DEVICE FOR FEEDING GAS TO CHAMBER AND METHOD FOR CONTROLLING CHAMBER INNER PRESSURE USING THE DEVICE

摘要

A device for feeding a gas to a chamber prevents flow rate control accuracy from greatly lowering in a small flow rate region, performs highly accurate flow rate control in the entire flow rate control region, and also controls a wide pressure range of a chamber by the highly accurate flow rate control. More particularly, the device for feeding a gas to a chamber is constituted of parallelly connected pressure-type flow rate control devices and a control device for controlling the operation of the flow rate control devices. The gas- feeding device feeds to the chamber a desired gas discharged by a vacuum pump while controlling the flow rate of the gas. One of the pressure-type flow rate control devices is a device controlling a gas flow rate range of up to 10% at a maximum of the maximum flow rate to be fed to the chamber, and the remaining flow rate control devices are devices controlling the remaining gas flow rate range.