Title:
レーザ光源における光電磁センサの較正
Document Type and Number:
Japanese Patent JP6820747
Kind Code:
B2
Abstract:
In a laser-produced plasma (LPP) extreme ultraviolet (EUV) system, laser pulses are used to produce EUV light. To determine the energy of individual laser pulses, a photoelectromagnetic (PEM) detector is calibrated to a power meter using a calibration coefficient. When measuring a unitary laser beam comprising pulses of a single wavelength, the calibration coefficient is calculated based on a burst of the pulses. A combined laser beam has main pulses of a first wavelength alternating with pre-pulses pulses of a second wavelength. To calculate the energy of the main pulses in the combined laser beam, the calibration coefficient calculated for a unitary laser beam of the main pulses is used. To calculate the energy of the pre-pulses in the combined laser beam, a new calibration coefficient is calculated. When the calculated energy values drift beyond a pre-defined threshold, the calibration coefficients are recalculated.
Inventors:
Ryu, Ron
Lafac, Robert, Jay.
Myers, David, W.
Bergstedt, Robert, A.
Mackenzie, Paul, A.
Lafac, Robert, Jay.
Myers, David, W.
Bergstedt, Robert, A.
Mackenzie, Paul, A.
Application Number:
JP2016571417A
Publication Date:
January 27, 2021
Filing Date:
June 18, 2015
Export Citation:
Assignee:
AS M Netherlands B.V.
International Classes:
G03F7/20; H01S3/00; H05G2/00
Domestic Patent References:
| JP6196789A | ||||
| JP6237028A | ||||
| JP2010161092A |
Foreign References:
| WO2014039221A1 | ||||
| US20060007432 | ||||
| KR101024559B1 |
Attorney, Agent or Firm:
Yoshiyuki Inaba
Toshifumi Onuki
Akihiko Eguchi
Kazuhiko Naito
Toshifumi Onuki
Akihiko Eguchi
Kazuhiko Naito