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RIK JONCKHEERE, KURT RONSE & JAN WAUTERS IMEC, Leuven, Belgium

ABSTRACT

The 1997 SIA Roadmap Mask Table does not unambiguously specify the quality factors that a high-end mask should meet, nor is it felt to be sufficiently complete. Linewidth control is presently in the focus, and the growing attention to the mask error factor (MEF) is a sign of the concern. Additional mask imperfections may cause problems at high resolutions. The authors suggest that a criterion of "pattern fidelity" would be helpful in assessing mask quality. The use of low voltage SEM for the assessment of extended mask qualification is discussed. The need for resolution enhancement techniques (RETs) for 0.2 micron and beyond is explained. It is shown that RETs may involve reduction of the MEF, which would result in more relaxed masks specifications.