NEw tool for plasma etching diagnostics developed by NIST

The understanding and control of the complex chemical processes that occur in semiconductor plasma-etching reactors is critical for the microelectronics industry, as it moves toward implementing multistep etching processes, to produce smaller and higher-aspect-ratio features. NIST scientists have developed a new spectroscopic technique for characterizing the complex chemistry that occurs in a semiconductor plasma-- etching reactor. The technique uses linear absorption spectroscopy to determine the density and temperature of plasma species, such as radicals, ions, and molecules, along the radiation path. The technique represents a significant improvement over previous methods, such as infrared diode-laser spectroscopy, by providing unambiguous molecular identification over a broad range of molecular species, and absolute concentrations and temperatures. The instrumentation fits in two suitcases, making it convenient for setting up at a remote plasma reactor.

Initial tests near 0.1 THz demonstrated the detection of important fluorocarbon species in a triflouromethane plasma, such as might be used for etching silicon wafers. Present efforts are being made to extend the measurement frequency to near I THz.

CONTACT: Gerald Fraser, [phone]; gerald. [email protected] and Eric Benck, [phone]; [email protected].