Pre-tinning and flux considerations on the reliability of solder surface
- Lawrence Livermore National Lab., CA (United States)
- Lawrence Berkeley Lab., CA (United States)
- Harry Diamond Labs., Adelphi, MD (United States)
The kinetics of wetting were studied on several different prepared surfaces of copper (Cu) to simulate the microstructure observed in pre-tinned Cu-clad printed circuit boards. The results illustrate the effectiveness of pre-tinning in maintaining the solderability of Cu surfaces. Pre-tinning with Pb-rich solder (95Pb-5Sn) is particularly effective since solderability is preserved even after a relatively long aging treatment. On the other hand, pre-tinning with eutectic solder risks the loss of solderability during aging or baking due to surface exposure of an {var epsilon}-phase intermetallic with poor wetting properties. The results also confirm the presence of carbon in pre-tinned specimens due to the use of flux. The effect of carbon on solderability is not yet known. 13 refs., 8 figs., 1 tab.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- USDOD; Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5239376
- Report Number(s):
- LBL-31074; CONF-9108172-2; ON: DE92000905; CNN: MIPR No.R91-056
- Resource Relation:
- Conference: Surface Mount International (SMI) conference, San Jose, CA (United States), 27-29 Aug 1991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COPPER
SOLDERING
WETTABILITY
CARBON
LEAD ALLOYS
MICROSTRUCTURE
PRINTED CIRCUITS
SOLDERED JOINTS
TIN ALLOYS
ALLOYS
CRYSTAL STRUCTURE
ELECTRONIC CIRCUITS
ELEMENTS
FABRICATION
JOINING
JOINTS
METALS
NONMETALS
TRANSITION ELEMENTS
WELDING
360101* - Metals & Alloys- Preparation & Fabrication
360102 - Metals & Alloys- Structure & Phase Studies