Electrostatic chucks support and help cool silicon wafers during manufacturing. Conventional types use expensive, dielectric materials in the chuck's face that can introduce contaminants. Moreover, mechanical damage may result if the static-holding charge takes too long to discharge, as is often the case.
To lower costs, decrease cycle time, and generate less scrap, a new chuck face made of an easily produced, patterned silicon wafer, uses tiny, non-conductive silicon dioxide islands on its surface. These micromachined, non-conductive raised areas on the chuck face prevent excessive currents when the strong electric field is applied between the chuck face and the clamped wafer. Result: fast on/off cycling for quicker de-chucking.
Carl Seager, Sandia National Laboratories, (E) Albuquerque, NM 87185; (505) 844-9168.