Optical measurement of the IC photomask pattern area.
Optical measurement of the integrated-circuit (IC) photomask pattern area is performed. The relationship between aperture dimension and diverging angle of diffracted light is numerically estimated after scalar electromagnetic theory, and the expected measurement error is derived. The experimental measurement of the pattern area is made using typical IC photomasks. In the experiment, converging optics and an integrating sphere are suitably arranged so as to minimize the error introduced by omitting the higher-order diffraction. Some of the measured data are compared with values which are calculated from the IC layout design data, and they are found to be in good agreement.
Karatsu
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