Sealed micromachined vacuum and gas filled devices
AssigneeThe Regents of the University of California
InventorsRichard S. Muller, Carlos H. Mastrangelo, Kirt R. Williams
Life of this patent
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Abstract
A surface and/or bulk micromachined hermetically sealed cavity containing at least one suspended structure in a low pressure ambient, and the associated fabrication method. The cavity is bounded by a thin-film membrane and a substrate which may have a recess. The method can be used for the production, for example, of thermionic-emission vacuum tubes, gas filled tubes and electromechanical devices. In vacuum tubes the cathode is a suspended refractory filament. Other electrodes may also be suspended. In electromechanical devices the suspended members may be cantilever beams capable of low friction motion.
Claims6
A method for forming a microstructure, said method comprising the steps of:
- providing a substrate including a first etchable structure, wherein said first etchable structure is at least partly exposed;
- forming a patterned planar unetchable structure having at least one layer on said substrate, at least a portion of which is above an exposed portion of said first etchable structure;
- forming a patterned second etchable structure on top of said unetchable structure, wherein a portion of said unetchable structure, but not the entire said unetchable structure, is between parts of the first and second etchable structures;
- depositing an unetchable membrane layer on top of said patterned second etchable structure;
- opening etching holes in said membrane layer in an area thereof where it overlaps one of said first and second etchable structures;
- etching said first and second etchable structures to a predetermined extent to form a cavity with a suspended member, the cavity including at least one etching channel bound by said membrane layer;
- creating a predetermined ambient in said cavity;
- and
- depositing additional material to fill said etching channel and seal the cavity.
A method for forming a microstructure, said method comprising the steps of:
- providing a substrate including a first etchable structure, wherein said first etchable structure is at least partly exposed;
- forming a patterned planar unetchable structure having at least one layer on said substrate, at least a portion of which is above an exposed portion of said first etchable structure;
- forming a patterned second etchable structure on top of said unetchable structure, wherein a portion of said unetchable structure, but not the entire said unetchable structure, is between parts of the first and second etchable structures;
- depositing an unetchable membrane layer on top of said patterned second etchable structure;
- opening etching holes in said membrane layer in an area thereof where it overlaps one of said first and second etchable structures;
- etching said first and second etchable structures to a predetermined extent to form a cavity with a suspended member, the cavity including at least one etching channel not bound by said unetchable structure;
- creating a predetermined ambient in said cavity;
- and
- depositing additional material to fill said etching channel and seal the cavity.
A method for forming a microstructure, said method comprising the steps of:
- providing a substrate including a first etchable structure, wherein said first etchable structure is at least partly exposed;
- forming a patterned planar unetchable structure having at least one layer on said substrate, at least a portion of which is above an exposed portion of said first etchable structure;
- forming a patterned second etchable structure on top of said unetchable structure, wherein a portion of said unetchable structure, but not the entire said unetchable structure, is between parts of the first and second etchable structures;
- depositing an unetchable membrane layer on top of said patterned second etchable structure;
- opening etching holes in said membrane layer in an area thereof where it overlaps one of said first and second etchable structures;
- etching said first and second etchable structures to a predetermined extent to form a cavity with a suspended member;
- creating a predetermined ambient in said cavity;
- and
- depositing additional material to seal the cavity.
Dependencies are inferred from the claim text.