Abstract

Particulate contamination is currently a major concern for the microelectronics industry and is a problem which is expected to increase significantly in future technologies. Because of this, much effort has been directed toward improving clean rooms and the handling of electronic materials. Recent studies, however, have shown that certain plasmas may generate contamination. Because of this, certain process steps involved in fabrication technology may contribute particulate contamination and thereby cause yield loss even in state-of-the-art clean rooms. We discuss the use of laser light scattering as a means for monitoring particulate contamination during plasma processing. Results of this technique show that particulate contamination in the plasma is electrostatically suspended at the sheath/plasma boundaries. Spatially resolved measurements of particulate contamination in reactive ion etch (RIE) environments and sputter plasmas are discussed and compared with laser-induced fluorescence measurements of reactive and ionic plasma species. Chemical and physical sources of particulate contamination are discussed along with a proposed mechanism for particle formation and electrostatic suspension in the plasma.

© 1989 Optical Society of America