Application of surface activation in local laser bonding

A new bonding technique to alleviate the high temperature adverse effect in silicon-glass bonding process was presented which combines the advantages of surface activated direct bonding and local laser bonding techniques.RCA solution was used to make the bonding surfaces hydrophilic and the silicon-glass prebonding was accomplished at room temperature.The laser with a wavelength of 1064nm was used and its spot diameter was 500μm and the power was 70W.Without any external pressure,the prebonded pairs were bonded locally and the bonding strength reaches 6.3MPa~6.8Mpa.The experimental results of show that this bonding technique,which employs surface activated prebonding to substitute pressure to maintain the intimate contact of bonding chips,has overcome the disadvantages that focusing is difficult and bonding chips and glass cover are easy to broken in normal local laser bonding processing.This technique also improves the efficiency of surface activated direct bonding by shortening the annealing time.