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AssigneeCymer, Inc.
InventorsJames Crouch, Robert Jacques, Matthew R. Graham, Andrew Liu
Estimating the term…
Described herein are embodiments of a method to control energy dose output from a laser-produced plasma extreme ultraviolet light system by adjusting timing of fired laser beam pulses. During stroboscopic firing, pulses are timed to lase droplets until a dose target of EUV has been achieved. Once accumulated EUV reaches the dose target, pulses are timed so as to not lase droplets during the remainder of the packet, and thereby prevent additional EUV light generation during those portions of the packet. In a continuous burst mode, pulses are timed to irradiate droplets until accumulated burst error meets or exceeds a threshold burst error. If accumulated burst error meets or exceeds the threshold burst error, a next pulse is timed to not irradiate a next droplet. Thus, the embodiments described herein manipulate pulse timing to obtain a constant desired dose target that can more precisely match downstream dosing requirements.
A method of regulating a dose of energy produced during continuous burst mode of an EUV light source comprising:
The method of claim 4 wherein the gain is 1.
The method of claim 6 wherein the accumulated burst error equals
The method of claim 7 wherein the gain is −1.
A system for regulating a dose of energy produced during continuous burst firing of an EUV light source configured to generate an energy dose target comprising:
The system of claim 9 wherein the current dose error equals the sensed EUV energy minus the energy dose target.
The system of claim 10 wherein the accumulated burst error equals
The system of claim 11 wherein the gain is equal to 1.
The system of claim 14 wherein the accumulated burst error equals
The system of claim 15 wherein the gain is −1.
Dependencies are inferred from the claim text.