CALIBRATION OF A MICROLITHOGRAPHIC FABRICATION PROCESS USING NONDESTRUCTIVE TESTING AND RIGOROUS ELECTROMAGNETIC THEORY

Comparison of rigorous electromagnetic calculations and measurements o f grating diffraction efficiencies are applied to estimate the profile of surface relief gratings. The depth of the gratings is estimated us ing a Linnik interferometer. Information regarding the grating duty cy cle (filling factor) and edge slope can then be extracted. The inverse scatter process is inexpensive, non-destructive, and easy to carry ou t and its accuracy is estimated. The results are applied to calibrate a manufacturing process involving writing with a laser-beam-writing sy stem and etching using reactive ion etching. It is shown that a combin ation of TE and TM polarisation measurements and calculations can be u sed to extract a great deal of accurate metrological information.