Title :
Directly deposited fluxless lead-indium-gold composite solder
Author :
Wang, Chen Y. ; Chen, Yi C. ; Lee, Chin C.
Author_Institution :
Dept. of Electr. & Comput. Eng., California Univ., Irvine, CA, USA
fDate :
12/1/1993 12:00:00 AM
Abstract :
Lead-indium-gold multilayer composite solder has been developed for bonding electronic devices without the use of flux. The composite is deposited directly on GaAs wafers in high vacuum to inhibit indium oxidation. The gold layer on the composite further protects the indium layer from oxidation in atmosphere. Using the composite solder without flux, GaAs dies have been successfully bonded to alumina substrates at a process temperature of 250°C. Nearly perfect joints are achieved as verified by a scanning acoustic microscope (SAM). Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy results indicate that the joint consists of AuIn2 grains embedded in an In-Pb solid solution phase, as predicted from the Au-In-Pb phase diagram. Thermal shock as well as shear tests confirm that high quality bonding is obtained with the lead-indium-gold composite
Keywords :
adhesion; gold alloys; indium alloys; lead alloys; lead bonding; packaging; scanning electron microscope examination of materials; soldering; 250 C; AlO3 substrate; Au-In-Pb phase diagram; AuIn2; AuIn2 grains; GaAs; GaAs dies; GaAs wafers; In-Pb solid solution phase; Pb-In-Au; directly deposited fluxless composite solder; electronic device bonding; energy-dispersive X-ray spectroscopy; high quality bonding; high vacuum; multilayer composite solder; oxidation; perfect joints; process temperature; scanning acoustic microscope; scanning electron microscopy; shear tests; thermal shock; Atmosphere; Gallium arsenide; Gold; Indium; Lead; Nonhomogeneous media; Oxidation; Protection; Scanning electron microscopy; Wafer bonding;
Journal_Title :
Components, Hybrids, and Manufacturing Technology, IEEE Transactions on
