Printed Circuit Design & Fab - February 2009 - (Page 21)

DEFECTS DATABASE Keep ‘em Together Thermal shock testing can avoid plating adhesion problems. The MICROSeCTION IMAGeS (FiGurES 1 and 2) show through-hole copper plating pulling away from the laminate surface. Copper separation from dr. dAvidE the hole is uncomdi mAio mon, or at least, it has been for many years. Yet, it has been seen in recent years with Pb-free and new laminate materials. Recent use of higher Tg laminates that require modification in the plating process to successfully key copper to the hole wall have been experienced. The occurrence of poor adhesion or the total lack of adhesion would increase under the higher soldering temperatures and moisture content typical of Pb-free assembly. It is necessary to examine the testing conducted for different laminate materials. Thermal shock testing on samples and microsectioning are the simplest test methods to show any improvement in the copper plating adhesion. Thermal shock testing is best conducted with a sand bath rather than a solder bath, as it makes the lack of copper adhesion easier to identify. pCd&f dr. davidE di Maio is with the National Physical Laboratory Industry and Innovation division (npl.co.uk); defectsdatabase@npl.co.uk. FiGurE 1. Microsection of copper pulling from the laminate. FiGurE 2. Barrel copper separating from the laminate. Simberian Inc. Tel: +1-206-726-1098 E-mail: info@simberian.com Simbeor 2008 ® The industry-first electromagnetic synthesis software for physical design of PCB/packaging interconnects operating at 6-10 Gb/s and beyond! Synthesis of controlled-impedance geometries for single and differential via-holes and transmission lines Interconnect budget exploration and verification with advanced 3D full-wave models for all elements of interconnects S-parameters and TDR compliance analysis of a complete data link including connector and package models Electromagnetic software to accomplish your design goals – No PhD in electromagnetics required… Visit www.simberian.com for more information and to download free fully functional software. FEBRUARY 2009 printEd CirCuit dESign & fAB 21 http://defectsdatabase.npl.co.uk/ http://www.simberian.com http://www.simberian.com

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - February 2009

Printed Circuit Design & Fab - February 2009 Contents Our Line Market Watch Around the World Happenings ROI Tip Jar BGA Bulletin Interconnect Strategies Final Finsh Forum Defects Database Embedded Active Components In Multilayer LCP Packages Simulation: The Need for Speed Advanced Registration Systems The DC Design Squeeze Ad Index Do You Really Want a Better Autorouter? Designing With Conductive Materials, Part 1 Off th eShelf Marketplace On the Forefront

Printed Circuit Design & Fab - February 2009

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