Fluxless laser soldering for electronic packaging
Conventional soldering typically requires the use of reactive fluxes to promote wetting. The resulting flux residues are removed primarily with halogenated or chlorofluorocarbon (CFC) solvents. With the mandated phaseout of CFCs by the year 2000, there has been a concentrated effort to develop alternative, environmentally compatible manufacturing and cleaning technologies that will satisfy the restrictions placed on CFCs, but still yield high quality product. Sandia National Laboratories is currently evaluating a variety of alternative fluxless soldering technologies which can be applied to electronic packaging. Laser soldering in a controlled atmosphere has shown great potential as an environmentally compatible process. The effects of laser heating with a 100 watt CW Nd:YAG laser, joint design, and base/filler metal reactions on achieving fluxless wetting with good metallurgical bonds were examined. Satisfactory Ni-Au plated Kovar{reg sign} solder joints were made with 80In-15Pb-5Ag and 63Sn-37Pb (wt. %) solder alloys in a slightly reducing cover gas. Wetting generally increased with increasing laser power, decreasing laser beam spot size, and decreasing part travel speed. The materials and processing interaction effects are identified and discussed.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5951956
- Report Number(s):
- SAND-91-2606C; CONF-920247--1; ON: DE92003958
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
42 ENGINEERING
426000 -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
ALLOYS
COBALT ALLOYS
ELECTROMAGNETIC RADIATION
ELEMENTS
FABRICATION
GOLD
HEATING
INDIUM ALLOYS
INDIUM BASE ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
JOINING
JOINTS
KOVAR
LASER RADIATION
LEAD ALLOYS
MANGANESE ADDITIONS
MANGANESE ALLOYS
METALLURGICAL FLUX
METALS
NICKEL
NICKEL ALLOYS
RADIATION HEATING
RADIATIONS
SILVER ALLOYS
SOLDERED JOINTS
SOLDERING
TIN ALLOYS
TIN BASE ALLOYS
TRANSITION ELEMENTS
WELDING