TAPER ETCHING METHOD FOR SILICON OXIDE FILM

摘要

PURPOSE:To perform etching by a method whrerin heat treatment is done after aiming vapor plasma including carbon halide at an SiO2 film and taper inclined angle is controlled at any value with good stability and reproducibility. CONSTITUTION:When the etching speed of SiO2 in the thickness direction and lateral direction are r1, r2, the taper angle theta is decided by sintheta=r1/r2. With heat treatment or laser irradiation applied to the surface immediately after CF4 plasma irradiation to an SiO2 film 11, the speed r2 can be decreased and the angle theta can be changed. In heat treatment, wider angle theta can be obtained under steam atmosphere compared with under N2 atmosphere. The angle under O2 or Ar is the same as that under N2. SiO2 12 is etched by a mixed solution of HH+ NH4F by applying a mask 13. Cf4 has an advantage because the Cf4 has slow etching speed and high safety to SiO2. SiO2 having any taper angle theta can be formed by controlling heat treatment temperature.