IMPLICATIONS OF USING LEAD-FREE SOLDERS ON X-RAY INSPECTION OF FLIP CHIPS AND BGAS

摘要

All contract manufacturers (CM) of printed circuit boardsrn(PCBs) are having to consider their approach to using leadfreernsolders to meet current, and future, environmental,rnlegislative and market demands. As these lead-free soldersrnhave markedly different operating parameters from those ofrnthe tried and tested lead-containing solders, the opportunityrnfor production problems rises. Therefore, the application ofrnappropriate test and inspection procedures now becomesrneven more important to ensuring product quality andrnreliability. However, the test and inspection equipment, andrnmethods, used for decades may not now be appropriate forrnthis new challenge. This may be because, at worst, some testrnparameters are no longer valid with the lead-free solders, or,rnless seriously, the inspection control settings must be variedrnto accept revised test responses based on acceptable levelsrnfor these new materials. Implementing lead-free solder intornproduction, therefore, raises questions as to the acceptabilityrnand adequacy of a company’s existing test methods. Thisrnpaper discusses the implications of using x-ray inspection onrnlead-free versions of flip chips and BGAs.