IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Monday Sessions
       Session TF+NS+SE+VST-MoA

Paper TF+NS+SE+VST-MoA5
Ion Beam Growth and Properties of SiN/TiN Multilayer Thin Films for Phase-shift Masks in Optical Lithography

Monday, October 29, 2001, 3:20 pm, Room 123

Session: Nanophase & Multilayered Thin Films
Presenter: P.F. Carcia, DuPont Central Research and Development
Authors: P.F. Carcia, DuPont Central Research and Development
M.H. Reilly, DuPont Central Research and Development
L.J. Pilione, Pennsylvania State University
R.F. Messier, Pennsylvania State University
L. Dieu, DuPont Photomask
R.S. McLean, DuPont Central Research and Development
Correspondent: Click to Email
Today's high speed microprocessors and dense memory chips are the result of modern optical lithography that allows printing smaller and smaller circuit features on a Si wafer. In 2002, optical lithographic tools with imaging radiation of 193 nm will produce leading edge devices with sub 100 nm critical dimensions. The continued success of optical lithography, which has delayed the introduction of next generation technologies with X-rays, ions, or electrons, can be attributed to the innovative application of optical resolution enhancement techniques that improve feature resolution and increase process latitude. One of these, the attenuating phase-shift mask (attPSM) improves image contrast with destructive optical interference by transmitting (6-17%) and simultaneously phase-shifting 180 degrees imaging radiation through the mask. In this paper we describe a systematic approach for designing wavelength tunable (248nm to 157 nm) attPSMs with SiN/TiN multilayers. We grew these multilayers by dual ion beam deposition (IBD) because it is potentially a cleaner process than magnetron sputtering. Compared to SiN/TiN multilayers grown by magnetron sputtering, IBD produced films with smaller surface roughness (AFM), less chemical contamination (XPS), and flatter interfaces (XRD, TEM). However, IBD films had higher stress, which can cause distortion of the mask and consequent image placement errors. We have therefore investigated strategies, which will also be discussed, to reduce stress in ion beam sputtered SiN/TiN multilayers.