The Study Of Optimized The Parameters By Using Nd:YAG 532nm Laser On The Surface Of Si For Flip Chip Package

In this paper,we study to optimize laser parameters which marked on the surface of Si die with 532 nm green laser.Flip chip package is a package of the most advanced,and bare die packaging is a form of flip chip package which the chip is directly exposed outside without the protection of molding or lead attach.Secondly,with the trend of IC package size,the size of the font is limited.In view of these two aspects,this paper has carried on the research to the related parameters of the font on the silicon die.First of all,laser mark on the Si die surface,using single factor experiment method,get the relationship between marking depth,line width laser time and the parameter of laser current,Q frequency and scanning speed.From the experimental results,the laser time is mainly affected by the scanning speed: the faster scanning speed is,the shorter the time of laser;line width is influenced by the strength of the current line and the Q-frequency,in a certain range,the increase in current or the Q-frequency the smaller,the line width greater;Laser depth is more complex and the influence of three factors at the same time,the current,Q-frequency and scanning speed,in a certain range,the increase in current or Q-frequency is small or the scanning speed is smaller,the greater the laser depth.Secondly,based on the Taguchi Method,make the experiments to mark on the Si surface which font is less than 0.4mm depth target in the 0.2mil.Using L27 orthogonal test table,analysis the SN Ratio of font height and marking depth with ANOVA(Analysis of Variance)and optimize the parameters,and finally get the best assembly of parameters.