Microfabricated structures with trench-isolation using bonded-substrates and cavities

Abstract

A microstructure and method for forming the microstructure are disclosed. The method includes: providing a handle substrate; providing a device substrate in which high-aspect-ratio structures and optional integrated circuitry will be fabricated; forming one or more filled isolation trenches within a recessed cavity on a first surface of the device substrate or alternatively forming one or more filled isolation trenches on a first surface of the device substrate and forming a recessed cavity on a first surface of the handle substrate; bonding the first surface of the device substrate to the first surface of the handle substrate; removing a substantially uniform amount of material from the second surface of the device substrate to expose at least one isolation trench; optionally forming circuits and interconnection on a second surface of the device substrate; and etching a set of features in the second surface of the device substrate to complete the definition of electrically isolated structural elements. The micromechanical device includes: a device substrate having a first surface, a second surface, and a semiconductor layer; a handle substrate, the first surface of the device substrate bonded to the handle substrate; one or more first trenches formed in the device substrate, the first trenches extending from the second surface of the device substrate through the device substrate towards the handle substrate; a dielectric within the first trenches; one or more cavities disposed below the second surface of the device layer, a cavity enclosing a portion of at least one trench; at least one second trench formed in the second surface of the device substrate, the second trench completing definition of one or more micromechanical devices.

Dependencies are inferred from the claim text.