Microbonds for Hybrid Microcircuits

This paper presents the results of an extensive micro bonding program designed to establish the reliability of techniques for providing interconnections within hybrid microcircuits. The program included in investigation of bonding equipment parameters, film thicknesses, materials, and evaluation techniques. One phase of this work consisted of the evaluation of fine wire microbonds (0.0007 inch, 0.001 inch, 0.002 inch, and 0.005 inch diameter gold and aluminum wire) to deposited gold-chromium or aluminum films on various substrates, including Vycor, as-fired and glazed alumina, sapphire, oxidized silicon, and beryllia. Both spilt-tip resistance welding and ultrasonic bonding techniques were employmented for the fabrication of these bonds. In addition, an evaluation program was conducted on the resistance welding of 0.002x 0.010 inch gold-plated nickel ribbon to nickel-gold-chromium films on as-fired and glazed alumina, sapphire, and beryllia substrates. A parallel gap resistance welder was used for this study. A third portion of the prgram was the evaluation of parallel-gap resistance welded interconnections of two types of flat-pack leads to three material combinations on multi-layer printed circuit boards. The lead types were gold-plated kovar and gold-plated nickel while the interconnection materials on the boards were gold-nickel-copper, gold-nickel while the interconnection materials on the boards were gold-nickel-copper, gold-nickel and gold-alnifer (laminate manufactured by Texas Instruments, Metals and Controls Division, Attleboro, Massachusetts).