| 摘要 |
A bandwidth meter method and apparatus for measuring the bandwidth of a spectrum of light emitted from a laser input to the bandwidth meter is disclosed, which may comprise an optical bandwidth monitor providing a first output representative of a first parameter which is indicative of the bandwidth of the light emitted from the laser and a second output representative of a second parameter which is indicative of the bandwidth of the light emitted from the laser; and, an actual bandwidth calculation apparatus utilizing the first output and the second output as part of a multivariable equation employing predetermined calibration variables specific to the optical bandwidth monitor, to calculate 10 an actual bandwidth parameter. The actual bandwidth parameter may comprise a spectrum full width at some percent of the maximum within the full width of the spectrum of light emitted from the laser ("F)WXM") or a width between two points on the spectrum enclosing some percentage of the energy of the full spectrum of the spectrum of light emitted from the laser ("EX"). The bandwidth monitor may comprise an etalon and the first output is representative of at least one of a width of a fringe of an optical output of the etalon at FWXM or a width between two points on the spectrum enclosing some percentage of the energy of the full spectrum of light emitted from the laser ("EX"') and the second output is representative of at least one of a second FWX"M or EX"', where X<>XX" and X'<>X"'. The precomputed calibration variables may be derived from a measurement of the value of the actual bandwidth parameter utilizing a trusted standard, correlated to the occurrence of the first and second outputs for a calibration spectrum. The value of the actual bandwidth parameter is calculated from the equation: estimated actual BW parameter = K*wl + L*w2 + M, where wl = the first measured output representative of FWXM or EX' and w2 is the second measured output representative of FWX"M or EX"'. The apparatus and method may be implemented in a laser lithography light source and/or in an integrated circuit lithography tool. |
