Patent ID: 8962471
Filing Date: 2015-02-24
Classification: H01L

Abstract:
1. A method of producing bumps of a conductive metal formed in a predetermined pattern on a substrate, the bump comprising: a two-layer structure of a first bump layer of a bulk body of a first conductive metal, which is any of gold, copper, and nickel, formed on the substrate and a second bump layer of a sintered body of a powder of a second conductive metal, which is either gold or silver, formed on the first bump layer; the bulk body composing the first bump layer being formed through any of plating, sputtering, and CVD; the sintered body composing the second bump layer being formed by sintering a metal powder of the second conductive metal having a purity of not lower than 99.9 wt % and an average particle diameter of 0.005 μm to 1.0 μm; and the second bump layer having a Young's modulus 0.1 to 0.4 times that of the first bump layer; the method comprising the steps of: forming the first bump layer on the substrate through any of plating, sputtering, and CVD; and forming the second bump layer by applying a metal paste containing a powder of the second conductive metal having a purity of not lower than 99.9 wt % and an average particle diameter of 0.005 μm to 1.0 μm onto the first bump layer, drying the metal paste, and then heating the metal paste at a sintering temperature of 70° C. to 320° C. for sintering.