A Neutron Activation Analysis Study of the Sources of Transition Group Metal Contamination in the Silicon Device Manufacturing Process

Abstract

A survey is given of the sources, species, and quantities of transition group metals residing on starting silicon substrates and introduced during the device manufacturing process. The survey begins with the polysilicon feed for silicon ingot fabrication and extends through all customary device fabrication steps, such as wafering, polishing, oxidations, epitaxy, ion implantation, etc. High temperature furnace operations in the absence of , such as steam oxidations, are presently the major source of contamination if all other steps of the fabrication process are under full control. However, contaminated polishing slurries, contaminated handling tools or carriers, impure boats or susceptors, or choice of unsuitable materials for beam catcher plates, etc. in ion implantation, can also lead to trouble. Several options are available to avoid the contamination introduced during high temperature treatments, and these are reviewed.