Ion implantation is a process used to create the functional units (pn junctions) of integrated circuits, photovoltaic (solar) cells and other semiconductor devices. During the process, ions of an impurity or a "dopant" material are created, accelerated and imbedded in wafers of silicon. Workers responsible for implantation equipment are believed to be at risk from exposure to both chemical (dopant compounds) and physical (ionizing radiation) agents. In an effort to characterize the chemical exposures, monitoring for chemical hazards was conducted near eleven ion implanters at three integrated circuit facilities, while ionizing radiation was monitored near four of these units at two of the facilities. The workplace monitoring suggests that ion implantation operators routinely are exposed to low-level concentrations of dopants. Although the exact nature of dopant compounds released to the work environment was not determined, area and personal samples taken during normal operating activities found concentrations of arsenic, boron and phosphorous below OSHA Permissible Exposure Limits (PELs) for related compounds; area samples collected during implanter maintenance activities suggest that a potential exists for more serious exposures. The results of badge dosimetry monitoring for ionizing radiation indicate that serious exposures are unlikely to occur while engineering controls remain intact. All emissions were detected at levels unlikely to result in exposures above the OSHA standard for the whole body (1.25 rems per calendar quarter). The success of existing controls in preventing worker exposures is discussed. Particular emphasis is given to the differential exposures likely to be experienced by operators and maintenance personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

The production of integrated circuits and other semiconductor devices requires the introduction of impurities or dopants into the crystal lattice of a silicon substrate. This "doping" or junction formation is achieved through one of two processes: thermal diffusion or ion implantation. Ion implantation, the more contemporary and more accurate of the two processes, accomplishes junction formation by bombarding selected areas of the silicon wafer with a beam of dopant ions. Inorganic arsenic, which is regulated by the Occupational Health and Safety Administration (OSHA) as a carcinogen, is frequently used as dopant material. Silicon wafers are found to emit inorganic arsenic following ion implantation. Data collected during this experiment demonstrate that arsenic is released over a 3.5-hour period following implantation and that the total amount of arsenic emitted may approach 6.0 micrograms per 100 wafers processed within 4 hours after implantation. The discovery and quantification of this phenomenon suggest that newly implanted silicon wafers are a potential source of arsenic contamination--a source that may impact both the quality of the work environment and the integrated circuit product.

This report describes equipment that converts a Philips Three Position X-Ray Spectrograph to semiautomatic operation for routine sample analysis. Up to ten independent sets of conditions for wavelength (2θ), pulse height analysis baseline, and total count can be selected in advance. The equipment will then automatically determine the “counting time” for a sample for each set of conditions selected At the end of each count the equipment prints out the sample number, code numbers for the goniometer position, baseline setting, the fixed count used, and the time, in tenths of a sec, required to reach the fixed count. Semiautomatic operation permits operation by personnel with minimum training, reduces invalid results due to operator mistakes, and increases sample output per day The results are identical with those obtained by manual operation

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A spherical 1-l flask that is half-filled with a liquid sample provides an unusual optical system. Light projected by a laser beam can display various symmetrical paths, and the reflections and refractions allow accurate adjustments that offer a practical means for making reliable quantitative measurements of the index of refraction. Polarization of the laser light is discussed and the theoretical and experimental aspects of fluxes are considered.