Patent ID: 8713792
Filing Date: 2014-05-06
Classification: H01L,H05K,Y10T

Abstract:
1. A manufacturing method of a printed wiring board, comprising: forming a first metal layer on a Cu wiring pattern formed on a substrate; forming a second metal layer on said first metal layer; and after forming said first and second metal layers, reflowing said first and second metal layers simultaneously to produce an eutectic reaction between said first and second metal layers, wherein said first metal layer has a less reactivity with Cu than said second metal layer, the manufacturing method further comprising: forming a first sacrifice layer between said substrate and said first metal layer, the first sacrifice layer having the same composition as said second metal layer; and forming a second sacrifice layer between said first metal layer and said second metal layer, the second sacrifice layer being formed of Cu, wherein said first sacrifice layer is depleted in a process of forming said first metal layer, and said second sacrifice layer is depleted in a process of forming said second metal layer.