Phase shift mask fabrication

摘要

Fabricating a phase shift mask comprises: (i) forming a first patterned photoresist layer on a quartz substrate to divide this into a light-transmitting region and a light-screening region; (ii) etching the quartz substrate in the areas exposed by the first photoresist mask to form an etched groove; (iii) removing the photoresist and forming distancing elements against the side walls of the groove; (iv) depositing Cr on the resulting structure, including the quartz substrate and the floor of the etched groove; (v) removing the distancing elements and depositing a photoresist layer on the resulting structure including the surface of the quartz substrate and the etched groove, (vi) undertaking further etching to form a second photoresist pattern in the etched groove; (vii) etching the Cr on the quartz substrate that has been exposed by the second etching process and (viii) removing the second photoresist pattern so that Cr remains on the floor of the etched groove.