Methodology to improve the die singulation quality for low-k and high TEG saw street wafer

This paper describes the development of a robust process to improve chipping and peeling defect on low-k/heavy metalised saw street wafer during die singulation process using laser grooving technique. After laser groove process, the sidewall tends to have voiding and become brittle, due to recast material formed with the complex material such as IMD, TEG, silicon nitrate and etc. The sidewall area will be easily fractured and lead to top surface peeling, chipping and sidewall crack. For low-k material, even a minor chipping will lead to low-k interlayer delamination and subsequently cause the unit fail at application. Hardware such as optical lens with 0 degree, 90 degree and circular polarization were used for optimization, design of experiment (DOE) were performing on the laser groove and sawing process/parameter to improve the singulation quality.