Li T.,Kester Components Pte Ltd. |
Tan J.Y.R.,Kester Components Pte Ltd. |
Khoo S.A.,Kester Components Pte Ltd. |
Breach C.D.,Kester Components Pte Ltd. |
Hawkins J.A.,Kester Inc.
IEEE Transactions on Components, Packaging and Manufacturing Technology | Year: 2014
The thermal and wetting properties of paste fluxes for use in water-soluble solder pastes largely determine solder paste performance during reflow. The thermal properties, wetting behavior, and reflow performance of a halogenated paste flux and solder paste (Flux A/Paste A) and a novel zero halogen paste flux and solder paste (Flux B/Paste B) were characterized and compared in air and nitrogen environments. In wetting balance tests with Sn96.5Ag3.0Cu0.5 (SAC305) solder at 250 °C, Flux A produced satisfactory wetting behavior in nitrogen, while Flux B produced excellent wetting in nitrogen with a high and stable wetting force that exceeded that of Flux A. In an air environment, Flux A exhibited a large and rapid decrease in wetting force, whereas Flux B achieved a higher wetting force than Flux A that remained relatively high over the duration of the wetting balance test. Thermogravimetric analysis (TGA) of Flux A showed significant degradation in air relative to N2, while Flux B showed almost identical weight loss behavior in air and N2. The TGA data for Paste A and Paste B were similar to that of the fluxes. The excellent thermal and wetting properties of Flux B/Paste B and the generally poorer properties of Flux A/Paste A were validated with reflow experiments that were designed to test the fluxing capability and resistance of the fluxes and pastes to air degradation. © 2011-2012 IEEE.
Hussain J.Z.,Kester Components Pte. Ltd. |
Khoo S.A.,Kester Components Pte. Ltd. |
Breach C.,Kester Components Pte. Ltd. |
Hawkins J.A.,ITW Kester
IEEE Transactions on Components, Packaging and Manufacturing Technology | Year: 2015
Selected physical properties of four water-soluble tacky fluxes were measured, including viscosity, acid number, pH, weight loss during heating, and rheological properties. The capability of the fluxes to perform ball attach in air and N2 using an in-house test board with Cu-organic solderability preservative surface finish was studied in a Malcom reflow simulator using highly oxidized SAC305 solder spheres. Flux performance was rated from the observations of fluxing action in a reflow simulator and the ability to realign deliberately misplaced solder balls and eliminate the occurrence of crescent defects. Two of the four fluxes exhibited good ability to realign misplaced solder balls and one flux exhibited outstanding ease of cleaning. Contrary to common perception, the best performing flux did not have the highest acid number. © 2015 IEEE.