Dry-etch selectivity

摘要

A method of etching exposed patterned heterogeneous structures is described and includes a remote plasma etch formed from a reactive precursor. The plasma power is pulsed rather than left on continuously. Plasma effluents from the remote plasma are flowed into a substrate processing region where the plasma effluents selectively remove one material faster than another. The etch selectivity results from the pulsing of the plasma power to the remote plasma region, which has been found to suppress the number of ionically-charged species that reach the substrate. The etch selectivity may also result from the presence of an ion suppression element positioned between a portion of the remote plasma and the substrate processing region.

主权项

1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon nitride region and an exposed second material region, the method comprising:
flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the plasma region to produce plasma effluents; pulsing a power of the plasma formed in the remote plasma region at a plasma frequency with a plasma duty cycle; and etching the exposed silicon nitride region by flowing the plasma effluents into the substrate processing region through holes in a showerhead.