Assessment of a lasersingulation process for Si-wafers with metallized back side and small die size

We report on the development of a "dry" lasersingulation process for Si-wafers with back side metallization targeting small die sizes below 0.07 mm2. The dicing technology aims at improved manufacturing of diodes with thicknesses ranging from approx. 100 mum to 150 mum, die sizes down to 230 times 230 mum2 and metallized back side metallization layers used for solder die attach. We discuss the impact of the laser process on subsequent assembly processes as well as on the die itself. Particular emphasis is set on the laser induced modification of the mechanical properties within the wafer, e. g. the reduction of the die strength. For the wafer technology under evaluation, the laser process is considered to be superior to standard blade dicing approaches.