An apparatus that includes an exposure system for exposing a substrate to an energy pattern, a vacuum chamber having an outside wall including first and second units which can be separated from each other, and a first anti-vibration mount being supported by the first unit, and for supporting a first constituent element of the exposure system. The first anti-vibration mount is disposed outside the vacuum chamber. The apparatus further includes a second anti-vibration mount, being supported by the second unit, for supporting a second constituent element of the exposure system.