TY - JOUR
AU - DiBiase, Tony
AB - An attempt is made to characterize the submicron litho process under confocal laser scanning microscope metrology, using `linearity' and `discrimination' as process control parameters. This was found to allow for a more detailed process characterization than the usual `CD value' information alone. This also allows one to determine how the CLSM system performs on a particular type of sample and over a specified linewidth range. The measurement substrates included silicon wafers coated with 1.1 micrometers of resist and printed with a gradient of isolated lines ranging from 0.6 micrometers to 1.0 micrometers in 0.05 micrometers increments. The CLSM measurement system was `tuned' to yield optimum precision and accuracy so that measurement linearity would be well established over the range of interest. There are two types of linearities considered here as `linear dependencies:' the measured CD values versus their nominal values and the measured CD sensitivity versus exposure changes for a given focus setting. These linearities are quantified by (1) coefficients of regression (slope), (2) coefficients of determination (R-SQ), and (3) intercept values. Changes in slope values indicate process operating conditions which range from normal to extreme (under/over exposure and positive/negative defocus). R-SQ indicates metrology robustness and the intercept represents the measurement offset over a wide range of operating conditions. There are also two types of capabilities considered here: the CLSM's ability to distinguish (differentiate) 50 nm feature biases over a range of linewidths and the system's ability to differentiate structural changes as a result of focus and exposure changes. Results indicate that a tuned CLSM system can be used to monitor effects of variations in operating conditions as small as 5 mJ/cm2 in exposure energy and 0.4 micrometers defocus.
TI - Performance of a submicron litho process under CLSM metrology with linearity and discrimination measurements
JO - Proceedings of SPIE
DO - 10.1117/12.59781
DA - 1992-06-01
UR - https://www.deepdyve.com/lp/spie/performance-of-a-submicron-litho-process-under-clsm-metrology-with-dTnLYBzcmD
SP - 14
EP - 25
VL - 1673
IS - 1
DP - DeepDyve
ER -