Plasma Etching Method for Forming Holes in Masked Silicon Dioxide

摘要

A plasma etching method is provided for forming a through hole having a small size of about 0.3 μm or less and a high aspect ratio in a doped or undoped silicon dioxide film covered with a patterned masking film. This method comprises the steps of forming a masking film with openings in the silicon dioxide film to be etched, and selectively etching the silicon dioxide film through the openings of the masking film using a fluorocarbon-based etching gas and plasma in the reaction chamber, thereby producing the silicon dioxide. Forming a through hole in the membrane. During the step of selectively etching the silicon dioxide film, the etching conditions are controlled by depositing a fluorocarbon polymer film on the masking film having a ratio of carbon to fluorine (ie, C / F ratio) in the range of 1.1 to 1.8. The masking film preferably has a thickness of about 1 μm or less. The method is preferably carried out using a surface wave plasma etching apparatus.