Polarization imaging
AssigneeRudolph Technologies, Inc.
InventorsScott A. Balak, Gang Sun
Life of this patent
Estimating the term…
Abstract
Methods of monitoring critical dimensions in a semiconductor fabrication process include capturing at least one image of a first structure that has an effect on the polarization state of light reflected therefrom. For at least some of the first structure images, a value is calculated indicative of intensity of light reflected from the first structure. A critical dimension of the first structure is obtained and correlated with the calculated value. At least one image of a subsequent structure is captured. A determination is made, based at least in part on the calculated value, of a critical dimension of the subsequent structure.
Claims20
A method of monitoring critical dimensions in a semiconductor fabrication process comprising:
- a. capturing at least one image of a first structure having a geometry which has an effect on the polarization state of light reflected therefrom;
- b. calculating, for each of the at least one images of the first structure a value that is indicative of an intensity of the light reflected from the first structure;
- c. obtaining a critical dimension of the first structure;
- d. correlating a critical dimension of the first structure with the calculated value;
- e. capturing at least one image of a subsequent structure;
- and,
- f. determining, based at least in part on the calculated value, a critical dimension of the subsequent structure.
A method of inspecting a substrate, comprising:
- capturing an image of the substrate;
- accessing a model indicative of a calibration substrate having a number of patterns formed thereon;
- comparing pixel characteristics of the image of the substrate with pixel characteristics of the model to identify differences between the image and the model;
- and
- determining whether the differences between the image and the model exceed a predetermined threshold.
A substrate inspection system, comprising:
- an optical sensor adapted to capture an image of the substrate;
- a computer adapted to access a model indicative of a calibration substrate having a number of patterns formed thereon, compare pixel characteristics of the image of the substrate with pixel characteristics of the model to identify differences between the image and the model and determine whether the differences between the image and the model exceed a predetermined threshold.
Dependencies are inferred from the claim text.