Reduction of byproduct particle size using low-pressure plasmas generated by a cylindrical-shaped electrode

In the case of a plasma-enhanced chemical vapor deposition, large amounts of byproduct particles arrive at a vacuum pump in spite of the use of cleaning process. As these particles are accumulated on internal components of a vacuum pump, its performance is reduced. A plasma reactor located right before a vacuum pump is proposed with an aim to reduce the size and quantity of byproduct particles, thereby to improve the durability of a vacuum pump. The plasma reactor and electrode all have a concentric cylindrical shape, which allows the device to be easily connected to pre-existing vacuum pipelines without any disturbance to the exhaust stream. The sizes of byproduct particles before the vacuum pump are quite diverse in the range of tens of nanometers to tens of micrometers. The plasma reactor makes the size and quantity of byproduct particles much smaller, and the particles larger than 1 μm are not observed anymore. This result indicates that the vacuum pump durability can be significantly improved by using plasmas.