Method of purging and pumping vacuum chamber to ultra-high vacuum

摘要

An improved method is disclosed for purging a vacuum chamber suitable for use in the production of integrated circuit structures on semiconductor wafers. The method comprises providing the chamber (4) to be purged and flowing a heated, non-reactive gas, such as argon gas, through the chamber (4). The non-reactive gas is heated to a temperature of at least 90 DEG C. Further, the chamber (4) is heated to maintain it at a temperature of at least 90 DEG C while flowing the gas therethrough. Flowing the heated non-reactive gas through the chamber (4) causes released impurities or contaminants to be efficiently swept from the chamber (4) in the non-reactive gas flow. After flowing the heated gas through the heated chamber (4), the flow of gas is interrupted and the chamber (4), while still hot, is pumped down to a vacuum of about 667 x 10-7 Pa (5 x 10-7 Torr) to determine whether or not the chamber (4) has a leakage problem. The presence of a leakage problem may be determined by comparing the pumping to past pumping of similar sized chambers, or by measuring the partial pressure of common gases such as nitrogen and/or oxygen. If the partial pressure of oxygen is higher than about 667 x 10-8 Pa (5 x 10-8 Torr) and the partial pressure of nitrogen is higher than 267 x 10-7 Pa (2 x 10-7 Torr), the vacuum chamber (4) can be considered to have a leakage problem. Pumping times may, therefore, be shortened by the use of such screening for leakage problems while the vacuum chamber (4) is still hot. IMAGE