NEWS // FEATURES // NEW PRODUCTS
This Month from the NPL Database, with Bob Willis: Flux Residues under QFN LGA
The side view image of solder joints on an LGA/ QFN package. Between the terminations evidence of fl ux residues is visible and would be common on a standard assembly process. Flux residues are also visible under the package. Looking at the fl ux residues it is suggested the process of cleaning has not been correctly or completely reviewed. The residues look to have been through a cleaning process and are not being dissolved or are insoluble due to poor process compatibility. A proper evaluation of the process, paste, cleaning system and chemistry needs to be conducted to confi rm the residues are compatible and the cleaning system is capable of cleaning the component stand off height on
this LGA QFN package. Normally the standoff height of these packages is below 0.004”, the example shown had a standoff height of 0.008” The NPL Database is available to readers to search
for solutions 24/7 or submit your own problems/ examples online to obtain a possible solution at
http://defectsdatabase.npl.co.uk/ For details on the NPL team’s investigation/ consultancy services or training workshops offered contact Ling Zou email
ling.zou@npl.co.uk Telephone 0208 943 6065. A full list of the extensive range of technical reports on electronic manufacturing reports produced by the electronics group can also be provided.
Finally, Pb-free solder paste that takes a shine to ENIG/gold PC boards.
Introducing NC-560-LF, the Pb-free no-clean solder paste designed for hard-to-solder metallization surfaces
Nothing increases production yields like AMTECH’s NC-560-LF, the lead-free, no-clean solder paste for hard-to-solder metallization surfaces, including ENIG (Gold), OSP, HASL and immersion silver
boards.This fully RoHS-compliant solder paste delivers unparalleled lot-to-lot and stencil printing consistency, and enhanced solderability due to superior print performance characteristics, including excellent wetting and activity, ideal viscosity, long stencil life, thermal stability up to 300°C, and minimal residue. NC-560-LF solder paste is also low beading, low voiding, and anti-tombstoning to reduce scrap and rework. Looking to strike it rich with greater hourly throughput? Call AMTECH today, and you’ll be golden.
www.amtechsolder.com
500 Main Street, Suite 18, PO Box 989, Deep River, CT 06417 USA 800.435.0317 • 860.526-8300 • Fax 860.526.8243
10 EIU
www.electronicscomponentsworld.com /
www.electronicsproductionworld.com
February 28th
2013
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