Abstract
Dry lithography is a promising micro/nanomanufacturing method owing to its advantages of solution-free, absence of undercut and resist swelling. However, heat-mode resist suitable for dry lithography is less reported. This work reported Ag doped Sb2Te thin film as heat-mode resist, and its etching selectivity and microstructures are investigated in detail. It is found that Ag1.44Sb2.19Te thin film possesses high etching selectivity in CHF3/O2 mixed gases and can act as a heat-mode resist. In order to elucidate the mechanism of high etching selectivity, the microstructures of the Ag doped Sb2Te thin films are analyzed according to XRD, Raman spectra, XPS, and TEM methods. Results implies that the etching selectivity is attributed to the phase separation of Ag1.44Sb2.19Te film and formation of Sb phase after laser exposure, leading to the reduction of etching resistance in CHF3/O2 mixed gases. Besides, the pattern transfers from Ag1.44Sb2.19Te to SiO2 and Si substrates are achieved successfully and the etching selectivity of Si or SiO2 to Ag1.44Sb2.19Te are both higher than 2:1. This work may provide a useful guide for the research of dry lithography without wet development.
