Printed wiring board

A method for manufacturing a printed wiring board, comprising:

• forming an opening in a resin insulating layer formed on a first conductor layer such that the opening exposes a portion of the first conductor layer;
• forming, on a surface of the resin insulating layer, a second conductor layer comprising a seed layer and an electrolytic plating layer formed on the seed layer;
• and
• forming, in the opening of the resin insulating layer, a via conductor comprising the seed layer and the electrolytic plating layer formed on the seed layer such that the via conductor is connecting the first conductor layer and the second conductor layer,
• wherein the seed layer has a first portion formed on the surface of the resin insulating layer, a second portion formed on an inner wall surface in the opening of the resin insulating layer, and a third portion formed on a portion of the first conductor layer exposed by the opening of the resin insulating layer such that a thickness of the first portion is greater than a thickness of the second portion and a thickness of the third portion, the resin insulating layer includes resin and inorganic particles such that the inorganic particles comprising first inorganic particles forming the inner wall surface and second inorganic particles embedded in the resin insulating layer and that the first inorganic particles have shapes that are different from shapes of the second inorganic particles, the forming of the opening includes forming a group of the second inorganic particles having protruding portions protruding from the inner wall surface in the opening of the resin insulating layer, and removing the protruding portions in the group of the second inorganic particles such that the first inorganic particles having flat parts are formed on the inner wall surface of the resin insulating layer.