DocumentCode :
774784
Title :
Models for characterizing phase-shift defects in optical projection printing
Author :
Socha, Robert J. ; Neureuther, Andrew R. ; Singh, Rajeev
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA
Volume :
8
Issue :
2
fYear :
1995
fDate :
5/1/1995 12:00:00 AM
Firstpage :
139
Lastpage :
149
Abstract :
An algebraic model is developed for characterizing the printability, inspection, and repair of phase-shift defects in optical projection printing. Phase-shift defects are particularly difficult to characterize because of the many parameters associated with the exposure tool and with the attenuating phase shift mask (PSM) pattern. Furthermore, the parameters change during inspection of the attenuating PSM because the mask is examined under illumination conditions which differ from the exposure illumination. An algebraic model which encompasses this large set of variables is derived by considering the electric fields under the mask to be a combination of the electric fields from the feature and defect. These fields are then combined according to the mutual coherence function for the mask illumination. A notable difficulty is the relative phase shift due to defocus between large and small features. The model is shown to be valid for defects up to 0.35 λ/NA by comparison to SPLAT. Experimental verification is made for defects impacting a 6% transmitting PSM for 0.35-μm features at i-line. The reliability of the model is illustrated by giving rules of thumb for defect printing in attenuating PSM´s
Keywords :
phase shifting masks; photolithography; printing; semiconductor process modelling; 0.35 micron; SPLAT; algebraic model; attenuating PSM; defocus; electric fields; exposure tool; i-line; inspection; mutual coherence function; optical projection printing; phase shift mask; phase-shift defects; printability; repair; transmitting PSM; Coherence; Computational modeling; Focusing; Helium; Inspection; Lighting; Optical attenuators; Predictive models; Printing; Thumb;
fLanguage :
English
Journal_Title :
Semiconductor Manufacturing, IEEE Transactions on
Publisher :
ieee
ISSN :
0894-6507
Type :
jour
DOI :
10.1109/66.382277
Filename :
382277
Link To Document :
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