0

Full Content is available to subscribers

Subscribe/Learn More  >

An Investigation of the Lead-Free Surface Mount Soldering Process: Solder Joint Evaluation and Process Optimisation

[+] Author Affiliations
Claire Ryan, Jeff M. Punch, Bryan Rodgers, Greg Heaslip, Shane O’Neill, Eamonn Murphy

University of Limerick

Paper No. IMECE2004-60491, pp. 187-195; 9 pages
doi:10.1115/IMECE2004-60491
From:
  • ASME 2004 International Mechanical Engineering Congress and Exposition
  • Electronic and Photonic Packaging, Electrical Systems Design and Photonics, and Nanotechnology
  • Anaheim, California, USA, November 13 – 19, 2004
  • Conference Sponsors: Electronic and Photonic Packaging Division
  • ISBN: 0-7918-4707-1 | eISBN: 0-7918-4178-2, 0-7918-4179-0, 0-7918-4180-4
  • Copyright © 2004 by ASME

abstract

A European Union ban on lead in most electrical and electronic equipment will be imposed as of July 1st 2006. The ban, along with market pressures, means that manufacturers must transfer from a tin-lead soldering process to a lead-free process. In this paper the implications on the surface mount (SMT) soldering process are presented. A set of experiments was conducted to investigate the screen-printing and reflow steps of the SMT process using a tin-silver-copper (95.5Sn3.8Ag0.7Cu) solder and a baseline of standard tin-lead (63Sn37Pb). 10×10 arrays of micro Ball Grid Array (micro-BGA) components mounted on 8-layer FR4 printed wiring boards (PWBs) were used. The screen-printing experiment addressed the deposition of the solder paste on the board. The parameters used in the investigation were print speed, squeegee pressure, snap-off distance, separation speed and cleaning interval, with the responses being measurements of paste height and volume. Optimum screen-printer settings were determined which give adequate paste volume and height and a good print definition. The reflow experiment investigated the following parameters of the temperature profile: preheat, soak, peak and cool down temperatures, and conveyor speed. The resulting solder joints were evaluated using cross-section analysis and x-ray techniques in order to determine the presence of defects. A mechanical fatigue test was also carried out in order to compare the strength of the solder joints. The overall quality of the lead-free solder joints was determined from these tests and compared to that of tin-lead. The outcome is a set of manufacturing guidelines for transferring to lead-free solder including optimum screen-printer and reflow oven settings for use with an SnAgCu solder.

Copyright © 2004 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In