Abstract: In this paper, the effect of laser ablation induced carbon residue and quartz damage near the mask repair region in a sub-half-micron DUV wafer printing process is discussed. In the study, we found that the laser ablation induced carbon residue and quartz damage during a clean-up process of a clear intrusion mask defect repair could cause both phase and transmission errors near the repaired region. As a result, the printing characteristics of the resist in the repaired region are different than that of the defect-free region, especially at defocus conditions. At zero defocus, the resist critical dimension (CD) difference between the repaired and defect-free regions is mainly determined by the repair edge error and the amount of transmission loss which is due to the quartz damage and carbon residue in the clear mask region. At positive defocus, the repaired region tends to print narrower than that of defect-free region and vice versa for the negative defocus conditions. This phenomenon is the result of quartz damage induced phase error in the clear mask area near the repair. This quartz damage induced effect is more pronounced at 0.25 micrometer regime than that of 0.4 micrometer regime. In the study, we also compared wafer level results of laser repaired features to that of focused ion beam repaired features to identify the carbon residue and quartz damage induced effects in the laser repair. Our simulations also predicted the above observed experimental results. !4
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