Fiber amplifier based light source for semiconductor inspection
AssigneeKLA-Tencor Technologies Corporation
InventorsYung-Ho Chuang, J. Joseph Armstrong
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Abstract
A laser illuminator for use in an inspection system, such as a semiconductor wafer inspection system or photomask inspection system is provided. The gain medium in the illuminator comprises optical fiber, and amplification, beam splitting, frequency and/or bandwidth conversion, peak power reduction, and q-switching or mode locking may be employed. Certain constructs including doped fiber, gratings, saturable absorbers, and laser diodes are disclosed to provide enhanced illumination.
Claims27
An illuminator employed in a specimen inspection system, comprising:
- a laser arrangement comprising a laser oscillator configured to produce coherent light;
- and
- a plurality of parallel fiber laser amplifiers configured to receive coherent light from the laser oscillator and transmit amplified coherent light toward a specimen for purposes of inspecting the specimen;
- wherein said laser arrangement employs mode-locking to selectively produce energy bursts having desired properties.
A method for inspecting a specimen, comprising:
- pumping a laser oscillator within a laser arrangement to generate coherent light;
- amplifying said coherent light using a fiber laser amplifier;
- and
- transmitting amplified coherent light from the fiber laser amplifier toward the specimen for purposes of inspecting the specimen;
- wherein said laser arrangement employs mode-locking to selectively produce energy bursts having desired properties and wherein said amplifying and transmitting occurs free of supercontinuum processing.
An illuminator employed in a specimen inspection system, comprising:
- a laser arrangement comprising a laser oscillator configured to be pumped to generate coherent light;
- and
- a fiber laser amplifier arrangement comprising a plurality of fiber laser amplifiers connected in parallel and configured to amplify coherent light generated by the at least one laser oscillator and transmit amplified coherent light toward a specimen for purposes of inspecting the specimen;
- wherein said laser oscillator employs mode-locking to selectively produce energy bursts having desired properties.
Dependencies are inferred from the claim text.