JP7459900B2 - Method for producing prepreg, prepreg, laminate, printed wiring board, and semiconductor package - Google Patents

Description

The present invention relates to a method for manufacturing prepreg, a prepreg, a laminate, a printed wiring board, and a semiconductor package.

In recent years, electronic devices have become smaller, lighter, and more multifunctional. Along with this, LSI (Large Scale Integration), chip components, etc. have become more highly integrated, and their forms have also become more pin-counted and smaller. Things are changing rapidly. For this reason, in order to improve the packaging density of electronic components, development of finer wiring in multilayer printed wiring boards is underway. As a manufacturing method for multilayer printed wiring boards that meets these requirements, for example, prepreg or the like is used as an insulating layer, and only the necessary parts are connected using, for example, via holes formed by laser irradiation (hereinafter also referred to as "laser vias"). Build-up multilayer printed wiring boards that form wiring layers are becoming mainstream as a method suitable for weight reduction, miniaturization, and finer wiring.

It is important that a multilayer printed wiring board has high electrical connection reliability between multiple layers of wiring patterns formed with a fine wiring pitch and excellent high frequency characteristics, and also requires high connection reliability with semiconductor chips. In particular, in recent years, in motherboards of multifunctional mobile phone terminals and the like, there is a tendency for the wiring width (L) and spacing (S) of the wiring board (hereinafter, the wiring width and spacing may be collectively referred to as [L/S]) to be narrowed along with high-speed communication, high-density wiring, and extremely thin wiring boards. With such narrowing of L/S, it is becoming difficult to stably produce wiring boards with good yield. In addition, in the design of conventional wiring boards, a layer without wiring patterns, called a "skip layer," is provided in some layers in consideration of communication failures, etc. As electronic devices become more highly functional, the amount of wiring design increases and the number of layers of the wiring board increases, but the provision of the skip layer causes a problem that the thickness of the motherboard increases even more.
An effective way to improve these problems is to reduce the relative dielectric constant of the insulating material used in the wiring board. By reducing the relative dielectric constant of the insulating material, it becomes easier to control the impedance of the L/S, which allows stable production of the L/S in a shape close to the current design, and by reducing the number of skip layers, it becomes possible to reduce the number of layers. Therefore, insulating materials used in wiring boards are required to have material properties with a small relative dielectric constant.

In recent years, as electronic devices have become more dense, motherboards for mobile phones and other devices have become thinner and cheaper, and materials with low dielectric constants are required to keep up with the trend toward thinner designs. In addition, communication devices such as servers, routers, and mobile base stations are now being used in higher frequency ranges, and high-melting-point lead-free solders are now being used to solder electronic components. As a result, there is a trend for substrate materials used in these devices to have low dielectric constants, high glass transition temperatures (high Tg), and excellent reflow heat resistance.

In addition, motherboards used in multi-function mobile phone terminals, etc., are required to use small-diameter laser vias when connecting layers due to the increase in wiring density and narrowing of pattern width. From the viewpoint of connection reliability, filled plating is often used, and since the connectivity at the interface between the inner layer copper and the plated copper is very important, there is also a tendency to demand improvement in the laser processability of the base material.
After the laser processing of the substrate, a process of removing residual resin components (desmear process) is generally performed. Since the desmear process is performed on the bottom and wall surfaces of the laser via, if a large amount of the resin components of the substrate are dissolved by the desmear process, the shape of the laser via may be significantly deformed by the dissolution of the resin, and various problems may occur, such as uneven plating due to variations in the unevenness of the wall surface. For this reason, it is required that the amount of the resin components of the substrate dissolved by the desmear process, that is, the amount of desmear dissolution, is an appropriate value.

Among the various properties required of insulating materials used for wiring boards, there are methods of containing epoxy resins with low dielectric constants, methods of introducing cyanate groups, and methods of using polyphenylene ether for the purpose of lowering the dielectric constant. A method of containing such substances has been used. For example, resin compositions containing epoxy resin (see Patent Document 1), resin compositions containing polyphenylene ether and bismaleimide (see Patent Document 2), resin compositions containing polyphenylene ether and cyanate resin (Patent Document 1), resin compositions containing polyphenylene ether and bismaleimide (see Patent Document 2), (see Patent Document 3), resin compositions containing at least one of styrenic thermoplastic elastomers and/or triallyl cyanurate (see Patent Document 4), resin compositions containing polybutadiene (see Patent Document 5), polyphenylene A resin composition obtained by preliminarily reacting an ether resin, a polyfunctional maleimide and/or a polyfunctional cyanate resin, and a liquid polybutadiene (see Patent Document 6), which is provided with a compound having an unsaturated double bond group Or a resin composition containing a grafted polyphenylene ether and triallyl cyanurate and/or triallyl isocyanurate (see Patent Document 7), a reaction between a polyphenylene ether and an unsaturated carboxylic acid or an unsaturated acid anhydride. A resin composition containing a product, a polyfunctional maleimide, etc. (see Patent Document 8), etc. have been proposed.

Japanese Patent Application Laid-Open No. 58-69046 Japanese Patent Application Laid-Open No. 56-133355 Special Publication No. 61-18937 Japanese Unexamined Patent Publication No. 61-286130 Japanese Patent Application Laid-Open No. 62-148512 Japanese Patent Application Laid-Open No. 58-164638 Japanese Unexamined Patent Publication No. 2-208355 Japanese Unexamined Patent Publication No. 6-179734

As mentioned above, various characteristics such as a small relative dielectric constant are required for insulating materials used in wiring boards, but one of the most important characteristics for interlayer connection using small diameter laser vias is a small variation in the amount of dimensional change of the prepreg. As motherboards become thinner, a multi-stage lamination method is required for laminating prepregs, and the prepreg is subjected to multiple heat and stress during lamination. Therefore, if the variation in the amount of dimensional change of the prepreg (meaning the variation in the amount of thermal shrinkage) is large, the positional deviation of the vias connecting the layers may occur every time the prepreg is laminated. For this reason, it is required to stabilize the variation in the amount of thermal shrinkage of the prepreg.
However, according to the investigations of the present inventors, it was found that the variation in the amount of dimensional change is not sufficiently suppressed in prepregs containing conventional resin compositions, and therefore there is room for further improvement in this regard.

Therefore, an object of the present invention is to provide a method for manufacturing a prepreg with small variations in the amount of dimensional change, and to provide a prepreg, a laminate, a printed wiring board, and a semiconductor package with small variations in the amount of dimensional change. .
Another object of the present invention is to provide a prepreg, a laminate, a printed wiring board, and a semiconductor package in which via misalignment defects are less likely to occur.

As a result of intensive research to solve the above problems, the inventors have found that the above problems can be solved by a prepreg obtained by impregnating a substrate with a thermosetting resin composition, B-staging the thermosetting resin composition to obtain a prepreg precursor, and then subjecting the surface of the prepreg precursor to a heat treatment at a specified heat source temperature to obtain a prepreg, thereby completing the present invention. The present invention was completed based on this finding.

The present invention relates to [1] to [20] below.
[1] After impregnating a base material with a thermosetting resin composition, the thermosetting resin composition is B-staged to obtain a prepreg precursor, and after the step of obtaining the prepreg precursor, the surface Has a heat treatment process,
The surface heat treatment step is a step of heat treating the surface of the prepreg precursor at a heat source temperature of 200 to 700 ° C.
Prepreg manufacturing method.
[2] A step of impregnating a base material with a thermosetting resin composition, and then B-staging the thermosetting resin composition to obtain a prepreg precursor; and after the step of obtaining the prepreg precursor, the surface Has a heat treatment process,
The surface heat treatment step is a step of heat treating the surface of the prepreg precursor so that the surface temperature of the prepreg precursor is 40 to 130 ° C.
Prepreg manufacturing method.
[3] The prepreg according to [1] or [2] above, which has a step of cooling the prepreg precursor to 5 to 60° C. after the step of obtaining the prepreg precursor and before the surface heat treatment step. manufacturing method.
[4] The prepreg manufacturing method according to any one of [1] to [3] above, wherein the surface heat treatment time is 1.0 to 10.0 seconds.
[5] The method for producing a prepreg according to any one of [1] to [4] above, wherein the thermosetting resin composition contains (A) a maleimide compound.
[6] Component (A) comprises (a1) a maleimide compound having at least two N-substituted maleimide groups, (a2) a monoamine compound represented by the following general formula (a2-1), and (a3) the following: The method for producing a prepreg according to the above [5], which is a maleimide compound having an N-substituted maleimide group obtained by reacting with a diamine compound represented by general formula (a3-1).

(In general formula (a2-1), R ^A4 represents an acidic substituent selected from a hydroxyl group, a carboxy group, and a sulfonic acid group. R ^A5 represents an alkyl group having 1 to 5 carbon atoms or a halogen atom. t is an integer of 1 to 5, u is an integer of 0 to 4, and satisfies 1≦t+u≦5.However, if t is an integer of 2 to 5, even if multiple R ^A4 are the same (Also, when u is an integer from 2 to 4, multiple R ^A5s may be the same or different.)

(In general formula (a3-1), X ^A2 represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms or -O-. R ^A6 and R ^A7 each independently represent an alkyl group having 1 to 5 carbon atoms group, halogen atom, hydroxyl group, carboxy group, or sulfonic acid group. v and w are each independently an integer of 0 to 4.)
[7] The thermosetting resin composition further comprises (B) an epoxy resin,
(C) a copolymer resin having a structural unit derived from a substituted vinyl compound and a structural unit derived from maleic anhydride; and (D) the above [5] containing silica treated with an aminosilane coupling agent; or The method for manufacturing prepreg according to [6].
[8] The component (B) is a bisphenol F-type epoxy resin, a phenol novolac-type epoxy resin, a cresol novolak-type epoxy resin, a naphthalene-type epoxy resin, an anthracene-type epoxy resin, a biphenyl-type epoxy resin, a biphenylaralkyl novolak-type epoxy resin, and The method for producing a prepreg according to [7] above, which is at least one selected from the group consisting of dicyclopentadiene type epoxy resins.
[9] The above [7] wherein the component (C) is a copolymer resin having a structural unit represented by the following general formula (C-i) and a structural unit represented by the following formula (C-ii). ] or the method for producing a prepreg according to [8].

(In the formula, R ^C1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ^C2 is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyl group having 6 to 20 carbon atoms. It is an aryl group, a hydroxyl group, or a (meth)acryloyl group. x is an integer of 0 to 3. However, when x is 2 or 3, multiple R ^C2 may be the same or different. )
[10] A prepreg containing a base material and a thermosetting resin composition and having a standard deviation σ of 0.012% or less as determined by the method below.
How to calculate standard deviation σ:
Copper foil with a thickness of 18 μm is layered on both sides of one sheet of prepreg, and heat and pressure molded at 190° C. and 2.45 MPa for 90 minutes to produce a double-sided copper-clad laminate with a thickness of 0.1 mm. In the thus obtained double-sided copper-clad laminate, holes with a diameter of 1.0 mm are drilled in the plane at locations 1 to 8 shown in FIG. Using an image measuring machine, measure the distance between three points each in the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) shown in Figure 1. and set each measured distance as the initial value. Thereafter, the outer layer copper foil was removed and heated in a dryer at 185° C. for 60 minutes. After cooling, three points each in the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) were measured in the same way as the initial value measurement method. Measure distance. The average value of the rate of change of each measurement distance with respect to the initial value is determined, and the standard deviation σ with respect to the average value is calculated.
[11] The prepreg according to the above [10], obtained by the manufacturing method according to any one of the above [1] to [9].
[12] The prepreg according to [10] above, wherein the thermosetting resin composition contains (A) a maleimide compound.
[13] The thermosetting resin composition further comprises (B) an epoxy resin,
(C) a copolymer resin having a structural unit derived from a substituted vinyl compound and a structural unit derived from maleic anhydride; and (D) the above [10] containing silica treated with an aminosilane coupling agent; or The prepreg described in [12].
[14] The prepreg according to [10] above, wherein the thermosetting resin composition contains (G) an epoxy resin and (H) an epoxy resin curing agent.
[15] The prepreg according to [10] above, wherein the thermosetting resin composition contains (K) a silicone-modified maleimide compound and (L) an imidazole compound.
[16] A laminate comprising the prepreg according to any one of [10] to [15] above and metal foil.
[17] A printed wiring board comprising the prepreg according to any one of [10] to [15] above or the laminate according to [16] above.
[18] A semiconductor package comprising a semiconductor element mounted on the printed wiring board according to [17] above.
[19] The method for producing a prepreg according to any one of [1] to [4] above, wherein the thermosetting resin composition contains (G) an epoxy resin and (H) an epoxy resin curing agent.
[20] The method for producing a prepreg according to any one of [1] to [4] above, wherein the thermosetting resin composition contains (K) a silicone-modified maleimide compound and (L) an imidazole compound.

According to the present invention, it is possible to provide a method for manufacturing a prepreg with small variations in the amount of dimensional change, and to provide a prepreg, a laminate, a printed wiring board, and a semiconductor package with small variations in the amount of dimensional change. Further, the present invention can also provide prepregs, laminates, printed wiring boards, and semiconductor packages in which via misalignment defects are less likely to occur.

FIG. 2 is a schematic diagram of an evaluation substrate used for measuring the variation in dimensional change in the examples.

In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with the values shown in the examples. In addition, the lower and upper limits of the numerical ranges may be arbitrarily combined with the lower and upper limits of other numerical ranges.
In addition, unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in the composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified.
The present invention also includes any combination of the features described in this specification.

[Prepreg manufacturing method]
The present invention relates to a method for producing a prepreg, comprising: a step (step 1) of impregnating a substrate with a thermosetting resin composition, and then B-staging the thermosetting resin composition to obtain a prepreg precursor; and a surface heat treatment step (step 3) following the step of obtaining the prepreg precursor, in which the surface of the prepreg precursor is heat-treated at a heat source temperature of 200 to 700° C. to obtain a prepreg.
The step 3 can also be referred to as a surface heat treatment step in which, after the step of obtaining the prepreg precursor, the surface of the prepreg precursor is heat-treated so that the surface temperature of the prepreg precursor is 40 to 130° C. to obtain a prepreg.
In addition, it is usually preferable to have a step (step 2) of cooling the prepreg precursor to 5 to 35° C. after the step (step 1) of obtaining the prepreg precursor and before the surface heat treatment step (step 3).
Steps 1 to 3 will be described in order below, and then the base material and the thermosetting resin composition that constitute the prepreg will be described.

<Step 1>
Step 1 is a step in which a base material is impregnated with a thermosetting resin composition, and then the thermosetting resin composition is B-staged to obtain a prepreg precursor.
Methods for impregnating the base material with the thermosetting resin composition include, but are not particularly limited to, a hot melt method, a solvent method, and the like.
The hot melt method is a method in which a base material is directly impregnated with a thermosetting resin composition whose viscosity has been reduced by heating. Examples include a method in which a resin film is formed and then laminated onto a base material, and a method in which a thermosetting resin composition is directly applied to a base material using a die coater or the like.
The solvent method is a method in which a thermosetting resin composition contains an organic solvent to form a resin varnish and is impregnated into a base material. Can be mentioned.

By impregnating a base material with a thermosetting resin composition and then subjecting it to heat treatment, a prepreg precursor in which the thermosetting resin composition is B-staged can be obtained.
Here, when applying the hot melt method, B-staging may be performed at the same time as heating when laminating the resin film to the base material. That is, the thermosetting resin composition may be B-staged by laminating the resin film onto the base material while heating and continuing the heating to obtain a prepreg precursor. In that case, the heating temperature during lamination and the heating temperature during B-staging may be the same or different. The heating temperature when laminating the resin film to the base material is not particularly limited, but is preferably 15 to 150°C, may be 20 to 130°C, or may be 20 to 100°C.
Furthermore, when applying the solvent method, B-staging may be performed simultaneously with heating when drying the resin varnish. That is, after the base material is immersed in the resin varnish, the heating may be continued while drying the organic solvent by heating to B-stage the thermosetting resin composition and obtain a prepreg precursor. In that case, the heating temperature during lamination and the heating temperature during B-staging may be the same or different. The heating temperature when drying the resin varnish is not particularly limited, but is preferably 10 to 190°C, may be 15 to 180°C, or may be 15 to 170°C.

The conditions for B-staging in Step 1 are not particularly limited as long as the thermosetting resin composition can be B-staged, and may be appropriately determined depending on the type of thermosetting resin. The heating temperature is, for example, preferably 70 to 190°C, may be 80 to 180°C, may be 120 to 180°C, or may be 140 to 180°C. The heating method is not particularly limited, and examples thereof include a heating method using a panel heater, a heating method using hot air, a heating method using high frequency waves, a heating method using magnetic lines of force, a heating method using a laser, and a heating method combining these. Among these, the heating method using a panel heater and the heating method using hot air are simple and preferred. Further, the heating time may be, for example, 1 to 30 minutes, 2 to 20 minutes, 2 to 10 minutes, or 2 to 6 minutes.

<Step 2>
Step 2 is a step of cooling the prepreg precursor obtained in step 1. That is, step 2 is a step of cooling the prepreg precursor obtained in step 1 by subjecting the thermosetting resin composition to a heat treatment to bring the composition to a B-stage, to a temperature that is at least lower than the temperature at which the heat treatment was performed.
By carrying out step 2, the thermosetting resin composition is subjected to a thermal history that is generally imparted when producing a prepreg, that is, B-staging and cooling, and the obtained prepreg precursor tends to have inherent distortion and the like that are a cause of dimensional change, which occurs in conventional prepregs.
In this way, it is preferable to have distortions and the like caused by the thermal history of heating (step 1) and cooling (step 2) present before step 3 described below, since this makes it easier to effectively eliminate the distortions and the like and to uniformize the amount of dimensional change by step 3. Furthermore, distortions caused by the thermal history of heating (step 1) and cooling (step 2) that have been eliminated by step 3 will not occur even if the same thermal history is applied after step 3, or will be very small if they do occur, so the prepreg obtained by the present invention tends to have very small variations in the amount of dimensional change.

The prepreg precursor may be cooled by natural cooling or by using a cooling device such as a blower or a cooling roll. From the viewpoint of productivity, it is preferable to cool the prepreg precursor by using a blower. The surface temperature of the prepreg precursor after cooling in this step is usually 5 to 60° C., preferably 10 to 45° C., more preferably 10 to 30° C., and even more preferably room temperature.
In this specification, room temperature refers to the ambient temperature without temperature control such as heating or cooling, and is generally about 15 to 25° C., but is not limited to this range as it may vary depending on the weather, season, etc.

<Step 3>
Step 3 is a surface heat treatment step in which the surface of the prepreg precursor obtained in step 1 or step 2 is heat-treated at a heat source temperature of 200 to 700°C to obtain a prepreg, and it can also be said to be a surface heat treatment step in which the surface of the prepreg precursor is heat-treated so that the surface temperature of the prepreg precursor becomes 40 to 130°C to obtain a prepreg.
The prepreg has a small variation in dimensional change due to this step 3. Although the exact reason is not clear, it is considered that the variation in dimensional change is reduced by eliminating the distortion of the base material in the prepreg precursor obtained in step 1 or step 2 and reducing the dimensional change during curing due to the distortion. The reduction in the variation in dimensional change reduces the occurrence of via positional deviation defects.

The heating method for the surface heat treatment in step 3 is not particularly limited, and may include a heating method using a panel heater, a heating method using hot air, a heating method using high frequency, a heating method using magnetic lines of force, a heating method using a laser, a heating method that combines these, etc. can be mentioned. Among these, a heating method using a panel heater and a heating method using hot air are preferred from the viewpoint of ease of controlling the surface temperature.
In one aspect of the present invention, the surface heat treatment is performed at a heat source temperature of 200 to 700°C, but from the viewpoint of maintaining better productivity of the prepreg, and keeping the prepreg in a B-stage state and maintaining good moldability. In order to reduce the variation in the amount of dimensional change, it is preferable to carry out the heat treatment at a higher temperature and for a shorter time than the heat treatment for B-stage formation in step 1. From this point of view, the heat source temperature during the surface heat treatment is preferably 250 to 700°C, more preferably 300 to 600°C, and still more preferably 350 to 550°C. In particular, when implementing a heating method using a panel heater or hot air, it is preferable to perform the surface heating treatment within the above temperature range.
In one embodiment of the present invention, the surface heat treatment is performed so that the surface temperature of the prepreg precursor is, for example, preferably 40 to The temperature is 130°C, more preferably 40 to 110°C, and even more preferably 60 to 90°C. It is preferable that the surface temperature of the prepreg precursor is within the range at the heat source temperature.
The heating time of the surface heat treatment is not particularly limited, but from the viewpoint of maintaining good productivity of the prepreg, keeping the prepreg in a B-stage state, and maintaining good formability while reducing variation in dimensional change. From the viewpoint of reduction, the time is preferably 1.0 to 10.0 seconds, more preferably 1.5 to 6.0 seconds, and even more preferably 2.0 to 4.0 seconds.
The value of increase in surface temperature of the prepreg precursor due to surface heat treatment (i.e., the absolute value of the difference between the surface temperature before surface heat treatment and the maximum surface temperature reached during surface heat treatment) improves the formability of the prepreg. From the viewpoint of reducing variations in the amount of dimensional change while maintaining the same temperature, the temperature is preferably 5 to 110°C, more preferably 20 to 90°C, and even more preferably 40 to 70°C.
However, the detailed heating conditions for the surface heat treatment may be such that the surface temperature of the prepreg precursor rises above the surface temperature before the surface heat treatment by setting the heat source temperature within the above-mentioned range. It is not particularly limited as long as it does not significantly affect various properties (for example, fluidity) of the prepreg, and may be appropriately determined depending on the type of thermosetting resin.

The prepreg obtained in step 3 is preferably subjected to a cooling step in which it is cooled from the viewpoint of handleability and tackiness of the prepreg. The prepreg may be cooled by natural cooling, or by using a cooling device such as an air blower or a cooling roll. The temperature of the prepreg after cooling is usually 5 to 80°C, preferably 8 to 50°C, more preferably 10 to 30°C, and even more preferably room temperature.

The solid content of the thermosetting resin composition in the prepreg of the present invention obtained as described above is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and 50 to 80% by mass. is even more preferable.
The thickness of the prepreg of the present invention is, for example, 0.01 to 0.5 mm, preferably 0.02 to 0.3 mm, and preferably 0.05 to 0.3 mm from the viewpoint of formability and enabling high-density wiring. 2 mm is more preferable.

The base material and the thermosetting resin composition used in the production of the prepreg of the present invention will be described in detail below.
〔Base material〕
As the substrate constituting the prepreg of the present invention, a sheet-like reinforcing substrate is used, and a well-known one used in various laminates for electrical insulating materials can be used. The material of the substrate can be natural fibers such as paper and cotton linters; inorganic fibers such as glass fibers and asbestos; organic fibers such as aramid, polyimide, polyvinyl alcohol, polyester, tetrafluoroethylene and acrylic; and mixtures thereof. Among these, glass fibers are preferred from the viewpoint of flame retardancy. Examples of glass fiber substrates include woven fabrics using E glass, C glass, D glass, S glass, etc., or glass woven fabrics in which short fibers are bonded with an organic binder; and mixtures of glass fibers and cellulose fibers. More preferably, it is glass woven fabric using E glass.
These substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. The material and shape are selected depending on the intended use and performance of the molded product, and one type may be used alone, or two or more types of materials and shapes may be combined as necessary.
The thickness of the substrate is, for example, 0.01 to 0.5 mm, and from the viewpoint of formability and enabling high-density wiring, it is preferably 0.015 to 0.2 mm, and more preferably 0.02 to 0.15 mm. From the viewpoints of heat resistance, moisture resistance, processability, etc., it is preferable that these substrates are surface-treated with a silane coupling agent or the like, or mechanically opened.

By the way, although the prepregs described in Patent Documents 1 to 8 have relatively good dielectric constants, there have been many cases in which they have not been able to meet the strict demands of the recent market. In addition, not only is the variation in the amount of dimensional change not sufficiently suppressed, but also high heat resistance, high metal foil adhesion, high glass transition temperature, low thermal expansion, formability, and plating coverage (laser processability) is often insufficient, and there is room for further improvement in this respect as well. Furthermore, in the past, the actual situation is that materials have not been sufficiently developed from the viewpoint of satisfying all of the above characteristics.
However, in the present invention, by using the prepreg manufacturing method of the present invention and using the following components of the thermosetting resin composition, in addition to sufficiently suppressing the variation in the amount of dimensional change, It can satisfy high heat resistance, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability, and plating coverage (laser processability). From this point of view, it is preferable to use the following thermosetting resin composition.

[Thermosetting resin composition]
The thermosetting resin composition usable in the present invention is not particularly limited, but from the viewpoint of sufficiently suppressing the variation in the amount of dimensional change and also satisfying high heat resistance, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability and plating adhesion (laser processability), (A) is preferably a thermosetting resin composition containing a maleimide compound (hereinafter referred to as thermosetting resin composition [I]). From the same viewpoint, it is more preferable that the thermosetting resin composition [I] further contains (B) an epoxy resin, (C) a copolymer resin having a structural unit derived from a substituted vinyl compound and a structural unit derived from maleic anhydride, and (D) silica treated with an aminosilane coupling agent. From the same viewpoint, the thermosetting resin composition [I] preferably contains (E) a curing agent, and from the viewpoint of flame retardancy, it is preferable to contain (F) a flame retardant.
From the viewpoint of sufficiently suppressing the variation in the amount of dimensional change, the composition may be an epoxy resin composition [II] containing an epoxy resin (G) and an epoxy resin curing agent (H), and, as necessary, an curing accelerator (I) and an inorganic filler (J), or a thermosetting resin composition [III] containing a silicone-modified maleimide compound (K) and an imidazole compound (L), and, as necessary, an inorganic filler (M).

First, each component contained in the thermosetting resin composition [I] will be described in detail.
<(A) Maleimide Compound>
The component (A) is a maleimide compound (hereinafter, sometimes referred to as maleimide compound (A)), preferably a maleimide compound having an N-substituted maleimide group, and more preferably, (a1) a maleimide compound having at least two N-substituted maleimide groups [hereinafter, abbreviated as maleimide compound (a1)] and (a2) a maleimide compound represented by the following general formula (a2-1):

(In general formula (a2-1), R ^A4 represents an acidic substituent selected from a hydroxyl group, a carboxy group, and a sulfonic acid group. R ^A5 represents an alkyl group having 1 to 5 carbon atoms or a halogen atom. t represents an integer of 1 to 5, u represents an integer of 0 to 4, and satisfies 1≦t+u≦5. However, when t is an integer of 2 to 5, multiple R ^A4s may be the same or different. In addition, when u is an integer of 2 to 4, multiple R ^A5s may be the same or different.)
[hereinafter, abbreviated as monoamine compound (a2)] and (a3) a monoamine compound represented by the following general formula (a3-1):

(In general formula (a3-1), X represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms or -O-. ^R and ^R each independently represent an alkyl group having 1 to 5 carbon atoms, a halogen atom, a hydroxyl group, a ^carboxyl group, or a sulfonic acid group. v and w each independently represent an integer of 0 to 4.)
[hereinafter, abbreviated as diamine compound (a3)].
Hereinafter, the description of the maleimide compound (A) can also be read as a description of the maleimide compound having the above-mentioned N-substituted maleimide group.

The weight average molecular weight (Mw) of the maleimide compound (A) is preferably 400 to 3,500, more preferably 400 to 2,300, and even more preferably 800 to 2,000, from the viewpoints of solubility in organic solvents and mechanical strength. The weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) method (standard polystyrene equivalent) using tetrahydrofuran as an eluent, and more specifically, a value measured by the method described in the examples.

(Maleimide compound (a1))
The maleimide compound (a1) is a maleimide compound having at least two N-substituted maleimide groups.
The maleimide compound (a1) may be a maleimide compound having an aliphatic hydrocarbon group between any two maleimide groups among a plurality of maleimide groups (but no aromatic hydrocarbon group is present) [hereinafter referred to as an aliphatic hydrocarbon group-containing maleimide], or a maleimide compound containing an aromatic hydrocarbon group between any two maleimide groups among a plurality of maleimide groups [hereinafter referred to as an aromatic hydrocarbon group-containing maleimide]. Among these, aromatic hydrocarbon group-containing maleimides are preferred from the viewpoints of high heat resistance, low relative dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability, and plating throwing power. The aromatic hydrocarbon group-containing maleimide may contain an aromatic hydrocarbon group between any combination of two arbitrarily selected maleimide groups, and may also have an aliphatic hydrocarbon group together with the aromatic hydrocarbon group.
From the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability and plating throwing power, the maleimide compound (a1) is preferably a maleimide compound having 2 to 5 N-substituted maleimide groups in one molecule, and more preferably a maleimide compound having 2 N-substituted maleimide groups in one molecule. Furthermore, from the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability and plating throwing power, the maleimide compound (a1) is more preferably an aromatic hydrocarbon group-containing maleimide represented by any one of the following general formulas (a1-1) to (a1-4), even more preferably an aromatic hydrocarbon group-containing maleimide represented by the following general formula (a1-1), (a1-2) or (a1-4), and particularly preferably an aromatic hydrocarbon group-containing maleimide represented by the following general formula (a1-2).

In the above formula, R ^A1 to R ^A3 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms. X ^A1 represents an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, -O-, -C(=O)-, -S-, -S-S-, or a sulfonyl group. p, q and r are each independently an integer of 0 to 4. s is an integer from 0 to 10.
Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by R ^A1 to R ^A3 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, Examples include n-pentyl group. The aliphatic hydrocarbon group preferably has 1 or more carbon atoms from the viewpoint of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, formability, and plating coverage. 3, more preferably a methyl group or an ethyl group.

Examples of the alkylene group having 1 to 5 carbon atoms represented by X ^A1 include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, a 1,5-pentamethylene group, etc. From the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability and plating throwing power, the alkylene group is preferably an alkylene group having 1 to 3 carbon atoms, more preferably a methylene group.
Examples of the alkylidene group having 2 to 5 carbon atoms represented by ^XA1 include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, an isopentylidene group, etc. Among these, an isopropylidene group is preferred from the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability, and plating throwing power.
Among the above options, ^XA1 is preferably an alkylene group having 1 to 5 carbon atoms, or an alkylidene group having 2 to 5 carbon atoms. More preferred ones are as described above.
p, q and r each independently represent an integer of 0 to 4, and from the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, formability and plating throwing power, each is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.
s is an integer of 0 to 10, and from the viewpoint of availability, is preferably 0 to 5, and more preferably 0 to 3. In particular, the aromatic hydrocarbon group-containing maleimide compound represented by general formula (a1-3) is preferably a mixture in which s is 0 to 3.

Specific examples of the maleimide compound (a1) include aliphatic hydrocarbon group-containing maleimides such as N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, bis(4-maleimidocyclohexyl)methane, and 1,4-bis(maleimidomethyl)cyclohexane; N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, and N,N'-[1,3-(4-methylphenylene)]bismaleimide. , N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, 1,4-bis(4-maleimidophenyl)cyclohexane hexane, 1,4-bis(maleimidomethyl)cyclohexane, 1,3-bis(4-maleimidophenoxy)benzene, 1,3-bis(3-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, bis[4-(4-maleimidophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(4-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1 ,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimidophenoxy)biphenyl, 4,4-bis(4-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ketone, bis[4-(4-maleimidophenoxy)phenyl]ketone, bis(4-maleimidophenyl) disulfide, bis[4-(3-maleimidophenoxy)phenyl] bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfoxide, bis[4-(4-maleimidophenoxy)phenyl]sulfoxide, bis[4-(3-maleimidophenoxy)phenyl]sulfone, bis[4-(4-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ether, bis[4-(4-maleimidophenoxy)phenyl] 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-maleimidophenoxy)-3,5-dimethylbenzyl]benzene Examples of aromatic hydrocarbon group-containing maleimides include 1,3-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, and polyphenylmethane maleimide.

Among these, from the viewpoints of high reactivity and higher heat resistance, bis(4-maleimidophenyl)methane, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)disulfide, N,N'-(1,3-phenylene)bismaleimide, and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane are preferred, from the viewpoints of low cost, bis(4-maleimidophenyl)methane and N,N'-(1,3-phenylene)bismaleimide are preferred, and from the viewpoint of solubility in solvents, bis(4-maleimidophenyl)methane is particularly preferred.
The maleimide compound (a1) may be used alone or in combination of two or more kinds.

(Monoamine compound (a2))
The monoamine compound (a2) is a monoamine compound represented by the following general formula (a2-1).

In the above general formula (a2-1), R ^A4 represents an acidic substituent selected from a hydroxyl group, a carboxy group, and a sulfonic acid group. R ^A5 represents an alkyl group having 1 to 5 carbon atoms or a halogen atom. t is an integer of 1 to 5, u is an integer of 0 to 4, and 1≦t+u≦5 is satisfied. However, when t is an integer of 2 to 5, the plurality of R ^A4s may be the same or different. Further, when u is an integer of 2 to 4, the plurality of R ^A5s may be the same or different.
The acidic substituent represented by R ^A4 is preferably a hydroxyl group or a carboxy group from the viewpoint of solubility and reactivity, and more preferably a hydroxyl group from the viewpoint of heat resistance.
t is an integer of 1 to 5, preferably 1 to 3 from the viewpoint of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, formability, and plating coverage. more preferably 1 or 2, still more preferably 1.
Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^A5 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, etc. Can be mentioned. The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms.
Examples of the halogen atom represented by R ^A5 include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.
u is an integer of 0 to 4, preferably 0 to 3 from the viewpoint of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, formability, and plating coverage. , more preferably an integer of 0 to 2, even more preferably 0 or 1, particularly preferably 0.
The monoamine compound (a2) is more preferably represented by the following general formula ( a2-2) or (a2-3), more preferably a monoamine compound represented by the following general formula (a2-2). However, R ^A4 , R ^A5 and u in general formulas (a2-2) and (a2-3) are the same as in general formula (a2-1), and preferred ones are also the same.

Examples of the monoamine compound (a2) include o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, Examples include monoamine compounds having acidic substituents such as m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline.
Among these, m-aminophenol, p-aminophenol, p-aminobenzoic acid, and 3,5-dihydroxyaniline are preferred from the viewpoint of solubility and reactivity, and o-aminophenol is preferred from the viewpoint of heat resistance. , m-aminophenol, and p-aminophenol are preferred, and p-aminophenol is more preferred in consideration of dielectric properties, low thermal expansion, and manufacturing cost.
The monoamine compound (a2) may be used alone or in combination of two or more.

(Diamine compound (a3))
The diamine compound (a3) is a diamine compound represented by the following general formula (a3-1).

(In the formula, X ^A2 represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms or -O-. R ^A6 and R ^A7 each independently represent an alkyl group having 1 to 5 carbon atoms, a halogen atom, a hydroxyl group, a carboxyl group or a sulfonic acid group. v and w each independently represent an integer of 0 to 4.)

Examples of the aliphatic hydrocarbon group having 1 to 3 carbon atoms represented by X ^A2 include a methylene group, an ethylene group, a propylene group, a propylidene group, and the like.
As X ^A2 , a methylene group is preferable.
Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^A6 and R ^A7 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group. Examples include groups. The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms.
v and w are preferably integers of 0 to 2, more preferably 0 or 1, and even more preferably 0.

The diamine compound (a3) is preferably a diamine compound represented by the following general formula (a3-1′).

(In the formula, X ^A2 , R ^A6 , R ^A7 , v and w are the same as those in the general formula (a3-1), and preferred embodiments are also the same.)

Specific examples of the diamine compound (a3) include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, 4,4'-diaminodi Examples of such compounds include phenyl ether, 4,4'-diaminodiphenyl thioether, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethylchloro-4,4'-diaminodiphenylmethane, and 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane. Among these, 4,4'-diaminodiphenylmethane and 3,3'-diethyl-4,4'-diaminodiphenylmethane are preferred from the viewpoint of low cost, and 4,4'-diaminodiphenylmethane is more preferred from the viewpoint of solubility in a solvent.

The reaction of the maleimide compound (a1), the monoamine compound (a2) and the diamine compound (a3) is preferably carried out in the presence of an organic solvent at a reaction temperature of 70 to 200° C. for 0.1 to 10 hours.
The reaction temperature is more preferably 70 to 160°C, further preferably 70 to 130°C, and particularly preferably 80 to 120°C.
The reaction time is more preferably 1 to 6 hours, and further preferably 1 to 4 hours.

(Amounts of maleimide compound (a1), monoamine compound (a2) and diamine compound (a3) used)
In the reaction of the maleimide compound (a1), the monoamine compound (a2) and the diamine compound (a3), it is preferable that the amounts of the three compounds used are such that the relationship between the sum of the primary amino group equivalents [referred to as —NH ₂ group equivalent] of the monoamine compound (a2) and the diamine compound (a3) and the maleimide group equivalent of the maleimide compound (a1) satisfies the following formula:
0.1≦[maleimide group equivalent]/[total of ₂ -NH group equivalents]≦10
By making the [maleimide group equivalent]/[sum of _two -NH group equivalents] 0.1 or more, gelation and heat resistance are not reduced, and by making it 10 or less, solubility in organic solvents, adhesion to metal foil and heat resistance are not reduced, which are preferable.
From the same viewpoint, more preferably,
The following relationship is satisfied: 1≦[maleimide group equivalent]/[total of ₂ -NH group equivalents]≦9, and more preferably,
The following condition is satisfied: 2≦[maleimide group equivalent]/[total of ₂ -NH group equivalents]≦8.

(organic solvent)
As mentioned above, the reaction of the maleimide compound (a1), monoamine compound (a2) and diamine compound (a3) is preferably carried out in an organic solvent.
The organic solvent is not particularly limited as long as it does not adversely affect the reaction. For example, alcohol solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as tetrahydrofuran; toluene, xylene, mesitylene Aromatic solvents such as; nitrogen atom-containing solvents including amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur atom-containing solvents including sulfoxide solvents such as dimethyl sulfoxide; ethyl acetate, γ- Examples include ester solvents such as butyrolactone. Among these, alcohol-based solvents, ketone-based solvents, and ester-based solvents are preferred from the viewpoint of solubility; from the viewpoint of low toxicity, cyclohexanone, propylene glycol monomethyl ether, methyl cellosolve, and γ-butyrolactone are more preferred; Considering that they have high properties and are unlikely to remain as a residual solvent during prepreg production, cyclohexanone, propylene glycol monomethyl ether, and dimethyl acetamide are more preferred, and dimethyl acetamide is particularly preferred.
One type of organic solvent may be used alone, or two or more types may be used in combination.
There is no particular restriction on the amount of organic solvent used, but from the viewpoint of solubility and reaction efficiency, it is preferably 25 parts by mass based on a total of 100 parts by mass of the maleimide compound (a1), monoamine compound (a2) and diamine compound (a3). The amount may be 1,000 parts by mass, more preferably 40 to 700 parts by mass, and even more preferably 60 to 250 parts by mass. Solubility can be easily ensured by setting the amount to 25 parts by mass or more based on a total of 100 parts by mass of the maleimide compound (a1), monoamine compound (a2), and diamine compound (a3), and the content should be 1,000 parts by mass or less. This makes it easy to suppress a significant decrease in reaction efficiency.

(Reaction catalyst)
The reaction of the maleimide compound (a1), the monoamine compound (a2) and the diamine compound (a3) may be carried out in the presence of a reaction catalyst, if necessary. Examples of the reaction catalyst include amine catalysts such as triethylamine, pyridine, and tributylamine; imidazole catalysts such as methylimidazole and phenylimidazole; and phosphorus catalysts such as triphenylphosphine.
The reaction catalyst may be used alone or in combination of two or more kinds.
The amount of the reaction catalyst used is not particularly limited, but is preferably 0.001 to 5 parts by mass per 100 parts by mass of the total mass of the maleimide compound (a1) and the monoamine compound (a2).

<(B) Epoxy resin>
Component (B) is an epoxy resin (hereinafter sometimes referred to as epoxy resin (B)), preferably an epoxy resin having at least two epoxy groups in one molecule.
Examples of epoxy resins having at least two epoxy groups in one molecule include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, glycidyl ester type epoxy resins, and the like. Among these, glycidyl ether type epoxy resins are preferred.
Epoxy resins (B) are classified into various epoxy resins depending on the main skeleton, and in each of the above types of epoxy resins, there are also bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, etc. Bisphenol type epoxy resin; biphenylaralkyl novolak type epoxy resin, phenol novolak type epoxy resin, alkylphenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthol alkylphenol copolymerized novolac type epoxy resin, naphthol aralkyl cresol copolymerized novolac type epoxy resin, Novolac type epoxy resins such as bisphenol A novolac type epoxy resins and bisphenol F novolac type epoxy resins; stilbene type epoxy resins; triazine skeleton-containing epoxy resins; fluorene skeleton-containing epoxy resins; naphthalene type epoxy resins; anthracene type epoxy resins; triphenylmethane It is classified into alicyclic epoxy resins such as epoxy resins; biphenyl epoxy resins; xylylene epoxy resins; and dicyclopentadiene epoxy resins.
Among these, bisphenol F type epoxy resin and phenol novolac type epoxy resin are preferred from the viewpoints of high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability and plating coverage. , cresol novolac type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl novolak type epoxy resin, and dicyclopentadiene type epoxy resin, and is preferably at least one selected from the group consisting of low thermal expansion. selected from the group consisting of cresol novolak type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl novolak type epoxy resin, and phenol novolac type epoxy resin from the viewpoint of properties and high glass transition temperature. At least one type is more preferable, and a cresol novolak type epoxy resin is even more preferable.
The epoxy resin (B) may be used alone or in combination of two or more.

The epoxy equivalent of the epoxy resin (B) is preferably 100 to 500 g/eq, more preferably 120 to 400 g/eq, even more preferably 140 to 300 g/eq, particularly preferably 170 to 240 g/eq.
Here, the epoxy equivalent is the mass (g/eq) of the resin per epoxy group, and can be measured according to the method specified in JIS K 7236 (2001). Specifically, using an automatic titration device "GT-200 model" manufactured by Mitsubishi Chemical Analytech Co., Ltd., 2 g of epoxy resin was weighed into a 200 ml beaker, 90 ml of methyl ethyl ketone was added dropwise, and after melting in an ultrasonic cleaner, it was poured into ice cubes. It is determined by adding 10 ml of acetic acid and 1.5 g of cetyltrimethylammonium bromide, and titrating with a 0.1 mol/L perchloric acid/acetic acid solution.
Commercially available epoxy resins (B) include cresol novolac type epoxy resin “EPICLON (registered trademark) N-673” (manufactured by DIC Corporation, epoxy equivalent: 205 to 215 g/eq), naphthalene type epoxy resin “HP-4032”. ” (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent; 152 g/eq), biphenyl-type epoxy resin “YX-4000” (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent; 186 g/eq), dicyclopentadiene-type epoxy resin “HP-7200H” (manufactured by DIC Corporation, epoxy equivalent: 280 g/eq). Note that the epoxy equivalent is the value listed in the catalog of the manufacturer of the product.

<(C) Specific copolymer resin>
Component (C) is a copolymer resin (hereinafter sometimes referred to as copolymer resin (C)) having a structural unit derived from a substituted vinyl compound and a structural unit derived from maleic anhydride. Examples of the substituted vinyl compound include aromatic vinyl compounds, aliphatic vinyl compounds, and functional group-substituted vinyl compounds. Examples of the aromatic vinyl compound include styrene, 1-methylstyrene, vinyltoluene, dimethylstyrene, and the like. Examples of the aliphatic vinyl compound include propylene, butadiene, isobutylene, and the like. Examples of the functional group-substituted vinyl compound include acrylonitrile; compounds having a (meth)acryloyl group such as methyl acrylate and methyl methacrylate.
Among these, as the substituted vinyl compound, aromatic vinyl compounds are preferred, and styrene is more preferred.
As component (C), a copolymer resin having a structural unit represented by the following general formula (C-i) and a structural unit represented by the following formula (C-ii) is preferable.

(In the formula, R ^C1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ^C2 is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 6 to 20 carbon atoms, a hydroxyl group, or a (meth)acryloyl group. x is an integer of 0 to 3. However, when x is 2 or 3, multiple R ^C2s may be the same or different.)

Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^C1 and R ^C2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms.
Examples of the alkenyl group having 2 to 5 carbon atoms represented by R ^C2 include an allyl group, a crotyl group, etc. The alkenyl group is preferably an alkenyl group having 3 to 5 carbon atoms, more preferably an alkenyl group having 3 or 4 carbon atoms.
Examples of the aryl group having 6 to 20 carbon atoms represented by R ^C2 include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, etc. The aryl group is preferably an aryl group having 6 to 12 carbon atoms, more preferably an aryl group having 6 to 10 carbon atoms.
x is preferably 0 or 1, more preferably 0.
In the structural unit represented by general formula (Ci), a structural unit represented by the following general formula (Ci-1) in which R ^C1 is a hydrogen atom and x is 0, that is, a structural unit derived from styrene, is preferred.

Content ratio of the structural unit derived from the substituted vinyl compound and the structural unit derived from maleic anhydride in the copolymer resin (C) [structural unit derived from the substituted vinyl compound/structural unit derived from maleic anhydride] (mol The ratio) is preferably 1 to 9, more preferably 2 to 9, even more preferably 3 to 8, particularly preferably 3 to 7. In addition, the content ratio of the structural unit represented by the general formula (C-i) to the structural unit represented by the formula (C-ii) [(C-i)/(C-ii)] (molar ratio) Similarly, the number is preferably 1 to 9, more preferably 2 to 9, even more preferably 3 to 8, particularly preferably 3 to 7. If the molar ratio of these is 1 or more, preferably 2 or more, the effect of improving dielectric properties tends to be sufficient, and if it is 9 or less, compatibility tends to be good.
The total content of the structural units derived from the substituted vinyl compound and the structural units derived from maleic anhydride in the copolymer resin (C), and the structural units represented by the general formula (Ci) and the formula ( The total content with the structural unit represented by C-ii) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, particularly preferably substantially 100% by mass. %.
The weight average molecular weight (Mw) of the copolymer resin (C) is preferably 4,500 to 18,000, more preferably 5,000 to 18,000, more preferably 6,000 to 17,000, even more preferably 8,000 to 16,000, particularly preferably 8,000 to 15,000, most preferably 9,000 to 13,000.

In addition, when applying the method of lowering the dielectric constant of epoxy resin by using a copolymer resin of styrene and maleic anhydride to materials for printed wiring boards, the impregnability into the base material and the peel strength of copper foil are insufficient. Therefore, it is generally avoided. Therefore, there is a tendency to generally avoid using the copolymer resin (C), but in the present invention, while using the copolymer resin (C), the (A) component and the (B) component By containing, a thermosetting resin composition has high heat resistance, low dielectric constant, high metal foil adhesion, high glass transition temperature, and low thermal expansion property, and has excellent moldability and plating coverage. This was achieved when it became clear that it would happen.

(Method for producing copolymer resin (C))
The copolymer resin (C) can be produced by copolymerizing a substituted vinyl compound and maleic anhydride.
The substituted vinyl compound is as described above. The substituted vinyl compound may be used alone or in combination of two or more. Furthermore, in addition to the substituted vinyl compound and maleic anhydride, various polymerizable components may be copolymerized.
In addition, a substituent such as an allyl group, a methacryloyl group, an acryloyl group, or a hydroxy group may be introduced into the substituted vinyl compound, particularly an aromatic vinyl compound, through a Friedel-Crafts reaction or a reaction using a metal catalyst such as lithium.

A commercially available product can also be used as the copolymer resin (C). Commercially available products include, for example, "SMA (registered trademark) 1000" (styrene/maleic anhydride = 1, Mw = 5,000), "SMA (registered trademark) EF30" (styrene/maleic anhydride = 3, Mw = 9,500), "SMA (registered trademark) EF40" (styrene/maleic anhydride = 4, Mw = 11,000), "SMA (registered trademark) EF60" (styrene / maleic anhydride = 6, Mw = 11, 500), "SMA (registered trademark) EF80" (styrene/maleic anhydride = 8, Mw = 14,400) [manufactured by CRAY VALLEY], and the like.

<(D) Silica treated with aminosilane coupling agent>
Among silicas, when silica treated with an aminosilane coupling agent (hereinafter sometimes referred to as silica treated with an aminosilane coupling agent (D)) is used as component (D), low thermal expansion is achieved. In addition to the effect of improvement, the adhesion with the components (A) to (C) is improved, which suppresses the falling off of the silica, which has the effect of suppressing the deformation of the laser via shape due to excessive desmear. preferred for.

Specifically, the aminosilane coupling agent is preferably a silane coupling agent having an amino group and a silicon-containing group represented by the following general formula (D-1).

(In the formula, R ^D1 is an alkyl group having 1 to 3 carbon atoms or an acyl group having 2 to 4 carbon atoms, and y is an integer of 0 to 3.)

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ^D1 include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Among these, a methyl group is preferable.
Examples of the acyl group having 2 to 4 carbon atoms represented by R ^D1 include an acetyl group, a propionyl group, and an acryl group. Of these, an acetyl group is preferred.

The aminosilane coupling agent may have one, two, or three or more amino groups, but usually has one or more amino groups. I have two.
Examples of the aminosilane coupling agent having one amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and 3-triethoxysilyl- Examples include N-(1,3-dimethyl-butylidene)propylamine, 2-propynyl[3-(trimethoxysilyl)propyl]carbamate, but are not particularly limited to these.
Examples of the aminosilane coupling agent having two amino groups include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, Examples include 1-[3-(trimethoxysilyl)propyl]urea, 1-[3-(triethoxysilyl)propyl]urea, and the like, but are not particularly limited to these.

Instead of the silica (D) treated with an aminosilane coupling agent, as an inorganic filler other than the (D) component, for example, silica treated with an epoxysilane coupling agent, a phenylsilane coupling agent, an alkylsilane coupling agent, an alkenylsilane coupling agent, an alkynylsilane coupling agent, a haloalkylsilane coupling agent, a siloxane coupling agent, a hydrosilane coupling agent, a silazane coupling agent, an alkoxysilane coupling agent, a chlorosilane coupling agent, a (meth)acrylsilane coupling agent, an aminosilane coupling agent, an isocyanurate silane coupling agent, a ureidosilane coupling agent, a mercaptosilane coupling agent, a sulfide silane coupling agent or an isocyanate silane coupling agent; silica that has not been surface-treated, etc. can also be used, but from the viewpoint of the above-mentioned effect, it is preferable to use the silica (D) treated with an aminosilane coupling agent.
Also, the silica (D) treated with aminosilane coupling agent can be used together with the silica treated with other coupling agents as described above.In this case, it is not particularly limited, but the content of the silica treated with other coupling agents is preferably 50 mass parts or less, more preferably 30 mass parts or less, even more preferably 15 mass parts or less, particularly preferably 10 mass parts or less, and most preferably 5 mass parts or less, relative to 100 mass parts of the silica (D) treated with aminosilane coupling agent.

Examples of the silica include precipitated silica produced by wet method and having high water content, and dry method silica produced by dry method and containing almost no bound water.Dry method silica further includes crushed silica, fumed silica, and fused silica (fused spherical silica) depending on the production method.The silica is preferably fused silica from the viewpoint of low thermal expansion and high fluidity when filled in resin.
The average particle size of the silica is not particularly limited, but is preferably 0.1 to 10 μm, more preferably 0.1 to 6 μm, even more preferably 0.1 to 3 μm, and particularly preferably 1 to 3 μm. By making the average particle size of the silica 0.1 μm or more, it is possible to maintain good fluidity when highly packed, and by making it 10 μm or less, it is possible to reduce the probability of coarse particles being mixed in and suppress the occurrence of defects caused by coarse particles. Here, the average particle size refers to the particle size at the point corresponding to 50% volume when a cumulative frequency distribution curve is calculated based on particle size, with the total volume of the particles being 100%, and can be measured using a particle size distribution measuring device using a laser diffraction scattering method, etc.
The specific surface area of the silica is preferably 4 cm ² /g or more, more preferably 4 to 9 cm ² /g, and even more preferably 5 to 7 cm ² /g.

<(E) Curing agent>
Thermosetting resin composition [I] may further contain a curing agent (hereinafter sometimes referred to as curing agent (E)) as component (E). Examples of the curing agent (E) include dicyandiamide; chain aliphatic amines other than dicyandiamide, such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylaminopropylamine, tetramethylguanidine, and triethanolamine; Isophorone diamine, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, bis(4-amino-3-methyldicyclohexyl)methane, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)-2,4,8 , 10-tetraoxaspiro[5.5]undecane; and aromatic amines such as xylene diamine, phenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Among these, dicyandiamide is preferred from the viewpoint of metal foil adhesion and low thermal expansion.
The dicyandiamide is represented by H ₂ N—C(=NH)—NH—CN, and the melting point is usually 205 to 215°C, and 207 to 212°C in higher purity. Dicyandiamide is a crystalline substance, and may be an orthorhombic crystal or a plate crystal. Dicyandiamide preferably has a purity of 98% or higher, more preferably a purity of 99% or higher, and even more preferably a purity of 99.4% or higher. As dicyandiamide, commercial products can be used, for example, commercial products manufactured by Nippon Carbide Industries Co., Ltd., Tokyo Kasei Kogyo Co., Ltd., Kishida Chemical Co., Ltd., Nacalai Tesque Co., Ltd., etc. can be used. .

<(F) Flame retardant>
Thermosetting resin composition [I] may further contain a flame retardant (hereinafter sometimes referred to as flame retardant (F)) as component (F). Here, among the curing agents, dicyandiamide and the like also have the effect as a flame retardant, but in the present invention, those that can function as a curing agent are classified as curing agents, and are not included in component (F). .
Examples of flame retardants include halogen-containing flame retardants containing bromine and chlorine; phosphorus flame retardants; nitrogen flame retardants such as guanidine sulfamate, melamine sulfate, melamine polyphosphate, and melamine cyanurate; cyclophosphazene and polyphosphazene. and phosphazene-based flame retardants; and inorganic flame retardants such as antimony trioxide. Among these, phosphorus-based flame retardants are preferred.
Phosphorus flame retardants include inorganic phosphorus flame retardants and organic phosphorus flame retardants.
Examples of inorganic phosphorus flame retardants include red phosphorus; ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate; inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide; ; phosphoric acid; phosphine oxide and the like.
Examples of organic phosphorus flame retardants include aromatic phosphoric acid esters, monosubstituted phosphonic acid diesters, disubstituted phosphinic esters, metal salts of disubstituted phosphinic acids, organic nitrogen-containing phosphorus compounds, cyclic organic phosphorus compounds, Examples include phosphorus-containing phenolic resins. Among these, aromatic phosphoric acid esters and metal salts of disubstituted phosphinic acids are preferred. Here, the metal salt is preferably any one of lithium salt, sodium salt, potassium salt, calcium salt, magnesium salt, aluminum salt, titanium salt, and zinc salt, and preferably aluminum salt. Further, among organic phosphorus-based flame retardants, aromatic phosphate esters are more preferred.

Examples of aromatic phosphate esters include triphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, cresyl diphenyl phosphate, cresyl di-2,6-xylenyl phosphate, resorcinol bis(diphenyl phosphate), 1,3 -phenylene bis(di-2,6-xylenyl phosphate), bisphenol A-bis(diphenyl phosphate), 1,3-phenylene bis(diphenyl phosphate) and the like.
Examples of monosubstituted phosphonic acid diesters include divinyl phenylphosphonate, diallyl phenylphosphonate, bis(1-butenyl) phenylphosphonate, and the like.
Examples of the 2-substituted phosphinate include phenyl diphenylphosphinate, methyl diphenylphosphinate, and the like.
Examples of metal salts of di-substituted phosphinic acids include metal salts of dialkylphosphinic acid, metal salts of diallylphosphinic acid, metal salts of divinylphosphinic acid, metal salts of diarylphosphinic acid, and the like. As mentioned above, these metal salts are preferably lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, aluminum salts, titanium salts, or zinc salts.
Examples of organic nitrogen-containing phosphorus compounds include phosphazene compounds such as bis(2-allylphenoxy)phosphazene and dicresylphosphazene; melamine phosphate, melamine pyrophosphate, melamine polyphosphate, and melam polyphosphate.
Examples of the cyclic organic phosphorus compound include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa- Examples include 10-phosphaphenanthrene-10-oxide.
Among these, at least one selected from aromatic phosphoric esters, metal salts of disubstituted phosphinic acids, and cyclic organic phosphorus compounds is preferred, and aromatic phosphoric esters are more preferred.

Further, the aromatic phosphoric acid ester is preferably an aromatic phosphoric acid ester represented by the following general formula (F-1) or (F-2), and the metal salt of the disubstituted phosphinic acid is as follows: A metal salt of a disubstituted phosphinic acid represented by the general formula (F-3) is preferred.

(In the formula, R ^F1 to R ^F5 are each independently an alkyl group having 1 to 5 carbon atoms or a halogen atom. e and f are each independently an integer of 0 to 5, and g, h and i are each They are independently integers from 0 to 4.
R ^F6 and R ^F7 are each independently an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 14 carbon atoms. M is a lithium atom, a sodium atom, a potassium atom, a calcium atom, a magnesium atom, an aluminum atom, a titanium atom, or a zinc atom. j is an integer from 1 to 4. )

Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^F1 to R ^F5 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms. Examples of the halogen atom represented by R ^F1 to R ^F5 include a fluorine atom, etc.
Each of e and f is preferably an integer of 0 to 2, and more preferably 2. Each of g, h and i is preferably an integer of 0 to 2, and more preferably 0 or 1, and even more preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^F6 and R ^F7 include the same as those represented by R ^F1 to R ^F5 .
Examples of the aryl group having 6 to 14 carbon atoms represented by R ^F6 and R ^F7 include a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, etc. As the aromatic hydrocarbon group, an aryl group having 6 to 10 carbon atoms is preferable.
j is equal to the valence of the metal ion, that is, it varies within the range of 1 to 4 depending on the type of M.
M is preferably an aluminum atom. When M is an aluminum atom, j is 3.

(Content of each component of thermosetting resin composition [I])
In the thermosetting resin composition [I], the content of components (A) to (D) is not particularly limited, but with respect to a total of 100 parts by mass of components (A) to (C), It is preferable that the amount of component (A) is 15 to 65 parts by weight, the amount of component (B) is 15 to 50 parts by weight, the amount of component (C) is 10 to 45 parts by weight, and the amount of component (D) is 30 to 70 parts by weight.
By containing component (A) in an amount of 15 parts by mass or more based on the total of 100 parts by mass of components (A) to (C), high heat resistance, low dielectric constant, high glass transition temperature, and low thermal expansion can be obtained. There is a tendency. On the other hand, when the amount is 65 parts by mass or less, the fluidity and moldability of the thermosetting resin composition [I] tend to be good.
When the amount of component (B) is 15 parts by mass or more relative to the total of 100 parts by mass of components (A) to (C), high heat resistance, high glass transition temperature, and low thermal expansion properties tend to be obtained. On the other hand, when the amount is 50 parts by mass or less, high heat resistance, low dielectric constant, high glass transition temperature, and low thermal expansion properties tend to be obtained.
When the amount of component (C) is 10 parts by mass or more relative to the total of 100 parts by mass of components (A) to (C), high heat resistance and low relative permittivity tend to be obtained. On the other hand, when the amount is 45 parts by mass or less, high heat resistance, high metal foil adhesion, and low thermal expansion properties tend to be obtained.
When the amount of component (D) is 30 parts by mass or more relative to the total of 100 parts by mass of components (A) to (C), excellent low thermal expansion properties tend to be obtained. On the other hand, when the amount is 70 parts by mass or less, heat resistance is obtained, and the fluidity and moldability of the thermosetting resin composition [I] tend to be good.

In addition, when the thermosetting resin composition [I] contains component (E), the content thereof is 0.5 to 6 parts by mass with respect to the total of 100 parts by mass of components (A) to (C). It is preferable that
When the amount of component (E) is 0.5 parts by mass or more relative to the total of 100 parts by mass of components (A) to (C), high metal foil adhesion and excellent low thermal expansion properties tend to be obtained. On the other hand, when the amount is 6 parts by mass or less, high heat resistance tends to be obtained.

In addition, when the thermosetting resin composition [I] contains the component (F), the content thereof is, from the viewpoint of flame retardancy, relative to the total of 100 parts by mass of the components (A) to (C). The amount is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight. In particular, when using a phosphorus-based flame retardant as component (F), from the viewpoint of flame retardancy, the phosphorus atom content is 0.1 to 3 parts by mass based on the total of 100 parts by mass of components (A) to (C). 1 part by weight, more preferably 0.2 to 3 parts by weight, even more preferably 0.5 to 3 parts by weight.

(Other ingredients)
The thermosetting resin composition [I] may contain other components such as additives and organic solvents, if necessary, within the range that does not impair the effects of the present invention. These may be contained alone or in combination of two or more.

(Additive)
Examples of the additives include inorganic fillers other than the component (D), curing accelerators, colorants, antioxidants, reducing agents, ultraviolet absorbers, fluorescent brighteners, adhesion improvers, organic fillers, etc. These may be used alone or in combination of two or more.

(Organic solvent)
The thermosetting resin composition [I] may contain an organic solvent from the viewpoint of making it easier to handle by diluting it and making it easier to manufacture the prepreg described below. In this specification, a thermosetting resin composition containing an organic solvent may be referred to as a resin varnish.
The organic solvent is not particularly limited, but includes, for example, methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol, Alcohol solvents such as propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether, and dipropylene glycol monopropyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as tetrahydrofuran ; Aromatic solvents such as toluene, xylene, and mesitylene; Nitrogen-containing solvents including amide solvents such as formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. Sulfur atom-containing solvents including sulfoxide solvents such as dimethyl sulfoxide; ester solvents such as methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, propylene glycol monomethyl ether acetate, and ethyl acetate.
Among these, from the viewpoint of solubility, alcohol solvents, ketone solvents, and nitrogen atom-containing solvents are preferred, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl cellosolve, and propylene glycol monomethyl ether are more preferred, and methyl ethyl ketone and methyl isobutyl ketone are preferred. More preferred is methyl ethyl ketone.
One type of organic solvent may be used alone, or two or more types may be used in combination.

The content of the organic solvent in the thermosetting resin composition [I] (resin varnish) may be appropriately adjusted to an extent that the thermosetting resin composition [I] is easy to handle, and is not particularly limited as long as the resin varnish has good coatability, but the solids concentration derived from the thermosetting resin composition [I] (concentration of components other than the organic solvent) is preferably 30 to 90 mass%, more preferably 40 to 80 mass%, and even more preferably 50 to 80 mass%.

Next, each component contained in the epoxy resin composition [II] will be described in detail. In order to avoid overlap with the thermosetting resin composition [I], the epoxy resin composition [II] may not contain the maleimide compound (A) contained in the thermosetting resin composition [I], but is not particularly limited to this embodiment, and may contain the maleimide compound (A).

<(G) Epoxy resin>
The epoxy resin (G) contained in the epoxy resin composition [II] includes the same epoxy resin as the epoxy resin (B) in the thermosetting resin composition [I], and will be explained in the same manner. Among them, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl novolac type epoxy resin and dicyclopentadiene type epoxy resin. At least one selected from the group consisting of is preferable, and from the viewpoint of low thermal expansion and high glass transition temperature, cresol novolac type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl novolak type. At least one selected from the group consisting of epoxy resins and phenol novolac type epoxy resins is more preferred, and biphenylaralkyl novolac type epoxy resins are even more preferred.

<(H) Epoxy resin curing agent>
Examples of the epoxy resin curing agent include various phenolic resin compounds, acid anhydride compounds, amine compounds, hydrazide compounds, and the like. Examples of the phenolic resin compound include novolac type phenol resin, resol type phenol resin, etc., and examples of the acid anhydride compound include phthalic anhydride, benzophenonetetracarboxylic dianhydride, methylhimic acid, etc. It will be done. Further, examples of the amine compound include dicyandiamide, diaminodiphenylmethane, and guanylurea.
Among these epoxy resin curing agents, from the viewpoint of improving reliability, novolac type phenolic resins are preferred, and cresol novolac resins are more preferred.

The novolac type phenolic resin may be a commercially available product, for example, a phenol novolac resin such as "TD2090" (manufactured by DIC Corporation, product name) or a cresol novolac resin such as "KA-1165" (manufactured by DIC Corporation, product name). In addition, examples of commercially available triazine ring-containing novolac type phenolic resins include "Phenolite LA-1356" (manufactured by DIC Corporation, product name) and "Phenolite LA7050 Series" (manufactured by DIC Corporation, product name), for example, a triazine-containing cresol novolac resin such as "Phenolite LA-3018" (manufactured by DIC Corporation, product name).

The epoxy resin composition [II] may contain, as necessary, (I) a curing accelerator and (J) an inorganic filler.
<(I) Curing Accelerator>
From the viewpoint of accelerating the reaction between the epoxy resin (G) and the epoxy resin curing agent (H), the epoxy resin composition [II] preferably contains a curing accelerator (I). Examples of the curing accelerator (I) include imidazole compounds such as 2-phenylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-phenylimidazolium trimellitate; organic phosphorus compounds such as triphenylphosphine; onium salts such as phosphonium borate; amines such as 1,8-diazabicycloundecene; and 3-(3,4-dichlorophenyl)-1,1-dimethylurea. These may be used alone or in combination of two or more. Among these, imidazole compounds are preferred, and 2-ethyl-4-methylimidazole is more preferred.

<(J) Inorganic Filler>
The epoxy resin composition [II] preferably contains (J) an inorganic filler from the viewpoint of low thermal expansion. (J) inorganic filler includes, for example, silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, etc. These may be used alone or in combination of two or more. Among these, silica is preferred from the viewpoint of low thermal expansion coefficient.
The average particle size of the inorganic filler is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.
The inorganic filler may be surface-treated. For example, when silica is used as the inorganic filler, it may be surface-treated with a silane coupling agent. Examples of the silane coupling agent include an aminosilane coupling agent, a vinylsilane coupling agent, and an epoxysilane coupling agent. Among these, the silica surface-treated with an aminosilane coupling agent is preferred.

(Content of each component of epoxy resin composition [II])
In the epoxy resin composition [II], the content of the components (G) to (J) is not particularly limited; It is preferable that the amount of component () is 5 to 50 parts by weight, the amount of component (H) is 5 to 50 parts by weight, the amount of component (I) is 0.001 to 1 part by weight, and the amount of component (J) is 20 to 80 parts by weight. More preferably, for a total of 100 parts by mass of components (G) to (J), component (G) is 5 to 35 parts by mass, component (H) is 5 to 40 parts by mass, and component (I) is 0. 001 to 1 part by mass, and component (J) is 35 to 80 parts by mass.

(Other ingredients)
The epoxy resin composition [II] may contain other components such as additives and organic solvents, as necessary, within a range that does not impair the effects of the present invention. These may be contained singly or in combination of two or more.

(Additive)
Examples of additives include colorants, antioxidants, reducing agents, ultraviolet absorbers, optical brighteners, adhesion improvers, and organic fillers. These may be used alone or in combination of two or more.

(Organic solvent)
The organic solvent is the same as that in the thermosetting resin composition [I].

Next, each component contained in the thermosetting resin composition [III] will be explained in detail.
<(K) Silicone-modified maleimide compound>
(K) The silicone-modified maleimide compound is not particularly limited as long as it is a maleimide compound having a siloxane skeleton. For example, a maleimide compound (k-1) having at least two N-substituted maleimide groups in one molecule [hereinafter also referred to as "maleimide compound (k-1)"], Preferred examples include addition reaction products with a siloxane compound (k-2) [hereinafter also referred to as "siloxane compound (k-2)"] having a primary amino group, and addition reaction products with a maleimide compound (k-1) and a siloxane compound ( More preferably, it is an addition reaction product of k-2) and a monoamine compound [hereinafter also referred to as "monoamine compound (k-3)"].
As the maleimide compound (k-1), the same maleimide compound (a1) in the description of the maleimide compound (A) in the thermosetting resin composition [I] can be used.
The siloxane compound (k-2) preferably contains a structural unit represented by the following general formula (k-2-1).

(In general formula (k-2-1), R ^k1 and R ^k2 each independently represent an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a phenyl group having a substituent.)

Examples of the alkyl group having 1 to 5 carbon atoms represented by R ^k1 and R ^k2 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group. Examples include groups. The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.
Examples of substituents on the phenyl group in "phenyl group having a substituent" include an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms. . Examples of the alkyl group having 1 to 5 carbon atoms include those mentioned above. Examples of the alkenyl group having 2 to 5 carbon atoms include a vinyl group and an allyl group. Examples of the alkynyl group having 2 to 5 carbon atoms include ethynyl group and propargyl group.
R ^k1 and R ^k2 are both preferably an alkyl group having 1 to 5 carbon atoms, more preferably a methyl group.

As the siloxane compound (k-2), siloxane diamine represented by the following general formula (k-2-2) is more preferable.

(In general formula (k-2-2), R ^k1 and R ^k2 are the same as those in general formula (k-2-1). R ^k3 and R ^k4 each independently represent an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a phenyl group having a substituent. R ^k5 and R ^k6 each independently represent a divalent organic group, and m is an integer of 2 to 100.)

The alkyl group having 1 to 5 carbon atoms, phenyl group, and phenyl group having a substituent represented by R ^k3 and R ^k4 are explained in the same manner as in R ^k1 and R ^k2 . As R ^k3 and R ^k4 , a methyl group is preferred.
Examples of the divalent organic group represented by R ^k5 and R ^k6 include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, -O-, or a divalent linking group containing a combination thereof. Examples of the alkylene group include alkylene groups having 1 to 10 carbon atoms such as methylene group, ethylene group, and propylene group. Examples of the alkenylene group include alkenylene groups having 2 to 10 carbon atoms. Examples of the alkynylene group include alkynylene groups having 2 to 10 carbon atoms. Examples of the arylene group include arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group.
Among these, as R ^k5 and R ^k6 , an alkylene group and an arylene group are preferable.
m is preferably an integer of 2 to 50, more preferably an integer of 3 to 40, still more preferably an integer of 5 to 30, still more preferably an integer of 7 to 30.

There are no particular limitations on the functional group equivalent weight of the siloxane compound (k-2), but it is preferably 300 to 3,000 g/mol, more preferably 300 to 2,000 g/mol, and even more preferably 300 to 1,500 g/mol.

As the siloxane compound (k-2), commercially available products can be used. Commercially available products include, for example, "KF-8010" (functional group equivalent of amino group: 430 g/mol), "X-22-161A" (functional group equivalent of amino group: 800 g/mol), "X-22- 161B” (functional group equivalent of amino group: 1,500 g/mol), “KF-8012” (functional group equivalent of amino group: 2,200 g/mol), “KF-8008” (functional group equivalent of amino group: 5,700 g/mol), "X-22-9409" (functional group equivalent of amino group: 700 g/mol), "X-22-1660B-3" (functional group equivalent of amino group: 2,200 g/mol) (all manufactured by Shin-Etsu Chemical Co., Ltd.), "BY-16-853U" (functional group equivalent of amino group: 460 g/mol), "BY-16-853" (functional group equivalent of amino group: 650 g/mol) , "BY-16-853B" (functional group equivalent of amino group: 2,200 g/mol) (manufactured by Dow Corning Toray Co., Ltd.), "XF42-C5742" (functional group equivalent of amino group: 1,280 g /mol), "XF42-C6252" (functional group equivalent of amino group: 1,255 g/mol), "XF42-C5379" (functional group equivalent of amino group: 745 g/mol) (Momentive Performance Materials・Manufactured by Japan LLC), etc. These may be used alone or in combination of two or more.

As the monoamine compound (k-3), the same monoamine compound (a2) in the thermosetting resin composition [I] can be used, and the preferable ones are also the same.

As described above, one embodiment of the silicone-modified maleimide compound (K) can be produced by reacting the maleimide compound (k-1), the siloxane compound (k-2), and, as necessary, the monoamine compound (k-3).
In the reaction, with regard to the respective proportions of the maleimide compound (k-1), the siloxane compound (k-2), and the monoamine compound (k-3) used as necessary, from the viewpoints of gelation prevention and heat resistance, it is preferable that the equivalent weight of the maleimide group of the maleimide compound (k-1) exceeds the sum of the equivalent weights of the primary amino groups of the siloxane compound (k-2) and the monoamine compound (k-3), and the ratio of the equivalent weight of the maleimide group of the maleimide compound (k-1) to the sum of the equivalent weights of the primary amino groups of the siloxane compound (k-2) and the monoamine compound (k-3), [(k-1)/[(k-2)+(k-3)], is preferably 1 to 15, more preferably 2 to 10, and even more preferably 3 to 10.
From the viewpoints of productivity and uniform reaction, the reaction temperature is preferably 70 to 150° C., more preferably 90 to 130° C. In addition, the reaction time is not particularly limited, but is preferably 0.1 to 10 hours, more preferably 1 to 6 hours.

<(L) Imidazole compound>
(L) Imidazole compounds include, for example, 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-1- Methylimidazole, 1,2-diethylimidazole, 1-ethyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 1-isobutyl-2-methylimidazole, 2-phenyl- 4-Methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4 -Methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 2 ,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]ethyl-s- Imidazole compounds such as triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]ethyl-s-triazine; modified imidazole compounds such as isocyanate mask imidazole and epoxy mask imidazole; Salts of the imidazole compound and trimellitic acid, such as 1-cyanoethyl-2-phenylimidazolium trimellitate; salts of the imidazole compound and isocyanuric acid; salts of the imidazole compound and hydrobromic acid, etc. . Among these, modified imidazole compounds are preferred, and isocyanate mask imidazole is more preferred. One type of imidazole compound may be used alone, or two or more types may be used in combination.

<(M) Inorganic Filler>
The inorganic filler (M) can be explained in the same manner as the inorganic filler (J) in the epoxy resin composition [II].

(Content of each component of thermosetting resin composition [III])
In the thermosetting resin composition [III], the content of components (K) to (M) is not particularly limited, but based on the total of 100 parts by mass of components (K) to (M), Preferably, the amount of component (K) is 15 to 80 parts by weight, the amount of component (L) is 0.01 to 5 parts by weight, and the amount of component (M) is 15 to 80 parts by weight. More preferably, for a total of 100 parts by mass of components (K) to (M), component (K) is 30 to 65 parts by mass, component (L) is 0.01 to 3 parts by mass, and component (M) is It is 30 to 65 parts by mass.

(Other ingredients)
The thermosetting resin composition [III] may contain other components such as additives and organic solvents, if necessary, within a range that does not impair the effects of the present invention. These may be contained singly or in combination of two or more.

(Additive)
Examples of the additives include inorganic fillers other than the component (M), colorants, antioxidants, reducing agents, ultraviolet absorbers, fluorescent brighteners, adhesion improvers, organic fillers, etc. These may be used alone or in combination of two or more.

(Organic solvent)
The organic solvent will be explained in the same manner as the organic solvent in the thermosetting resin composition [I].

[Prepreg]
The prepreg obtained by the production method of the present invention has small variation in dimensional change, and further, if the thermosetting resin composition is used, the prepreg also has high heat resistance, high metal foil adhesion, high glass transition temperature, low thermal expansion, moldability, and excellent plating throwing power (laser processability).

Furthermore, according to the present invention, the following prepregs can be provided. The prepregs obtained by the manufacturing method of the present invention also fall under the following prepregs, in other words, the following prepregs can be manufactured by the manufacturing method of the present invention.
A prepreg comprising a substrate and a thermosetting resin composition, the prepreg having a standard deviation σ of 0.012% or less as determined by the following method.
How to calculate standard deviation σ:
A copper foil having a thickness of 18 μm is laminated on both sides of one prepreg, and the laminate is heated and pressurized at 190° C. and 2.45 MPa for 90 minutes to produce a double-sided copper-clad laminate having a thickness of 0.1 mm. The double-sided copper-clad laminate thus obtained is subjected to drilling of holes having a diameter of 1.0 mm in the plane at positions 1 to 8 shown in FIG. 1. The distances of three points in each of the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) shown in FIG. 1 are measured using an image measuring device, and each measured distance is taken as the initial value. Thereafter, the outer layer copper foil is removed, and the laminate is heated in a dryer at 185° C. for 60 minutes. After cooling, the distances of three points in each of the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) are measured in the same manner as in the measurement method for the initial value. The average of the change rates of each measured distance from the initial value [(measured value after heat treatment-initial value) x 100/initial value] is calculated, and the standard deviation σ for the average is calculated.
The image measuring instrument is not particularly limited, but for example, a "QV-A808P1L-D" (manufactured by Mitutoyo Corporation) can be used.

The standard deviation σ is preferably 0.011% or less, more preferably 0.010% or less, and even more preferably 0.009% or less. There is no particular limit to the lower limit of the standard deviation σ, but it is usually 0.003% or more, and may be 0.005% or more, 0.006% or more, or 0.007% or more.

[Laminated board]
The laminate of the present invention contains the prepreg and metal foil. For example, it can be produced by using one prepreg or stacking 2 to 20 prepregs as necessary, with metal foil arranged on one or both sides, preferably by heating and lamination molding. Note that a laminate on which metal foil is arranged is sometimes referred to as a metal-clad laminate.
The metal of the metal foil is not particularly limited as long as it is used as an electrically insulating material, but from the viewpoint of conductivity, copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, Iron, titanium, chromium, or an alloy containing at least one of these metal elements is preferable, copper and aluminium are more preferable, and copper is even more preferable.
As the forming conditions for the laminate, known forming methods for electrically insulating material laminates and multilayer boards can be applied, such as using a multistage press, multistage vacuum press, continuous molding, autoclave molding machine, etc. Molding can be performed at 100 to 250°C, pressure of 0.2 to 10 MPa, and heating time of 0.1 to 5 hours.
Moreover, a multilayer board can also be manufactured by combining the prepreg of the present invention and an inner layer printed wiring board and performing lamination molding.
The thickness of the metal foil is not particularly limited, and can be appropriately selected depending on the intended use of the printed wiring board. The thickness of the metal foil is preferably 0.5 to 150 μm, more preferably 1 to 100 μm, even more preferably 5 to 50 μm, particularly preferably 5 to 30 μm.

It is also preferable to form a plating layer by plating the metal foil.
The metal of the plating layer is not particularly limited as long as it is a metal that can be used for plating. The metal of the plating layer is preferably selected from copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, and an alloy containing at least one of these metal elements.
The plating method is not particularly limited, and known methods such as electrolytic plating and electroless plating can be used.

[Printed wiring board]
The present invention also provides a printed wiring board containing the prepreg or the laminate.
The printed wiring board of the present invention can be manufactured by performing circuit processing on the metal foil of the metal-clad laminate. For circuit processing, for example, after forming a resist pattern on the surface of the metal foil, removing unnecessary parts of the metal foil by etching, peeling off the resist pattern, forming the necessary through holes with a drill, forming the resist pattern again, This can be done by applying plating to make the through holes conductive, and finally peeling off the resist pattern. The above-mentioned metal-clad laminate is further laminated on the surface of the printed wiring board obtained in this way under the same conditions as described above, and further circuit processing is performed in the same manner as above to obtain a multilayer printed wiring board. Can be done. In this case, it is not necessarily necessary to form a through hole, a via hole may be formed, or both can be formed. Such multilayering is performed for the required number of layers.

[Semiconductor package]
The semiconductor package of the present invention is formed by mounting a semiconductor on the printed wiring board of the present invention. The semiconductor package of the present invention can be manufactured by mounting a semiconductor chip, a memory, etc. at a predetermined position on the printed wiring board of the present invention.

Next, the present invention will be explained in more detail with reference to the following examples, but these examples are not intended to limit the present invention in any way. Using the thermosetting resin composition according to the present invention, a resin varnish, a prepreg precursor produced using the resin varnish, a prepreg prepared by subjecting the prepreg precursor to surface heat treatment, and a copper-clad laminate are produced, The produced copper clad laminate was evaluated. The evaluation method is shown below.

[Evaluation method]
<1. Heat resistance (reflow soldering heat resistance)>
Using the four-layer copper-clad laminate prepared in each example, the maximum temperature was set to 266° C., and the four-layer copper-clad laminate was passed through a thermostatic chamber environment of 260° C. or higher for 30 seconds (one cycle), and the number of cycles until the board was visually confirmed to have bulged was determined. The more cycles, the better the heat resistance.

2. Dielectric constant (Dk)
Using a network analyzer "8722C" (manufactured by Hewlett-Packard), the dielectric constant of the double-sided copper-clad laminate at 1 GHz was measured by a triplate structure straight line resonator method. The test piece size was 200 mm x 50 mm x 0.8 mm thick, and a straight line (line length 200 mm) with a width of 1.0 mm was formed in the center of one side of one double-sided copper-clad laminate by etching, and the copper was left on the entire back surface to form a ground layer. For the other double-sided copper-clad laminate, one side was entirely etched, and the back surface was made into a ground layer. These two double-sided copper-clad laminates were stacked with the ground layer on the outside to form a strip line. The measurement was performed at 25°C.
The smaller the relative dielectric constant, the more preferable.

<3. Metal foil adhesion (copper foil peel strength)>
Metal foil adhesion was evaluated by copper foil peel strength. An evaluation board was prepared by immersing the double-sided copper-clad laminate prepared in each example in copper etching solution "Ammonium Persulfate (APS)" (manufactured by ADEKA Co., Ltd.) to form a 3 mm wide copper foil. The peel strength of the copper foil was measured using "AG-100C" (manufactured by Shimadzu Corporation). The larger the value, the better the metal foil adhesiveness.

<4. Glass transition temperature (Tg)>
The double-sided copper-clad laminate prepared in each example was immersed in a copper etching solution "ammonium persulfate (APS)" (manufactured by ADEKA CORPORATION) to remove the copper foil, thereby preparing a 5 mm square evaluation board. Using a TMA tester "Q400EM" (manufactured by TA Instruments), the thermal expansion characteristics of the evaluation board in the surface direction (Z direction) at 30 to 260°C were observed, and the inflection point of the expansion amount was taken as the glass transition temperature.

<5. Low thermal expansion>
A 5 mm square evaluation board was prepared by removing the copper foil by immersing the double-sided copper-clad laminate prepared in each example in a copper etching solution "ammonium persulfate (APS)" (manufactured by ADEKA Co., Ltd.). Q400EM" (manufactured by TA Instruments), the coefficient of thermal expansion (coefficient of linear expansion) in the plane direction of the evaluation board was measured. In addition, in order to remove the influence of thermal strain that the sample has, the heating-cooling cycle was repeated twice, and the coefficient of thermal expansion [ppm/°C] from 30 ° C to 260 ° C in the second temperature change chart was measured, It was used as an index of low thermal expansion. The smaller the value, the better the low thermal expansion property. In addition, in the table, the coefficient of thermal expansion below Tg (denoted as "<Tg") and the coefficient of thermal expansion above Tg (denoted as ">Tg") are listed separately.
Measurement conditions ^1st Run: Room temperature → 210°C (heating rate 10°C/min)
^2nd Run: 0°C → 270°C (heating rate 10°C/min)
Copper-clad laminates are desired to be made even thinner, and in conjunction with this, efforts are also being made to make the prepregs that make up copper-clad laminates thinner. Since a thinner prepreg is more likely to warp, it is desirable that the prepreg warp less during heat treatment. In order to reduce warpage, it is effective for the base material to have a small coefficient of thermal expansion in the plane direction.

<6. Plating throwing power (laser processability)>
For the four-layer copper-clad laminates produced in each example, laser drilling was performed using a laser machine "LC-2F21B/2C" (manufactured by Hitachi Via Mechanics Co., Ltd.) with a target hole diameter of 80 μm, Gaussian, and cycle mode, using the copper direct method and a pulse width of 15 μs x 1 time and 7 μs x 4 times.
The obtained laser-drilled substrate was desmeared using a swelling solution "Swelling Dip Securigant P" (manufactured by Atotech Japan Co., Ltd.) at 70°C for 5 minutes, a roughening solution "Dosing Securigant P500J" (manufactured by Atotech Japan Co., Ltd.) at 70°C for 9 minutes, and a neutralizing solution "Reduction Conditioner Securigant P500" (manufactured by Atotech Japan Co., Ltd.) at 40°C for 5 minutes. Thereafter, the laser-processed substrate was plated using an electroless plating solution "Prigant MSK-DK" (manufactured by Atotech Japan Co., Ltd.) at 30°C for 20 minutes and an electroplating solution "Capracid HL" (manufactured by Atotech Japan Co., Ltd.) at 24°C, ² A/dm2 for 2 hours.
The cross-section of the obtained laser-drilled substrate was observed to confirm the throwing power of the plating. As a method for evaluating the throwing power of the plating, the percentage (%) of holes among 100 holes that fell within the difference between the plating thickness at the top of the laser hole and the plating thickness at the bottom of the laser hole was calculated, since it is preferable for the throwing power to be within 10% of the plating thickness at the top of the laser hole.

<7. Formability>
For the four-layer copper-clad laminates produced in each example, after removing the outer copper layer, the presence or absence of voids and scratches within a 340 mm x 500 mm plane was visually confirmed as an indicator of moldability. And so. If there are no voids or blurring, it is indicated as "good", and if there are voids or blurring, it is indicated to that effect. If there are no voids or scratches, it can be said that the moldability is good.

<8. Evaluation of variation in dimensional change>
A hole with a diameter of 1.0 mm was drilled in the plane of the double-sided copper-clad laminate produced in each example as shown in FIG. As shown in Figure 1, the distance between three points each in the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) of the glass cloth is imaged. Measurement was performed using a measuring device "QV-A808P1L-D" (manufactured by Mitutoyo), and each measured distance was used as an initial value. Thereafter, the outer layer copper foil was removed and heated at 185° C. for 60 minutes in a dryer. After cooling, three points each in the warp direction (1-7, 2-6, 3-5) and weft direction (1-3, 8-4, 7-5) were measured in the same way as the initial value measurement method. The distance was measured. Find the average value of the rate of change from the initial value of each measurement distance [(measured value - initial value) x 100/initial value], calculate the standard deviation σ for the average value, and calculate the standard deviation σ. This was used as an index of the variation in the amount of dimensional change. A small value of standard deviation σ indicates that the variation in the amount of dimensional change is small, which is preferable.

The components used in the examples and comparative examples are explained below.

Component (A): A solution of the maleimide compound (A) produced in Production Example 1 below was used.
[Production Example 1]
A 1 L reaction vessel equipped with a thermometer, a stirrer, and a moisture meter equipped with a reflux condenser was charged with 19.2 g of 4,4'-diaminodiphenylmethane, 174.0 g of bis(4-maleimidophenyl)methane, 6.6 g of p-aminophenol, and 330.0 g of dimethylacetamide, and the mixture was reacted at 100°C for 2 hours to obtain a dimethylacetamide solution of maleimide compound (A) (Mw = 1,370) having an acidic substituent and an N-substituted maleimide group, which was used as component (A).
The weight average molecular weight (Mw) was calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation]. The GPC conditions are shown below.
Apparatus: (Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation]),
(Detector: L-3300 RI [manufactured by Hitachi High-Technologies Corporation]),
(Column oven: L-655A-52 [manufactured by Hitachi High-Technologies Corporation])
Column: TSKgel SuperHZ2000 + TSKgel SuperHZ2300 (all manufactured by Tosoh Corporation)
Column size: 6.0 mm x 40 mm (guard column), 7.8 mm x 300 mm (column)
Eluent: tetrahydrofuran Sample concentration: 20 mg/5 mL
Injection volume: 10 μL
Flow rate: 0.5 mL/min Measurement temperature: 40° C.

Component (B): Cresol novolac epoxy resin "EPICLON (registered trademark) N-673" (manufactured by DIC Corporation)
Component (C-1): "SMA (registered trademark) EF40" (styrene/maleic anhydride=4, Mw=11,000, manufactured by CRAY VALLEY)
Component (C-2): "SMA (registered trademark) 3000" (styrene/maleic anhydride=2, Mw=7,500, manufactured by CRAY VALLEY)
Component (C-3): "SMA (registered trademark) EF80" (styrene/maleic anhydride=8, Mw=14,400, manufactured by CRAY VALLEY)
Component (C-4): "SMA (registered trademark) 1000" (styrene/maleic anhydride = 1, Mw = 5,000, manufactured by CRAY VALLEY)

Component (D): fused silica treated with an aminosilane coupling agent (average particle size: 1.9 μm, specific surface area: 5.8 m ² /g)
Other inorganic filler: "F05-30" (untreated crushed silica, average particle size: 4.2 μm, specific surface area: 5.8 m ² /g, manufactured by Fukushima Ceramics Co., Ltd.)

Component (E): Dicyandiamide (manufactured by Nippon Carbide Industries Co., Ltd.)
Component (F): "PX-200" (aromatic phosphate ester (see structural formula below), manufactured by Daihachi Chemical Industry Co., Ltd.)

[Examples 1 to 13, Comparative Examples 1 to 4]
The components shown above are mixed as shown in Tables 1 to 4 below (however, in the case of solutions, the solid content equivalent amounts are shown), and methyl ethyl ketone is added so that the nonvolatile content of the solution is 65 to 75% by mass. Additionally, resin varnishes were prepared using the thermosetting resin compositions of each Example and each Comparative Example.
Each resin varnish obtained was impregnated into IPC standard #3313 glass cloth (0.1 mm) and dried for 4 minutes with a panel heater set at a temperature of 160°C to form a B-stage (step 1). (Step 2) to obtain a prepreg precursor. In addition, in the comparative example, it was used as a prepreg as it was.
In each example, the obtained prepreg precursor was subjected to surface heat treatment (product surface temperature 70 °C) for 3 seconds using a panel heater set at a temperature of 500 °C, and then at room temperature (approx. 20° C.) to produce a prepreg (Step 3).

(Preparation of double-sided copper-clad laminates and performance evaluation)
A copper foil "3EC-VLP-18" (manufactured by Mitsui Kinzoku Co., Ltd.) having a thickness of 18 μm was laminated on both sides of the eight prepregs, and the laminate was heated and pressurized for 90 minutes at a temperature of 190° C. and a pressure of 25 kgf/cm ² (2.45 MPa) to produce a double-sided copper-clad laminate having a thickness of 0.8 mm (equivalent to eight prepregs). The copper-clad laminate was used to measure and evaluate the dielectric constant, metal foil adhesion, glass transition temperature (Tg) and low thermal expansion properties according to the methods described above.
In addition, 18 μm thick copper foil "3EC-VLP-18" (manufactured by Mitsui Kinzoku Co., Ltd.) was laminated on both sides of one prepreg, and heated and pressurized for 90 minutes at a temperature of 190°C and a pressure of 25 kgf/ ^cm2 (2.45 MPa) to produce a double-sided copper-clad laminate with a thickness of 0.1 mm (for one prepreg). Using this double-sided copper-clad laminate, the variation in the amount of dimensional change was measured and evaluated according to the method described above.

(Preparation and performance evaluation of four-layer copper-clad laminate)
On the other hand, one sheet of the prepreg was used, and 18 μm thick copper foil "YGP-18" (manufactured by Nippon Denkai Co., Ltd.) was laminated on both sides, and heated and pressurized for 90 minutes at a temperature of 190° C. and a pressure of 25 kgf/cm ² (2.45 MPa) to produce a double-sided copper-clad laminate with a thickness of 0.1 mm (for one prepreg). Then, both copper foil surfaces were subjected to an inner layer adhesion treatment (using "BF treatment liquid" (manufactured by Hitachi Chemical Co., Ltd.)), and one sheet of 0.05 mm thick prepreg was laminated on each side, and 18 μm thick copper foil "YGP-18" (manufactured by Nippon Denkai Co., Ltd.) was laminated on both sides, and heated and pressurized for 90 minutes at a temperature of 190° C. and a pressure of 25 kgf/cm ² (2.45 MPa) to produce a four-layer copper-clad laminate. Using the four-layer copper-clad laminate, evaluations of heat resistance, plating throwing power and moldability were carried out according to the above-mentioned method.
The results are shown in Tables 1 to 4.

[Example 14]
Instead of preparing the resin varnish in Example 1, a resin varnish was prepared using the following components.
Biphenylaralkyl novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product name: NC-3000, epoxy equivalent: 280-300 g/eq) 19 parts by mass, cresol novolac resin (manufactured by DIC Corporation, product name: KA-1165, Hydroxyl group equivalent: 119 g/eq) 16 parts by mass, 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.02 parts by mass, fused silica (manufactured by Admatex Co., Ltd., fused with aminosilane coupling agent treatment) A resin varnish (solid content concentration: 70% by mass) was prepared by mixing 65 parts by mass of silica (average particle size: 2 μm) and diluting with a solvent (methyl ethyl ketone).
A prepreg was obtained by performing the other steps in the same manner as in Example 1. A double-sided copper-clad laminate was produced using the obtained prepreg in the same manner as in Example 1, and the variation in dimensional change was measured and evaluated using the double-sided copper-clad laminate. The value was 0.010%.

[Example 15]
Instead of preparing the resin varnish in Example 1, a resin varnish was prepared using the following components.
In a 2 L reaction vessel that can be heated and cooled and equipped with a stirring device and a water meter with a reflux condenser, 75.7 g of KF-8010 (double-end amine-modified silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.) and bis( 168.0 g of 4-maleimidophenyl)methane (manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name: BMI-1000), 6.4 g of p-aminophenol (manufactured by Tokyo Kasei Co., Ltd.), and 250.0 g of a solvent (methyl ethyl ketone). was added and reacted at 100°C for 3 hours to obtain a silicone-modified maleimide compound. 49.5 parts by mass of the silicone-modified maleimide compound, 50 parts by mass of fused silica (manufactured by Admatex Co., Ltd., fused silica treated with an aminosilane coupling agent), and 0.5 parts by mass of isocyanate mask imidazole (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) , trade name: G-8009L) and diluted with a solvent (methyl ethyl ketone) to prepare a resin varnish (solid content concentration: 70% by mass).
The other steps were performed in the same manner as in Example 1 to obtain a prepreg. A double-sided copper-clad laminate was produced using the obtained prepreg in the same manner as in Example 1, and the variation in dimensional change was measured and evaluated using the double-sided copper-clad laminate. The value was 0.009%.

From the above results, we found the following.
In the example, since the prepreg precursor was subjected to surface heat treatment, the standard deviation σ was smaller than that of the comparative example in which the surface heat treatment was not performed, and variations in the amount of dimensional change were sufficiently suppressed.
Furthermore, in Examples 1 to 13, reflow soldering heat resistance was achieved for 10 cycles or more, exceeding the required heat resistance level, and low relative dielectric constant, high metal foil adhesion, and high glass transition temperature were obtained, and low thermal expansion was achieved. Indicated. In addition, it was confirmed that the glass cloth had good coverage due to the fact that the glass cloth did not protrude from the wall surface and had a moderately roughened shape. In terms of moldability, the embeddability of the resin was good, and no abnormalities such as scratches or voids were observed. Among them, Examples 1 to 10 had better dielectric constant and metal foil adhesion than Examples 11 to 13, and other properties were also stably expressed.

The prepreg obtained by the present invention and the laminate containing the prepreg have small variation in dimensional change, making them useful as printed wiring boards for electronic devices.

Claims (10)

a step of impregnating a base material with a thermosetting resin composition containing an inorganic filler , and then B-staging the thermosetting resin composition to obtain a prepreg precursor; and a step of obtaining the prepreg precursor. After that, there is a surface heat treatment step,
In the surface heat treatment step , the surface temperature of the prepreg precursor is increased to 40°C by a heating method using a panel heater, a heating method using hot air, a heating method using high frequency, a heating method using magnetic lines of force, a heating method using a laser, or a heating method that combines these methods. A step of heat-treating the surface of the prepreg precursor to ~130°C, which is carried out at a higher temperature and shorter time than the heating temperature and heating time during B-staging in the surface heat treatment step. ,
Prepreg manufacturing method. The prepreg manufacturing method according to claim 1 , further comprising a step of cooling the prepreg precursor to 5 to 60° C. after the step of obtaining the prepreg precursor and before the surface heat treatment step. The method for producing a prepreg according to claim 1 or 2 , wherein the surface heat treatment time is 1.0 to 10.0 seconds. The method for producing a prepreg according to any one of claims 1 to 3 , wherein the thermosetting resin composition contains (A) a maleimide compound. The method for producing a prepreg according to claim 4, wherein the component (A) is a maleimide compound having an N-substituted maleimide group obtained by reacting (a1) a maleimide compound having at least two N-substituted maleimide groups, (a2) a monoamine compound represented by the following general formula (a2-1), and (a3) a diamine compound represented by the following general formula ( a3-1) :

(In general formula (a2-1), R ^A4 represents an acidic substituent selected from a hydroxyl group, a carboxy group, and a sulfonic acid group. R ^A5 represents an alkyl group having 1 to 5 carbon atoms or a halogen atom. t represents an integer of 1 to 5, u represents an integer of 0 to 4, and satisfies 1≦t+u≦5. However, when t is an integer of 2 to 5, multiple R ^A4s may be the same or different. In addition, when u is an integer of 2 to 4, multiple R ^A5s may be the same or different.)

(In general formula (a3-1), X represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms or -O-. ^R and ^R each independently represent an alkyl group having 1 to 5 carbon atoms, a halogen atom, a hydroxyl group, a ^carboxyl group, or a sulfonic acid group. v and w each independently represent an integer of 0 to 4.) The thermosetting resin composition further comprises (B) an epoxy resin,
Claim 4 or 5 , comprising (C) a copolymer resin having a structural unit derived from a substituted vinyl compound and a structural unit derived from maleic anhydride, and (D) silica treated with an aminosilane coupling agent. The method for manufacturing prepreg described in . The component (B) is bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl novolac type epoxy resin, and dicyclopentadiene. The method for producing a prepreg according to claim 6 , wherein the prepreg is at least one selected from the group consisting of type epoxy resins. The method for producing a prepreg according to claim 6 or 7 , wherein the component (C) is a copolymer resin having a structural unit represented by the following general formula (C-i) and a structural unit represented by the following formula (C-ii):

(In the formula, R ^C1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ^C2 is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an aryl group having 6 to 20 carbon atoms, a hydroxyl group, or a (meth)acryloyl group. x is an integer of 0 to 3. However, when x is 2 or 3, multiple R ^C2s may be the same or different.) The method for producing a prepreg according to any one of claims 1 to 3 , wherein the thermosetting resin composition contains (G) an epoxy resin and (H) an epoxy resin curing agent. The method for producing a prepreg according to any one of claims 1 to 3 , wherein the thermosetting resin composition contains (K) a silicone-modified maleimide compound and (L) an imidazole compound.