Plasma processing method

Abstract

A method for forming shallow trench isolation, including a first step of etching silicon by plasma; a second step of depositing a film containing a silicon element on a mask; a third step of etching the silicon by plasma such that an etching shape becomes perpendicular; and a fourth step of depositing a film containing SiO on the mask, in which the first step to the fourth step are repeated a predetermined number of times, the plasma in the third step is generated by radio frequency power modulated by a first pulse, the third step is performed while radio frequency power modulated by a second pulse is supplied to a sample having the silicon as a substrate, and a frequency of the first pulse in the third step is higher than a frequency of the second pulse in the third step.

Dependencies are inferred from the claim text.