BiIn: a sensitive bimetallic thermal resist

Glenn H. Chapman; Richard Yuqiang Tu; Marinko V. Sarunic; Jagjot Dhaliwal

doi:10.1117/12.436888

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24 August 2001 BiIn: a sensitive bimetallic thermal resist

Glenn H. Chapman, Richard Yuqiang Tu, Marinko V. Sarunic, Jagjot Dhaliwal

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Proceedings Volume 4345, Advances in Resist Technology and Processing XVIII; (2001) https://doi.org/10.1117/12.436888
Event: 26th Annual International Symposium on Microlithography, 2001, Santa Clara, CA, United States

Abstract

A class of DC-sputter deposited bimetallic thermal resists (BiIn, SnIn, BiSn) have been investigated with exposure sensitivities (7mj/cm²) near those of current organic photoresists. A prototype resist consists of stacked bismuth on indium layers (30-45nm thick) with thickness ratios matching the eutectic alloy points in BiIn binary phase diagram. Laser exposed areas have significantly different optical characteristics, with lower reflectivity and higher transparency, hence showing the imaged pattern before development, thus confirming correct exposures. Predicted exposure levels are almost wavelength invariant: <5% change between 248 and 157nm. Profilometery results and SEM images showed no signs of ablation in the exposed areas. The BiIn resist was wet developed using a HNO₃:CH₃COOH:H₂O (1:3:6) acid solution which preferentially removed the unexposed areas leaving written patterns of alloyed lines seen both under profilometery and SEM, and stripped in a dilute HCl:H₂O2:H₂O bath. Shelf tests shows that the BiIn film is stable under 50#C/90% humidity conditions. XRD and TEM show that the film is polycrystalline. Both SnIn and BiSn exhibit similar resist property as BiIn that the exposed area converts to greater transparencies that unexposed areas, indicating these three bimetallic films can be a group of potential inorganic thermal resist.

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Glenn H. Chapman, Richard Yuqiang Tu, Marinko V. Sarunic, and Jagjot Dhaliwal "BiIn: a sensitive bimetallic thermal resist", Proc. SPIE 4345, Advances in Resist Technology and Processing XVIII, (24 August 2001); https://doi.org/10.1117/12.436888

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