| 摘要 |
A method for reducing noise generated by a vacuum pumping system 20 operating to evacuate a chamber 10, where the method comprises operating the vacuum pumping system at a rated speed to reduce chamber pressure to a first pressure; determining that the pressure at the vacuum pumping systemâ s inlet is about to change to a second pressure that is higher than the first pressure; in response to the determining step, reducing the speed of a booster pump 28 in the vacuum pumping system to a second speed that is below the rated speed; and then increasing the speed of the booster pump to the rated speed when the pressure at the vacuum pumping systemâ s inlet is above the second pressure. A vacuum pumping system and a method of reducing noise when connected to a semiconductor processing tool is also claimed. |
