Slurry free lapping of silicon wafer for the application of thinning of wafer backside during TSV and packaging

In the semiconductor industry, the thinning of wafer is carried out by back grinding in two steps; coarse grinding and fine grinding. In this work, a new slurry free abrasive pad was developed to perform the thinning process of Si wafers with a single lapping step to achieve higher removal rate and lower roughness. Different lapping pads were prepared with the diamond agglomerates containing different primary size of the diamonds (2, 5 and 10μm). Two different shapes (spherical and irregular) of agglomerates were prepared and evaluated their lapping performance. The lapping was performed at different pressure conditions to obtain optimum lapping performance. From the results it was found that irregular shaped agglomerated pad could show better performance than the spherical shaped agglomerates. Increase of primary size of the diamond increases the removal rate and also roughness. From the results optimum condition was selected for the achieving the better performance.