Method of minimizing reactive ion etch damage of organic insulating layers in semiconductor fabrication

Abstract

A method of limiting surface damage during reactive ion etching of an organic polymer layer on a semiconductor substrate combines particular choices of process gases and plasma conditions with a post-etch passivation treatment. According to the method, a low density plasma etcher is used with a process gas mixture of one or more of an inert gas such as argon, helium, or nitrogen; methane; hydrogen; and oxygen, where the percentage of oxygen is up to about 5%. Typically a parallel plate plasma etcher is used. The reactive ion etching is followed by a post-etch passivation treatment in a which a gas containing hydrogen is flowed over the etched layer at an elevated temperature. The method is particularly useful in reactive ion etching of fluorinated organic polymer layers such as films formed from parylene AF4, and layers of poly(arylene ethers) and TEFLON®.