International Business Machines Corporation

Other

Snigdha Ghoshal

Steven Alan Cordes

Uttam Shymalindu Ghoshal

James Patrick Doyle

Matthew J Farinelli

Chandler Todd McDowell

Li Shi

David R DiMilia

Uttam Shyamalindu Ghoshal

A scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. In other forms, the invention relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.

Scanning heat flow probe

A method of fabricating a scanning heat flow probe for making quantitative measurements of heat flow through a device under test is provided. In one embodiment the scanning heat flow probe includes an electric current conductor in a cantilever beam connected to a probe tip and coupled to two voltmeter leads. The probe also includes two thermocouple junctions in the cantilever beam electrically isolated from the electric current conductor and the two voltmeter leads. Heat flow is derived quantitatively using only voltage and current measurements. The invention also relates to the calibration of scanning heat flow probes through a method involving interconnected probes, and relates to the minimization of heat flow measurement uncertainty by probe structure design practices.

Scanning heat flow probe and the method of fabricating the same

A system for measuring magnetic fields produced by an integrated circuit device-under-test includes a clock generator configured to generate a clock signal, a delay circuit configured to generate a delayed clock signal having a known delay relative to the clock signal, a pulse generator configured to generate a series of pulses having a frequency corresponding to a frequency of the clock signal, the pulses of the series of pulses being offset from the clock signal by the known delay, and a sensor having a property that varies in response to a magnetic field at the sensor. A sampling circuit connected to the sensor and to the pulse generator is configured to measure the property of the sensor at times corresponding to pulses of the series of pulses, and to produce a sampling signal having, for each pulse, a first value (e.g., a logical one) when the property of the sensor indicates that the magnetic field at the sensor exceeds a threshold amount and a second value (e.g., a logical zero) when the property of the sensor indicates that the magnetic field at the sensor does not exceed the threshold amount. A digital filter is connected to the sampling circuit and configured to produce a first indicator when a number of first values in the sampling signal exceeds a predetermined amount and to produce a second indicator when a number of first values in the sampling signal does not exceed a predetermined amount. A counter connected to the digital filter is configured to increment an output signal in response to one of the first and second indicators and to decrement the output signal in response the other of the first and second indicators. A feedback loop including a digital-to-analog converter is connected to the counter and configured to produce an electrical signal proportional to the output signal, the electrical signal causing the feedback loop to produce a feedback magnetic field in proportion to the output signal, the feedback magnetic field being a component of the magnetic field at the sensor. The output signal of the counter corresponds to a magnetic field produced by the device-under-test.

High speed magnetic flux sampling

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Austin, TX, United States of America

Snigdha Ghoshal