We need a photomask that can withstand high laser intensity. We use a 248nm excimer laser to perform photomask patterning processing on materials. The acting power on the photomask is 250MJ/cm², and the photomask needs to have long-term stability.
There are three major laser mask-making techniques. The first is to directly remove the thin films of the photomasks (laser engraving). The second is to use laser beams as the light source to expose photoresists covered on the photomasks (laser-based lithography). The third is to generate patterns on the photomasks via photoresist (laser pattern generation).