In-depth survey report: control technology for the microelectronics industry at NEC Electronics USA, Mountain View, California.
In order to made an accurate assessment of the hazard control technology as applied to the microelectronic industry, an in-depth survey was made of NEC Electronics USA (SIC-3674), Mountain View, California. Detailed studies were conducted of the four process operations of photolithography, operations using radio frequency radiation, and gas handling and distribution systems. This facility currently manufactures random logic products including read/only and random access memories. Descriptions were offered of the following processes: thermal oxidation, photolithography, plasma etching, wafer doping, chemical vapor deposition, metallization, and hydrogen alloying. Concentrations of chemicals were measured and monitoring was also conducted of physical agents such as radiofrequency radiation and gamma or x-radiation. Chemical mix operators wear chemical resistant aprons, acid or chemical resistant sleevelets and gloves, and chemical splash goggles and face shields. Airborne levels of contaminants at the photolithography area proved to be only a fraction of the recommended threshold limit values (TLVs) for several substances including hexamethyldisilizane, acetone (67641), n-butyl-acetate (123864), and xylene (1330207). Both direct and indirect emissions of radiofrequency radiations were detected at levels in excess of the TLVs for both the electric and magnetic field components of a 13.56 megahertz source. According to the authors, proper fitting and maintenance of equipment cabinets, the installation of metal screens across view ports and proper grounding of instruments should help to reduce these exposures.