Colin G. Gordon
The importance of vibration in microelectronics production can be appreciated when one considers the extreme sensitivity of the "tools" and systems used in the chip fabrication process and the large amount of mechanical energy that is consumed in a modern cleanroom. The most sensitive tools used in the process are greater than one hundred times, more sensitive to vibration than a human occupying, say, a desk in an office building. At the same time the total mechanical power consumed per unit area of cleanroom floor is one hundred times, or more, that consumed by the operation of an office building. The great difference in the ratio of "power consumed" to "sensitivity" lies at the heart of the vibration problem in cleanroom design.
There is a dearth of reliable information from tool manufacturers about the vibration and noise sensitivity of their products. And where information is available there is wide variation in sensitivity from tool to tool. This is not surprising considering the complexity of these tools. To provide a basis against which the vibration Îquality" of process floors supporting these tools can be quantified, various criteria have been proposed. The most widely used criteria are the "generic" vibration criterion (VC) curves.
Reprinted from Proceedings of Internoise 96, Liverpool, England (July, 1996)