Patent ID: 8087164

Claim:
A method of manufacturing a printed wiring board having bumps, comprising: forming a solder-resist layer having a small-diameter aperture and a large-diameter aperture, each aperture exposing a respective conductive pad of the printed wiring board; loading a solder ball in each of the small-diameter aperture and the large-diameter aperture using a mask having aperture areas that correspond to the small-diameter aperture and the large-diameter aperture of said solder-resist layer; forming a first bump, having a first height, from said solder ball in the small-diameter aperture; forming a second bump, having a second height, from said solder ball in the large-diameter aperture, the first height being greater than the second height; and pressing a top of the first bump in the small-diameter aperture such that the first height of the first bump becomes substantially the same as the second height of the second bump, wherein the pressing is performed by a flat plate that is heated.