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Proceedings Paper

Semiconductor fabrication techniques for producing an ultra-flat reflective slit
Author(s): Thomas E. Vandervelde; Michael J. Cabral; John Wilson; Michael Skrutskie
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Paper Abstract

The most difficult aspects in manufacturing a reflective slit substrate are achieving a precisely fabricated slit surrounded by an optically flat surface. A commonly used technique is to polish a metal substrate that has a slit cut by electric discharge machine (EDM) methods. This process can produce 'optically flat' surfaces; however, the EDM can produce a slit with edge roughness on the order of 10 microns and a RMS field roughness of ~1 micron. Here, we present a departure from these traditional methods and employ the advantages inherent in integrated circuit fabrication. By starting with a silicon wafer, we begin with a nearly atomically flat surface. In addition, the fabrication tools and methodologies employed are traditionally used for high precision applications: this allows for the placement and definition of the slit with high accuracy. If greater accuracy in slit definition is required, additional tools, such as a focused ion beam, are used to define the slit edge down to tens of nanometers. The deposition of gold, after that of a suitable bonding layer, in an ultra-high vacuum chamber creates a final surface without the need of polishing. Typical results yield a surface RMS-roughness of approximately 2nm. Most of the techniques and tools required for this process are commonly available at research universities and the cost to manufacture said mirrors is a small fraction of the purchase price of the traditional ones.

Paper Details

Date Published: 6 July 2006
PDF: 6 pages
Proc. SPIE 6273, Optomechanical Technologies for Astronomy, 62731Z (6 July 2006); doi: 10.1117/12.672369
Show Author Affiliations
Thomas E. Vandervelde, Univ. of Virginia (United States)
Univ. of Illinois Urbana-Champaign (United States)
Michael J. Cabral, Univ. of Virginia (United States)
John Wilson, Univ. of Virginia (United States)
Michael Skrutskie, Univ. of Virginia (United States)

Published in SPIE Proceedings Vol. 6273:
Optomechanical Technologies for Astronomy
Eli Atad-Ettedgui; Joseph Antebi; Dietrich Lemke, Editor(s)

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