Patent ID: 7481887

Claim:
An apparatus for depositing materials onto a micro-device workpiece in a reaction chamber, comprising: a gas source system configured to provide a first precursor, a second precursor, and a purge gas; a valve assembly coupled to the gas source system, the valve assembly being configured to control a flow of the first precursor, a flow of the second precursor, and a flow of the purge gas; a reaction chamber including an inlet coupled to the valve assembly, a workpiece holder, and an outlet; a monitoring system comprising a radiation source that directs a selected radiation through the flow of the first precursor, the flow of the second precursor and/or the flow of the purge gas, and a detector that senses a parameter of the selected radiation; and a controller operatively coupled to the monitoring system and the valve assembly, the controller having a computer readable medium containing computer operable instructions that cause the controller to perform a method comprising: commanding the valve assembly to start the flow of the first precursor into the reaction chamber; monitoring a concentration of the first precursor in the reaction chamber based on the parameter sensed by the monitoring system; detecting an end point of a concentration increase of the first precursor in the reaction chamber based on the monitored concentration of the first precursor; commanding the valve assembly to continue the flow of the first precursor for a predetermined duration once the end point is detected; commanding the valve assembly to stop the flow of the first precursor and start the flow of the purge gas after the predetermined duration expires; monitoring the flow of the purge gas in the reaction chamber based on the parameter sensed by the monitoring system; commanding the valve assembly to continue the flow of the purge gas for a predetermined purge duration; commanding the valve assembly to stop the flow of the purge gas and start a flow of the second precursor after the purge duration expires; monitoring a concentration of the second precursor in the reaction chamber based on the parameter sensed by the monitoring system; detecting an end point of a concentration increase of the second precursor in the reaction chamber based on the monitored concentration of the second precursor; commanding the valve assembly to continue the flow of the second precursor for a predetermined duration once the end point is detected; and commanding the valve assembly to stop the flow of the second precursor and start a flow of the purge gas after the predetermined duration expires.