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 of top layer, serious heat affected zone and micro-crack.
Thanks to the unique laser & optic 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, through the simple set-up of recipe which enhances the production yield.
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|