CFD Modeling and Modification of Cleanroom Design to Achieve ISO Class 6 Performance

The Charles Stark Draper Laboratory Microfabrication Lab, located in Cambridge, Massachusetts, was commissioned in November 2012. The design and construction of this lab was discussed in a previous paper.^[1] The laboratory comprises an area of 700.1 m² (7545 ft²) under filter with 280 m² (3014 ft²) of clean chase space, divided into 11 distinct cleanrooms. This paper focuses on the design and operation of one ISO Class 6 ^[2] cleanroom (3335) used for wet processing of microelectromechanical systems (MEMS) and multichip modules (MCM). The initial design criteria are discussed, along with installation of the tools and the non-compliance of ISO Class 6 particle counts. Based on these results, computational fluid dynamics (CFD) modeling software was employed to study the airflow in the room and modify the airflow to be compliant with ISO Class 6 standards.