Monitored burn-in system
AssigneeNEC Corporation
InventorEiki Matsuoka
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Abstract
The invention relates to a monitored burn-in system for operating a group of semiconductor devices such as ICs under an accelerated aging condition. To automatically and appropriately determine the burn-in duration, the disclosed system includes a counting means to count a cumulative number of failed devices at predetermined time intervals, a computing means to compute a cumulative failure rate of the devices at the same time intervals and further compute an increment of the cumulative failure rate during each of the time intervals, and a comparison and control means to compare the computed increment of the cumulative failure rate with a predetermined reference increment of cumulative failure rate and produce a command signal to terminate the burn-in procedure when the computed increment is not greater than the reference increment.
Claims4
A monitored burn-in system for screening a group of semiconductor devices kept in a burn-in chamber, the system comprising:
- power and signal supplying means for supplying power to said burn-in chamber to control the burn-in temperature in said chamber and supplying operational current and driving input signals to said semiconductor devices in said chamber;
- monitoring means for monitoring the manner of operation of each of said devices in said chamber;
- counting means for counting a cumulative number of failed devices among said devices in said chamber at predetermined time intervals;
- computing means for computing a cumulative failure rate of said devices in said chamber at said time intervals each time based on said cumulative number counted by said counting means and producing a feedback signal representative of an increment of the cumulative failure rate during each of said time intervals;
- and
- control means for comparing said increment of the cumulative failure rate represented by said feedback signal with a predetermined reference increment of cumulative failure rate and commanding said power and signal supplying means to terminate the power and signal supplying operation to thereby automatically terminate the burn-in procedure when said increment of the cumulative failure rate represented by said feedback signal becomes equal to said reference increment of cumulative failure rate or less.
Dependencies are inferred from the claim text.