New dicing and thinning concept improves mechanical reliability of ultra thin silicon

Ultra thin silicon ICs with a remaining thickness of less than 30 μm are investigated with respect to their manufacturing technology and mechanical behavior. Thin wafers which were diced using a standard sawing process reveal low fracture resistance when a bending force is applied to single chips. To eliminate influence of micro-cracks induced by sawing extremely thin wafers, the new concept of “dicing by thinning” was developed and is explained in the paper. The concept allows manufacturing of 10-30 μm thin wafers and includes self-acting die separation during the thinning procedure. Best results are achieved when dicing lines between chips are prepared at the front side of wafer by dry etching methods. Initial analysis results of mechanical reliability of thin silicon samples are presented and discussed