| Autor: |
Tony DiBiase, Harris J. Keston, Mircea V. Dusa |
| Rok vydání: |
1992 |
| Předmět: |
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| Zdroj: |
SPIE Proceedings. |
| ISSN: |
0277-786X |
| DOI: |
10.1117/12.59781 |
| Popis: |
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.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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