Abstract: Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, an apparatus for controlling gas flow is disclosed, the apparatus delivering two gas flows at a known ratio. Specifically, the apparatus has first and second on/off valves and first and second flow restrictors. The first and second on/off valves may be altered between an open state and a closed state. When both the first and second on/off valves are in an open state, first and second gas flows are delivered to first and second outlets. The first and second gas flows are provided at a known ratio to one another, this ratio determined by the ratio of the resistance to flow of the first and second flow restrictors.

Abstract: Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, a gas flow control system for achieving improved transient response in apparatuses for controlling gas flow is disclosed. Specifically, by providing a command to an apparatus to deliver a predetermined mass flow rate at a future turn on time, the apparatus is able to pre-pressurize a P1 volume so that the response time of the apparatus is no longer dependent on the speed of the apparatus's control valves and the limitations of the control loop.

Abstract: Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, a method of achieving improved transient response in apparatuses for controlling gas flow is disclosed. Specifically, by providing a command to the apparatus to deliver a predetermined mass flow rate at a future turn on time, the apparatus is able to pre-pressurize a P1 volume so that the response time of the apparatus is no longer dependent on the speed of the apparatus's control valves and the limitations of the control loop.

Abstract: Apparatuses for controlling gas flow are important components for delivering process gases for semiconductor fabrication. In one embodiment, a method of calibrating an apparatus for controlling gas flow is disclosed. Specifically, the apparatus may be calibrated on installation using a two-step process of measuring the volume of gas box downstream from the apparatus by flowing nitrogen gas into the gas box and measuring the resulting temperature and rate of pressure rise. Using the computed volume of the gas box, a sweep of several mass flow rates may be performed using the process gas and the gas map for the process gas. The apparatus is calibrated based on the measured temperature and pressure values, which allow calculation of the actual mass flow rate for the process gas as compared with the commanded mass flow rates.