In most state-of-the-art microelectronics facilities, process equipment (tools), including vibration-sensitive equipment, is set on a structure to bring the equipment to the level of the raised access floor. Depending on their design these bases can amplify, through resonance, the vibration amplitudes that travel from the structural floor to the equipment base. Similarly, benches that are commonly used to support microscopes and other equipment will often amplify the floor vibrations. Data are presented from recent measurements that illustrate the nature and magnitude of these effects. The concept of "rigid body rotation" as a source of horizontal vibration on bases and tables is discussed briefly.
Colin G. Gordon and Yung Q. Tran, “The Influence of Bases and Benches on the Performance of Vibration-Sensitive Equipment,” Vibration Control in Microelectronics, Optics and Metrology, SPIE Proceedings Volume 1619, (Nov. 1991).80d02864859cafaf95952917e61f1d16