Self-referencing integrated alignment sensor

An integrated optical device, comprising:

• a radiation source configured to:
• emit a multi-wavelength radiation beam toward a region of a surface of a substrate, wherein the multi-wavelength radiation beam comprises a first wavelength and a second wavelength;
• and
• a metrology system comprising a multimode dispersion waveguide structure and a detector,
• wherein the multimode dispersion waveguide structure is configured to:
• receive and propagate a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam;
• and
• receive and propagate a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam;
• wherein the metrology system is configured to measure the first and second diffracted radiation beams, and
• wherein the detector is configured to generate an electronic signal based on the measured first diffracted radiation beam and the measured second diffracted radiation beam.

A method, comprising:

• generating, by a radiation source, a multi-wavelength radiation beam having a first wavelength and a second wavelength;
• transmitting, by the radiation source, the multi-wavelength radiation beam toward a region of a surface of a substrate;
• receiving, by a multimode dispersion waveguide structure in a metrology system, a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam;
• receiving, by the multimode dispersion waveguide structure in the metrology system, a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam;
• measuring, by the metrology system, the first diffracted radiation beam;
• measuring, by the metrology system, the second diffracted radiation beam;
• and
• generating, by a detector in the metrology system, an electronic signal based on the measured first and second diffracted radiation beams.