Hal Amick, Ph.D., P.E., Colin Gordon & Associates, San Bruno, CA, USA

ABSTRACT

Vibration has long been recognized as a contaminant in a fab. This article presents one possible approach for using the building itself to mitigate vibrations. Concrete is the structural material of choice for the vibration-sensitive areas in a fab, via waffle slabs or concrete two-way grillages. Some benefits arise from altering the vibration damping characteristics of the concrete itself. A recent research project examined various options for concrete damping modification, finding that the use of a particular family of admixtures was the most straightforward approach. We will look at damping itself and the role it can play in vibration control.