Patent ID: 8293615

Claim:
A method for fabricating a device, the method comprising the steps of: providing a wafer having a substrate, a buried oxide (BOX) over the substrate and a semiconductor-on-insulator (SOI) layer over the BOX; depositing a hardmask layer over the SOI layer; depositing a photoresist layer over the hardmask layer; patterning the photoresist layer into groups of segments, wherein the segments in each of the groups are spaced apart from one another in a first direction and wherein the groups are spaced apart from one another in a second direction, and wherein the first direction and the second direction are perpendicular to one another; performing a tilted implant along the first direction to damage all but those portions of the hardmask layer covered or shadowed by the photoresist layer segments; patterning the hardmask layer along the first direction by removing portions of the hardmask layer damaged by the implant; performing a first etch through the hardmask layer to form a deep trench in the SOI layer, the BOX and at least a portion of the substrate along the first direction, wherein the deep trench comprises a deep isolation region of the device; patterning the hardmask layer along the second direction using the patterned photoresist layer; and performing a second etch through the hardmask layer to form shallow trenches in the SOI layer along the second direction, wherein the shallow trenches comprise shallow isolation regions of the device, and wherein the deep isolation region and the shallow isolation regions formed in this manner are self-aligned to one another.