PRODUCTION ENGINEERING MEASURES TO INCREASE TRANSISTOR RELIABILITY FOR THE 2N656.
Final progress rept. for 1 Jul 62-31 Mar 64.
TEXAS INSTRUMENTS INC DALLAS
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The process improvement work on the 2N656 device was completed during the first twelve months of the contract. The resultant transistor is a rugged planar device utilizing gold alloy wafer mounting, ultrasonic lead bonding with no inline etch or wafer coating and is capable of 15 watts dissipation at 100C case temperature. Improved facilities, processes and process controls in the diffusion, photo resist, contract evaporation and assembly areas have all contributed to the significantly improved product quality and uniformity. The major portion of reliability improvement has resulted from the planarization of the device and the re-design of the package which replaced the single 0.017 in. diameter wire slug support with two approximately 0.015 in. thick by 0.090 in. wide tabs. Stress tests conducted on 1,100 production planar devices confirm that the improved transistor exceeds the contract objective of 0.01 per thousand operating hours at a 90 confidence level. Author