2005 Volume 18 Issue 2 Pages 181-185
This study developed a new method for removing positive-tone diazonaphtho- quinone/novolak resist. The fourth harmonic wave (&lamda;=266nm) of a pulse Nd3+:YAG laser was used. Ablation occurred at the resist surface when it was irradiated with over 35mJ/cm2. The amounr of removed resist increased with an increase in the laser energy, and it was possible to remove a 250nm thick resist layer by one pulse irradiation with 94mJ/cm2. Resist with an initial thickness of 1100nm and could be completely removed with no damage to the Si wafer after being irradiated seven times with 94mJ/cm2. The XPS measurement indicated that the residual amount of carbon from the Si surface irradiated by a laser under the vacuum was almost same to that from a Si wafer without resist coating. Resist removal method by laser is environmentally sound and will contribute to energy reduction.