Abstract: W-Ti film was comprehensively investigated for its application as an x-ray mask absorber. A stress-free and amorphous W-Ti film was successfully deposited by dc sputtering with a W-Ti (1 wt%) target using a gas mixture of Ar and N$-2$/. To obtain much lower stress, we firstly improve the accuracy of stress measurement up to $POM 1 MPa, and ultra-low stress film was obtained by step- annealing. The stress of the film has been found stable enough to apply to x-ray masks in an air atmosphere and for x-ray exposure. The density, composition, and microstructure of the film were also evaluated by SEM, XD, XPS, and TDS. The film surface was very smooth and the roughness measured by AFM was about 2 nm. The etching properties of the absorber using a Cr mask, ITO stopper and electron cyclotron resonance (ECR) discharge plasmas were also investigated in order to achieve a resolution of below 0.1 $mu@m. Highly selective and anisotropic etching has been realized using a mixture of SF$-6$/ and CHF$-3$/, by cooling the stage to about $MIN@50$DGR@C under controlled plasma conditions. Moreover, the microfabrication of a smooth W-Ti absorber has been demonstrated for lines and spaces patterns of 0.06 $mu@m and for 1-Gbit-class dynamic random access memory patterns. !16
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