It is successful to obtain 180 ' phase shift in the pattern of intersection area so that contrast and resolution are enhanced in each edge by increasing optical density during wafer exposure. With PSM , the life of wafer stepper could be extended and the cost could be saved more in process. PSM product is aimed at CONTACT and FINE LINE reticle under 0.18 um process. Currently, TMC manufactures PSM by Attenuated Type (half tone) and also concentrates on Alternating Type (Etched Quartz) PSM developing.
PSM - Phase Shift Mask
There are two types of PSM Masks
- Half tone phase shift
- Etched quartz