Apparatus for use in a metrology process or lithographic process

摘要

The invention provides an apparatus for use in a metrology process or a lithographic process, the apparatus comprising: an object support module adapted to hold an object; a first gas shower arranged on a first side of the object support module and adapted to emit a gas with a first velocity in a first gas direction which is a horizontal direction to cause a net gas flow in the apparatus to be a substantially horizontal gas flow in the first gas direction at least above the object support module.