Stress is a constant presence in the manufacture of semiconductors. It can cause wafers to become warped and less manageable; it can even cause breakage. Depending upon the workpiece, Dicing Before Grinding can be an excellent way to counteract stress, preempt wafer warpage, and reduce overall breakage rates.
The Cause of Wafer Warpage
When a wafer is ground thin, the stress differential between its pattern side and backside increases, resulting in warpage. The ultimate cause of this increased differential is the micro-cracking that occurs as a result of diamond grit impacting the wafer. As these micro-cracks occur only on the side that is ground (the wafer backside), the outward stress they produce is not counterbalanced by similar stress on the pattern side, resulting in warpage. Moreover, warpage typically becomes more severe as wafer diameter increases.
The DBG Solution
The Dicing Before Grinding process is inherently conducive to reduced warpage and wafer breakage. In the DBG process, the wafer is first grooved on the pattern side and then ground thin, during which latter step die singulation occurs. Wafer-level is eliminated as an issue because the wafers are singulated as they are thinned. And because wafers are never diced or otherwise handled in a thin state, wafer breakage rates are greatly reduced.
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| Standard process wafer | DBG wafer |
