Hybrid 3D inspection system

An optical inspection apparatus, comprising:

• an interferometer module, which is configured to direct a beam of coherent light along a first optical axis to impinge on an area under inspection, to receive the beam reflected from the area, and to produce a first image of interference fringes produced by combining the reflected beam with a reference beam;
• a triangulation module, comprising a projector configured to project a pattern of structured light along a second optical axis to impinge on the area under inspection;
• at least one image sensor configured to capture the first image of the interference fringes and a second image of the pattern that is reflected from the area under inspection;
• a scanning mechanism configured to translate the first and second optical axes in mutual registration across the area under inspection;
• and
• a processor configured to drive the scanning mechanism so as to cause the first and second optical axes to impinge in succession on locations in the area under inspection, to process the first and second images in order to extract respective first and second three-dimensional (3D) measurements of the area under inspection, and to combine the first and second 3D measurements in order to generate a 3D map of the area.

A method for optical inspection, comprising:

• directing a beam of coherent light toward an area under inspection, receiving the beam reflected from the area, and capturing a first image of interference fringes produced by combining the reflected beam with a reference beam;
• projecting a pattern of structured light onto the area under inspection, and capturing a second image of the pattern that is reflected from the area under inspection;
• positioning beam combiner optics to direct the beam of coherent light along a first optical axis to impinge on a location on the area under inspection at a first angle of incidence, and to direct the projected pattern to impinge on the location along a second optical axis, at a second angle of incidence that is different from the first angle of incidence;
• processing the first and second images in order to extract respective first and second three-dimensional (3D) measurements of the area under inspection;
• and
• combining the first and second 3D measurements in order to generate a 3D map of the area.

A method for optical inspection, comprising:

• directing a beam of coherent light along a first optical axis to impinge an area under inspection, receiving the beam reflected from the area, and capturing a first image of interference fringes produced by combining the reflected beam with a reference beam;
• projecting a pattern of structured light along a second optical axis to impinge the area under inspection, and capturing a second image of the pattern that is reflected from the area under inspection;
• translating the first and second optical axes in mutual registration across the area under inspection so as to cause the first and second optical axes to impinge in succession on locations in the area under inspection;
• processing the first and second images in order to extract respective first and second three-dimensional (3D) measurements of the area under inspection;
• and
• combining the first and second 3D measurements in order to generate a 3D map of the area.