Sputtered tungsten films on polyimide, an application for X-ray masks

• Published in: Solid-state electronics 1999, Vol.43 (6), p.1075-1078
• Main Authors: Ligot, J, Benayoun, S, Hantzpergue, J.J, Remy, J.C
• Format: Article
• Language: English
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/S0038-1101(99)00027-1

Among processes of lithography for submicron technologies, X-ray lithography shows the great advantage of high resolution. In the fabrication of X-ray masks, tungsten (W) is one of the alternative absorber materials that can be used instead of gold, but it requires a low stress film with high density. Tungsten films were deposited on Kapton and Upilex polyimides using a triode discharge system. The dependence of thin W films properties on the working argon pressure is reported. X-ray diffraction, AFM and curvature radius measurements were used to characterize the coatings in terms of microstructure and mechanical properties. Average stress and density were found to be significantly dependent on the argon pressure. Microstructural analysis indicated that the grain size and the proportion of metastable phase, β-W, could vary in a wide range. The adhesion of W to polyimide verified with the scratch testing technique seemed very acceptable.