Abstract: Provided is a production method of an FRP precursor. The method includes: a pre-coating step of applying a resin varnish having a filler content of 5 vol % or less in a solid content thereof, to a sheet-shaped aggregate, and a melt-pasting step of melt-pasting a pair of resin films, each having a filler content of 30 vol % or more, to both surfaces of the aggregate, after the pre-coating step.

Abstract: Provided are a metal-clad laminate, a printed circuit board, and a semiconductor package, wherein the warps therein are effectively suppressed. Specifically the metal-clad laminate comprises a prepreg, wherein the prepreg has a resin composition attached to a fiber base material and satisfies a following formula (1) as well as a Mowing formula (2), provided that in the formulae, a1 represents an average thickness of the resin composition after being cured which is present on one surface of the fiber base material; a2 represents an average thickness of the resin composition after being cured which is present on other surface of the fiber base material; and B represents an average thickness of the fiber base material. 0.12<{(a1+a2)/2}/B??(1) 0.8?a1/a2?1.

Abstract: Provided are a printed circuit board in which warps are effectively suppressed, and a semiconductor package having a semiconductor device mounted on said printed circuit board, even though circuit patterns of different amounts of metal are formed on both sides of one cured product of a prepreg. Specifically, said printed circuit board is a printed circuit board which comprises a cured product of a prepreg comprising a fiber base material and a resin composition, in which circuit patterns of different amounts of metal are formed on both sides of one cured product of the prepreg, in which said prepreg has layers on the front and back of said fiber base material, wherein said layers comprise resin compositions having different heat curing shrinkage rates, in which among these layers, the layer made of the resin composition having a smaller heat curing shrinkage rate is present on the side on which the circuit pattern with a smaller amount of metal is formed.

Abstract: Provided are a method for producing an FRP precursor and a device for producing an FRP precursor, wherein the method and the device have a good productivity, and under a normal pressure, enable filling of a resin into a bulk gap of an aggregate as well as prevent the resin from spouting out from an edge portion thereof. The method for producing the FRP precursor is to produce the FRP precursor by melt-adhering each of a pair of thermosetting resin films 54 to each of both surfaces 40a and 40b of an aggregate 40 that is in a form of a sheet, the method comprising: an aggregate's surface heating process to heat aggregate's both surfaces, i.e.

Abstract: Provided are a prepreg including two or more fiber substrate layers and one or more resin composition layers, in which at least one of the one or more resin composition layers has a fiber substrate layer on each of both surfaces thereof, a printed circuit board using the prepreg and a method of producing the printed circuit board, and a semiconductor package.

Abstract: Provided are a metal-clad laminate, a printed circuit board, and a semiconductor package, wherein the warps therein are effectively suppressed. Specifically the metal-clad laminate comprises a prepreg, wherein the prepreg has a resin composition attached to a fiber base material and satisfies a following formula (1) as well as a Mowing formula (2), provided that in the formulae, a1 represents an average thickness of the resin composition after being cured which is present on one surface of the fiber base material; a2 represents an average thickness of the resin composition after being cured which is present on other surface of the fiber base material; and B represents an average thickness of the fiber base material. 0.12<{(a1+a2)/2}/B??(1) 0.8?a1/a2?1.

Abstract: Provided are a printed circuit board in which warps are effectively suppressed, and a semiconductor package having a semiconductor device mounted on said printed circuit board, even though circuit patterns of different amounts of metal are formed on both sides of one cured product of a prepreg. Specifically, said printed circuit board is a printed circuit board which comprises a cured product of a prepreg comprising a fiber base material and a resin composition, in which circuit patterns of different amounts of metal are formed on both sides of one cured product of the prepreg, in which said prepreg has layers on the front and back of said fiber base material, wherein said layers comprise resin compositions having different heat curing shrinkage rates, in which among these layers, the layer made of the resin composition having a smaller heat curing shrinkage rate is present on the side on which the circuit pattern with a smaller amount of metal is formed.

Abstract: Provided are: an FRP precursor capable of providing a metal-clad laminate having small surface waviness and reduced number of a light spot, even if thickness of a metal foil is 40 ?m or less; a laminated plate including the FRP precursor; a metal-clad laminate having a metal foil on the laminated plate; a printed circuit board having a circuit pattern formed on the metal-clad laminate; a semiconductor package including the printed circuit board; and methods for producing them. The FRP precursor has the surface waviness of 12 ?m or less on both surfaces thereof.

Abstract: Provided are a prepreg including two or more fiber substrate layers and one or more resin composition layers, in which at least one of the one or more resin composition layers has a fiber substrate layer on each of both surfaces thereof, a printed circuit board using the prepreg and a method of producing the printed circuit board, and a semiconductor package.

Abstract: Provided are a method for producing an FRP precursor and a device for producing an FRP precursor, wherein the method and the device have a good productivity, and under a normal pressure, enable filling of a resin into a bulk gap of an aggregate as well as prevent the resin from spouting out from an edge portion thereof. The method for producing the FRP precursor is to produce the FRP precursor by melt-adhering each of a pair of thermosetting resin films 54 to each of both surfaces 40a and 40b of an aggregate 40 that is in a form of a sheet, the method comprising: an aggregate's surface heating process to heat aggregate's both surfaces, i.e.

Abstract: Provided are a method for producing an FRP precursor and a device for producing an FRP precursor, wherein the said FRP precursor is excellent in impregnability of a thermosetting resin as well as in heat resistance of the FRP precursor to be obtained. The method for producing the FRP precursor, wherein each of one pair of thermosetting resin films 54 are adhered to each of both surfaces 40a and 40b of an aggregate 40 in a form of a sheet, comprises: an attaching process to attach an organic solvent 13a to the both surfaces 40a and 40b of the aggregate 40; a film press-adhering process wherein under a normal pressure, each of the aggregate-side film surfaces 54a of the pair of the films 54 and 54 is press-adhered to each of the both surfaces 40a and 40b of the soaked aggregate 40 to obtain the FRP precursor 60; and an attached amount adjusting process to adjust amount of the organic solvent 13a that is attached to the soaked aggregate 40.