圆片级封装铝锗键合后残余应力的测量和分析

Measurement and analysis of residual stress in WLP with Al-Ge bonding

以圆片级铝锗键合后的残余应力为研究对象,在键合环下方和周围制作了一系列形状相同的力敏电阻条,通过比较键合前后力敏电阻条的阻值变化,分析电阻条处残余应力的大小及与工艺相关性。结果表明:键合环内外的压阻变化约为键合环下方压阻变化的3倍。这种方法可以作为晶圆级键合质量的有效在线表征手段之一。

Taking residual stress in wafer level packaging（WLP） with A1-Ge bonding as research object, a series of resistor stripe with the same shape are fabricated beneath or adjacent to the bond pad. Analyze magnitude of residual stresses on resistors strip and its correlation with the process by comparing resistance variation of resistor stripe before and after bonding. Results show that the resistance variation of piezoresistors inside and outside the bond pad is three times larger than that beneath the bond pad. This method can be one of the effective means for online characterization of wafer level bonding quality.