3D microscope including insertable components to provide multiple imaging and measurement capabilities
A three-dimensional (3D) microscope includes various insertable components that facilitate multiple imaging and measurement capabilities. These capabilities include Nomarski imaging, polarized light imaging, quantitative differential interference contrast (q-DIC) imaging, motorized polarized light imaging, phase-shifting interferometry (PSI), and vertical-scanning interferometry (VSI).
1. A method of 3D imaging or measuring a sample, the sample including a plurality of surface features with different vertical levels, the method comprising:
varying a relative distance between the sample and an objective lens at a plurality of predetermined steps;
at each of a first set of predetermined steps of the plurality of predetermined steps:
projecting an image of a patterned article onto a focal plane of the objective lens; and
capturing a first image with a pattern associated with the patterned article and the sample, and storing the first image in a first image array; and
at each of a second set of predetermined steps of the plurality of predetermined steps:
capturing a second image of the sample without the pattern associated with the patterned article, and storing the second image in a second image array, wherein the second set of predetermined steps has a different number of steps than the first set of predetermined steps; and
generating a 3D image of the sample or measuring the sample by analyzing the first and second images.
2. The method of claim 1 , wherein a number of the second set of predetermined steps is less than that of the first set of predetermined steps.
3. The method of claim 2 , wherein first set of predetermined steps includes all of the plurality of predetermined steps, and the second set of predetermined steps includes less than all of the plurality of predetermined steps.
4. The method of claim 2 , wherein each of the second set of predetermined steps coincides with a corresponding one of the first set of predetermined steps.
5. The method of claim 1 , wherein the first and second sets of predetermined steps are allocated to vertical regions, including a first vertical region between a first pair of specific vertical levels and a second vertical region between a second pair of specific vertical levels, wherein none of the plurality of predetermined steps exist between the first and second vertical regions.
6. The method of claim 5 , wherein at least one of the first and second sets of predetermined steps has finer step sizes in the first vertical region than in the second vertical region.
7. The method of claim 5 , wherein the first vertical region corresponds with a first one of the plurality of surface features and the second vertical region corresponds with a second one of the plurality of surface features.
8. The method of claim 5 , wherein the first and second sets of predetermined steps are entirely allocated to vertical regions associated with the plurality of surface features.
9. The method of claim 8 , wherein the first and second sets of predetermined steps are entirely allocated to vertical regions associated with top, middle and bottom surfaces of the sample.
10. The method of claim 1 , wherein the first and second sets of predetermined steps skip predetermined vertical levels of the sample.
11. The method of claim 1 , wherein at least one of the first and second sets of predetermined steps has finer step sizes at specific vertical levels.
12. The method of claim 1 , further comprising:
using the first images in the first image array to generate a depth profile, and
using the second images in the second image array to generate an image intensity.
13. The method of claim 1 , wherein the plurality of predetermined steps specify a one-pass scan of the sample.
14. The method of claim 1 , wherein the plurality of pre-determined steps specify both a downward scan of the sample and an upward scan of the sample.