Environment and Site Survey Measurement
H157654_9_011 49 / 120
Criterion
Curve
Amplitude µm/s
(11µi/s)
*
Description of Use
Residential day
(ISO)
200 (8 000)
Barely perceptible vibration. Appropriate to sleep
areas in most instances. Usually adequate for
computer equipment, hospital recovery rooms.
semiconductor probe test equipment, and micro-
scopes less than 40x.
Operating the-
ater (ISO)
100 (4 000)
Vibration not perceptible. Suitable in most in-
stances for surgical suites, microscopes to 100x
and for other equipment of low sensitivity.
VC-A 50 (2 000)
Adequate in most instances for optical micro-
scopes to 400x, microbalances, optical balances,
proximity and projection aligners, etc.
VC-B 25 (1 000)
Appropriate for inspection and lithography equip-
ment (including steppers) to 311m line widths.
VC-C 12.5 (500)
Appropriate standard for optical microscopes to
1000x, lithography and inspection equipment (in-
cluding moderately sensitive electron microscopes)
to 1 11m detail size, TFT-LCD stepper/scanner
processes.
VC-D 6.25 (250)
Suitable in most instances for demanding equip-
ment, including many electron microscopes (SEMs
and TEMs) and E-Beam systems.
VC-E 3.12 (125)
A challenging criterion to achieve. Assumed to be
adequate for the most demanding of sensitive sys-
tems including long path, laser- based, small target
systems, E-Beam lithography systems working at
nanometer scales, and other systems requiring ex-
traordinary dynamic stability.
VC-F 1.56 (62.5)
Appropriate for extremely quiet research spaces;
generally difficult to achieve in most instances, es-
pecially cleanrooms. Not recommended for use as
a design criterion, only for evaluation.
VC-G 0.78 (31.3)
Appropriate for extremely quiet research spaces;
generally difficult to achieve in most instances, es-
pecially cleanrooms. Not recommended for use as
a design criterion, only for evaluation.
*As measured in one-third octave bands of frequency over the frequency range 8 to 80
Hz (VC-A and VC-B) or 1 to 80 Hz (VC-C through VC-G).
The information given in this table is for guidance only. In most instances, it is recom-
mended that the advice of someone knowledgeable about applications and vibration re-
quirements of the equipment and processes be sought.
Source: Reprinted with permission from Colin Gordan Associates.
Table7.1: Application and Interpretation of the Generic Vibration Criterion (VC) Curves
To Next Page
Loading...
Need help?
General
