Method to reduce leakage during a semi-conductor burn-in procedure

When semi-conductor circuits are fabricated to manufacture such items as a computer microprocessor or other microelectronics, a certain number of failures from the total production run is expected. Typically, these failures come early or late in the life of the circuit. shows a graph of the number of expected failures over a period of time. The curve is commonly referred to as a "bathtub curve". It shows three distinct regions: the "infant stage" , the "operational life stage" ; and the "old age stage" . During the infant stage , the number of failures maybe high and they decrease in number rapidly as the curve moves in the operational life stage . While in the operational stage , the number of failures falls to practically zero until the curve moves in the old age stage . Once in the old age stage , the number of failures begins the increase rapidly as the product's effective life expires. A method for reducing sub-threshold leakage during the burn-in procedure for a semi-conductor is disclosed. The method includes applying a back-bias voltage to the device during the burn-in procedure. The back-bias voltage increases the threshold voltage of the semi-conductor device and consequently, reduces the sub-threshold leakage current.