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

Volume

16

Issue

8

fYear

1993

fDate

12/1/1993 12:00:00 AM

Firstpage

789

Lastpage

793

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;

fLanguage

English

Journal_Title

Components, Hybrids, and Manufacturing Technology, IEEE Transactions on

Publisher

ieee

ISSN

0148-6411

Type

jour

DOI

10.1109/33.273675

Filename

273675