Detecting defects in integrated circuits
OwnerGlenn Baldwin Alers, Kathleen Susan Krisch +1inventors
InventorsGlenn Baldwin Alers, Kathleen Susan Krisch, Bonnie Elaine Weir
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Abstract
The breakdown of an ultra-thin dielectric layer is detected by applying a test signal to the layer. Measurements are taken of noise signals present in the layer during the application of the test signal. At breakdown, a significant increase occurs in the amplitude of the measured noise signals. Similarly, fluctuations in quiescent current, I.sub.DDQ, (I.sub.DDQ noise signals), rather than the values of I.sub.DDQ, are utilized during testing as the basis for detecting defects in integrated circuits.
Claims11
A method of testing a multi-pin integrated-circuit chip, said method comprising the steps of
- applying a voltage source(V.sub.DD), ground and signals to some or all of the pins of said circuit during a quiescent test period to produce a current flow, I.sub.DDQ, through said circuit,
- successively measuring the values of I.sub.DDQ that flow through said circuit during the test period,
- processing said measured values to determine the amplitude of noise signals in said measured values
- and rejecting said chip being tested if the noise signal exceeds a predetermined amplitude.
Apparatus for detecting defects in an integrated circuit, said apparatus comprising
- means for applying a voltage source (V.sub.DD), ground and signals to said circuit during a quiescent test period to produce a current flow, I.sub.DDQ, through said circuit,
- means for successively measuring the values of I.sub.DDQ that flow through said circuit during the test period,
- and a master controller responsive to said measured values of I.sub.DDQ for calculating the amplitude of noise signals in said measured values.
Apparatus for testing an integrated circuit to detect defects, said apparatus comprising
- means for applying test signals to said circuit,
- means for successively measuring the values of I.sub.DDQ in said circuit in response to said applied test signals,
- means for processing said values of I.sub.DDQ to measure the amplitude of noise signals therein,
- and means for detecting whether or not said circuit contains defects based on the amplitude of said noise signals.
A method of testing an integrated circuit to detect defects, said method comprising the steps of
- applying test signals to said circuit,
- succesively measuring the values of I.sub.DDQ in said circuit in response to said applied test signals,
- processing said values of I.sub.DDQ to measure the amplitude of noise signals therein,
- and determining whether or not said circuit contains defects based on the amplitude of said noise signals.
Dependencies are inferred from the claim text.