Patent ID: 7838411
Filing Date: 2010-11-23
Classification: B23K,H01L

Abstract:
1. A fluxless reflow process for bump formation, comprising: a purifying process for keeping a solder alloy in a melting or half-melting state for 40 seconds (s) to 540 s by maintaining the temperature of the solder alloy being in the proximity of the eutectic point of the solder alloy, wherein the purifying process includes three temperature-constant stages, the temperature of the first temperature-constant stage is Tc−2° C., the temperature of the second temperature-constant stage is Tc, and the temperature of the third temperature-constant stage is Tc+2° C., in which Tc is the melting point of the solder; a ball-forming process for melting the solder completely to form ball-like bumps; and a cooling process.