Patent ID: 7378346

Claim:
A method for fabricating a monolithically integrated structure, comprising: forming alternating layers of a material and etch stop layers formed over a substrate; forming a first mirror between the substrate and the alternating layers; forming a first patterned photoresist over the alternating layers, thereby leaving a first opening over a portion of the material in a first portion of the alternating layers; performing a first etch to remove the portions of the material in the first opening; forming a second patterned photoresist over the alternating layers, thereby leaving a second opening within the first opening and exposing one of the etch stop layers within the second opening; applying an oxygen plasma to convert the one of the etch stop layers in the second opening to silicon dioxide; performing a second etch to remove the silicon dioxide and a second portion of the material in the second opening; forming, subsequent to the performing a second etch, a second mirror on a side of the alternating layers opposed to the first mirror, the second mirror having at least two levels having different distances from the first mirror.