The goal of this project is to design, fabricate, and characterize alternating phase shift masks for 248nm DUV lithography. The characterization of the masks was to include etch depth and sidewall angle measurements via atomic force microscopy (AFM). Etch times were to be varied in order to induce phase changes of 900, 1800, and 270°; one binary chrome on glass mask was also supposed to be fabricated to show the enhancements offered in processing by the phase shifting masks. The measurements of the etch profiles should not only be useful in determining the achieved phase shift and their correlation to CD in photoresist, but also in the feasibility of using atomic force microscopy on alternating phase shift masks as a form of metrology; a standard profilometer was also going to be used for metrology in comparison to AFM measurements. After characterization of the mask set, minimum CD performance was to be evaluated using PROLITH simulation, followed by experiments in the RIT SMFL.
Estroff, Andrew C.
"Design, Fabrication, and Characterization of an Alternating Phase Shifting Mask for DUV Lithography,"
Journal of the Microelectronic Engineering Conference: Vol. 13
, Article 10.
Available at: http://scholarworks.rit.edu/ritamec/vol13/iss1/10