Wiring board, semiconductor device, and wiring board manufacturing method

A semiconductor device comprising:

• a wiring board;
• a semiconductor chip that is mounted on the wiring board;
• and
• an underfill material that is filled in a space between the wiring board and the semiconductor chip, wherein
• the wiring board includes
• an insulating layer that includes a first surface coming into contact with the underfill material and a second surface on an opposite side of the first surface, and includes an opening portion that is formed so as to penetrate through the first surface and the second surface;
• a connection terminal that is arranged in the opening portion;
• and
• a wiring structure that is formed on the second surface of the insulating layer and connected to the connection terminal,
• the connection terminal includes
• a pad that is formed in the opening portion and that has a bottom surface located on a same plane as the second surface of the insulating layer;
• and
• a surface treatment layer that covers an upper surface and side surfaces of the pad,
• the pad protrudes from the first surface of the insulating layer at a position of the opening portion,
• the surface treatment layer forms a gap between the surface treatment layer and an inner wall surface of the opening portion, and
• the gap is filled with the underfill material.