Wafer metrology apparatus and method
View Patent ↗This invention is an apparatus for imaging metrology, which in particular embodiments may be integrated with a processor station such that a metrology station is apart from but coupled to a process station. The metrology station is provided with a first imaging camera with a first field of view containing the measurement region. Alternate embodiments include a second imaging camera with a second field of view. Preferred embodiments comprise a broadband ultraviolet light source, although other embodiments may have a visible or near infrared light source of broad or narrow optical bandwidth. Embodiments including a broad bandwidth source typically include a spectrograph, or an imaging spectrograph. Particular embodiments may include curved, reflective optics or a measurement region wetted by a liquid. In a typical embodiment, the metrology station and the measurement region are configured to have 4 degrees of freedom of movement relative to each other.
1. An apparatus for evaluating a predetermined region of a sample, said apparatus comprising:
a solid state light source for illuminating the sample;
a first camera for capturing a first image of the sample, illuminated by the solid state light source, in order to identify a location of the predetermined region to be measured;
a second light source for illuminating the predetermined region;
a detector for measuring light from the second light source that is reflected from the predetermined region; and
a second camera for capturing a second image of the sample in order to identify the location of the predetermined region to be measured.
2. An apparatus as recited in claim 1 , wherein the second camera has a smaller field of view than the first camera.
3. An apparatus as recited in claim 1 , wherein the second camera captures a second image of the sample while the sample is illuminated by the second light source.