The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1999
Filed:
May. 21, 1997
Michael W Cresswell, Frederick, MD (US);
R N Ghoshtagore, Elliot City, MD (US);
Loren W Linholm, Ijamsville, MD (US);
Richard A Allen, Germantown, MD (US);
Jeffry J Sniegowski, Albuquerque, NM (US);
William B Penzes, Sunderland, MD (US);
Michael Gaitan, North Potomac, MD (US);
The United States of America as represented by the Secretary of Commerce, Washington, DC (US);
Abstract
An improved test structure for measurement of width of conductive lines formed on substrates as performed in semiconductor fabrication, and an improved reference grid for calibrating instruments for such measurements, is formed from a monocrystalline starting material, having an insulative layer formed beneath its surface by ion implantation or the equivalent, leaving a monocrystalline layer on the surface. The monocrystalline surface layer is then processed by preferential etching to accurately define components of the test structure. The substrate can be removed from the rear side of the insulative layer to form a transparent window, such that the test structure can be inspected by transmissive-optical techniques. Measurements made using electrical and optical techniques can be correlated with other measurements, including measurements made using scanning probe microscopy. Nested quadrilateral calibration reference grids particularly useful in calibrating optical coordinate measurement instruments are disclosed.