In-depth survey report: control technology for the microelectronics industry at United Technologies Corporation's Mostek Facility, Carrollton, Texas, report no. CT-115-16b.
An in depth survey was performed at United Technologies Corporation MOSTEK facility (SIC-3674) located in Carrollton, Texas, as part of a larger effort to characterize basic exposures and describe the processes and controls so that an assessment can be made of the hazard control technology used within the microelectronic industry. Six operations were studied in detail, including wet chemical stations, diffusion, ion implantation, radio frequency, radiation sources, and gas handling and distribution systems. The chemical handling tasks at the company offered an example of good contemporary engineering design incorporating exhausted gas cabinets for safe storage of gas cylinders, flow limiting valves, solenoid valves for emergency shutdown, and welded stainless steel lines that contain a minimum of compression fittings. Personal protective equipment was heavily used. Monitoring of hydrofluoric-acid (7664393) exposure showed that no exposure hazard existed at the wet chemical station. Phosphate emissions were detected at the diffusion furnace using phosphorus-oxychloride as a dopant. While exposures to emissions of toxic dopants were below current recommended standards, the ventilation controls on both cassette and palette type ion implanters did not completely eliminate worker exposure as had been previously thought. Measurements also indicated that it was unlikely that significant exposures to radio frequency radiation would occur.