| US 7,368,305 B2 | ||
| High aspect ratio micromechanical probe tips and methods of fabrication | ||
| Daniel W. van der Weide, Madison, Wis. (US); and Yaqiang Wang, Madison, Wis. (US) | ||
| Assigned to Wisconsin Alumni Research Foundation, Madison, Wis. (US) | ||
| Filed on Jun. 10, 2005, as Appl. No. 11/150,856. | ||
| Prior Publication US 2006/0278825 A1, Dec. 14, 2006 | ||
| Int. Cl. H01L 21/00 (2006.01) | ||
| U.S. Cl. 438—20 [438/734] | 14 Claims |
| 1. A method of fabrication of high aspect ratio micromechanical tips comprising:
forming an etchant protective island on a surface of a silicon substrate with the silicon exposed around the island;
isotropically etching the silicon substrate by reactive ion etching around the protective island to partially undercut the
silicon substrate beneath the protective island;
anisotropically etching, by deep reactive ion etching the silicon surrouding the island to a desired depth to define a tip
shaft of the desired height supported at a base by the substrate;
smoothing the walls of the defined tip shaft using a wet chemical clean and reactive ion etchin RIE;
removing the protective island from the tip; and
sharpening the top of the tip shaft to an apex.
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