In case you missed it.

Packaging

"Advanced Cover Tape Technology for Electronic Component Packaging"

Author: James T. Adams, [e-mail].

Abstract: A single, transparent plastic film, with a synthetic, room temperature, pressure-sensitive adhesive zone, is designed to provide a smooth consistent peel with tight ranges and controlled variability. In lab testing, the cover tape removal force method helps resolve component migration, flipping, vibration, and chip-sticking concerns associated with bare die, CSP and other small components. In a case study with a pick-and-place manufacturer, the tape showed no standup or mispick defects following 3,840 units picked from pockets, no chip stick issues, machine stoppage due to reworked areas, jamming in gears or collection bins, or chip rotation. (EIA ACH committee, April 2007)

Market Research

"Benchmark Study Shows ODM Industry Still Stronger than EMS Industry"

Author: Bill Roberts, [e-mail]

Abstract: The study examined 2006 financial results and other metrics for 45 EMS providers with annual revenue ranging from less than $100 million to more than $2 billion. It also examined 2006 results and metrics for 87 ODMs. In 2006, the average revenue growth rate was 7.7% for EMS companies, and 23.1% for ODMs. EMS profitability (net profit divided by revenue) was a scant 1.5%, but at least it lurched out of the negative zone (-0.1%) where it was stalled in 2005. ODM profitability actually declined between 2005 and 2006, to 3.3% from 4%, but was still more than double that of the EMS sector. To improve profitability, EMS companies may need to not only mimic the ODM model, but to look at a slew of strategies, adopted through acquisition or organically, that add value through services like design, logistics and after-sales work. And the research strongly suggests EMS companies must improve inventory management and cash collection. (Company white paper, July 2007)

Solder Materials

"An Investigation of Lead-Free Nano Solder Paste Microstructure"

Author: Won Seok Choi, [e-mail].

Abstract: This paper presents the microstructure and hardness of composite solders obtained by nanopowders of SAC solder. SAC powder of composite solders was prepared by thoroughly blending nano-size Pb-free solder and flux. The blended solder paste was melted and permitted to solidify on a commercial PCB substrate in reflow equipment and maintained at a constant temperature. Optical microscopy observations revealed that for nano-size Pb-free SAC, the grain size and width of the grain boundary decreased. Microhardness measurements revealed that the nano-size SAC nanopowder is helpful in enhancing the overall strength of Pb-free solder. (SMTAI, October 2007)

"Thermo-Electrical Numerical Analysis of Sn-2.5Ag-0.8Cu-0.5Sb Solder Joint with Interfacial Void Propagation"

Authors: Yao Yao and Leon M. Keer, [e-mail].

Abstract: Recently, solder joint failure has been found to occur experimentally near the interface between the intermetallic layer and solder bulk due to void nucleation and propagation. The effect of joule heating plays a more important role under high electrical current density. To understand the phenomenon, a coupled thermo-electrical finite element analysis has been conducted to predict the electrical concentration and joule heating effects on the failure of SnAg2.5Cu0.8Sb0.5 solder under different current densities. The temperature and current density distribution in a solder joint with a void propagates near the interface of the bulk solder, and intermetallic layer has been predicted. Pronounced temperature and electrical current concentration is observed near the void tip. Although the Pb-free solder is usually regarded as having a higher melting temperature compared with Pb-rich solder, the concentration of heat near the void tip caused by joule heating may still melt the solder material under high current density. The propagation of void will be enhanced and cause circuit failure. (SMTAI, October 2007)