Designing a facility to meet the stringent Vibration Criteria of extremely precise imaging equipment can be very challenging, and often cost-prohibitive, particularly when not all tools in the facility require these very low vibration levels.[1]
Statistical representation (in terms of Mean plus Sigma Spectra) of vertical vibrations in a typical semiconductor fab production area at "as built" and two times thereafter [2]
It is very difficult to isolate very large areas such as entire buildings, or an entire floor. It is also well documented that building vibration levels will increase relative to a design specification as the facility is populated with equipment and people. Repeated vibration measurements a few months, or a year later, show that floor vibration levels typically rise over time.[2]
The more cost effective and successful approach for achieving the stringent requirements of vibration sensitive tools, is to employ point-of use active vibration control with serial piezoelectric technology, particularly to mitigate challenging low frequency (less than 5 Hz) vibration (example here).
TMC can work with the your team to design a tool-specific Quiet Island solution. This process allows us to look at each tool specifically and provide the best performing solution. A building design incorporating one large concrete sub-floor “slab” with a “raised floor” allows for flexibility of tool selection post-construction. Replacing the raised floor with a Quiet Island only where needed provides the most sensitive tool set with a vibration environment an order of magnitude, at least, lower than the sub-floor.
See also The Benefits of Including Floor Vibration Control for Nano-Tech Facilities over Designing "Quiet" Buildings article on AZO Nano.
1Evolving criteria for research facilities: I – Vibration, Colin Gordon Associates, SPIE Conference 5933: Buildings for Nanoscale Research and Beyond, 2005, Source
2Maturation of the Vibration Environment in Advanced Technology Facilities, Colin Gordon Associates, Journal of the IEST, V. 48, No. 1, 2005, Source