While exposure risks have been minimized over the past decade, VOC emissions still warrant diligent attention in the workplace.

In the semiconductor industry, VOCs are produced as a byproduct in applications such as solvent cleaning and photoresist coating and stripping. Because these processes may contribute significant amounts of VOCs to the exhaust air stream, tool design incorporates appropriate exhaust airflows to remove these VOCs and dilute them to safe levels that meet local and industry codes.¹

VOCs are also released during the changing of photochemical filters, with the operator exposed without adequate ventilation. Operators exposed to VOCs may experience skin, eye, and respiratory irritation. To improve worker safety, Semiconductor Equipment and Materials International (SEMI) developed a standard for workroom air² recommending that VOC concentrations present in workroom air be <1.0% of the Threshold Limit Value (TLV) as established by the American Conference of Governmental Industrial Hygienists (ACGIH).³

The purpose of this article is to present data showing VOC emissions levels that may be expected from typical photochemicals during a filter change. A discussion of Raoult’s Law is included to enable the reader to extend these results to a variety of other photochemical solvents.