Abstract: Provided is a technique that can achieve an insulating layer with small surface undulations and can suppress a haloing phenomenon in manufacturing a printed wiring board even when using a thin resin composition layer. Specifically, provided is a method for manufacturing a printed wiring board that includes the steps of: (A) preparing a resin sheet with an inorganic layer including (i) a support with an inorganic layer including an inorganic layer, a support in contact with the inorganic layer, and a release layer and (ii) a resin composition layer in contact with the release layer of the support with an inorganic layer; (B) laminating the resin sheet with an inorganic layer onto an internal layer substrate so that the resin composition layer of the resin sheet with an inorganic layer is in contact with the internal layer substrate; (C) curing the resin composition layer to form an insulating layer; and (D) perforating the insulating layer.

Abstract: Resin compositions containing (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler in which the content of (C) the inorganic filler is 55% by mass or higher with respect to 100% by mass of a non-volatile component within the resin composition, the average particle diameter of (C) the inorganic filler is 0.05 to 0.35 ?m, the product of the specific surface area (m2/g) of (C) the inorganic filler and the true density of (C) the inorganic filler is 1 to 77 m2/g and the moisture permeation of a cured product obtained by thermally cured the resin composition is 0.05 to 2.8 g·mm/m2·24 h are useful for making printed wiring boards.

Abstract: Resin compositions containing (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler in which the content of (C) the inorganic filler is 55% by mass or higher with respect to 100% by mass of a non-volatile component within the resin composition, the average particle diameter of (C) the inorganic filler is 0.05 to 0.35 ?m, the product of the specific surface area (m2/g) of (C) the inorganic filler and the true density of (C) the inorganic filler is 1 to 77 m2/g and the moisture permeation of a cured product obtained by thermally cured the resin composition is 0.05 to 2.8 g˜mm/m2·24 h are useful for making printed wiring boards.

Abstract: Resin compositions which contain an epoxy resin, an alkoxy oligomer, and an inorganic filler provide insulating layers that have a surface with not only low arithmetic mean roughness but also low root mean square roughness in a wet roughening step and that are capable of forming thereon a plated conductive layer having a sufficient peel strength that can be formed while maintaining the glass transition temperature and thermal expansion coefficient.

Abstract: Resin compositions which contain an epoxy resin, an alkoxy oligomer, and an inorganic filler provide insulating layers that have a surface with not only low arithmetic mean roughness but also low root mean square roughness in a wet roughening step and that are capable of forming thereon a plated conductive layer having a sufficient peel strength that can be formed while maintaining the glass transition temperature and thermal expansion coefficient.