Abstract: An alignment sensor apparatus includes an illumination system, a first optical system, a second optical system, a detector system, and a processor. The illumination system is configured to transmit an illumination beam along an illumination path. The first optical system is configured to transmit the illumination beam toward a diffraction target on a substrate. The second optical system includes a first polarizing optic configured to separate and transmit an irradiance distribution. The detector system is configured to measure a center of gravity of the diffraction target based on the irradiance distribution outputted from a first polarization branch and a second polarization branch. The processor is configured to measure a shift in the center of gravity of the diffraction target caused by an asymmetry variation in the diffraction target and determine a sensor response function of the alignment sensor apparatus based on the center of gravity shift.

Abstract: An alignment sensor apparatus includes an illumination system, a first optical system, a second optical system, a detector system, and a processor. The illumination system is configured to transmit an illumination beam along an illumination path. The first optical system is configured to transmit the illumination beam toward a diffraction target on a substrate. The second optical system includes a first polarizing optic configured to separate and transmit an irradiance distribution. The detector system is configured to measure a center of gravity of the diffraction target based on the irradiance distribution outputted from a first polarization branch and a second polarization branch. The processor is configured to measure a shift in the center of gravity of the diffraction target caused by an asymmetry variation in the diffraction target and determine a sensor response function of the alignment sensor apparatus based on the center of gravity shift.

Abstract: A lithographic cluster includes a track unit and a lithographic apparatus. The lithographic apparatus includes an alignment sensor and at least one controller. The track unit is configured to process a first lot and a second lot. The lithographic apparatus is operatively coupled to the track unit. The alignment sensor is configured to measure an alignment of at least one alignment mark type of a calibration wafer. At least one controller is configured to determine a correction set for calibrating the lithographic apparatus based on the measured alignment of the at least one alignment mark type and apply first and second weight corrections to the correction set for processing the first and second lots, respectively, such that overlay drifts or jumps during processing the first and second lots are mitigated.

Abstract: A lithographic cluster includes a track unit and a lithographic apparatus. The lithographic apparatus includes an alignment sensor and at least one controller. The track unit is configured to process a first lot and a second lot. The lithographic apparatus is operatively coupled to the track unit. The alignment sensor is configured to measure an alignment of at least one alignment mark type of a calibration wafer. At least one controller is configured to determine a correction set for calibrating the lithographic apparatus based on the measured alignment of the at least one alignment mark type and apply first and second weight corrections to the correction set for processing the first and second lots, respectively, such that overlay drifts or jumps during processing the first and second lots are mitigated.

Abstract: An alignment system obtains the characteristics of the light coming back from a wafer stack. A beam analyzer measures changes in wavelength, polarization, and beam profile. This measured information allows for in-line process variation corrections. The correction provides optical monitoring of individual mark stack variations, and in turn provides information to reduce individual mark process variation-induced accuracy error.

Abstract: An alignment system obtains the characteristics of the light coming back from a wafer stack. A beam analyzer measures changes in wavelength, polarization, and beam profile. This measured information allows for in-line process variation corrections. The correction provides optical monitoring of individual mark stack variations, and in turn provides information to reduce individual mark process variation-induced accuracy error.