As the microelectronics industry trends toward 157nm lithography and device geometries shrink below O.1μm, it seems more than likely that phase shift masking will be necessary as a means of optical enhancement. The attenuated phase shift mask is an attractive tool by which lithographers hope to push their art to its limits. However, potential niaterials for use as the attenuating film at wavelengths as low as 157nm have yet to be determined. There are several requirements that must be met by a material before it will be considered seriously for use on attenuating phase shift masks. One material that shows promise as a possible attenuating film is a compound film of tantalum silicon oxide, Ta~Si~O~. The rationale behind the selection of TaxSiyOz as a material worthy for use on the technology in question will be presented, as will a preliminary overview of the characterization of the film’s constituents, Si02 and Ta205. The process by which a composite film with varying levels of Ta205 incorporation can be sputter deposited will be shown. Work that will have to be performed before the adoption or rejection of TaSiO as an APSM film will be discussed.
"Investigation of Tantalum Silicon Oxide as an Attenuated Phase Shift Masking Material for 157nm Lithography,"
Journal of the Microelectronic Engineering Conference: Vol. 10
, Article 3.
Available at: http://scholarworks.rit.edu/ritamec/vol10/iss1/3