A Semi-Conductor Industry Exposure Assessment

A high quality study was conducted to characterize exposures at two wafer fabrication facilities and a test and package line. The study used rigorous scientific methodology that is reliable, relevant and reproducible.  The study was approached in three stages:  Stage 1 (Qualitative Evaluation of Operations) - Develop the Conceptual Manufacturing Model template, identify similar exposure groups (“SEG”), identify Priority Ratings (“PR”) for each SEG, and identify tasks with moderate or high PRs.  Stage 2 (Quantitative Data Collection to Characterize and Validate Exposures) - Sample 1) tasks with moderate or high PRs, 2) tasks with data gaps, and 3) valid 20% of tasks with trivial or low PRs. Some 600 samples for 40 chemical were collected as were measurements for ionizing and non-ionizing radiation.  Stage 3 – (Combine Qualitative and Quantitative Assessments) - Develop SEG profiles from the QLRA outcomes and from existing and new quantitative data. A single chemical was identified for each SEG which represents the worst case exposure profile for a given SEG.  A Job Exposure Matrix (JEM) was modeled using QLRAs, Bayesian statistics, and quantitative data.  Study results indicate:  • Thirty three (33) or 94% of the thirty five (35) SEGs indicate exposures at or below 10% of the OELs at least 95% of the time.  Exposures are trivial or highly controlled.  • The remaining two (2) SEGs – both for the Implantation Process tasks - showed exposures at or below 50% of the OELs at least 95% of the time. Exposures are well controlled.  • No chemical related OEL exceedances would be expected.  • The semiconductor operations are well controlled with regards to potential exposures to physical agents (e.g., ionizing radiation and non-ionizing radiation).  • Industrial hygiene control programs are effective at controlling employee exposures to levels that are trivial, highly controlled or well controlled.