Measurement Of Overlay Offset In Semiconductor Processing
First Claim
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1. A system for overlay offset measurement in semiconductor manufacturing, comprising:
- a radiation source, wherein the radiation source is operable to irradiate an overlay offset measurement target;
a detector, wherein the detector is operable to detect a first reflectivity and a second reflectivity of the irradiated overlay offset measurement target; and
a calculation unit, wherein the calculation unit is operable to determine an overlay offset using the detected first and second reflectivity by determining a predetermined overlay offset amount which provides an actual offset of zero.
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Abstract
A system for overlay offset measurement in semiconductor manufacturing including a radiation source, a detector, and a calculation unit. The radiation source is operable to irradiate an overlay offset measurement target. The detector is operable to detect a first reflectivity and a second reflectivity of the irradiated overlay offset measurement target. The calculation unit is operable to determine an overlay offset using the detected first and second reflectivity by determining a predetermined overlay offset amount which provides an actual offset of zero.
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Citations
20 Claims
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1. A system for overlay offset measurement in semiconductor manufacturing, comprising:
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a radiation source, wherein the radiation source is operable to irradiate an overlay offset measurement target; a detector, wherein the detector is operable to detect a first reflectivity and a second reflectivity of the irradiated overlay offset measurement target; and a calculation unit, wherein the calculation unit is operable to determine an overlay offset using the detected first and second reflectivity by determining a predetermined overlay offset amount which provides an actual offset of zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus comprising a computer-readable medium encoded with a computer program that, when executed performs the steps of:
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receiving a first reflectivity measurement at a single irradiated wavelength; receiving a second reflectivity measurement at the single irradiated wavelength; generating a reflectivity profile which has a first axis of reflectivity at the single wavelength and a second axis of predetermined overlay offset, wherein the generating the reflectivity profile includes; plotting the first reflectivity measurement; generating a first line fitted to the plotted first reflectivity measurement; plotting the second reflectivity measurement; and generating a second line fitted to the plotted second reflectivity measurement; and calculating an overlay offset for a first layer of a semiconductor wafer and a second layer of a semiconductor wafer from the reflectivity profile. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A computer readable medium comprising computer-readable instructions to determine an overlay offset measurement in semiconductor manufacturing, the computer-readable instructions comprising instructions to:
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receive a first reflectivity measurement; receive a second reflectivity measurement; receive a third reflectivity measurement, wherein each of the first, second and third reflectivity measurements are measurements taken at a single wavelength of radiation of features on a first and second layer of a semiconductor substrate having different predetermined offsets; and calculate an overlay offset for the first layer and the second layer by determining a greatest reflectivity. - View Dependent Claims (18, 19, 20)
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Specification