Chip torque testing
Abstract
Abstract METHOD AND APPARATUS ARE DISCLOSED FOR TORQUE TESTING A SEMICONDUCTOR DEVICE. THE DEVICE IS OF THE TYPE IN WHICH A SEMICONDUCTOR WAFER OR CHIP IS MOUNTED ON A SUBSTRATE BY A PLURALITY OF SOLDER COLUMNS SPACED AROUND THE CHIP. IN USE, SUCH DEVICES ARE SUBJECT TO THERMAL CYCLING AND HENCE ARE SUBJECTED TO THERMAL STRESSES DUE TO THE DIFFERENT THERMAL EXPANSION CHARACTERISTICS BETWEEN THE CHIP AND SUBSTRATE. THE INTERACTION OF THE THERMAL STRESSES EXERTED BY THE VARIOUS COLUMNS PRODUCES A NEUTRAL POINT IN THE CHIP. THE RESULTANT THERMAL STRAINS INDUCED IN THE SEVERAL JOINTS ARE PROPORTIONAL TO THE DISTANCE FROM THIS NEUTRAL POINT. THE TESTING METHOD COMPRISES ROTATING THE CHIP RELATIVE TO THE SUBSTRATE UNTIL IT RUPTURES THEREFROM AND, DURING SUCH ROTATION, MEASURING THE AMOUNT OF TORQUE AS A FUNCTION OF THE ANGLE OF TWIST OR ROTATION. APPARATUS CARRIES OUT THE METHOD BY HOLDING THE SEMICONDUCTOR DEVICE, ROTATING THE CHIP RELATIVE TO THE BASE, MEASURING THE TORQUE AND DEGREE OF TWIST, AND PLOTTING SUCH CHARACTERISTICS TO PROVIDE A RECORD THEREOF.
Inventors
- 👤 Lewis S Goldmann
- 👤 Leonard E Liander
Bibliographic Details
Claims Analysis
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