SiNx Anti-reflective Coating Removal for c-Si PV

industrial laser
application note

SiNx Anti-reflective Coating Removal for c-Si PV

Figure 1: Series of contact pads opened in SiNx on c-Si PV wafer with area removal rate >10 cm2/sec

Photovoltaic companies continue the march toward higher performing solar cells while at the same time reducing manufacturing costs. To achieve both of these goals, lasers are increasingly being implemented for novel c-Si photovoltaic process. One area for solar cell improvement is the metallization technique. While traditional screen printing is reliable and mature, researchers are casting their eyes toward more advanced, plating-based techniques. Lasers can enable these techniques by creating an opening in the SiNx anti-reflection coating (ARC) on the wafer’s front surface.

The process work flow is as follows:

  • SiNx layer is deposited onto c-Si solar cell wafer
  • Laser “opens” (removes) the SiNx in areas to be metalized (finger lines, etc.)
  • Metallization seed layer is plated on to exposed silicon via inkjet printing, light-induced plating, etc.

The application demonstrated is the removal of SiNx anti-reflection coating on crystalline silicon solar cell wafer. In this instance, we have used the 355 nm Q-switched DPSS nanosecond Pulseo 355-10 laser.

Figure 2: Closeup of single SiNx removal spot generated with Pulseo 355-10 laser.