Electromigration Lifetest System
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Publishing Venue
IBM
Related People
Double, GP: AUTHOR [+2]
Abstract
This tester automatically stresses, detects and records in a unique way the elapsed time until fast intermittent opens or permanent opens, which are probably due to electromigration, occur in semiconductor devices containing thin metal stripes. Devices under test (DUT's) are individually protected against large transient voltage spikes that result from fast breaks in the metal stripes. Continuous monitoring rather than scanning is used to detect failures.
Electromigration Lifetest System
This tester automatically stresses, detects and records in a unique way the elapsed time until fast intermittent opens or permanent opens, which are probably due to electromigration, occur in semiconductor devices containing thin metal stripes. Devices under test (DUT's) are individually protected against large transient voltage spikes that result from fast breaks in the metal stripes. Continuous monitoring rather than scanning is used to detect failures.
Each device under test (DUT) is placed at position 10. When a DUT develops an open for longer than a microsecond, the increased drop across R1 and R2 triggers the silicon controlled rectifier (SCR) 11 and a negative pulse is sent through capacitor 12 to matrix M. Zener diode 14 suppresses any high- voltage transients that begin to develop across the DUT. Diodes 15, produce a voltage drop greater than the drop across the SCR so that, in the event the failed DUT heals, the turned on SCR will keep the DUT permanently latched out of the circuit. Current is controlled by transistor 16 in series with each line of twelve DUT's. There are 100 of such lines.
Matrix M consists of 100 pairs of SCR's. A negative pulse entering this matrix from a particular line 1, of the 100 lines of DUT's, activates a pair of SCR's 17 which correspond to line 1. One of the SCR pair 17 activates a "units" wheel in the printer and the other SCR in the pair activates a "tens" wheel in the printer. A timer has...