Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2000-11-02
2004-04-06
Nguyen, Vinh P. (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S1540PB
Reexamination Certificate
active
06717428
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to circuit test procedures and, more particularly, to techniques for detecting defects in circuits at a macroscopic level.
BACKGROUND OF THE INVENTION
As part of the digital circuit manufacturing process, tests are commonly performed to detect defects within the fabricated circuits. Two types of defects that can occur in digital circuits are “stuck at” defects and delay defects. A “stuck at” defect is presently in a circuit when a portion of the circuit that is supposed to transition between logic values (e.g., from logic zero to logic one, and vice versa) during circuit operation does not transition. That is, the circuit portion is “stuck at” either a logic one value or a logic zero value. A delay defect is present when a circuit portion can transition between logic values, but the transition occurs either before or after it is supposed to. As can be appreciated, both types of defect can have a devastating effect on circuit performance and circuits having such defects should normally be identified and discarded. Delay defects are generally detected by operating a circuit at full speed while monitoring the transition activity at selected nodes in the circuit. A known test sequence is applied to the circuitry that should generate transitions at the selectable nodes within predetermined time windows. If one or more of the transitions occur outside of the corresponding time window, the circuit is deemed to have a delay defect.
As is well known, the speed at which digital circuits operate is continually increasing. Thus, to continue to perform defect tests at full operational speed in the future, higher performance test equipment will be needed. However, higher performance test equipment is typically expensive and can significantly increase the overall cost of the circuit manufacturing process. As can be appreciated, it is generally desirable to keep manufacturing costs down to increase the competitiveness of manufactured products in the marketplace by minimizing price to the consumer.
Therefore, there is a need for a method and apparatus for detecting defects within manufactured circuitry that does not require full speed operation of a device under test.
REFERENCES:
patent: 4415852 (1983-11-01), Ashley et al.
patent: 5179344 (1993-01-01), Najle et al.
patent: 5671147 (1997-09-01), McKim et al.
patent: 5949798 (1999-09-01), Sakaguchi
patent: 6043662 (2000-03-01), Alers et al.
patent: 6246248 (2001-06-01), Yamagishi
Baker, K., et al., “Defect-Based Delay Testing of Resistive Vias-Contacts a Critical Evaluation”,ITC International Test Conference, IEEE, 467-476, (1999).
Cole, E.I., et al., “Transient Power Supply Voltage (vDDT) Analysis for Detecting IC Defects”,International Test Conference, IEEE, 23-31, (1997).
Germida, A., et al., “Defect Detection using Power Supply Transient Signal Analysis”,ITC International Test Conference, IEEE, 67-76, (1999).
Gielen, G., et al., “Fault Detection and Input Stimulus Determination for the Testing of Analog Integrated Circuits Based on Power-Supply Current Monitoring.”, ACM, 495-498, (1994).
Jiang, W., et al., “Statistical Threshold Formulation For Dynamic Idd Test”,ITC International Test Conference, IEEE, 57-66, (1999).
Kruseman, B., et al., “Transient Current Testing of 0.25&mgr;m CMOS Devices”,ITC International Test Conference, IEEE, 47-56, (1999).
Nguyen Vinh P.
Schwegman Lundberg Woessner & Kluth P.A.
LandOfFree
Method and apparatus for detecting defects in a circuit... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for detecting defects in a circuit..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for detecting defects in a circuit... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3263752