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An optical measurement system and wafer processing tool for correcting systematic errors in which a first diffraction spectrum is measured from a standard substrate including a layer having a known refractive index and a known extinction coefficient by exposing the standard substrate to a spectrum o

An optical measurement system and wafer processing tool for correcting systematic errors in which a first diffraction spectrum is measured from a standard substrate including a layer having a known refractive index and a known extinction coefficient by exposing the standard substrate to a spectrum of electromagnetic energy. A tool-perfect diffraction spectrum is calculated for the standard substrate. A hardware systematic error is calculated by comparing the measured diffraction spectrum to the calculated tool-perfect diffraction spectrum. A second diffraction spectrum from a workpiece is measured by exposing the workpiece to the spectrum of electromagnetic energy, and the measured second diffraction spectrum is corrected based on the calculated hardware systematic error to obtain a corrected diffraction spectrum.

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The invention claimed is: 1. An optical measurement system comprising: an optical measurement tool configured to expose a substrate to a spectrum of energy; the optical measurement tool including a detection unit configured to measure, a first diffraction spectrum from a standard substrate includin

The invention claimed is: 1. An optical measurement system comprising: an optical measurement tool configured to expose a substrate to a spectrum of energy; the optical measurement tool including a detection unit configured to measure, a first diffraction spectrum from a standard substrate including a layer having a known refractive index and extinction coefficient by exposing the standard substrate to the spectrum of electromagnetic energy, and a second diffraction spectrum from a workpiece by exposing the workpiece to the spectrum of electromagnetic energy; a computational unit configured to calculate a tool-perfect diffraction spectrum for the standard substrate, compare the measured diffraction spectrum to the calculated tool-perfect diffraction spectrum to generate a calculated a hardware systematic error, and correct the measured second diffraction spectrum based on the calculated hardware systematic error to obtain a corrected diffraction spectrum. 2. The system of claim 1, wherein the computational unit is configured to: determine a depolarization factor based on the standard substrate. 3. The system of claim 1, wherein the computational unit is configured to: compare the corrected diffraction spectrum to a spectrum library to determining an interim spectrum match; and modify the corrected diffraction spectrum using the depolarization factor to form an iterate diffraction spectrum. 4. The system of claim 1, wherein the computational unit is configured to determine physical properties of the workpiece. 5. The system of claim 1, wherein the computational unit is configured to: measure the first diffraction spectrum by analyzing data from a psi-delta data set; calculate the tool-perfect diffraction spectrum by calculating a tool-perfect psi-delta data set; and calculate the hardware systematic error by comparing the measured psi-delta data set to the tool-perfect psi-delta data set. 6. The system of claim 1, wherein the optical measurement tool comprises at least one of an ellipsometric tool and a reflectrometric tool. 7. The system of claim 6, further comprising: plural optical measurement tools connected to a wafer processing tool as an integrated optical metrology system. 8. The system of claim 1, wherein the optical measurement tool comprises an optical profilometry tool. 9. The system of claim 8, wherein the optical profilometry tool is configured to determine at least one of a sidewall angle, a film thickness, a column width, and a space between a plurality of features on the workpiece. 10. The system of claim 1, wherein the optical measurement tool comprises a detector to analyze diffracted light for various wavelengths. 11. The system of claim 10, wherein the detector is configured to measure wavelengths of diffracted light from 175 nm to 33 μm. 12. The system of claim 10, wherein the detector is configured to measure angles of diffracted light ranging from 22.5° to 70° of normal. 13. The system of claim 10, wherein the optical measurement tool is configured to apply light incident to the workpiece at angles from 0° to 90° of normal. 14. The system of claim 10, wherein the optical measurement tool comprises at least one of a single wavelength source and a broad wavelength source. 15. The system of claim 10, wherein the optical measurement tool comprises multiple single wavelength sources. 16. A semiconductor wafer processing tool comprising: a wafer handler which exchanges a substrate between plural wafer processing units; and an optical measurement system associated with the wafer handler and including, an optical measurement tool configured to expose the substrate to a spectrum of energy, and the optical measurement tool including a detection unit configured to measure, a first diffraction spectrum from a standard substrate including a layer having a known refractive index and extinction coefficient by exposing the standard substrate to the spectrum of electromagnetic energy, and a second diffraction spectrum from a workpiece by exposing the workpiece to the spectrum of electromagnetic energy, and a computational unit configured to calculate a tool-perfect diffraction spectrum for the standard substrate, compare the measured diffraction spectrum to the calculated tool-perfect diffraction spectrum to generate a calculated hardware systematic error, and correct the measured second diffraction spectrum based on the calculated hardware systematic error to obtain a corrected diffraction spectrum. 17. The wafer processing tool of claim 16, wherein the computational unit is configured to determine a depolarization factor based on the standard substrate. 18. The wafer processing tool of claim 17, wherein the computational unit is configured to: compare the corrected diffraction spectrum to a spectrum library to determining an interim spectrum match; and modify the corrected diffraction spectrum using the depolarization factor to form an iterate diffraction spectrum. 19. The wafer processing tool of claim 16, wherein the computational unit is configured to determine physical properties of the workpiece. 20. The wafer processing tool of claim 16, wherein the computational unit is configured to: measure the first diffraction spectrum by analyzing data from a psi-delta data set; calculate the tool-perfect diffraction spectrum by calculating a tool-perfect psi-delta data set; and calculate the hardware systematic error by comparing the measured psi-delta data set to the tool-perfect psi-delta data set. 21. The wafer processing tool of claim 16, wherein the optical measurement tool comprises at least one of an ellipsometric tool and a reflectrometric tool. 22. The wafer processing tool of claim 16, wherein the optical measurement tool comprises an optical profilometry tool. 23. The wafer processing tool of claim 22, wherein the optical profilometry tool is configured to determine at least one of a sidewall angle, a film thickness, a column width, and a space between a plurality of features on the workpiece. 24. The wafer processing tool of claim 22, further comprising: plural optical measurement tools connected to a wafer processing tool as an integrated optical metrology system. 25. The wafer processing tool of claim 16, wherein the optical measurement tool comprises a detector to analyze diffracted light for various wavelengths. 26. The wafer processing tool of claim 25, wherein the detector is configured to measure wavelengths of diffracted light from 175 nm to 33 μm. 27. The wafer processing tool of claim 25, wherein the detector is configured to measure angles of diffracted light ranging from 22.5° to 70° of normal. 28. The wafer processing tool of claim 16, wherein the optical measurement tool is configured to apply light incident to the workpiece at angles from 0° to 90° of normal. 29. The wafer processing tool of claim 16, wherein the optical measurement tool comprises at least one of a single wavelength source and a broad wavelength source. 30. The wafer processing tool of claim 16, wherein the optical measurement tool comprises multiple single wavelength sources.