Improved ion implant exhaust management for reduced energy and capital costs

Climate change, as a consequence of increased greenhouse gas emissions, is a growing concern. Reducing energy usage in semiconductor manufacturing is an effective way to be responsive to this global issue and reduce costs. Compared to other manufacturing tools in the fab, ion implanters require the largest exhaust volume, typically using 2500 CFM in total ventilation, split between the gas box and the containment shell enclosure. Considering a fab may contain 30+ implanters, the energy needed to replace this volume of clean, highly conditioned air is substantial and requires large infrastructure expenditures. In 2009, Texas Instruments published a methodology to save both variable and capital costs by reusing about 75% of the exhausted air volume associated with operating the implanters in one of their 300 mm fabs. This article examines the energy savings, avoided capital spending and safety of operation associated with this change. Building on TI´s advances, this article also proposes ways to further reduce exhaust requirements and integrate ventilation management into the operating architecture of the ion implanter to produce a smart system capable of operating at or below 95% of historical levels and at an even higher level of safety.