Patent ID: 7918251
Filing Date: 2011-04-05
Classification: H01L

Abstract:
1. An apparatus, comprising: a first enclosure defined by a plurality of walls; a first enclosure door configured to cover an opening in one of said plurality of walls; a second enclosure comprising a second enclosure door configured to cover an opening in the second enclosure; a sealing apparatus disposed between the first enclosure and the second enclosure to seal the second enclosure to the first enclosure, the sealing apparatus surrounding the opening in said one of said plurality of walls and the opening in the second enclosure, wherein an included space is formed between the first enclosure door, the second enclosure door and the sealing apparatus; a first valve coupled to first enclosure for introducing a first gas to the first enclosure; and a second valve coupled to the included space for introducing a second gas to the included space; wherein the first valve is disposed proximate to a bottom region of the first enclosure and a molecular weight of the first gas is less than a molecular weight of the gas within the first enclosure, or the first valve is disposed proximate to a top region of the first enclosure and the molecular weight of the first gas is more than the molecular weight of the gas within the first enclosure.