Embodiments of the present invention are directed to apparatus and methods
of attenuating vibration, particularly for modern stepper machines and
other types of vibration sensitive equipment. The attenuation system
exhibits good vibration attenuation in the axial or support direction,
and exhibits low or substantially zero lateral stiffness to prevent
transmission of any vibrations between any of various portions of the
machine. In one embodiment, an apparatus for attenuating transmission of
lateral vibration between a first mass and a second mass comprises a
vibration attenuation device including at least one bellows oriented
along a support axis. The at least one bellows is connected between the
first mass and the second mass and has an interior volume pressurized
with a fluid to an internal fluid pressure which is greater than a
zero-stiffness pressure such that the vibration attenuation device
exhibits a negative lateral stiffness. A positive stiffness device is
coupled between the first mass and the second mass. The positive
stiffness device has a positive lateral stiffness which may be
substantially equal to or greater than the negative lateral stiffness in
magnitude.