Methods for planarization and encapsulation of micromechanical devices in semiconductor processes
AssigneeAnalog Devices, Inc.
InventorJoseph T. Kung
Life of this patent
Estimating the term…
Abstract
A method for fabricating a micromechanical device and a semiconductor circuit on a substrate includes the steps of forming the micromechanical device on a device area of the substrate, the micromechanical device being embedded in a sacrificial material, selectively depositing a planarization layer on the substrate in a circuit area thereof, forming the semiconductor circuit on the planarization layer in the circuit area and removing the sacrificial material from the embedded micromechanical device. In a preferred embodiment, the planarization layer is an epitaxial silicon layer. A protective cap may be formed over the micromechanical device, so that it is completely encapsulated and is thereby protected against particulate contamination.
Claims27
A method for fabricating a micromechanical device in a device area of a substrate and a semiconductor circuit in a circuit area of the substrate, comprising the steps of:
- forming a micromechanical device on the device area of said substrate, said micromechanical device being embedded in a sacrificial material and having an upper surface;
- forming a planarization layer on said substrate in said circuit area, said planarization layer being formed with an upper surface that is substantially coplanar with the upper surface of said micromechanical device;
- forming a semiconductor circuit comprising at least one semiconductor device on said planarization layer in said circuit area;
- and
- removing the sacrificial material from said embedded micromechanical device.
A method for fabricating a micromechanical device on a substrate, comprising the steps of:
- forming a micromechanical device on a device area of said substrate, said micromechanical device being embedded in sacrificial material and having an upper surface;
- exposing a circuit area of said substrate;
- selectively depositing an epitaxial layer on said substrate in said circuit area, said epitaxial layer being formed with an upper surface that is substantially coplanar with the upper surface of said embedded micromechanical device;
- forming a semiconductor circuit comprising at least one semiconductor device on the upper surface of said epitaxial layer in said circuit area;
- and
- removing the sacrificial material from said embedded micromechanical device.
A method for fabricating a micromechanical device on a substrate, comprising the steps:
- forming a first epitaxial layer on said substrate;
- forming a micromechanical device on a device area of said first epitaxial layer, said micromechanical device being embedded in sacrificial material and having an upper surface;
- exposing a circuit area of said first epitaxial layer;
- forming a second epitaxial layer on said first epitaxial layer in said circuit area, said second epitaxial layer being formed with an upper surface that is substantially coplanar with the upper surface of said embedded micromechanical device;
- forming a semiconductor circuit comprising at least one semiconductor device on the upper surface of said second epitaxial layer in said circuit area;
- and
- removing the sacrificial material from said embedded micromechanical device.
Dependencies are inferred from the claim text.