| 摘要 |
<p>A vacuum pumping system comprises a primary foreline for receiving a gas stream from an outlet of a chamber, a first vacuum pump for evacuating the chamber, a second vacuum pump for evacuating the chamber, a first secondary foreline for conveying gas from the primary foreline to the first vacuum pump, a second secondary foreline for conveying gas from the primary foreline to the second vacuum pump, and valve means for selectively connecting a chosen one of the first and second secondary forelines to the primary foreline. The condition of the vacuum pumps is monitored during use. When both vacuum pumps are operating normally, the valve means is controlled to divert a first reactant-rich gas from the primary foreline into the first secondary foreline, and to divert a second reactant-rich gas from the primary foreline to the second secondary foreline, thereby inhibiting mixing of the first and second reactants within the vacuum pumps. However, in the event that the condition of one of the vacuum pumps indicates that one of the pumps is likely to fail during a current process within the chamber, the valve means is controlled to divert both the first reactant-rich gas and the second reactant-rich gas to the other vacuum pump, thereby preventing the potentially costly loss of a batch of substrates within the chamber.</p> |
