embodiment is adopted, the same circuit substrate as the manufacturing method of the first embodiment can be manufactured. Therefore, if the manufacturing method of the circuit substrate of the second embodiment is adopted, the same advantages as the manufacturing method of the circuit substrate of the first embodiment can be obtained.

[0093] <Explanation of resin sheet> The resin sheet used in the above-mentioned production method comprises a support and a resin composition layer. Examples of the support include films made of plastic materials, metal foils, and release papers, and films made of plastic materials and metal foils are preferred.

[0094] When a film formed of a plastic material is used as a support, the plastic material includes polyesters such as polyethylene terephthalate (hereinafter also abbreviated as "PET") and polyethylene naphthalate (hereinafter also abbreviated as "PEN"), polycarbonate (hereinafter also abbreviated as "PC"), acrylic polymers such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0095] When a metal foil is used as a support, examples of the metal foil include copper foil and aluminum foil, preferably copper foil. As the copper foil, a foil formed of a single metal of copper can be used, or a foil formed of an alloy of copper and other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) can be used.

[0096] The surface of the support to be in contact with the resin composition layer may be subjected to matte treatment, corona discharge treatment, or antistatic treatment.

[0097] As the support, a support with a release layer having a release layer on the surface bonded to the resin composition layer can be used. As a release agent for the release layer of the support with a release layer, for example, one or more release agents selected from alkyd resins, polyolefin resins, polyurethane resins and silicone resins can be cited. Commercially available products can be used for the support with a release layer, for example, "SK-1", "AL-5", "AL-7" manufactured by Lintec Co., Ltd., which is a PET film having a release layer with an alkyd resin release agent as the main component, "LUMIRROR T60" manufactured by Toray Industries, Ltd., "Purex" manufactured by Teijin Limited, "Unipeel" manufactured by Unitika Co., Ltd., etc. can be cited.

[0098] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably within the above range.

[0099] The resin composition layer is a layer formed on the support, and contains a resin composition. The resin composition layer preferably contains only the resin composition.

[0100] The resin composition layer and the resin composition as its material usually include (A) curable resin. The (A) curable resin as the (A) component may be a thermosetting resin, a photocurable resin, or a combination thereof. Among them, the (A) curable resin preferably includes a thermosetting resin, and may only include a thermosetting resin. The (A) curable resin may be used alone or in combination of two or more.

[0101] As a thermosetting resin, a resin that can be cured when heated can be used. Examples of thermosetting resins include epoxy resins, phenolic resins, active ester resins, carbodiimide resins, cyanate resins, acid anhydride resins, amine resins, benzoxazine resins, thiol resins, and free radical polymerizable resins. One type of thermosetting resin can be used alone, or two or more types can be used in combination. Among them, the thermosetting resin preferably includes at least one selected from epoxy resins, phenolic resins, active ester resins, carbodiimide resins, and free radical polymerizable resins.

[0102] From the viewpoint of improving the adhesion of the insulating layer and the conductor layer that can be formed on the insulating layer, it is preferred to use epoxy resin and a resin combination that can react with the epoxy resin to solidify the resin composition. Hereinafter, the resin that can react with the epoxy resin to solidify the resin composition is sometimes referred to as a "curing agent". As a curing agent, for example, phenol resin, active ester resin, cyanate resin, carbodiimide resin, anhydride resin, amine resin, benzoxazine resin, thiol resin, etc. can be cited. Among them, phenol resin, active ester resin and carbodiimide resin are preferred. In addition, the curing agent can be used alone or in combination of two or more.

[0103] Epoxy resin is a thermosetting resin having an epoxy group. Examples of epoxy resin include biphenylol epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AF epoxy resin, dicyclopentadiene epoxy resin, trisphenol epoxy resin, naphthol novolac epoxy resin, phenol novolac epoxy resin, tert-butylcatechol epoxy resin, naphthalene epoxy resin, naphthol epoxy resin, anthracene epoxy resin, glycidylamine epoxy resin, glycidylester epoxy resin. The epoxy resins include cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro-ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, naphthyl ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, isocyanurate type epoxy resins, phenol phthalimidine type epoxy resins, etc. The epoxy resins may be used alone or in combination of two or more.

[0104] From the viewpoint of obtaining an insulating layer with excellent heat resistance, the epoxy resin preferably includes an epoxy resin containing an aromatic structure. An aromatic structure refers to a chemical structure generally defined as an aromatic, and also includes polycyclic aromatics and aromatic heterocycles. As the epoxy resin containing an aromatic structure, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butylcatechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, bixylenol type epoxy resin, glycidylamine type epoxy resin with an aromatic structure, and epoxy resin with an aromatic structure can be cited. The epoxy resins include glycidyl ester epoxy resins with aromatic structure, cresol novolac epoxy resins, biphenyl epoxy resins, linear aliphatic epoxy resins with aromatic structure, epoxy resins with butadiene structure with aromatic structure, alicyclic epoxy resins with aromatic structure, heterocyclic epoxy resins, spiro ring-containing epoxy resins with aromatic structure, cyclohexanedimethanol epoxy resins with aromatic structure, naphthyl ether epoxy resins, trimethylol epoxy resins with aromatic structure, tetraphenylethane epoxy resins with aromatic structure, etc.

[0105] (A) curable resin is preferably an epoxy resin having two or more epoxy groups in one molecule as epoxy resin. Relative to 100 mass % of the non-volatile component of the epoxy resin, the ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50 mass % or more, more preferably 60 mass % or more, and particularly preferably 70 mass % or more.

[0106] Epoxy resins include epoxy resins that are liquid at a temperature of 20° C. (hereinafter also referred to as “liquid epoxy resins”) and epoxy resins that are solid at a temperature of 20° C. (hereinafter also referred to as “solid epoxy resins”). The resin composition may contain only a liquid epoxy resin as the epoxy resin, or may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin.

[0107] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0108] As liquid epoxy resins, preferred are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, and epoxy resins having a butadiene structure.

[0109] Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation, "828US", "828EL", "jER828EL", "825", and "EPIKOTE 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation, "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation, "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "630", "630LSD", and "604" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation, and "ED-523T" (GLYCIROL-type epoxy resin) manufactured by ADEKA Corporation. , "EP-3950L" and "EP-3980S" (glycidylamine type epoxy resin) manufactured by ADEKA Corporation, "EP-4088S" (dicyclopentadiene type epoxy resin) manufactured by ADEKA Corporation, "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd., "YD-8125G" (bisphenol A type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd., Nagase "EX-721" manufactured by ChemteX Corporation (glycidyl ester type epoxy resin), "CELLOXIDE 2021P" manufactured by Daicel Corporation (alicyclic epoxy resin having an ester skeleton), "PB-3600" manufactured by Daicel Corporation, "JP-100" and "JP-200" manufactured by Nippon Soda Co., Ltd. (epoxy resins having a butadiene structure), "ZX1658" and "ZX1658GS" manufactured by Nippon Steel Chemical Materials Co., Ltd. (liquid 1,4-glycidylcyclohexane type epoxy resin), etc. These resins may be used alone or in combination of two or more.

[0110] The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups in one molecule, more preferably an aromatic solid epoxy resin having three or more epoxy groups in one molecule.

[0111] As solid epoxy resins, preferred are biphenylol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, naphthol novolac type epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthyl ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, phenol aralkyl type epoxy resins, tetraphenylethane type epoxy resins, and phenol benzopyrrolidone type epoxy resins.

[0112] Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin) manufactured by DIC Corporation, "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC Corporation, "N-690" (cresol novolac-type epoxy resin) manufactured by DIC Corporation, "N-695" (cresol novolac-type epoxy resin) manufactured by DIC Corporation, "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene-type epoxy resin) manufactured by DIC Corporation, and "HP-7200HH" and "HP-7200H" (dicyclopentadiene-type epoxy resin) manufactured by DIC Corporation. "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", "HP6000L" (naphthyl ether type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "ESN475V", "ESN4100V" (naphthalene type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd., "ESN485" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd., "ESN375" (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd., "YX4000H", "YX4000", "YX4000HK", "YL7890" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation , "YX7700" (phenol aralkyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., "YX7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "WHR991S" (phenol benzopyrrolidone type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., etc. These resins may be used alone or in combination of two or more.

[0113] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the mass ratio thereof (liquid epoxy resin:solid epoxy resin) is preferably from 20:1 to 1:20, more preferably from 10:1 to 1:10, particularly preferably from 7:1 to 1:7.

[0114] The epoxy equivalent of the epoxy resin is preferably in the range of 50 g / eq. to 5000 g / eq., more preferably 60 g / eq. to 3000 g / eq., further preferably 80 g / eq. to 2000 g / eq., and particularly preferably 110 g / eq. to 1000 g / eq. The epoxy equivalent represents the mass of the resin per 1 equivalent of epoxy groups. The epoxy equivalent can be measured according to JIS K7236.

[0115] The weight average molecular weight (Mw) of the epoxy resin is preferably in the range of 100 to 5000, more preferably 250 to 3000, further preferably 400 to 1500. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by gel permeation chromatography (GPC).

[0116] Relative to the non-volatile component 100% by mass in the resin composition layer, the range of the amount of epoxy resin is preferably more than 1% by mass, more preferably more than 2% by mass, further preferably more than 5% by mass, preferably less than 35% by mass, more preferably less than 30% by mass, and further preferably less than 20% by mass. In addition, the range of the amount of epoxy resin relative to the non-volatile component 100% by mass in the resin composition can be the same as the range of the amount of epoxy resin relative to the non-volatile component 100% by mass in the resin composition layer. Unless otherwise specified, the non-volatile component of the resin composition layer refers to the component other than the solvent in the component of the resin composition. In addition, unless otherwise specified, the non-volatile component of the resin composition refers to the component other than the solvent in the component of the resin composition.

[0117] Relative to the resin composition 100% by mass in the resin composition layer, the range of the amount of epoxy resin is preferably more than 5% by mass, more preferably more than 10% by mass, further more preferably more than 20% by mass, preferably less than 80% by mass, more preferably less than 70% by mass, and further more preferably less than 60% by mass. In addition, the range of the amount of epoxy resin relative to the resin composition 100% by mass of the resin composition can be the same as the range of the amount of epoxy resin relative to the resin composition 100% by mass in the resin composition layer. Unless otherwise specified, the resin composition of the resin composition layer refers to the composition other than the inorganic filler in the non-volatile component of the resin composition layer. In addition, unless otherwise specified, the resin composition of the resin composition refers to the composition other than the inorganic filler in the non-volatile component of the resin composition.

[0118] As the phenolic resin, a compound having one or more, preferably two or more, hydroxyl groups bonded to aromatic rings such as a benzene ring or a naphthalene ring in one molecule can be used. From the viewpoint of heat resistance and water resistance, a phenolic resin having a phenolic structure is preferred. In addition, from the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a phenolic resin containing a triazine skeleton is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance and adhesion, a linear phenolic resin containing a triazine skeleton is preferred. Specific examples of phenol resins include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Chemicals Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", and "SN-395" manufactured by Nippon Steel Chemicals Co., Ltd., and "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", and "TD-2090-60M" manufactured by DIC Corporation.

[0119] As active ester resin, it is generally preferred to use compounds having ester groups with more than two high reactive activities in one molecule, such as phenolic esters, thiophenolic esters, N-hydroxylamine esters, and esters of heterocyclic hydroxy compounds. The active ester resin is preferably a compound obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improved heat resistance, it is preferably an active ester resin obtained from a carboxylic acid compound and a hydroxy compound, and more preferably an active ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound. As carboxylic acid compounds, for example benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc. can be cited. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, pyrogallol, dicyclopentadiene-type diphenol compounds, and novolac resins. Here, the “dicyclopentadiene-type diphenol compound” refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

[0120] Specifically, as the active ester resin, preferably, a dicyclopentadiene type active ester resin, a naphthalene type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of a novolac resin, and an active ester resin containing a benzoylated product of a novolac resin are preferred, and more preferably, at least one selected from the group consisting of a dicyclopentadiene type active ester resin and a naphthalene type active ester resin. As the dicyclopentadiene type active ester resin, preferably, an active ester resin containing a dicyclopentadiene type diphenol structure is preferred.

[0121] Commercially available products of active ester resins include, for example, "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation) as active ester resins containing a dicyclopentadiene type diphenol structure, and "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", "EXB- Examples of the active ester resins include "EXB-8150-62T", "EXB-9416-70BK", "HPC-8150-60T", "HPC-8150-62T", and "EXB-8" (manufactured by DIC Corporation). Examples of the phosphorus-containing active ester resins include "EXB9401" (manufactured by DIC Corporation). Examples of the active ester resins of acetylated linear phenolic resins include "DC808" (manufactured by Mitsubishi Chemical Corporation). Examples of the active ester resins of benzoylated linear phenolic resins include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation). Examples of the active ester resins containing styrene and naphthalene structures include "PC1300-02-65MA" (manufactured by Airwater Corporation).

[0122] As the carbodiimide resin, a compound having one or more, preferably two or more, carbodiimide structures in one molecule can be used. Specific examples of the carbodiimide resin include: aliphatic biscarbodiimides such as tetramethylene-bis(tert-butylcarbodiimide) and cyclohexanebis(methylene-tert-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly( Aromatic polycarbodiimides such as naphthylene carbodiimide), poly(tolylene carbodiimide), poly(methyl diisopropyl phenylene carbodiimide), poly(triethyl phenylene carbodiimide), poly(diethyl phenylene carbodiimide), poly(triisopropyl phenylene carbodiimide), poly(diisopropyl phenylene carbodiimide), poly(xylylene carbodiimide), poly(tetramethyl xylylene carbodiimide), poly(methylene diphenylene carbodiimide), and poly[methylene bis(methyl phenylene) carbodiimide] are also included. Examples of commercially available carbodiimide resins include "CARBODILITE V-02B", "CARBODILITE V-03", "CARBODILITE V-04K", "CARBODILITE V-07" and "CARBODILITE V-09" manufactured by Nisshinbo Chemical Co., Ltd. and "Stabaxol P", "Stabaxol P400" and "Hycasyl 510" manufactured by LANXESS.

[0123] As the cyanate resin, a compound having one or more, preferably two or more, cyanate groups in one molecule can be used. Examples of the cyanate resin include difunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4′-methylenebis(2,6-dimethylphenylcyanate), 4,4′-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyano)phenylpropane, 1,1-bis(4-cyanophenylmethane), bis(4-cyano-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanophenyl-1-(methylethylidene))benzene, bis(4-cyanophenyl)sulfide and bis(4-cyanophenyl)ether; polyfunctional cyanate resins derived from phenol novolac resins and cresol novolac resins; and prepolymers obtained by triazinization of a portion of these cyanate resins. Specific examples of cyanate resins include "PT30" and "PT60" manufactured by Lonza (both are novolac-type multifunctional cyanate resins), "BA230" and "BA230S75" (prepolymers in which a part or all of bisphenol A dicyanate is triazine-treated to form a trimer), etc.

[0124] As the acid anhydride resin, a compound having one or more, preferably two or more, acid anhydride groups in one molecule can be used. Specific examples of the acid anhydride resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, Polymer-type acid anhydrides such as benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(trimellitic anhydride), and styrene-maleic acid resin obtained by copolymerizing styrene with maleic acid. Commercially available products of the acid anhydride resin include, for example, "HNA-100", "MH-700", "MTA-15", "DDSA", and "OSA" manufactured by Shin Nippon Rika Co., Ltd., "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation, "HN-2200" and "HN-5500" manufactured by Resonac Co., Ltd., and "EF-30", "EF-40", "EF-60", and "EF-80" manufactured by Cray Valley Co., Ltd.

[0125] As the amine resin, a compound having one or more, preferably two or more, amino groups in one molecule can be used. As the amine resin, for example, aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. can be mentioned, among which aromatic amines are preferred. The amine resin is preferably a primary amine or a secondary amine, and a primary amine is more preferred. Specific examples of the amine resin include: 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, metaphenylenediamine, metaphenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxy phenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Commercially available products of the amine resin include, for example, "SEIKACURE-S" manufactured by Seika Corporation, "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd., "EPICURE W" manufactured by Mitsubishi Chemical Corporation, and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0126] Specific examples of the benzoxazine resin include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Industry Co., Ltd., "HFB2006M" manufactured by Showa Highpolymer Co., Ltd., and "Pd" and "Fa" manufactured by Shikoku Chemical Industry Co., Ltd.

[0127] Examples of the thiol resin include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0128] The active group equivalent of the curing agent is preferably in the range of 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., further preferably 100 g / eq. to 500 g / eq., particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent indicates the mass of the curing agent per 1 equivalent of active groups.

[0129] The range of the weight average molecular weight of the curing agent may be the same as the range of the weight average molecular weight (Mw) of the epoxy resin.

[0130] When the number of epoxy groups of epoxy resin is set to 1, the range of the number of active groups of curing agent is preferably 0.1 or more, more preferably 0.2 or more, further preferably 0.3 or more, preferably 5.0 or less, more preferably 3.0 or less, and further preferably 2.0 or less. "The number of epoxy groups of epoxy resin" represents the value obtained by adding up all the values ​​obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition layer by the epoxy equivalent. In addition, "the number of active groups of curing agent" represents the value obtained by adding up all the values ​​obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition layer by the active group equivalent.

[0131] Relative to the non-volatile component 100% by mass in the resin combination layer, the range of the amount of the curing agent is preferably more than 1% by mass, more preferably more than 2% by mass, further more preferably more than 5% by mass, preferably less than 35% by mass, more preferably less than 25% by mass, further more preferably less than 15% by mass. In addition, the range of the amount of the curing agent relative to the non-volatile component 100% by mass in the resin combination can be the same as the range of the amount of the curing agent relative to the non-volatile component 100% by mass in the resin combination layer.

[0132] Relative to the resin composition 100% by mass in the resin combination layer, the scope of the amount of the curing agent is preferably more than 10% by mass, more preferably more than 15% by mass, further more preferably more than 20% by mass, preferably below 80% by mass, more preferably below 70% by mass, further more preferably below 60% by mass. In addition, the scope of the amount of the curing agent relative to the resin composition 100% by mass in the resin combination can be identical with the described scope of the amount of the curing agent relative to the resin composition 100% by mass in the resin combination layer.

[0133] As a free radical polymerizable resin, a resin containing an ethylenically unsaturated bond can be used. Thus, a free radical polymerizable resin may generally have a free radical polymerizable group containing an ethylenically unsaturated bond. As a free radical polymerizable group, for example, unsaturated hydrocarbon groups such as vinyl, allyl, 1-propenyl, 3-cyclohexenyl, 3-cyclopentenyl, 2-vinylphenyl, 3-vinylphenyl, 4-vinylphenyl, α, β-unsaturated carbonyl groups such as acryl, methacryloyl, maleimide (2,5-dihydro-2,5-dioxo-1H-pyrrole-1-yl) can be cited. The free radical polymerizable resin preferably has two or more free radical polymerizable groups.

[0134] Examples of the radical polymerizable resin include (meth)acrylic radical polymerizable resins, styrene radical polymerizable resins, allyl radical polymerizable resins, maleimide radical polymerizable resins, etc. The radical polymerizable resin may be used alone or in combination of two or more.

[0135] As the (meth)acrylic radical polymerizable resin, a resin having one or more, preferably two or more, acryloyl groups and / or methacryloyl groups in one molecule can be used. Examples of the (meth)acrylic radical polymerizable resin include low molecular weight (molecular weight less than 1000) aliphatic (meth)acrylate compounds such as cyclohexane-1,4-dimethanol di(meth)acrylate, cyclohexane-1,3-dimethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, glycerol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate; and Ether-containing (meth)acrylate compounds having a low molecular weight (molecular weight less than 1000) such as glycol di(meth)acrylate, 3,6,9-trioxaundecane-1,11-diol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, etc.; isocyanurate-containing (meth)acrylate compounds having a low molecular weight (molecular weight less than 1000) such as tris(3-hydroxypropyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, etc.; and high molecular weight (molecular weight 1000 or more) acrylate compounds such as (meth)acrylic acid-modified polyphenylene ether resin, etc. Here, the term "(meth)acrylic acid" includes acrylic acid, methacrylic acid and combinations thereof. In addition, the term "(meth)acrylate" includes acrylate, methacrylate and combinations thereof. As commercially available products of (meth)acrylic free radical polymerizable resins, for example, "A-DOG" (dioxanediol diacrylate) manufactured by Shin-Nakamura Chemical Industry Co., Ltd., "DCP-A" (tricyclodecane dimethanol diacrylate), "DCP" (tricyclodecane dimethanol dimethacrylate), "BPE-1300N" (ethoxylated bisphenol A dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd., "KAYARAD R-684" (tricyclodecane dimethanol diacrylate), "KAYARAD R-604" (dioxanediol diacrylate) manufactured by Nippon Kayaku Co., Ltd., "SA9000", "SA9000-111" (methacryloyl-modified polyphenylene ether) manufactured by SABIC Innovative Plastics, etc. can be cited.

[0136] As the styrene-based free radical polymerizable resin, a resin having one or more, preferably two or more, vinyl groups directly bonded to aromatic carbon atoms in one molecule can be used. As the styrene-based free radical polymerizable resin, for example, low molecular weight (molecular weight less than 1000) styrene-based compounds such as divinylbenzene, 2,4-divinyltoluene, 2,6-divinylnaphthalene, 1,4-divinylnaphthalene, 4,4'-divinylbiphenyl, 1,2-bis(4-vinylphenyl)ethane, 2,2-bis(4-vinylphenyl)propane, and bis(4-vinylphenyl)ether; and high molecular weight (molecular weight greater than 1000) styrene-based compounds such as vinylbenzyl-modified polyphenylene ether resin and styrene-divinylbenzene copolymer can be cited. Commercially available products of styrene-based free radical polymerizable resins include, for example, "ODV-XET (X03)", "ODV-XET (X04)", and "ODV-XET (X05)" (styrene-divinylbenzene copolymers) manufactured by Nippon Steel Chemical Materials Co., Ltd., and "OPE-2St 1200" and "OPE-2St 2200" (vinyl benzyl-modified polyphenylene ether resins) manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0137] As the allyl radical polymerizable resin, a resin having one or more, preferably two or more, allyl groups in one molecule can be used. As the allyl radical polymerizable resin, for example, aromatic carboxylic acid allyl ester compounds such as diallyl diphenate, triallyl trimellitate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalene dicarboxylate, and diallyl 2,3-naphthalene dicarboxylate; isocyanuric acid allyl ester compounds such as 1,3,5-triallyl isocyanurate and 1,3-diallyl-5-glycidyl isocyanurate; 2,2-bis[3 Aromatic allyl compounds containing epoxy such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; aromatic allyl compounds containing benzoxazine such as bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane; aromatic allyl compounds containing ether such as 1,3,5-triallyl ether benzene; allyl silane compounds such as diallyldiphenylsilane. Commercially available products of allyl radical polymerizable resins include, for example, "TAIC" (1,3,5-triallyl isocyanurate) manufactured by Nippon Chemical Industry Co., Ltd., and "DIS" manufactured by Nisshoku Techno Fine Chemical Co., Ltd. Co., Ltd.), “DAD” (diallyl biphenyldicarboxylate) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., “TRIAM-705” (triallyl trimellitate) manufactured by FUJIFILM Co., Ltd., “DAND” (diallyl 2,3-naphthalenedicarboxylate) manufactured by Nichiku Techno Seika Co., Ltd., “ALP-d” (bis[3-allyl-4-(3,4-dihydro-2H-1,3-benzoxazin-3-yl)phenyl]methane) manufactured by Shikoku Chemicals Co., Ltd., “RE-810NM” (2,2-bis[3-allyl-4-(glycidyloxy)phenyl]propane) manufactured by Nippon Kayaku Co., Ltd., and “DA-MGIC” (1,3-diallyl-5-glycidyl isocyanurate) manufactured by Shikoku Chemicals Co., Ltd.

[0138] As the maleimide free radical polymerizable resin, a resin having one or more, preferably two or more maleimide groups in one molecule can be used. The maleimide free radical polymerizable resin can be an aromatic maleimide resin having a maleimide group directly bonded to an aromatic ring, or an aliphatic maleimide resin having no maleimide group directly bonded to an aromatic ring. Commercially available products of maleimide-based free radical polymerizable resins include, for example, "SLK-2600" manufactured by Shin-Etsu Chemical Co., Ltd., "BMI-1500", "BMI-1700", "BMI-3000J", "BMI-689", and "BMI-2500" (maleimide compounds containing a dimer diamine structure) manufactured by Designer Molecules Inc., "BMI-6100" (aromatic maleimide compound) manufactured by Designer Molecules Inc., "MIR-5000-60T" and "MIR-3000-70MT" (biphenyl aralkyl type maleimide compounds) manufactured by Nippon Kayaku Co., Ltd., "BMI-70" and "BMI-80" manufactured by KI Chemicals Co., Ltd., and "BMI-2300" and "BMI-TMH" manufactured by Yamato Chemicals Co., Ltd. In addition, as the maleimide-based radical polymerizable resin, a maleimide resin (maleimide compound containing an indane ring skeleton) disclosed in Japan Invention Association Unexamined Technical Publication No. 2020-500211 can be used.

[0139] The radical polymerizable group equivalent of the radical polymerizable resin is preferably 20 to 3000 g / eq., more preferably 50 to 2500 g / eq., further preferably 70 to 2000 g / eq., particularly preferably 90 to 1500 g / eq. The radical polymerizable group equivalent means the mass of the radical polymerizable resin per 1 equivalent of the radical polymerizable group.

[0140] The weight average molecular weight (Mw) of the radical polymerizable resin is preferably at most 40000, more preferably at most 10000, further preferably at most 5000, particularly preferably at most 3000. The lower limit is not particularly limited and may be, for example, at least 150.

[0141] The range of the amount of the radical polymerizable resin relative to 100% by mass of the non-volatile component in the resin composition layer is preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 3% by mass or more, preferably 35% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less. In addition, the range of the amount of the radical polymerizable resin relative to 100% by mass of the non-volatile component in the resin composition may be the same as the range of the amount of the radical polymerizable resin relative to 100% by mass of the non-volatile component in the resin composition layer.

[0142] The range of the amount of the radical polymerizable resin relative to 100% by mass of the resin component in the resin composition layer is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. In addition, the range of the amount of the radical polymerizable resin relative to 100% by mass of the resin component in the resin composition may be the same as the range of the amount of the radical polymerizable resin relative to 100% by mass of the resin component in the resin composition layer.

[0143] Relative to the non-volatile component 100% by mass in the resin composition layer, the range of the amount of (A) curable resin is preferably more than 2% by mass, more preferably more than 5% by mass, further more preferably more than 10% by mass, preferably less than 35% by mass, more preferably less than 30% by mass, further more preferably less than 25% by mass. In addition, the range of the amount of (A) curable resin relative to the non-volatile component 100% by mass in the resin composition can be the same as the range of the amount of (A) curable resin relative to the non-volatile component 100% by mass in the resin composition layer.

[0144] Relative to the resin composition 100% by mass in the resin composition layer, the range of the amount of (A) curable resin is preferably more than 40% by mass, more preferably more than 60% by mass, further more preferably more than 80% by mass, usually below 100% by mass, preferably below 99% by mass. In addition, the range of the amount of (A) curable resin relative to 100% by mass of the resin composition can be the same as the range of the amount of (A) curable resin relative to 100% by mass of the resin composition layer.

[0145] The resin composition layer and the resin composition as its material preferably include (B) inorganic filling material. (B) inorganic filling material as (B) component is a particle of inorganic material. Thus, (B) inorganic filling material is contained in the resin composition layer in the state of particles, and is usually contained in the insulating layer while maintaining the state of the particles. If (B) inorganic filling material is adopted, the linear thermal expansion coefficient of the insulating layer can be reduced, so the warping of the circuit board can be reduced. In addition, in general, when using a resin composition layer including (B) inorganic filling material, there is a tendency to easily generate holes in the cavity, but if the above-mentioned manufacturing method is adopted, even when a resin composition layer that is easy to generate holes is adopted like this, the generation of the holes can be suppressed.

[0146] As the inorganic material forming (B) inorganic filler, inorganic compounds are generally used. As the material of (B) inorganic filler, for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, barium zirconate, calcium zirconate, zirconium phosphate and zirconium tungstate phosphate, etc., can be cited. Among them, silica and alumina are preferred, and silica is particularly preferred. Thus, (B) inorganic filler preferably includes silica, and may only include silica. As silica, amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, etc. can be cited. Further, as the silica, spherical silica is preferred. (B) The inorganic filler may be used alone or in combination of two or more.

[0147] Examples of commercially available inorganic fillers (B) include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical Materials Co., Ltd., "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Yaduma Co., Ltd., "UFP-30", "DAW-03", and "FB-105FD" manufactured by DENKA Corporation, "SILFIL NSS-3N", "SILFIL NSS-4N", and "SILFIL NSS-5N" manufactured by Tokuyama Co., Ltd., and "CellSpheres" and "MGH-005" manufactured by Pacific Cement Co., Ltd.

[0148] The average particle size of the inorganic filler (B) is preferably at least 0.01 μm, more preferably at least 0.05 μm, further preferably at least 0.1 μm, and is preferably at most 10 μm, more preferably at most 5 μm, further preferably at most 3 μm.

[0149] (B) The average particle size of the inorganic filler can be measured by a laser diffraction scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be made on a volume basis by a laser diffraction scattering particle size distribution measuring device, and the median particle size can be measured as the average particle size. The sample can be measured using a sample obtained by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing it by ultrasonic waves for 10 minutes. For the sample, a laser diffraction particle size distribution measuring device can be used, using a light source wavelength using blue and red, and the particle size distribution of the volume basis of the inorganic filler can be measured in a flow cell manner, and the average particle size can be calculated as the median particle size according to the obtained particle size distribution. As a laser diffraction particle size distribution measuring device, for example, "LA-960" made by Horiba Manufacturing Co., Ltd. can be cited.

[0150] (B) The specific surface area of ​​the inorganic filler is preferably 0.1 m 2 / g or more, preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, particularly preferably 3m 2 / g or more, preferably 100m 2 / g or less, preferably 70m 2 / g or less, more preferably 50m 2 / g or less, particularly preferably 40m 2 The specific surface area of ​​the inorganic filler can be measured by adsorbing nitrogen gas on the surface of a sample using a specific surface area measuring apparatus (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) according to the BET method and calculating the specific surface area by the BET multipoint method.

[0151] From the viewpoint of improving moisture resistance and dispersibility, (B) inorganic filler material is preferably treated by a surface treatment agent. As the surface treatment agent, for example, fluorine-containing silane coupling agent, aminosilane coupling agent, epoxysilane coupling agent, mercaptosilane coupling agent, silane coupling agent, alkoxysilane, organosilazane compound, titanate coupling agent, etc. can be cited. The surface treatment agent can be used alone or in any combination of two or more.

[0152] Commercially available products of the surface treatment agent include, for example, “KBM403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM803” (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBE903” (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM573” (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “SZ-31” (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM103” (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM-4803” (long-chain epoxy-type silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd., and “KBM-7103” (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

[0153] From the viewpoint that the dispersibility of inorganic filler improves, the degree of surface treatment performed by surface treatment agent is preferably within a specific range. Specifically, inorganic filler 100% by mass is preferably surface treated by 0.2% by mass to 5% by mass of surface treatment agent, more preferably surface treated by 0.2% by mass to 3% by mass of surface treatment agent, and further preferably surface treated by 0.3% by mass to 2% by mass of surface treatment agent.

[0154] The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is preferably 0.02 mg / m 2 More than 0.1 mg / m 2 More preferably, 0.2 mg / m 2 On the other hand, from the viewpoint of preventing the increase in the melt viscosity of the resin composition layer, 1.0 mg / m 2 Below, preferably 0.8mg / m 2 Below, more preferably 0.5 mg / m 2 the following.

[0155] (B) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is cleaned with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK is added as a solvent to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid component, a carbon analyzer can be used to measure the amount of carbon per unit surface area of ​​the inorganic filler. As a carbon analyzer, "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0156] Relative to the non-volatile component 100% by mass in the resin composition layer, the range of the amount of (B) inorganic filler in the resin composition layer is preferably 65% ​​by mass or more, more preferably 68% by mass or more, further preferably 70% by mass or more, preferably 90% by mass or less, more preferably 88% by mass or less, and further preferably 87% by mass or less. In addition, the range of the amount of (B) inorganic filler relative to the non-volatile component 100% by mass in the resin composition can be the same as the range of the amount of (B) inorganic filler relative to the non-volatile component 100% by mass in the resin composition layer. The resin composition layer containing the (B) inorganic filler of the amount of such a range can reduce the linear thermal expansion coefficient of the insulating layer and suppress the warping of the circuit substrate. In addition, the resin composition layer containing more (B) inorganic filler has a tendency to easily generate holes in the cavity in the past. In contrast, if the above-mentioned circuit substrate manufacturing method is adopted, even in the case of using a resin composition layer containing more (B) inorganic filler like this, the generation of holes can also be suppressed.

[0157] The resin composition layer and the resin composition as the material thereof may contain (C) thermoplastic resin as an arbitrary component. The (C) thermoplastic resin as the (C) component does not include components belonging to the (A) to (B) components. The (C) thermoplastic resin is usually contained in the resin composition layer in a state compatible with resin components other than the (C) thermoplastic resin, and is contained in the insulating layer while maintaining the compatible state.

[0158] (C) Thermoplastic resins usually have a relatively large molecular weight. Specifically, the weight average molecular weight Mw of the thermoplastic resin (C) is preferably greater than 5,000, more preferably 8,000 or more, further preferably 10,000 or more, particularly preferably 20,000 or more, preferably 100,000 or less, more preferably 70,000 or less, further preferably 60,000 or less, particularly preferably 50,000 or less.

[0159] Examples of the thermoplastic resin (C) include phenoxy resins, polyimide resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyamide-imide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone, polyester resins, etc. The thermoplastic resin (C) may be used alone or in combination of two or more.

[0160] Examples of the phenoxy resin include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, phenolic skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both are phenoxy resins containing a bisphenol A skeleton), "YX8100" manufactured by Mitsubishi Chemical Corporation (a phenoxy resin containing a bisphenol S skeleton), "YX6954" manufactured by Mitsubishi Chemical Corporation (a phenoxy resin containing a bisphenol acetophenone skeleton), "FX280" and "FX293" manufactured by Nippon Steel Chemical Materials Co., Ltd., "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482" and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation, etc.

[0161] Specific examples of the polyimide resin include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "RIKACOAT SN20" and "RIKACOAT PN20" manufactured by Shin Nippon Rika Co., Ltd.

[0162] As the polyvinyl acetal resin, for example, polyvinyl formal resin and polyvinyl butyral resin can be mentioned, and polyvinyl butyral resin is preferred. As specific examples of the polyvinyl acetal resin, S-LEC BH series, BX series (for example, BX-5Z), KS series (for example, KS-1), BL series, BM series, etc. manufactured by Sekisui Chemical Co., Ltd. can be mentioned.

[0163] Examples of the polyolefin resin include low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers and other ethylene copolymer resins; polyolefin polymers such as polypropylene and ethylene-propylene block copolymers; and the like.

[0164] Examples of the polybutadiene resin include resins containing a hydrogenated polybutadiene skeleton, polybutadiene resins containing a hydroxyl group, polybutadiene resins containing a phenolic hydroxyl group, polybutadiene resins containing a carboxyl group, polybutadiene resins containing an acid anhydride group, polybutadiene resins containing an epoxy group, polybutadiene resins containing an isocyanate group, polybutadiene resins containing a urethane group, polyphenylene ether-polybutadiene resins, etc. A part or all of the polybutadiene structure of the polybutadiene resin may be hydrogenated. Specific examples of polybutadiene resins include "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", and "Ricon 184MA6" (polybutadiene containing anhydride groups) manufactured by Cray Valley Co., Ltd., "GQ-1000" (polybutadiene into which hydroxyl groups and carboxyl groups are introduced), "G-1000", "G-2000", and "G-3000" (polybutadiene containing hydroxyl groups at both ends), "GI-1000", "GI-2000", and "GI-3000" (hydrogenated polybutadiene containing hydroxyl groups at both ends) manufactured by Nippon Soda Co., Ltd., and "FCA-061L" (hydrogenated polybutadiene skeleton epoxy resin) manufactured by Nagase ChemteX Co., Ltd. In addition, as the specific example of polybutadiene resin, polyimide resin having polybutadiene structure, carbamate structure and imide structure in molecule can be enumerated. For this polyimide resin, hydroxyl-terminated polybutadiene, diisocyanate compound and tetrabasic acid anhydride can be made into linear polyimide resin (polyimide recorded in Japanese Unexamined Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208) as raw materials. The content of the butadiene structure of this polyimide resin is preferably 60 mass %~95 mass %, more preferably 75 mass %~85 mass %. The details of this polyimide resin can be referred to the records of Japanese Unexamined Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208, and the content is quoted in this specification.

[0165] Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imide containing a polysiloxane skeleton) manufactured by Riseno Corporation.

[0166] Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. and the like.

[0167] Specific examples of the polysulfone resin include polysulfone "P1700" and "P3500" manufactured by Solvay High Performance Polymers.

[0168] Specific examples of the polyphenylene ether resin include "NORYL SA90" manufactured by SABIC Innovative Plastics, Inc. Specific examples of the polyetherimide resin include "ULTEM" manufactured by GE, Inc.

[0169] As polycarbonate resins, for example, carbonate resins containing hydroxyl groups, carbonate resins containing phenolic hydroxyl groups, carbonate resins containing carboxyl groups, carbonate resins containing acid anhydride groups, carbonate resins containing isocyanate groups, carbonate resins containing carbamate groups, etc. can be cited. As specific examples of polycarbonate resins, "FPC0220" manufactured by Mitsubishi Gas Chemical Co., Ltd., "T6002", "T6001" (polycarbonate diol) manufactured by Asahi Kasei Corporation, "C-1090", "C-2090", "C-3090" (polycarbonate diol) manufactured by Kuraray Co., Ltd., etc. can be cited. In addition, as specific examples of polycarbonate resins, polyimide resins having an imide structure, a carbamate structure, and a polycarbonate structure in the molecule can be cited. For the polyimide resin, a hydroxyl-terminated polycarbonate, a diisocyanate compound, and a tetrabasic acid anhydride can be used as raw materials to prepare a linear polyimide resin. The content of the carbonate structure of the polyimide resin is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. For details of the polyimide resin, reference may be made to the description of International Publication No. 2016 / 129541, the contents of which are incorporated herein by reference.

[0170] Specific examples of the polyetheretherketone resin include "SUMIPLOY K" manufactured by Sumitomo Chemical Co., Ltd. and the like.

[0171] Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexylene dimethyl terephthalate resin.

[0172] (C) The thermoplastic resin may include an elastomer. The elastomer is a flexible resin, preferably a resin having rubber elasticity or a resin that exhibits rubber elasticity by polymerization with other components. Examples of rubber elasticity include, for example, a resin that exhibits an elastic modulus of 1 GPa or less when subjected to a tensile test at 25° C. and 40% RH in accordance with Japanese Industrial Standards (JIS K7161).

[0173] The elastomer is preferably one or more selected from a resin having a glass transition temperature (Tg) of 25°C or less and a resin that is liquid at 25°C or less. The glass transition temperature of the resin having a glass transition temperature (Tg) of 25°C or less is preferably 20°C or less, more preferably 15°C or less. The lower limit of the glass transition temperature is not particularly limited, and may usually be -15°C or more. In addition, as the resin that is liquid at 25°C, a resin that is liquid at 20°C or less is preferably a resin that is liquid at 15°C or less. The glass transition temperature can be measured by DSC (differential scanning calorimetry).

[0174] Relative to 100% by mass of the non-volatile components in the resin composition layer, the range of the amount of the (C) thermoplastic resin is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less. In addition, the range of the amount of the (C) thermoplastic resin relative to 100% by mass of the non-volatile components in the resin composition may be the same as the range of the amount of the (C) thermoplastic resin relative to 100% by mass of the non-volatile components in the resin composition layer.

[0175] Relative to 100% by mass of the resin component in the resin composition layer, the range of the amount of the (C) thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. In addition, the range of the amount of the (C) thermoplastic resin relative to 100% by mass of the resin component in the resin composition may be the same as the range of the amount of the (C) thermoplastic resin relative to 100% by mass of the resin component in the resin composition layer.

[0176] The resin composition layer and the resin composition used as the material thereof may contain (D) a flame retardant as an optional component. The (D) flame retardant used as the (D) component does not include components belonging to the (A) to (C) components. If the (D) flame retardant is used, the flame retardancy of the insulating layer can be improved.

[0177] Examples of the flame retardant (D) include phosphazene compounds, organophosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, organosilicon flame retardants, metal hydroxides, etc. The flame retardant (D) may be used alone or in combination of two or more.

[0178] (D) Flame retardants include, for example, "SPH-100", "SPS-100", "SPB-100", "SPE-100" (phosphazenes) manufactured by Otsuka Chemical Co., Ltd., "FP-100", "FP-110", "FP-300", "FP-400" (phosphazenes) manufactured by Fushimi Pharmaceutical Co., Ltd., "HCA-NQ", "HCA-HQ", "HCA-HQ-HST" (phosphonates (containing phenolic hydroxyl groups)) manufactured by Sanko Co., Ltd., and "PX-200", "PX-201", "PX-202", "CR-733S", "CR-741", "CR-747" (phosphate esters) manufactured by Daihachi Chemical Industry Co., Ltd.

[0179] Relative to 100% by mass of the non-volatile component in the resin composition layer, the range of the amount of the (D) flame retardant is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 1% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less. In addition, the range of the amount of the (D) flame retardant relative to 100% by mass of the non-volatile component in the resin composition can be the same as the range of the amount of the (D) flame retardant relative to 100% by mass of the non-volatile component in the resin composition layer.

[0180] Relative to 100% by mass of the resin component in the resin composition layer, the range of the amount of the (D) flame retardant is preferably more than 0.1% by mass, more preferably more than 1% by mass, further more preferably more than 2% by mass, preferably less than 20% by mass, more preferably less than 10% by mass, and further more preferably less than 5% by mass. In addition, the range of the amount of the (D) flame retardant relative to 100% by mass of the resin component in the resin composition can be the same as the range of the amount of the (D) flame retardant relative to 100% by mass of the resin component in the resin composition layer.

[0181] The resin composition layer and the resin composition as the material thereof may contain (E) a curing accelerator as an optional component. The (E) curing accelerator as the (E) component does not include the components belonging to the above-mentioned (A) to (D) components. The (E) curing accelerator has a function as a curing catalyst that accelerates the curing of the (B) curable resin.

[0182] As the (E) curing accelerator, an appropriate curing accelerator may be used depending on the type of the (A) curable resin. For example, when the (A) curable resin includes an epoxy resin, the (E) curing accelerator that can accelerate the curing of the epoxy resin may include, for example, phosphorus curing accelerators, urea curing accelerators, guanidine curing accelerators, imidazole curing accelerators, metal curing accelerators, amine curing accelerators, etc. The (E) curing accelerator may be used alone or in combination of two or more.

[0183] Examples of the phosphorus curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, and p-tolyltriphenylphosphonium; Aromatic phosphonium salts such as tetra-p-tolyl borate, tetraphenylphosphonium tetraphenyl borate, tetraphenylphosphonium tetra-p-tolyl borate, triphenylethylphosphonium tetraphenyl borate, tris(3-methylphenyl)ethylphosphonium tetraphenyl borate, tris(2-methoxyphenyl)ethylphosphonium tetraphenyl borate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition reactants such as triphenylphosphine-p-benzoquinone addition reactants; tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2- aliphatic phosphines such as dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tri(4-ethylphenyl)phosphine, tri(4-propylphenyl)phosphine, tri(4-isopropylphenyl)phosphine, tri(4-butylphenyl)phosphine, tri(4-tert-butylphenyl)phosphine, tri(2,4-dimethylphenyl)phosphine, tri(2,5-dimethylphenyl)phosphine, tri(2,6-dimethylphenyl)phosphine Aromatic phosphines such as tris(diphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether.

[0184] Examples of the urea curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dimethylphenyl)-1,1 -dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluenebisdimethylurea] and the like.

[0185] Examples of the guanidine curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene, 1-methyldiphenylamine, 1-ethyldiphenylamine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, and 1-(o-tolyl)biguanidine.

[0186] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1') imidazole compounds such as 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins. Commercially available products of imidazole curing accelerators include, for example, "1B2PZ", "2E4MZ", "2MZA-PW", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2PHZ", "2PHZ-PW", "C11Z", "C11Z-CN", "C11Z-CNS", and "C11Z-A" manufactured by Shikoku Chemical Industry Co., Ltd. and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0187] As metal curing accelerators, organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin can be cited. Specific examples of organic metal complexes include organic cobalt complexes such as cobalt acetylacetonate (II) and cobalt acetylacetonate (III); organic copper complexes such as copper acetylacetonate (II); organic zinc complexes such as zinc acetylacetonate (II); organic iron complexes such as iron acetylacetonate (III); organic nickel complexes such as nickel acetylacetonate (II); organic manganese complexes such as manganese acetylacetonate (II). As organic metal salts, for example, zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, etc. can be cited.

[0188] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo[5.4.0]undecene. A commercially available amine curing accelerator may be used, and examples thereof include "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd.

[0189] Relative to the non-volatile component 100% by mass in the resin composition layer, the range of the amount of (E) curing accelerator is preferably more than 0.01% by mass, more preferably more than 0.02% by mass, further more preferably more than 0.03% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, further more preferably less than 0.5% by mass. In addition, the range of the amount of (E) curing accelerator relative to the non-volatile component 100% by mass in the resin composition can be the same as the range of the amount of (E) curing accelerator relative to the non-volatile component 100% by mass in the resin composition layer.

[0190] Relative to the resin composition 100% by mass in the resin composition layer, the range of the amount of (E) curing accelerator is preferably more than 0.01% by mass, more preferably more than 0.05% by mass, further more preferably more than 0.1% by mass, preferably less than 5% by mass, more preferably less than 2% by mass, further more preferably less than 1% by mass. In addition, the range of the amount of (E) curing accelerator relative to the resin composition 100% by mass can be the same as the range of the amount of (E) curing accelerator relative to the resin composition 100% by mass in the resin composition layer.

[0191] The resin composition layer and the resin composition used as the material thereof may contain (F) a polymerization initiator as an optional component. The (F) polymerization initiator used as the (F) component does not include components belonging to the above-mentioned (A) to (E) components. The (F) polymerization initiator may be used alone or in combination of two or more.

[0192] The type of (F) polymerization initiator can be selected according to the type of (A) curable resin. For example, when (A) curable resin contains a free radical polymerizable resin, it is preferred to use a free radical polymerization initiator as (F) polymerization initiator. As free radical polymerization initiators, for example, peroxide free radical polymerization initiators, azo free radical polymerization initiators, etc. can be cited. Among them, peroxide free radical polymerization initiators are preferred.

[0193] Examples of the peroxide-based radical polymerization initiator include hydroperoxide compounds such as 1,1,3,3-tetramethylbutyl hydroperoxide; dialkyl peroxide compounds such as tert-butyl isopropyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, 1,4-bis(1-tert-butylperoxy-1-methylethyl)benzene, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; dilauroyl peroxide, didecanoyl peroxide, dicyclohexyl peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxide Peroxy diacyl compounds such as oxidized dicarbonates; peroxy ester compounds such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxylaurate, 1,1-dimethylpropyl 2-ethylperoxyhexanoate, tert-butyl 2-ethylperoxyhexanoate, tert-butyl 3,5,5-trimethylperoxyhexanoate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-butyl peroxymaleate, etc.; etc.

[0194] (F) Examples of commercially available products of the polymerization initiator include “PERBUTYL C”, “PERBUTYL A”, “PERBUTYL P”, “PERBUTYL L”, “PERBUTYL O”, “PERBUTYL ND”, “PERBUTYL Z”, “PERBUTYL I”, “PERCUMYLP”, “PERCUMYL D”, “PERHEXYL D”, “PERHEXYL A”, “PERHEXYL I”, “PERHEXYL Z”, “PERHEXYL ND”, “PERHEXYL O”, and “PERHEXYL PV” manufactured by NOF Corporation.

[0195] Relative to 100% by mass of the non-volatile component in the resin composition layer, the range of the amount of (F) polymerization initiator is preferably more than 0.01% by mass, more preferably more than 0.02% by mass, further more preferably more than 0.05% by mass, preferably less than 5% by mass, more preferably less than 1% by mass, further more preferably less than 0.1% by mass. In addition, the range of the amount of (F) polymerization initiator relative to 100% by mass of the non-volatile component in the resin composition can be the same as the range of the amount of (F) polymerization initiator relative to 100% by mass of the non-volatile component in the resin composition layer.

[0196] Relative to the resin component 100% by mass in the resin composition layer, the range of the amount of (F) polymerization initiator is preferably more than 0.01% by mass, more preferably more than 0.05% by mass, further more preferably more than 0.1% by mass, preferably less than 5% by mass, more preferably less than 2% by mass, further more preferably less than 1% by mass. In addition, the range of the amount of (F) polymerization initiator relative to 100% by mass of the resin component in the resin composition can be the same as the range of the amount of (F) polymerization initiator relative to 100% by mass of the resin component in the resin composition layer.

[0197] The resin composition layer and the resin composition as the material thereof may contain (G) any additive as an arbitrary component. (G) The arbitrary additive does not include the components belonging to the above-mentioned (A) to (F) components. As (G) arbitrary additives, for example, organic metal compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds, colorants such as phthalocyanine blue, phthalocyanine green, olive green, diazo yellow, crystal violet, titanium oxide, and carbon black, polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and thiophene, leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents, thickeners such as bentonite (Benton) and montmorillonite, defoaming agents such as silicone-based defoaming agents, acrylic defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents, ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers, adhesion enhancers such as urea silane, triazole-based adhesion imparting agents, tetrazole-based adhesion enhancers. Adhesion imparting agents such as adhesive imparting agents, triazine adhesion imparting agents, antioxidants such as hindered phenol antioxidants, fluorescent whitening agents such as stilbene derivatives, surfactants such as fluorine-based surfactants and silicone surfactants, dispersants such as phosphate dispersants, polyoxyalkylene dispersants, acetylene dispersants, silicone dispersants, anionic dispersants, cationic dispersants, borate stabilizers, titanate stabilizers, aluminate stabilizers, zirconate stabilizers, isocyanate stabilizers, carboxylic acid stabilizers, carboxylic anhydride stabilizers, photopolymerization initiation aids such as tertiary amines, photosensitizers such as pyrazolines, anthracenes, coumarins, xanthones, and thioxanthones. (G) Any additive may be used alone or in combination of two or more.

[0198] The resin composition may further contain (H) a solvent as an arbitrary volatile component in combination with the above-mentioned (A) to (G) components, which are non-volatile components. As the (H) solvent, an organic solvent is generally used. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and carbitol acetate. Ether ester solvents such as acetate, γ-butyrolactone, and methyl methoxypropionate, ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate, ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol), amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, sulfoxide solvents such as dimethyl sulfoxide, nitrile solvents such as acetonitrile and propionitrile, aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (H) The solvent may be used alone or in combination of two or more.

[0199] The amount of the solvent (H) is not particularly limited, and may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, etc., relative to 100% by mass of all components in the resin composition layer, or 0% by mass.

[0200] The resin composition layer preferably has a melt viscosity in a specific range at a temperature of at least one of the pressing temperature in the process (3) and the pressing temperature in the process (5), and more preferably has a melt viscosity in a specific range at a temperature of the pressing temperature in the process (3) and the pressing temperature in the process (5). The specific range is preferably more than 300 poise, more preferably more than 700 poise, further preferably more than 1000 poise, preferably less than 60000 poise, more preferably less than 50000 poise, and further preferably less than 40000 poise. Usually, at a temperature of at least one of the pressing temperature in the process (3) and the pressing temperature in the process (5), preferably at a temperature of both, the resin composition also has a melt viscosity in the same range as the resin composition layer. In the case where the melt viscosity is within the range, the generation of holes can be effectively suppressed.

[0201] The melt viscosity can be measured using a dynamic viscoelasticity measuring device. The measurement is performed from a starting temperature of 70°C to 180°C at a heating rate of 5°C / min. The measurement conditions may be a measurement temperature interval of 2.5°C, a vibration frequency of 1 Hz, and a deformation of 5 degrees. The specific measurement operation may be the operation described in the <Test for the measurement of melt viscosity and tan δ> described in the examples.

[0202] The resin composition layer preferably has a loss tangent tanδ in a specific range at a temperature of at least one of the pressing temperature in the process (3) and the pressing temperature in the process (5), and more preferably has a loss tangent tanδ in a specific range at a temperature of the pressing temperature in the process (3) and the pressing temperature in the process (5). The specific range is preferably 0.8 or more, more preferably 0.9 or more, further preferably 1.0 or more, preferably 2.0 or less, more preferably 1.8 or less, and further preferably 1.7 or less. Usually, at a temperature of at least one of the pressing temperature in the process (3) and the pressing temperature in the process (5), preferably at a temperature of both, the resin composition also has a loss tangent tanδ in the same range as the resin composition layer. When the loss tangent tanδ is within the range, the generation of voids can be effectively suppressed.

[0203] The loss tangent tanδ can be measured using a dynamic viscoelasticity measuring device. The measurement is performed from a starting temperature of 70°C to 180°C at a heating rate of 5°C / min. The measurement conditions may be a measurement temperature interval of 2.5°C, a vibration frequency of 1Hz, and a deformation of 5 degrees. The specific measurement operation may be the operation described in the <Test for the measurement of melt viscosity and tanδ> described in the examples.

[0204] In the manufacturing method of the above-mentioned circuit substrate, an insulating layer is obtained as a cured product obtained by curing the resin composition layer. The formed insulating layer comprises a cured product of the resin composition, preferably only comprises a cured product of the resin composition. Usually, the resin composition layer is heated during curing, so among the components contained in the resin composition layer, volatile components such as (H) solvents will volatilize due to the heat during curing. Therefore, the insulating layer and the cured product of the resin composition as its material may contain non-volatile components of the resin composition or its reaction product.

[0205] The average linear thermal expansion coefficient of the cured product obtained by curing the resin composition layer of the resin sheet at 200°C and 90 minutes is preferably within a specific range. Specifically, the range of the average linear thermal expansion coefficient is preferably less than 25ppm / °C, more preferably less than 22ppm / °C, further preferably less than 20ppm / °C, and particularly preferably less than 18ppm / °C. The lower limit may be, for example, 1ppm / °C or more, 3ppm / °C or more, etc. In the case of using a resin sheet having such a resin composition layer, an insulating layer with a small average linear thermal expansion coefficient can be obtained, so the warping of the circuit substrate can be suppressed. In addition, in general, in order to obtain such a small average linear thermal expansion coefficient, the resin composition layer is required to contain more inorganic filler materials, but if a resin composition layer containing more inorganic filler materials is used, there is a tendency to easily generate holes in the past. In contrast, if the manufacturing method involved in the present embodiment is adopted, even if a resin composition layer with a small average linear thermal expansion coefficient is used, the generation of holes can be suppressed.

[0206] The average linear thermal expansion coefficient can be measured by curing the resin composition layer at 200°C for 90 minutes to obtain a cured product, and then performing a thermomechanical analysis using a thermomechanical analyzer by a tensile load method. The measurement can be performed under the measurement conditions of a load of 1g and a heating rate of 5°C / min, and can be measured in a temperature range of 25°C to 150°C. The specific measurement operation can be the operation described in the <CTE measurement test> of the embodiment described later.

[0207] The cured product obtained by curing the resin composition layer of the resin sheet at 200°C and 90 minutes can generally have excellent dielectric properties, for example, it can have a lower dielectric loss tangent. In one example, the dielectric loss tangent of the cured product is preferably less than 0.0100, more preferably less than 0.0080, and further preferably less than 0.0070. The lower limit of the dielectric loss tangent is not particularly limited and can be, for example, more than 0.0010. In the case of using a resin sheet having such a resin composition layer, an insulating layer with a low dielectric loss tangent can be obtained. The dielectric loss tangent can be measured by a resonant cavity perturbation method at a measurement frequency of 5.8 GHz and a measurement temperature of 23°C.

[0208] The thickness of the resin composition layer may be more than the depth of the cavity, or less than the depth of the cavity. Thus, the thickness of the resin composition layer may be more than the thickness of the core substrate, or less than the thickness of the core substrate. From the viewpoint of supplying a sufficient amount of resin composition into the cavity, the thickness of the resin composition layer is preferably more than 10 μm, more preferably more than 20 μm, and further preferably more than 30 μm. In addition, from the viewpoint of the thinning of the circuit substrate, the thickness of the resin composition layer is preferably less than 400 μm, more preferably less than 300 μm, and further preferably less than 200 μm.

[0209] According to the research of the inventors, it is clear that in the past, when a thinner resin composition layer is used to fill a resin composition into a deeper cavity, there is a tendency to be particularly easy to produce holes. In contrast, even in the case of using a thinner resin composition layer like this, if the manufacturing method involved in the above-mentioned embodiment is adopted, the generation of holes can also be suppressed. From the point of view of effectively utilizing the effect of suppressing the generation of holes, the ratio of the thickness of the resin composition layer to the depth of the cavity (the thickness of the resin composition layer / the depth of the cavity) can be within a specific range. Specifically, the range of the ratio (the thickness of the resin composition layer / the depth of the cavity) is preferably less than 1.0, more preferably less than 0.5, further preferably less than 0.3, further preferably less than 0.2, further preferably less than 0.1, preferably more than 0.005, more preferably more than 0.01, and further preferably more than 0.02. Generally speaking, the depth of the cavity is consistent with the thickness of the core substrate, so the range of the ratio of the thickness of the resin composition layer to the thickness of the core substrate (thickness of the resin composition layer / thickness of the core substrate) can be the same as the range of the ratio of the thickness of the resin composition layer to the depth of the cavity (thickness of the resin composition layer / depth of the cavity).

[0210] In addition, according to the research of the inventors, it is clear that in the past, when a thinner resin composition layer is used to bury a thicker component, there is a tendency to be particularly easy to produce holes. In contrast, even when a thinner resin composition layer is used, if the manufacturing method involved in the above-mentioned embodiment is adopted, the generation of holes can also be suppressed. From the point of view of effectively utilizing the effect of suppressing the generation of holes, the ratio of the thickness of the resin composition layer to the thickness of the component (the thickness of the resin composition layer / the thickness of the component) can be within a specific range. Specifically, the range of the ratio (the thickness of the resin composition layer / the thickness of the component) is preferably less than 1.0, more preferably less than 0.5, further preferably less than 0.3, further preferably less than 0.2, particularly preferably less than 0.15, preferably more than 0.01, more preferably more than 0.03, further preferably more than 0.05, and further preferably more than 0.08.

[0211] The resin sheet can be combined with a support and a resin composition layer to include any layer. As an arbitrary layer, for example, a protective film selected according to the support and provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface on the opposite side of the support) can be cited. The thickness of the protective film is not particularly limited, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress the adhesion of garbage and damage to the surface of the resin composition layer. In the case where the resin sheet has a protective film, the resin sheet can usually be used by peeling off the protective film.

[0212] The resin sheet can be produced, for example, by a method including preparing a resin composition and forming a resin composition layer on a support using the resin composition.

[0213] The resin composition can be manufactured by, for example, mixing the components that may be contained in the resin composition. These components can be mixed partially or entirely at the same time, or can be mixed sequentially. In the process of mixing the components, the temperature can be appropriately set, so heating and / or cooling can be performed part of the time or all the time. In addition, stirring or vibration can be performed in the process of mixing the components.

[0214] The formation of the resin composition layer on the support can be carried out, for example, as follows: a liquid (varnish-like) resin composition is directly prepared, or a liquid (varnish-like) resin composition is prepared by dissolving the resin composition in a solvent, and the liquid (varnish-like) resin composition is applied to the support using a coating device such as a die coater, and then dried to form the resin composition layer.

[0215] Examples of the solvent include the same solvents as those described above as the (H) solvent as a component of the resin composition. The solvent may be used alone or in combination of two or more.

[0216] Drying can be carried out by heating, hot air blowing and other methods. The drying conditions are not particularly limited, and the drying is carried out under the conditions that the content of the solvent in the resin composition layer is usually 10% by mass or less, preferably 5% by mass or less. Depending on the boiling point of the solvent in the resin composition, for example, in the case of using a resin composition containing 30% by mass to 60% by mass of a solvent, the resin composition layer can be formed by drying at 50° C. to 150° C. for 2 minutes to 10 minutes.

[0217] <Semiconductor devices> The circuit substrate can be used for the manufacture of semiconductor devices. The semiconductor device has the circuit substrate. As semiconductor devices, various semiconductor devices for electrical products (such as computers, mobile phones, smart phones, tablet devices, wearable devices, digital cameras, medical devices, and televisions, etc.) and transportation tools (such as two-wheeled vehicles, automobiles, trams, ships, and aircraft, etc.) can be cited. These semiconductor devices can be manufactured by, for example, a method including manufacturing a circuit substrate using the above-mentioned manufacturing method. Example

[0218] The present invention is specifically described below with reference to the following examples. However, the present invention is not limited to these examples. In the following description, unless otherwise expressly stated, "parts" and "%" indicating quantities refer to "parts by mass" and "% by mass", respectively. In addition, unless otherwise expressly stated, the operations described below are performed at room temperature (23° C.) and atmospheric pressure (1 atm).

[0219] <Synthesis Example 1. Synthesis of Elastomer A> 69 g of difunctional hydroxy-terminated polybutadiene ("G-3000" manufactured by Nippon Soda Co., Ltd., number average molecular weight = 3000, hydroxyl equivalent = 1800 g / eq.), 40 g of aromatic hydrocarbon mixed solvent ("Ipzole 150" manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005 g of dibutyltin laurate were added to a reaction container and mixed to be uniformly dissolved. After becoming uniform, the temperature was raised to 60° C., and 8 g of isophorone diisocyanate ("IPDI" manufactured by Evonik Degussa Japan Co., Ltd., isocyanate equivalent = 113 g / eq.) was added while stirring, and the reaction was carried out for about 3 hours.

[0220] Next, 23 g of cresol novolac resin ("KA-1160" manufactured by DIC Corporation, hydroxyl equivalent = 117 g / eq.) and 80 g of carbitol acetate (manufactured by Daicel Corporation) were added to the reactant, and the temperature was raised to 150°C while stirring, and the reaction was carried out for about 10 hours. FT-IR was performed at 2250 cm -1 The disappearance of the NCO peak was confirmed. The disappearance of the NCO peak was regarded as the end point of the reaction, and the reactants were cooled to room temperature. Then, the reactants were filtered with a 100-mesh filter cloth to obtain an elastomer A having a butadiene structure and phenolic hydroxyl groups (butadiene resin containing phenolic hydroxyl groups: non-volatile components 45% by mass). The number average molecular weight of elastomer A was 5900, and the glass transition temperature was -7°C.

[0221] <Description of Inorganic Fillers Used> Inorganic filler A: average particle size 3 μm, specific surface area 3.5 m 2 / g, silica particles surface-treated with a surface treatment agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.); Inorganic filler B: average particle size 0.5 μm, specific surface area 5.9 m 2 / g, and silica particles surface-treated with a surface treatment agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.).

[0222] <Manufacturing Example 1. Manufacture of Resin Sheet 1 (Resin Sheet Used in Examples 1 to 2 and Comparative Example 1)> 30 parts of a biphenyl type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight of about 185 g / eq.), 20 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight of about 272 g / eq.) and 10 parts of a naphthyl ether type epoxy resin ("HP-6000L" manufactured by DIC Corporation, epoxy equivalent weight of 215 g / eq.) were heated and dissolved in a mixed solvent of 20 parts of solvent naphtha and 30 parts of cyclohexanone while stirring. The mixture was cooled to room temperature to prepare a dissolved composition of epoxy resin. Into the epoxy resin dissolving composition, 30 parts of elastomer A (45% by mass of nonvolatile components), 20 parts of a phenolic curing agent having a triazine skeleton and a phenolic structure ("LA3018-50P" manufactured by DIC Corporation, an active group equivalent of about 151 g / eq., a 2-methoxypropanol solution of 50% nonvolatile components), 50 parts of an active ester curing agent ("HPC-8000-65T" manufactured by DIC Corporation, an active group equivalent of about 223 g / eq., a toluene solution of 65% nonvolatile components), and 1 0 parts of a carbodiimide curing agent ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group equivalent 216 g / eq., a toluene solution containing 50% by mass of non-volatile components), 1 part of a curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), a MEK solution containing 10% by mass of non-volatile components), 10 parts of a curing accelerator (4-dimethylaminopyridine (DMAP), a MEK solution containing 2.5% by mass of solid components), and 650 parts of an inorganic filler A are uniformly dispersed using a high-speed rotary mixer to prepare a resin varnish 1.

[0223] As a support, a polyethylene terephthalate film ("AL5" manufactured by Lintec Corporation, thickness 38 μm) having a release layer was prepared. The resin varnish 1 was evenly applied on the release layer of the support so that the thickness of the resin composition layer after drying was 65 μm. Then, the resin varnish 1 was dried at 80° C. to 120° C. (average 100° C.) for 2.5 minutes to obtain a resin sheet 1a including a support and a resin composition layer.

[0224] Next, a resin sheet 1b for CTE measurement was prepared by the same method as the method for producing the resin sheet 1a except that the coating amount of the resin varnish 1 was changed so that the thickness of the resin composition layer after drying would be 40 μm.

[0225] <Manufacturing Example 2. Manufacture of Resin Sheet 2 (Resin Sheet Used in Examples 3 to 4 and Comparative Example 2)> 2 parts of bisphenol A type epoxy resin ("YD-8125G" manufactured by Nippon Steel Chemical Materials Co., Ltd., epoxy equivalent of about 174 g / eq.), 5 parts of biphenyl type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 185 g / eq.), 5 parts of naphthyl ether type epoxy resin ("EXA-7311-G4" manufactured by DIC Corporation, epoxy equivalent of about 213 g / eq.), 15 parts of biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent of about 272 g / eq.), and 10 parts of phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, a 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) with a solid content of 30% by mass) were heated and dissolved in a mixed solvent of 15 parts of solvent naphtha and 10 parts of cyclohexanone while stirring. After cooling to room temperature, 5 parts of a triazine skeleton-containing cresol novolac curing agent ("LA3018-50P" manufactured by DIC Corporation, a hydroxyl equivalent of about 151 g / eq., a 2-methoxypropanol solution of 50% solid content), 12 parts of an active ester curing agent ("HPC-8000-65T" manufactured by DIC Corporation, an active group equivalent of about 223 g / eq., a toluene solution of 65% non-volatile content), and 10 parts of a carbodiimide resin ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., Carbodiimide group equivalent 216g / eq., non-volatile matter 50 mass % toluene solution), 3 parts of curing accelerator (4-dimethylaminopyridine (DMAP), solid content 2.5 mass % MEK solution), 2 parts of flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 1.2μm) and 130 parts of inorganic filler B are uniformly dispersed in a high-speed rotating mixer to make resin varnish 2.

[0226] A resin sheet 2a having a support and a resin composition layer (thickness 65 μm), and a resin sheet 2b for CTE measurement having a support and a resin composition layer (thickness 40 μm) were manufactured by the same method as in Manufacturing Example 1, except that the resin varnish 2 obtained in this way was used instead of the resin varnish 1.

[0227] <Manufacturing Example 3. Manufacture of Resin Sheet 3 (Resin Sheet Used in Examples 5 to 6 and Comparative Example 3)> 10 parts of bisphenol epoxy resin ("ZX1059" manufactured by Nippon Steel Chemicals Co., Ltd., a 1:1 mixture of bisphenol A and bisphenol F, epoxy equivalent 169 g / eq.) and 50 parts of naphthol epoxy resin ("ESN475V" manufactured by Nippon Steel Chemicals Co., Ltd., epoxy equivalent about 330 g / eq.) were heated and dissolved in 40 parts of solvent naphtha while stirring. The mixture was cooled to room temperature to prepare a dissolved composition of epoxy resin. To the dissolved composition of the epoxy resin, 5 parts of a phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, a 1:1 solution of MEK and cyclohexanone with a solid content of 30% by mass), 5 parts of a phenolic curing agent having a triazine skeleton and a phenolic structure ("LA3018-50P" manufactured by DIC Corporation, an active group equivalent of about 151 g / eq., a 2-methoxypropanol solution with a non-volatile content of 50%), and 70 parts of an active ester curing agent ("HPC-8000-65T" manufactured by DIC Corporation, an active group equivalent of about 223 g / eq.) were mixed. 65 mass % non-volatile matter toluene solution), 20 parts of (meth)acrylate ("A-DOG" manufactured by Shin-Nakamura Chemical Co., Ltd., (meth)acryloyl equivalent 156 g / eq.), 15 parts of carbodiimide curing agent ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide group equivalent 216 g / eq., 50 mass % non-volatile matter toluene solution), 6 parts of curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), 10 mass % non-volatile matter MEK solution), 2 parts of polymerization initiator ("PERCUMYL D" manufactured by NOF Corporation, 20 mass % non-volatile matter MEK solution), 420 parts of inorganic filler B, 10 parts of cyclohexanone, and 10 parts of MEK are uniformly dispersed by a high-speed rotary mixer to prepare resin varnish 3.

[0228] A resin sheet 3a having a support and a resin composition layer (thickness 65 μm), and a resin sheet 3b for CTE measurement having a support and a resin composition layer (thickness 40 μm) were manufactured by the same method as in Manufacturing Example 1, except that the resin varnish 3 obtained in this way was used instead of the resin varnish 1.

[0229] <Testing of melt viscosity and tan δ> From the resin sheets having a 65 μm thick resin composition layer produced in Production Examples 1 to 3 (i.e., resin sheets 1a, 2a, or 3a), only the resin composition layer was peeled off and compressed using a mold to prepare pellets for measurement of the resin composition (diameter 18 mm, 1.2 g to 1.3 g).

[0230] The dynamic viscoelastic modulus was measured for 1.3 g of the test pellets of the resin composition using a dynamic viscoelasticity measuring device ("Rheosol-G3000" manufactured by UBM Co., Ltd.), and the melt viscosity (poise) and loss tangent tanδ at the pressing temperature shown in Tables 1 and 2 were calculated. The dynamic viscoelastic modulus was measured using a parallel plate with a diameter of 18 mm, and the temperature was increased from a starting temperature of 70°C to 180°C at a heating rate of 5°C / min. In addition, the measurement conditions were a measurement temperature interval of 2.5°C, a vibration frequency of 1 Hz, and a deformation of 5 degrees.

[0231] <CTE measurement test> A polyethylene terephthalate film (“501010” manufactured by Lintec Corporation, thickness 38 μm, 240 mm square, hereinafter sometimes referred to as “release PET film”) having a release surface subjected to release treatment and an untreated surface subjected to no release treatment was prepared. The release PET film was placed on the glass cloth-based epoxy resin double-sided copper-clad laminate (“R5715ES” manufactured by Matsushita Electric Works Co., Ltd., thickness 0.7 mm, 255 mm square) in such a manner that the untreated surface of the release PET film was in contact with the glass cloth-based epoxy resin double-sided copper-clad laminate. The four sides of the release PET film were fixed to the glass cloth-based epoxy resin double-sided copper-clad laminate with polyimide adhesive tape (width 10 mm).

[0232] The resin sheets having a resin composition layer having a thickness of 40 μm prepared in Preparation Examples 1 to 3 (i.e., resin sheets 1b, 2b or 3b, 200 mm square) were laminated on the center of the release PET film using a batch vacuum pressurization laminator (a two-stage stack laminator "CVP700" manufactured by Nikko-Materials Co., Ltd.) in such a manner that the resin composition layer was in contact with the release surface of the release PET film. The lamination was performed by reducing the pressure for 30 seconds to 13 hPa or less, and then pressing at 100° C. and a pressure of 0.74 MPa for 30 seconds.

[0233] Next, the support was peeled off from the resin sheet and heated in an oven at 200°C for 90 minutes to thermally cure the resin composition layer. The glass cloth substrate epoxy resin double-sided copper-clad laminate and the release PET film were peeled off to obtain a cured product for evaluation as a thermally cured product of the resin composition layer.

[0234] The above-mentioned "cured material for evaluation" was cut to obtain a test piece with a width of about 5 mm and a length of about 15 mm. For the test piece, a thermomechanical analysis was performed by a tensile load method using a thermomechanical analyzer ("Thermo Plus TMA8310" manufactured by Rigaku Corporation). Specifically, after the test piece was loaded into the device, it was continuously measured twice under the measurement conditions of a load of 1 g and a heating rate of 5°C / min. The temperature was raised to 200°C for the first time and to 260°C for the second time. Calculate the average linear thermal expansion coefficient (ppm / °C) from 25°C to 150°C in the second measurement.

[0235] <Example 1> (Manufacturing of Evaluation Substrate) Figure 7 1 is a schematic top view showing a state where the core substrate is viewed from the thickness direction, for explaining the position of the cavity formed in Example 1. Figure 7 As shown, 20 cavities 211 to 214, 221 to 224, 231 to 234, 241 to 244, and 251 to 254 are formed in a copper-clad laminate (MCL-E-705G manufactured by Riseno Corporation, 250 mm in length, 250 mm in width, and 1.4 mm in thickness) as a core substrate 200. Specifically, four cavities 211 to 214 are formed in the central portion 210 of the core substrate 200. The opening of each cavity 211 to 214 is set to a square with a length of 2.2 mm and a width of 2.2 mm. In addition, the intervals between these cavities 211 to 214 are set to 1 mm. Furthermore, four cavities 221 to 224 , 231 to 234 , 241 to 244 and 251 to 254 are formed in four corners 220 , 230 , 240 and 250 , which are 75 mm away from the central portion 210 in the longitudinal and transverse directions, respectively, similarly to the central portion 210 .

[0236] A temporary fixing film ("PFDKE-1525TT" manufactured by Arisawa Manufacturing Co., Ltd.) was attached to one side of the core substrate to seal one side of the cavity opening. A silicon chip (2.0 mm long, 2.0 mm wide, 650 μm thick) was placed as a component in each cavity to obtain an intermediate substrate.

[0237] The resin sheet 1a manufactured in Manufacturing Example 1 was laminated on one side of the intermediate substrate using a batch vacuum pressurizing laminator (Nikko-Materials Co., Ltd., 2-stage stacking laminator "CVP700") in such a way that the resin composition layer of the resin sheet was bonded to the core substrate of the intermediate substrate. The lamination was performed as follows: after reducing the pressure for 30 seconds to make the air pressure below 3 hPa, the resin sheet was pressed with a rigid member made of SUS. In addition, the lamination conditions were a pressing temperature of 100°C and a pressing pressure of 15 kgf / cm 2 , press time 300 seconds.

[0238] After lamination, the support was peeled off. Then, the resin composition layer was thermally cured by heating in an oven at 200° C. for 90 minutes to obtain an evaluation substrate equivalent to a circuit substrate. In the obtained evaluation substrate, the silicon chip in the cavity of the core substrate was buried in the cured product of the resin composition filled in the cavity.

[0239] (Evaluation test of holes) All 20 cavities of the evaluation substrate were observed and the number of voids generated in the cavities was counted. Based on the number of voids, the evaluation was performed according to the following criteria: Excellent: No holes Acceptable: There are holes in 1 to 3 cavities Bad: There are holes in 4 to 20 cavities.

[0240] <Example 2> An intermediate substrate is prepared by the same method as in Example 1. The resin sheet 1a prepared in Example 1 is laminated on one side of the intermediate substrate using a batch vacuum pressurization laminator (manufactured by Nikko-Materials Co., Ltd., a two-stage stacking laminator "CVP700") in such a way that the resin composition layer of the resin sheet 1a is bonded to the core substrate of the intermediate substrate. The lamination is carried out as follows: after reducing the pressure for 30 seconds so that the air pressure is below 3 hPa, the resin sheet is pressed with an elastic member made of rubber, and then the resin sheet is further pressed with a rigid member made of SUS. As for the lamination conditions, in the pressing process using the elastic member, the pressing temperature is 100°C and the pressing pressure is 10 kgf / cm 2 , pressing time 10 seconds. In addition, in the pressing process using a rigid component, the pressing temperature is 100°C and the pressing pressure is 7kgf / cm 2 , press time 35 seconds.

[0241] After lamination, the support was peeled off. Then, the resin composition layer was thermally cured in an oven at 200°C for 90 minutes to obtain an evaluation substrate equivalent to a circuit substrate. In the obtained evaluation substrate, the silicon chip in the cavity of the core substrate was buried in the cured product of the resin composition filled in the cavity. For the evaluation substrate, a hole evaluation test was performed by the same method as in Example 1.

[0242] <Example 3> An evaluation substrate was produced and evaluated in the same manner as in Example 1, except that the resin sheet 2a produced in Production Example 2 was used instead of the resin sheet 1a produced in Production Example 1 and the pressing temperature during lamination was changed to 70°C.

[0243] <Example 4> The evaluation substrate was manufactured and evaluated by the same method as in Example 2, except that the resin sheet 2a manufactured in Manufacturing Example 2 was used instead of the resin sheet 1a manufactured in Manufacturing Example 1, and the pressing temperature during lamination was changed to 70°C in both the pressing process using the elastic component and the pressing process using the rigid component.

[0244] <Example 5> A substrate for evaluation was produced and evaluated by the same method as in Example 1, except that the resin sheet 3a produced in Production Example 3 was used instead of the resin sheet 1a produced in Production Example 1.

[0245] <Example 6> An evaluation substrate was produced and evaluated by the same method as in Example 2, except that the resin sheet 3a produced in Production Example 3 was used instead of the resin sheet 1a produced in Production Example 1.

[0246] <Comparative Example 1> The pressing pressure in the pressing process using the elastic member was changed to 7 kgf / cm 2 , the pressing time was changed to 30 seconds. Furthermore, the pressing pressure in the pressing process using the rigid member was changed to 5.5 kgf / cm 2 The pressing time was changed to 60 seconds. Except for the above matters, the same method as in Example 2 was used to produce and evaluate the evaluation substrate.

[0247] <Comparative Example 2> The resin sheet 2a produced in Production Example 2 was used instead of the resin sheet 1a produced in Production Example 1. In addition, the pressing temperature in the pressing step using the elastic member was changed to 70°C and the pressing pressure was changed to 7 kgf / cm 2 , the pressing time was changed to 30 seconds. Furthermore, the pressing temperature in the pressing process using the rigid member was changed to 70°C, and the pressing pressure was changed to 5.5 kgf / cm 2 The pressing time was changed to 60 seconds. Except for the above matters, the same method as in Example 2 was used to produce and evaluate the evaluation substrate.

[0248] <Comparative Example 3> The resin sheet 3a produced in Production Example 3 was used instead of the resin sheet 1a produced in Production Example 1. In addition, the pressing pressure in the pressing step using the elastic member was changed to 7 kgf / cm 2 , the pressing time was changed to 30 seconds. Furthermore, the pressing pressure in the pressing process using the rigid member was changed to 5.5 kgf / cm 2The pressing time was changed to 60 seconds. Except for the above matters, the same method as in Example 2 was used to produce and evaluate the evaluation substrate.

[0249] <Comparative Example 4> In addition to changing the pressing pressure to 20kgf / cm in the pressing process using the elastic member, 2 , except that the pressing time was changed to 60 seconds, the evaluation substrate was manufactured and evaluated in the same manner as in Example 2.

[0250] <Comparative Example 5> In addition to changing the pressing pressure to 2kgf / cm in the pressing process using rigid components 2 , except that the pressing time was changed to 30 seconds, the evaluation substrate was manufactured and evaluated in the same manner as in Example 2.

[0251] <Comparative Example 6> In addition to changing the pressing pressure to 5kgf / cm in the pressing process using rigid components 2 , except that the pressing time was changed to 20 seconds, the evaluation substrate was manufactured and evaluated in the same manner as in Example 1.

[0252] <Results> The results of the embodiments and comparative examples are shown in the following table. In the following table, the meanings of the abbreviations are as follows: (B) content: the content of (B) inorganic filler relative to 100% by mass of the non-volatile component; Pressing temperature: the pressing temperature in steps (3) and (5); Melt viscosity: melt viscosity of the resin composition layer at pressing temperature; tanδ: tanδ of the resin composition layer at the pressing temperature; CTE: average linear thermal expansion coefficient from 25° C. to 150° C. of a cured product obtained by curing the resin composition layer at 200° C. for 90 minutes.

[0253] [Table 1] [Table 1. Results of Example]

[0254] [Table 2] [Table 2. Results of Comparative Example]

[0255] Explanation of symbols 10-core substrate 10U first side 10D Second Side 20 Cavity 21 Opening 22 opening 30 Temporary fixing film 30U adhesive surface 40 parts 50 resin sheet 51 Support 52 resin composition layer 60 Rigid components 60D press surface 70 insulation layer 80 elastic member 80D press surface 100 circuit substrates.

Claims

1. A method for manufacturing a circuit substrate, which is a method for manufacturing a circuit substrate using a core substrate having a cavity formed therein and penetrating the core substrate, a temporary fixing film, and a resin sheet having a support and a resin composition layer, wherein: The manufacturing method sequentially comprises: Step (1) of bonding a temporary fixing film to one side of the core substrate, Step (2) of placing a component in the cavity, a step (3) of laminating the resin sheet and the core substrate by pressing the support body with a rigid member so that the resin composition layer is bonded to the core substrate, and A step (4) of curing the resin composition layer; The manufacturing method includes, between step (2) and step (3), a step (5) of pressing the support body with an elastic member so that the resin composition layer is bonded to the core substrate, or does not include the step (5); In step (3), the pressing force F of the rigid member pressing the support body is R and pressing time T R The product of H R 200kgf·sec / cm 2 above; When the manufacturing method includes step (5), in the step (5), the pressing force F of the elastic member pressing the support body is E and pressing time T E The product of H E Satisfies the following formula (I): 2×H E <H R (I)。 2. The method for manufacturing a circuit substrate according to claim 1, wherein: The pressing temperature in the step (3) is 50° C. or higher and 140° C. or lower.

3. The method for manufacturing a circuit substrate according to claim 1, wherein: The pressing temperature in the step (5) is 50° C. or higher and 140° C. or lower.

4. The method for manufacturing a circuit substrate according to claim 1, wherein: The resin composition layer contains (A) a curable resin and (B) an inorganic filler.

5. The method for manufacturing a circuit substrate according to claim 4, wherein: The amount of the (B) inorganic filler contained in the resin composition layer is 65% by mass or more relative to 100% by mass of the nonvolatile components in the resin composition layer.

6. The method for manufacturing a circuit substrate according to claim 1, wherein: The average linear thermal expansion coefficient of a cured product obtained by curing the resin composition layer at 200° C. for 90 minutes from 25° C. to 150° C. was less than 25 ppm / ° C.

7. The method for manufacturing a circuit substrate according to claim 1, wherein: The ratio of the volume of the component placed in the cavity to the volume of the cavity is 30 volume % or more.

Images