Noninvasive optical method for measuring internal switching and other dynamic parameters of CMOS circuits
First Claim
1. A method for measuring the internal timing of integrated circuits comprising:
- a. obtaining periodic optical emissions from an integrated circuit operating with time-varying internal currents, andb. time resolving said emissions by photon timing to provide information about said integrated circuit.
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Abstract
Intrinsic, transient optical emission from a CMOS integrated circuit is used to determine the internal switching of such a circuit including the temporal evolution of its logic states. By joining an appropriate optical microscope to a suitable, photon counting, multichannel optical detector which is capable of time resolution better than 100 psec, and a spatial resolution of better than 60 microns, full temporal information, including the relative phases of switching events, can be obtained from many devices in a circuit simultaneously. The time and spatial resolution are suitable for analyzing timing problems in present and future sub-micron-scale CMOS integrated circuits with switching speeds up to at least 10 GHz. The invention comprises a combination of an optical microscope and a detector capable of providing optical waveforms and/or spatial images of the light emitted during electrical switching by the individual devices which comprise an integrated circuit. The microscope and detector are combined such that an image of all or a portion of an integrated circuit under test is provided by the microscope to the detector. The spatial and temporal information from the detector is used to determine switching times and other dynamic information about the devices in the circuit.
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Citations
31 Claims
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1. A method for measuring the internal timing of integrated circuits comprising:
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a. obtaining periodic optical emissions from an integrated circuit operating with time-varying internal currents, and b. time resolving said emissions by photon timing to provide information about said integrated circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A device for measuring the internal timing of integrated circuits comprising:
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a. means for obtaining periodic emissions from an integrated circuit operating with time varying internal currents, and b. means for time resolving said emissions by photon timing to provide information about said integrated circuit. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An optical method for determining the electrical state of an integrated circuit, and the temporal evolution of said electrical state for a circuit undergoing switching transitions, the method comprising:
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a. obtaining one or more optical waveforms corresponding to optical emissions generated by time varying internal currents in the integrated circuit, and b. analyzing said one or more optical waveforms to identify and characterize the electrical waveforms associated with said currents. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A device for determining the electrical state of an integrated circuit, and the temporal evolution of said electrical state for a circuit undergoing switching transitions, the device comprising:
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a. means for obtaining one or more optical waveforms corresponding to optical emissions generated by time varying internal currents in the integrated circuit, and b. means for analyzing said one or more optical waveforms to identify and characterize the electrical waveforms associated with said currents. - View Dependent Claims (21, 22, 23, 24, 25)
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26. An optical method for determining the logic state of a CMOS integrated circuit, and the temporal evolution of said logic state for a circuit undergoing switching transitions during normal operation comprising,
a. obtaining optical pulses generated by switching transitions in a CMOS integrated circuit, b. analyzing the optical pulses to identify 0-1 and 1-0 transitions, c. assigning 1-0 and 0-1 transitions at the outputs of individual gates of the circuit.
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28. A device for determining a logic state of a CMOS integrated circuit at an instant of time as the circuit undergoes information processing comprising:
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a. a means for measuring the individual optical pulses generated by discrete switching transitions in said circuit, b. a means for analyzing the relative intensities of the switching induced optical pulses observed from the individual gates of said circuits to determine the initial and final states of each switching transition, c. a means for assigning the 1-0 and 0-1 transitions at the outputs of individual gates of the said circuit. - View Dependent Claims (29)
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30. A method for measuring the number of switching events occurring in any interval of time and any area of the circuit in CMOS integrated circuits comprising:
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a. obtaining optical emission pulses coincident with switching transitions from a CMOS integrated circuit and b. analyzing said emission to obtain a spatial and temporal density of switching activity in the said integrated circuit.
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31. A device for measuring the number of switching events occurring in any interval of time and any area of the circuit in CMOS integrated circuits comprising:
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a. means for measuring the optical emission pulses coincident with switching transitions from a CMOS integrated circuit, b. a means for determining a number of switching induced optical pulses per unit area and time interval, and displaying said densities.
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Specification