MONOLAYER HALF-TONE PHASE-SHIFTING MASK FOR KRF EXCIMER-LASER LITHOGRAPHY

A new monolayer halftone phase-shifting mask has been developed. The p hase-shifting film consists of the compounds SiO2 and Cr2O3. The trans mittance of the film is controlled by changing the mixing ratio of the two materials. Our mask can be easily fabricated because the structur e of the mask is very simple and the film is considerably thicker than the Cr layer of the original double-layer halftone phase-shifting mas k. Experimental results using a KrF excimer laser stepper confirm the effect of increasing the depth of focus of hole patterns.