VACUUM SYSTEM FOR IMMERSION PHOTOLITHOGRAPHY

摘要

A vacuum system for extracting a stream of a multi-phase fluid from a photo­lithography tool comprises a pumping arrangement for drawing the fluid from the tool, and an extraction tank (32) located upstream from the pumping arrangement for separating the fluid drawn from the tool into gas and liquid phases. The pumping arrangement comprises a first pump (36) for extracting gas from the tank, and a second pump (38) for extracting liquid from the tank (32). In order to minimise any pressure fluctuations transmitted from the vacuum system back to the fluid (32) within the tool, a pressure control system maintains a substantially constant pressure in the tank (32) by regulating the amounts of liquid and gas within the tank (32).