International Business Machines Corporation

University of Vermont and State Agricultural College

Terence Barrett

Jeffrey P Gambino

Robert K Leidy

Britt Holmen

A micro-fabricated double condenser method and apparatus for the measurement of number-size distribution of airborne nanoparticles is provided. The invention is an instrument which can measure particle size under 100 nanometers in-situ. The present invention includes features such as a small nanoparticle airborne particulate analyzer, with a voltage-stable and feedback-controlled instrument package. The invention features also include a micro-fabricated nanoparticle charging and sorting device (NCaS). The present invention provides a portable, lightweight, and efficacious particle-sizing instrument that is able to effectively count and size nanoparticles over a wide range of operating conditions.

Micro-fabricated double condenser method and apparatus for the measurement of number-size distribution of airborne nano-particles

A flat-top convex-bottom lower lens is formed by first applying a positive tone photoresist over a silicon oxide layer and an optional metallic barrier layer thereupon in a back-end-of-line (BEOL) metallization structure. The positive tone photoresist is exposed under defocused illumination conditions and/or employing a half-tone mask so that a cross-sectional profile of the positive tone photoresist after exposure contains a continuous and smooth concave profile, which is transferred into the underlying silicon oxide layer to form a concave cavity therein. After removing the photoresist, the cavity is filled with a high refractive index material such as silicon nitride, and planarized to form a flat-top convex-bottom lower lens. Various aluminum metal structures, a color filter, and a convex-top flat-bottom upper lens are thereafter formed so that the upper lens and the lower lens constitute a composite lens system.

Growing community of inventors

Burlington, VT, United States of America

Terence Barrett