Method and apparatus for fast gas exchange, fast gas switching, and programmable gas delivery

Embodiments of the invention relate to a gas delivery system. The gas delivery system includes a fast gas exchange module in fluid communication with one or more gas panels and a process chamber. The fast gas exchange module has first and second sets of flow controllers and each of first and second sets of flow controllers has multiple flow controllers. The flow controller is configured such that each of the flow controllers in the first and second sets of the flow controllers is independently operated to selectively open to divert gas to the process chamber or an exhaust. The first and second sets of flow controllers are operated for synchronized switching of gases in a pre-determined timed sequence of flow controller actuation. The invention enables fast switch of resultant gas flow in the process chamber while having individual flow controller operated at lower switching speed to provide longer service life.