Multi-state rf pulsing in cycling recipes to reduce charging induced defects

Abstract

A method for etching in plasma processing in a plasma chamber, including continually rotating between a first etch cycle and a second etch cycle for a period of time to etch a feature in a masked substrate. The method including performing the first etch cycle on the masked substrate using a first etching chemistry for a first sub-period. The first etch cycle is continually rotated between a first state configured for passivation, a second state, and third state configured for etching the masked substrate. During the second state of the first etch cycle, a first tuning step is performed by tuning the first etching chemistry, a high frequency RF power and a low frequency RF power to provide extended passivation to the feature in the masked substrate. The method including performing the second etch cycle on the masked substrate using a second etching chemistry for a second sub-period. The second etch cycle is continually rotated between the first state configured for electrical discharge, a fourth state, and the third state configured for etching the feature in the masked substrate. During the fourth state of the second etch cycle, a second tuning step is performed by tuning the second etching chemistry, the high frequency RF power, and the low frequency RF power to provide punch-through etching to the feature in the masked substrate.