Patent ID: 7601625
Filing Date: 2009-10-13
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device having a solder layer, the method comprising the steps of: grinding a mounting surface of a semiconductor chip; etching the mounting surface of the chip; and after the etching, the mounting surface having an average surface roughness equal to or smaller than 2 nm; forming an electrode on the mounting surface of the chip, wherein the step of forming the electrode includes directly bonding the electrode to the mounting surface of the semiconductor chip; assembling the chip, the solder layer and a base in this order; and heating the chip, the solder layer and the base to be equal to or higher than a solidus temperature of the solder layer so that the solder layer is reflowed for soldering the chip on the base, wherein the solder layer includes tin in an amount equal to or larger than 95% of the solder layer and is formed from Sn—Ag, Sn—Ag—Cu, Sn—Cu, or Sn—Cu—Ni, and of a Pb free solder, and the step of forming the electrode includes the step of forming a nickel layer having a thickness equal to or larger than 600 nm on the mounting surface.