Monitored burn-in system

Claim 1

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.