Laser Grooving – the „Swiss Army Knife“ to make the Best of a Wafer

Abstract:
Laser grooving is an increasingly important technique to “open” dicing streets as a preceding step before singulating various kinds of delicate chips and wafers via blade dicing. Here, we demonstrate alternative laser grooving applications beyond the initial task. We show (1) that line grooves allow removing back-end of line (BEOL) layers to make way for through silicon via (TSV) processing and for building redistribution layers (RDLs) on top. We show (2) how laser grooving is applied to smoothly open protective resist for well-defined subsequent masked wafer treatments. And we show (3) first results of our investigations on combining laser grooving with stealth dicing as final singulation step. Based on our findings, we are confident that the importance of laser grooving will increase not only for laying the groundwork for blade dicing. Laser grooving can be considered as a “Swiss Army Knife” which will have a huge impact on many other (intermediate) steps in various wafer processing chains.