Printed circuit board

A printed circuit board comprising:

• a first insulating layer;
• a first metal layer disposed on one surface of the first insulating layer;
• a second metal layer disposed on an other surface facing the one surface of the first insulating layer;
• a via hole penetrating through the first insulating layer;
• a via disposed in the via hole and penetrating through the first insulating layer to connect the first and second metal layers to each other;
• and
• a heterogeneous metal region including a material different from that of the via, wherein the heterogeneous metal region is disposed in an area in which the via is adjacent to the first metal layer and on an inner wall of the via hole, where the inner wall is adjacent to the first insulating layer,
• wherein the heterogeneous metal region includes silicon (Si) and either titanium (Ti) or nickel (Ni).