Patent ID: 7368365

Claim:
A method of forming a buried digit line comprising: forming a trench in a substrate, wherein the trench has a base, a first trench side wall, and a second trench side wall; forming a first spacer along the first trench side wall and a second spacer along the second trench side wall; filling the trench with a first sacrificial material after forming the first spacer and the second spacer; removing the second spacer to expose a first portion of the base of the trench after filling the trench; etching the exposed first portion of the base of the trench to form an isolation window with a first depth; depositing a first insulating liner along the first trench side wall and a second insulating liner along the second trench side wall and into the isolation window; forming a recess in the substrate by etching a second exposed portion of the base of the trench between the first insulating liner and the second insulating liner to a second depth; and forming a digit line in the recess.