vacuum chamber purging method and apparatus

A vacuum chamber load lock purging method and apparatus is disclosed. The purging apparatus includes a purging gas diffusion device disposed in a rear portion of a load lock chamber. The purged gas diffusion device is located proximate the vacuum door and distal from the atmospheric door such that the purge gas diffuses towards the atmospheric door during purging. The purging gas diffusion device is porous and permits a purge gas such as nitrogen to purge a load-lock chamber of oxygen or other contaminants from the load lock. The purge gas diffusion device may be tubular and is positioned in the load lock chamber in an offset channel portion in communication with and offset from a through path portion of the load lock chamber, through which a product, such as a semiconductor wafer may proceed without disruption by the diffusion device. The load lock purging system is useful, for example, in a film deposition or other process in which precisely-controlled conditions of pressure and concentration affect the integrity of the process.