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US 6,553,545 B1Granted
Process parameter extraction
AssigneeIntel Corporation
InventorsJason C. Stinson, Erik A. De La Iglesia
Life of this patent
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Abstract
An apparatus includes a test circuit, a first counter and a second counter. The test circuit is fabricated on a semiconductor substrate to generate an oscillating signal. The oscillating signal has a frequency that is dependent on at least in part a parameter of a process used to fabricate the test circuit. The first counter measures a time interval, and the second counter is coupled to the first counter to count a number of periods of the oscillating signal during the time interval.
Claims22
An apparatus comprising:
- a first circuit fabricated on a semiconductor substrate to generate a first oscillating signal that propagates through the first circuit, the first oscillating signal having a frequency dependent on at least in part a parameter of a process used to fabricate the first circuit;
- a second circuit fabricated on the semiconductor substrate near the first circuit to generate a second oscillating signal that propagates through the second circuit, a phase relationship existing between the first and second oscillating signals at adjacent points of the first and second circuits;
- and
- a third circuit coupled to the first and second circuits to regulate logical state transitions in the first and second oscillating signals to cause the phase relationship to be near a predetermined value.
1 more element
A test apparatus comprising:
- a first oscillator fabricated in a semiconductor substrate to generate a first oscillating signal, a frequency of the first oscillating signal being substantially influenced by a first process parameter of the substrate and not being substantially influenced by a second process parameter of the substrate;
- and
- a second oscillator fabricated in the semiconductor substrate to generate a second oscillating signal, a frequency of the second oscillating signal being substantially influenced by the second process parameter and not being substantially influenced by the first process parameter.
A method comprising:
- fabricating a first circuit in a semiconductor substrate;
- fabricating a second circuit in the semiconductor substrate;
- using the first circuit to generate a first oscillating signal;
- using the second circuit to generate a second oscillating signal;
- and
- regulating the generation of the first oscillating signal and regulating the generation of the second oscillating signal to establish a phase relationship between the signals, wherein the first oscillating signal has a frequency that is a function of one or more process parameters that characterize a process used to fabricate the first circuit.
3 more elements
A method comprising:
- generating a first oscillating signal, a frequency of the first oscillating signal being substantially influenced by a first process parameter of a substrate and not being substantially influenced by a second process parameter of the substrate;
- generating a second oscillating signal, a frequency of the second oscillating signal being substantially influenced by a second process parameter and not being substantially influenced by the first process parameter;
- and
- using the first and second oscillating signals to extract at least one of the first and second process parameters.
1 more element
Dependencies are inferred from the claim text.