METHOD FOR FORMING STAIR-STEP STRUCTURES

摘要

A method for forming a stair-step structure in a substrate is provided. An organic mask is formed over the substrate. A hardmask with a top layer and sidewall layer is formed over the organic mask. The sidewall layer of the hard mask is removed while leaving the top layer of the hardmask. The organic mask is trimmed. The substrate is etched. The forming the hardmask, removing the sidewall layer, trimming the organic mask, and etching the substrate are repeated a plurality of times.

主权项

1. A method for forming a stair-step structure in a substrate under an organic mask, comprising:
a) forming a hardmask with a top layer and a sidewall layer over a top and a sidewall of the organic mask; b) removing the sidewall layer of the hardmask while leaving the top layer of the hardmask; c) trimming the organic mask; d) etching the substrate, which etches away the top layer of the hardmask; and e) repeating steps a-d a plurality of times forming the stair-step structure.