Etching of buried photoresist layers and its application to the formation of three-dimensional layered structures

The fabrication of three-dimensional layered structures with 180-nm-thick TaOx top layers supported by 1.5-μm-thick Mo pillars formed on a glass substrate is presented. The photoresist used for planarization was successfully removed through the TaOx layers using heat treatment at 270 °C with mixed vapors of ethyl alcohol and pure water at high pressure for 3 h. Vacancies underlying the TaOx layers were consequently formed. The possibility of rapid and lateral crystallization of amorphous silicon films was demonstrated when the silicon films formed on the TaOx overlaying the vacancy regions were irradiated using a frequency-doubled YAG laser at 250 mJ/cm2. Energy sensors using Cr/Al metal wires, with a high sensitivity of 0.07 mW/cm2, were also demonstrated using the present structure with vacancy regions for reduction of heat diffusion.