Printed wiring board

A printed wiring board, comprising:

• a first conductor layer;
• a resin insulating layer formed on the first conductor layer;
• 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 the resin insulating layer such that the via conductor is connecting the first conductor layer and the second conductor layer and includes the seed layer and electrolytic plating layer extending from the second conductor layer,
• wherein the second conductor layer and the via conductor are formed such that the seed layer includes a first layer comprising copper, aluminum and at least one metal selected from the group consisting of nickel, zinc, gallium, silicon and magnesium, and a second layer formed on the first layer and comprising copper, and the seed layer in the via conductor has a first portion and a second portion such that the first portion is electrically connected to the second portion and has a portion formed on the second portion.