Trench isolation methods including plasma chemical vapor deposition and

Abstract

Isolation methods for integrated circuits use plasma chemical vapor deposition of an insulating layer followed by lift-off to remove at least portions of the insulating layer. In particular, a lift-off layer is formed on an integrated circuit substrate. The lift-off layer and the integrated circuit substrate beneath the lift-off layer are etched to form a trench in the integrated circuit substrate. The trench defines a first region on one side of the trench and a second region that is narrower than the first region on the other side of the trench. Plasma chemical vapor deposition is then performed to form an insulating layer filling the trench, on the first region and on the second region, with the insulating layer on the first region being thicker than on the second region. The insulating layer is then etched to expose the lift-off layer in the second region. The lift-off layer is then lifted off from the first region. Isolation trenches so formed can have improved isolation characteristics and can be planarized with reduced dishing effects.