SYSTEMS FOR AND METHODS OF CONTROLLING TIME-MULTIPLEXED DEEP REACTIVE-ION ETCHING PROCESSES

摘要

An improved gas delivery system and method delivers a sequence of pulses of prescribed amounts of at least two gases to a process chamber of a process tool in accordance with a predetermined recipe of steps of a gas delivery process. The system comprises: a plurality of channels, each including a control valve connected so as to control each pulse of gas flowing through the corresponding channel into the process chamber of the process tool; and an exhaust valve for controlling the pressure within the process chamber, the exhaust valve including a valve controller for controlling the operation of the gas delivery system including the control valves and the exhaust valve in accordance with the predetermined recipe of steps. In one embodiment, the exhaust valve controller is configured to operate in a hybrid feedback mode including both open feedback loop control wherein the exhaust valve is set at a preselected position based on a past learned position for each step of the gas delivery process, and closed feedback loop control of the system for each step of the gas delivery process as a function of the pressure within the process chamber following the open loop control.