Printed wiring board

A printed wiring board, comprising:

• a first conductor layer;
• a resin insulating layer formed on the first conductor layer and comprising inorganic particles and resin;
• a second conductor layer formed on the resin insulating layer and comprising a seed layer and an electrolytic plating layer formed on the seed layer;
• and
• a via conductor formed in an opening formed in the resin insulating layer such that the via conductor is connecting the first conductor layer and the second conductor layer and that the via conductor includes the seed layer and electrolytic plating layer extending from the second conductor layer,
• wherein the inorganic particles in the resin insulating layer include first particles, second particles, third particles and fourth particles formed such that the first and second particles are solid particles, the third and fourth particles are hollow particles, the first and third particles form an inner wall surface of the opening formed in the resin insulating layer, the second and fourth particles are embedded in the resin insulating layer, the first particles have shapes that are different from shapes of the second particles, and the third particles have shapes that are different from shapes of the fourth particles.