Circuits Assembly - December 2007 - (Page 23) COB for SMT ability with selective nickel or gold plating on the bond sites, or simply a uniform nickel as a common soldering and bond site finish together with aluminum wedge bonding, provides the lowest-cost alternative. ■ Ed: This article was first published at SMTA International in October 2007, and is used with permission. Mukul Luthra is business director and founder of Waterfall Technologies (waterfalltech.com); mukul@waterfalltech.com. Figure 7. COB in a “toy” fan with motion-activated LED lights. Reference Books by Dr. Jennie Hwang Figure 8. COB in a PC mouse. TO ORDER: Online: www.LeadFreeService.com Fax: 216-896-0405 bonders.5 The metalization choice can help provide the right balance between wire bond reliability, soldering yields, and solder joint reliability. At the lowto-mid cost spectrum, the metalization tends to lean toward alignment with the soldering process. Despite this compromise, the wire bonding process for this product class proves sufficiently robust for the application. The required metalization for reliable wire bonding is not necessarily the same as that needed for high quality solder joints. ENIG – or its derivative, ENEPIC – provided the nickel and gold plating control is carefully maintained 4,6,7 when combined with selective pure thick gold on the wire bond sites, provides the highest reliability for both soldering and wire bonding but also incurs the highest cost. At the next lower level, ENIG is an option for both soldering and wire bonding without selective plating on the wire bonding sites. ENIG metalization yields an excellent solder joint quality and while not “the” best for wire bonding, proves adequate for midrange product needs. Where cost sensitivity is acute, either OSP over copper for solder- Dr. Hwang’s upcoming Lead-free lectures/seminars Visit: www.LeadFreeService.com circuitsassembly.com Circuits Assembly DECEMBER 2007 23 http://waterfalltech.com http://www.LeadFreeService.com http://www.LeadFreeService.com http://circuitsassembly.com
Table of Contents Feed for the Digital Edition of Circuits Assembly - December 2007 Circuits Assembly - December 2007 Contents Caveat Lector Industry News Market Watch Talking Heads Global Sourcing Screen Printing Better Manufacturing Metalization Options for COB Assembly A Test Comparison of SAC and Non-SAC Pb-Free Solders An A-to-Z Guide to X-Ray Inspection BEST: A ‘Funky Chicken’ with an EMS Niche Tech Tips Wave Soldering Process Doctor Pb-Free Lessons Learned Getting Lean Eastern Approaches Product Spotlight Ad Index Assembly Insider Technical Abstracts Circuits Assembly - December 2007 Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page Cover1) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page Cover2) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page 1) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page 2) Circuits Assembly - December 2007 - Contents (Page 3) Circuits Assembly - December 2007 - Caveat Lector (Page 4) Circuits Assembly - December 2007 - Caveat Lector (Page 5) Circuits Assembly - December 2007 - Industry News (Page 6) Circuits Assembly - December 2007 - Industry News (Page 7) Circuits Assembly - December 2007 - Industry News (Page 8) Circuits Assembly - December 2007 - Industry News (Page 9) Circuits Assembly - December 2007 - Industry News (Page 10) Circuits Assembly - December 2007 - Industry News (Page 11) Circuits Assembly - December 2007 - Market Watch (Page 12) Circuits Assembly - December 2007 - Market Watch (Page 13) Circuits Assembly - December 2007 - Market Watch (Page 14) Circuits Assembly - December 2007 - Market Watch (Page 15) Circuits Assembly - December 2007 - Talking Heads (Page 16) Circuits Assembly - December 2007 - Talking Heads (Page 17) Circuits Assembly - December 2007 - Global Sourcing (Page 18) Circuits Assembly - December 2007 - Global Sourcing (Page 19) Circuits Assembly - December 2007 - Screen Printing (Page 20) Circuits Assembly - December 2007 - Better Manufacturing (Page 21) Circuits Assembly - December 2007 - Metalization Options for COB Assembly (Page 22) Circuits Assembly - December 2007 - Metalization Options for COB Assembly (Page 23) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 24) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 25) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 26) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 27) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 28) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 29) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 30) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 31) Circuits Assembly - December 2007 - BEST: A ‘Funky Chicken’ with an EMS Niche (Page 32) Circuits Assembly - December 2007 - BEST: A ‘Funky Chicken’ with an EMS Niche (Page 33) Circuits Assembly - December 2007 - Tech Tips (Page 34) Circuits Assembly - December 2007 - Tech Tips (Page 35) Circuits Assembly - December 2007 - Wave Soldering (Page 36) Circuits Assembly - December 2007 - Process Doctor (Page 37) Circuits Assembly - December 2007 - Pb-Free Lessons Learned (Page 38) Circuits Assembly - December 2007 - Pb-Free Lessons Learned (Page 39) Circuits Assembly - December 2007 - Getting Lean (Page 40) Circuits Assembly - December 2007 - Getting Lean (Page 41) Circuits Assembly - December 2007 - Eastern Approaches (Page 42) Circuits Assembly - December 2007 - Eastern Approaches (Page 43) Circuits Assembly - December 2007 - Eastern Approaches (Page 44) Circuits Assembly - December 2007 - Product Spotlight (Page 45) Circuits Assembly - December 2007 - Ad Index (Page 46) Circuits Assembly - December 2007 - Assembly Insider (Page 47) Circuits Assembly - December 2007 - Technical Abstracts (Page 48) Circuits Assembly - December 2007 - Technical Abstracts (Page Cover3) Circuits Assembly - December 2007 - Technical Abstracts (Page Cover4)
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