Reactive ion Etching of SiO2 and Mo Sidewall Profile Process

Abstract

This paper investigates the process parameters affecting the sidewall angle of Mo and SiO2 films based on the reactive ion etching (RIE) system, firstly, the photoresist mask with a certain sidewall angle was obtained by adjusting the hardening temperature and hardening time of the photoresist during the lithography process, and their effects on the sidewall angle of the photoresist mask were investigated. In the RIE etching of SiO2 and Mo, the etching gas type (CHF3, CF4, SF6), O2 flow rate, and their effects on the sidewall angle of SiO2 were adjusted to obtain the sidewall angle of SiO2 in the range of 15°~53°, During the RIE etching of Mo, the RF power, SF6 flow rate, and O2 flow rate were adjusted and their effects on the Mo sidewall angle were investigated, resulting in a range of 17.3° to 30.2° for the Mo sidewall angle. This is useful for the study of the thin film body acoustic resonator (FBAR) process.