Solder paste for tomorrow’s electronics manufacturing technology

Abstract

Journal of Electronics ManufacturingVol. 04, No. 04, pp. 181-202 (1994) PAPERSNo AccessSolder paste for tomorrow’s electronics manufacturing technologyNING-CHENG LEE, MANCHAO XIAO, KEVIN J. LAWLESS, JAMES A. SLATTERY and JOHN R. SOVINSKYNING-CHENG LEEIndium Corporation of America, Utica, NY, USA Search for more papers by this author , MANCHAO XIAOIndium Corporation of America, Utica, NY, USA Search for more papers by this author , KEVIN J. LAWLESSIndium Corporation of America, Utica, NY, USA Search for more papers by this author , JAMES A. SLATTERYIndium Corporation of America, Utica, NY, USA Search for more papers by this author and JOHN R. SOVINSKYIndium Corporation of America, Utica, NY, USA Search for more papers by this author https://doi.org/10.1142/S0960313194000201Cited by:2 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract12-mil pitch processing is achievable with solder paste. It may however be the limit of solder paste printing technology, mainly due to the scooping problem associated with thin stencils. With decreasing pitch size, both smear and insufficiency rates increase. Tapering of the stencil aperture helps thick stencil prints, but harms thin stencil printing. Apertures with orientation parallel to squeegee movement results in a higher print defect rate. Overall, the use of fine powders is the most effective means to meet most challenges. It helps in achieving high performance in printability, tack, and non-slump, with acceptable trade-off in rheology and tack time. Solder balling may be the primary hurdle. The problem may be resolved by using an inert reflow atmosphere or through flux chemistry improvements. A metal load of 90.5–91% seems to be the optimum for most properties. Besides paste technology, the chemistry of solder alloys is also a focus for future electronics manufacturing technology. Environmental and toxicity concerns related to the use of lead have initiated the search for acceptable, alternative joining materials for electronics assembly. This paper describes a novel lead-free solder designed as a ‘drop in’ replacement for common tin-lead eutectic solder. The physical and mechanical properties are discussed in detail with comparison to tin-lead eutectic solder. The performance of this solder when used for electronics assembly is discussed and compared to other common solders. Fatigue testing results are reported for thermal cycling electronics assemblies soldered with this lead-free composition.Keywords:Soldersolder pastefine pitchprintslumpsolder balllead-free FiguresReferencesRelatedDetailsCited By 2The influence of wall slip in the measurement of solder paste viscosityN.N. Ekere, D. He and L. Cai1 Sep 2001 | IEEE Transactions on Components and Packaging Technologies, Vol. 24, No. 3Interfacial reactions of tin‐zinc‐bismuth alloysPaul Harris1 Dec 1999 | Soldering & Surface Mount Technology, Vol. 11, No. 3 Recommended Vol. 04, No. 04 Metrics History KeywordsSoldersolder pastefine pitchprintslumpsolder balllead-freePDF download