Non-solder mask defined (NSMD) type wiring substrate for ball grid array (BGA) package and method for manufacturing such a wiring substrate

摘要

In one embodiment, a pad is formed on a substrate surface. The pad is connected with a connecting pattern. A first mask is formed on the substrate. The first mask has a first opening exposing at least a portion of the pad and a portion of the connecting pattern. A second mask is formed on the first mask. The second mask has a second opening exposing at least a portion of the pad and a portion of the connecting pattern. A boundary surface or sidewall of the first opening is not coplanar with a boundary surface or sidewall of the second opening. Therefore, stresses may be prevented from concentrating on the boundary surface of the first opening, thereby allowing dispersion of the stresses and restraining pattern cracks.