High resolution material ablation and deposition with femtosecond lasers and applications to photomask repair

We describe experiments using 100 femtosecond pulses of 266 nm light to ablate Cr defects from photomasks with resolution below 100 nm. In addition to the ablative removal of Cr, experiments were carried out to deposit Cr metal onto fused silica substrates using 100 fs, 400 nm light at atmospheric pressure. Multiphoton dissociation of Cr(CO)6 adsorbed on fused silica substrates initiates Cr deposition. The mechanisms for deposition on both transparent (fused silica) and absorbing (Cr metal) substrates are discussed. Finally we describe initial experiments to ablate Cr metal at wavelengths below 200 nm using light generated by frequency mixing of ultrashort, 30 fs pulses in an Ar filled capillary. © 2004 Taylor & Francis Group, LLC.