Microcasting of microminiature tips
AssigneeThe Board of Trustees of the Leland Jr. University
InventorThomas E. Carver
Life of this patent
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Abstract
A microminiature tip and tip assembly is fabricated using microelectronic fabrication techniques. A masking aperture is formed in a dielectric layer which overlies a (100) silicon substrate. For a square aperture, a pyramidal pit is anisotropically etched into the surface of the silicon substrate. Tungsten is selectively deposited in the pit to form a pyramid-shaped microminiature point. Continued deposition of tungsten fills the aperture to form a base portion of the tip which integrally locks the tip to the dielectric layer, which is fabricated to form a support member for the tip.
Claims26
A method of forming a microminiature tip, comprising the steps of:
- coating a (100) silicon substrate with a layer of dielectric material;
- forming an aperture in said layer of dielectric material to expose a predetermined portion of the surface of said silicon substrate;
- anisotropically etching a pit in the predetermined portion of the surface of the (100) silicon substrate;
- depositing a tip material by chemical vapor deposition into said anisotropically etched pit to form a tip body using said anisotropically etched pit as a mold, said tip body being defined to extend from bas s and tapering inwardly to a predetermined extent, said tip body having a polygonal cross section at any point along its length;
- depositing said tip material into the aperture in said layer of dielectric material to form a base portion of said tip, which base portion is formed to engage said aperture and integrally attach the tip to said layer of dielectric material;
- removing the silicon substrate surrounding said deposited tip to provide a microminiature tip.
A method of fabricating a microminiature tip assembly, comprising the steps of:
- providing a (100) oriented silicon substrate;
- forming a masking layer of dielectric material on the top surface of said silicon wafer;
- forming an opening in said dielectric masking layer to expose a selected portion of the top surface of said silicon wafer;
- anisotropically etching the selected portion of the top surface of said (100) oriented silicon wafer to form a pyramidal pit in said silicon surface;
- undercutting said dielectric material adjacent to said pyramidal pit to leave a lip of dielectric material around the edge of the pit;
- selectively filling said pyramidal pit with LPCVD tungsten such that said tungsten follows the contours of said pyramidal pit and also forms underneath and over the lip of dielectric material to form a conductive tip mechanically bonded to said layer of dielectric material;
- depositing a conducting layer over said conductive tip and said layer of dielectric material;
- patterning said layer of dielectric material into a cantilever structure;
- removing said silicon substrate to provide a cantilever of said dielectric material with said conductive tip attached thereto.
A microminiature tip assembly, comprising:
- a support arm member having an aperture formed therein;
- a microminiature tip member having a base portion engaged by said support arm member within said aperture, said microminiature tip also having a body portion extending from said base portion and tapering inward to a predetermined extent, said body portion having a polygon cross section at any point along its length.
A microminiature tip for atomic force microscopy, scanning tunneling microscopy, field emission microscopy, and microfilming, comprising a microminiature tip member having a base from which a body portion extends and tapers inwardly to a predetermined extent, said body portion having a polygonal cross-section at any point along its length.
Dependencies are inferred from the claim text.