Driven by Moore's Law, the quest to double the number of transistors on a given chip every 18-24 months, the density and complexity of patterns on photomasks has increased steadily and significantly. To maintain the fidelity of shrinking features, reticle enhancement techniques such as OPC (Optical Proximity Correction) and Phase Shift Masks are now widely used in optical lithography to extend the lifetime of the existing technology. These techniques (or advanced reticles) provide the desired improvements in spatial resolution, but also complicate the task of reticle defect inspection. In this paper, we present results from ongoing contamination inspections of Embedded (Attenuated) Phase Shift Masks (EPSMs) for 248nm and 193nm lithography. A variety of 248nm masks have been successfully inspected on the KLA-Tencor STARlightTM SL3UV and SL3 tools at Intel Mask Operations (IMO) in Santa Clara, CA. Lessons learned from inspection of 248nm masks are being applied towards inspection of 193nm masks. A representative sample of inspection parameters such as algorithm options, and corresponding inspection results (defect types, capture rates etc.) are presented and discussed in the paper.

Date Published: 16 July 2002
PDF: 8 pages
Proc. SPIE 4689, Metrology, Inspection, and Process Control for Microlithography XVI, (16 July 2002); doi: 10.1117/12.473485

Published in SPIE Proceedings Vol. 4689:
Metrology, Inspection, and Process Control for Microlithography XVI
Daniel J. C. Herr, Editor(s)