Purging and reduction of out-gassing are very important issues that need to be treated in order to realize F2 laser lithography system. Several methods of purging are tried and out-gases from metals, O-rings, lubricants, and an adhesive are analyzed. Metal surfaces mainly release oxygen and water independent of surface roughness, Ni plating, or elements. Other substances are not detected by API-MS or GC-MS. Since O-rings are indispensable to make gas-tight structures, several kinds of O-rings made of fluoro-compounds are tested. Black fluoro-rubber o-ring, O-ring F, is recommended from the view of organic out-gassing but Teflon-based fluoro-elastomer, O-ring A, is a good candidate in terms of the water out-gassing. Greases emit a large amount of out-gases even when the samples are not irradiated by 157 nm laser. As an adhesive, Adhesive A is recommended because of the fact that it does not release as much organic and inorganic compounds which may absorb 157 nm laser light. Finally preliminary demonstration using a model exposure system is performed to obtain purging time for several cases.