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US 5,854,563 AGranted
Process control monitoring system and method therefor
AssigneeVLSI Technology, Inc.
InventorsSung-Hun Oh, Richard Ulmer
Life of this patent
Estimating the term…
Abstract
The present invention relates to a process control monitoring system and method. The system and method uses current comparator circuits for monitoring process changes. Process sensitive current sources are compared with weighted reference current sources in a manner that each output of the current comparators demonstrates the inequality of the current sources. By setting the weighted reference current sources properly, the outputs of the current comparators may be used to locate the process corner of the fabricated integrated circuit.
Claims39
A process control monitoring system comprising, in combination:
- reference current source means for generating a stable reference current;
- a plurality of differently weighted reference current source means coupled to said reference current source means for receiving said stable reference current and for generating a plurality of differently weighted reference currents;
- a plurality of current comparator means each of said plurality of current comparator means having a variable input signal which varies with at least one of temperature, power supply voltage, and process changes and each of said plurality of current comparator means being individually coupled to a separate one of said plurality of differently weighted reference current source means for providing an output voltage corresponding to said differently weighted reference current source means coupled thereto and said variable input signal;
- and
- wherein each of said plurality of current comparator means is of a same process corner thus producing said output voltage for process control monitoring and correction.
2 more elements
A process control monitoring system comprising, in combination:
- reference current source means for generating a stable reference current;
- a plurality of nominal current source means coupled to said reference current source means for receiving said stable reference current and for generating a plurality of reference currents;
- a plurality of differently weighted current comparator means each of said plurality of differently weighted current comparator means having a variable input signal which varies with at least one of temperature, power supply voltage and process changes and which is individually coupled to a separate one of said plurality of nominal current source means for providing an output voltage corresponding to said nominal current source means coupled thereto and said variable input signal;
- and
- wherein each of said plurality of differently weighted current comparator means is of a same process corner thus producing said output voltage for process control monitoring and correction.
2 more elements
A process control monitoring method comprising the steps of:
- generating a stable reference current from a reference current source;
- providing a plurality of differently weighted reference current source means coupled to said reference current source for receiving said stable reference current and for generating a plurality of differently weighted reference currents;
- providing a plurality of current comparator means each of said plurality of current comparator means having a variable input signal which varies with at least one of temperature, power supply voltage, and process changes and each of said plurality of current comparator means being individually coupled to a separate one of said plurality of differently weighted reference current source means for providing an output voltage corresponding to said weighted reference current source means coupled thereto and said variable input signal;
- and
- wherein each of said plurality of current comparator means is of a same process corner thus producing said output voltage for process control monitoring and correction.
2 more elements
A process control monitoring method comprising the step of:
- generating a stable reference current from a reference current source;
- providing a plurality of nominal current source means coupled to said reference current source for receiving said stable reference current and for generating a plurality of reference currents;
- providing a plurality of differently weighted current comparator means each of said plurality of differently weighted current comparator means having a variable input signal which varies with at least one of temperature, power supply voltage, and process changes and each of said plurality of differently weighted current comparator means being individually coupled to a separate one of said plurality of nominal current source means for providing an output voltage corresponding to said nominal current source means coupled thereto and said variable input signal;
- and
- wherein each of said plurality of differently weighted current comparator means is of a same process corner thus producing said output voltage for process control monitoring and correction.
2 more elements
Dependencies are inferred from the claim text.