Low temperature metalorganic chemical vapor deposition of conformal silvercoatings for applications in high aspect ratio structures

A low temperature metalorganic chemical vapor deposition process has been d eveloped for the growth of conformal silver coatings for applications in re flective mirror arrays, computer chip metallization, and superconducting wi re and cable technologies. The process employed the silver source precursor Ag(COD)hfac, where COD = 1,5-cyclooctadiene and hfac = 1,1,1,5,5,5-hexaflu oro 2,4-pentanedionate. Silver films were deposited at wafer temperature, s ource temperature, and processing pressure in the range of, respectively, 1 60-240 degreesC, 80-150 degreesC, and 0.5-5 Torr. Experiments were carried out in the presence of either argon or hydrogen as coreactant. The resultin g films were characterized by Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, x-ray diffraction, and cross-section scanning electron microscopy. These investigations indicated that the silver films w ere pure, highly specular, and exhibited excellent conformality in 180 nm w ide trench structures with 7:1 aspect ratio. (C) 2001 American Vacuum Socie ty.