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U.S. Department of Energy
Office of Scientific and Technical Information

Infrared vacuum soldering process for thick-film hybrid microcircuits

Technical Report ·
OSTI ID:6792231

An infrared vacuum soldering (IVS) process was developed for thick-film hybrid microcircuits (HMCs) being manufactured at Allied-Signal Inc., Kansas City Division (KCD). Sample HMCs were assembled and destructively tested to determine the intermetallic growth of the thick-film metallization when soldered to a mounting plate using 50-indium/50-lead solder and 63-tin/37-lead solder. The large voids in a solder joint reduce the area of solder contact to the metallization and contribute to nonuniform stress across the substrate. The indium-rich areas that feed the intermetallic growth in the solder joint can cause the electrical ground of the microcircuit to fail when enough of the remaining gold is consumed, affecting the ceramic-to-gold adhesion properties. Vacuum soldering has reduced the voids to between 1 to 5 percent, as compared to 50 percent using the belt soldering process. The development of IVS has provided a process that is more efficient, safer, easier to maintain, and more economical to operate than CVS but which still restricts the amount of intermetallic growth and reduces the voids in the solder joint. The IVS process was characterized and released for production in January 1991.

Research Organization:
Allied-Signal Aerospace Co., Kansas City, MO (United States). Kansas City Div.
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC04-76DP00613
OSTI ID:
6792231
Report Number(s):
KCP-613-4983; ON: DE93007483
Country of Publication:
United States
Language:
English