CHARACTERIZATION OF EMBEDDED PHASE-SHIFT MASKS BY REFLECTANCE-TRANSMITTANCE MEASUREMENT

A simple and inexpensive method has been applied to the determination of transmission and phase shifting of fully embedded phase shift masks . The method is based on the measurement of reflectance and transmitta nce (R-T) of the embedded layer. A S-mirror reflection system has been developed to carry out the R-T measurement and a computer program has been written to calculate the real and imaginary components of refrac tive index (n, k), and hence the phase shifting and attenuating proper ties, of an embedded layer. The effectiveness and accuracy of the R-T method has been confirmed by experiment.