Identifying defects in a conductive structure of a wafer, based on heat transfer therethrough
First Claim
1. A method of identifying a defect in a semiconductor wafer, the method comprising:
- applying heat to a conductive structure formed on said semiconductor wafer;
measuring a signal indicative of temperature of a portion of the conductive structure heated by conduction of the applied heat therethrough, thereby to obtain a measurement;
repeating the act of measuring at each of a number of different locations on the conductive structure, thereby to obtain a plurality of measurements; and
determining presence of the defect in the conductive structure, depending on the plurality of measurements.
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Accused Products
Abstract
Heat is applied to a conductive structure that includes one or more vias, and the temperature at or near the point of heat application is measured. The measured temperature indicates the integrity or the defectiveness of various features (e.g. vias and/or traces) in the conductive structure, near the point of heat application. Specifically, a higher temperature measurement (as compared to a measurement in a reference structure) indicates a reduced heat transfer from the point of heat application, and therefore indicates a defect. The reference structure can be in the same die as the conductive structure (e.g. to provide a baseline) or outside the die but in the same wafer (e.g. in a test structure) or outside the wafer (e.g. in a reference wafer), depending on the embodiment.
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Citations
30 Claims
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1. A method of identifying a defect in a semiconductor wafer, the method comprising:
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applying heat to a conductive structure formed on said semiconductor wafer;
measuring a signal indicative of temperature of a portion of the conductive structure heated by conduction of the applied heat therethrough, thereby to obtain a measurement;
repeating the act of measuring at each of a number of different locations on the conductive structure, thereby to obtain a plurality of measurements; and
determining presence of the defect in the conductive structure, depending on the plurality of measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for determining the quality of a conductive structure, the method comprising:
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applying heat to the conductive structure using a modulated heat source;
measuring a phase difference between temperature change of said conductive structure and modulation of said heat source; and
analyzing said phase difference to determine quality of said conductive structure. - View Dependent Claims (19, 20, 21)
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22. A method for determining the quality of a conductive structure, the method comprising:
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applying heat to the conductive structure using a modulated heat source;
varying the frequency of modulation of said heat source;
measuring a change in temperature of said conductive structure, as a function of the frequency of modulation; and
analyzing said function to determine the quality of said conductive structure. - View Dependent Claims (23, 24, 25, 26, 27, 29, 30)
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28. An apparatus for identifying a defect in a conductive structure, the apparatus comprising:
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a laser for applying heat to the conductive structure;
the sensor for measuring a signal indicative of temperature of a portion of the conductive structure heated by conduction of the applied heat therethrough; and
means for determining presence of the defect in the conductive structure, based on the measured temperature.
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Specification