Along with more material layers stacked on the dicing lanes to fabricate the more powerful IC, traditional laser grooving faces new challenges to obtain the required kerf depth and width without forming unwanted defects, i.e. peeling, serious heat affected zone and micro-crack. Some defects even invisible on the surface, but exist in the under layer.
No visible defects observed on the surface, after short-pulse laser grooving.
In fact, shrinkage and peeling defects are existed in the under layer, after short-pulse laser grooving.
Thanks to the unique laser & optical technologies, E&R’s laser system can groove a variety of material layers, i.e. copper, aluminum, low-k, silicon oxide, silicon nitride and silicon, without compromise of quality and throughput.
Complicated topography and material layers on the dicing lanes
Before laser grooving
After laser grooving
Gallium Nitride(GaN) epitaxially grown on the Silicon substrate(GaN-on-Si) is a promising process for the power IC industry. But due to the mismatch of CTE between GaN and Si, internal stress will potentially induce defects like peeling, chipping or crack, during the wafer dicing process.
E&R’s laser system employs the cold ablation technology to carry out the laser grooving prepared for the subsequent blade dicing, with the uncompromised performance in terms of quality and throughput.
GaN-on-Si wafer diced by blade saw only
GaN-on-Si wafer diced blade saw with laser grooving first
Wafer deposited with backside metal is a common process for power IC and discrete components. Metal peeling or burring of backside metal is usually observed, when blade saw dicing the wafer.
Another challenge for the blade saw is the chip size gets smaller and smaller, it takes time to cut one wafer. Plasma dicing is an effective solution to etch through all dicing lanes in parallel. But plasma species for etching silicon can’t etch the metal layer as well.
Laser grooving on the wafer backside before the dicing can prevent the defects generated by the subsequent blade or plasma dicing.
Thanks to the unique backside alignment algorithm, E&R’s laser system can groove the wafer precisely on the wafer backside.
Peeling or burring of backside metal, after the blade saw dicing the wafer
|Laser grooving on the backside metal before the plasma dicing||After the plasma dicing|