“Selecting an Electronics Manufacturing Services (EMS) Partner for Military/Government Applications: 7 Things You Must Know,” by Ed Evangelista of Federal Electronics,
Abstract: Seven things defense contractors must know before selecting an EMS partner for outsourcing military and government projects is the theme of a free white paper. This paper provides how-to advice on such issues as determining the appropriate outsourcing strategy; matching business profiles and capabilities; addressing product mix; enterprise resource planning; new product introductions, and cost strategies and issues. It is available at www.federalelec.com/militarypaper.
The debate on the effect of voiding on BGA reliability has continued for years. Many PCB assemblers strive to minimize voiding, particularly with the advent of lead-free processing and in fine feature area array devices. Although solder pastes have been designed to minimize voiding, and processing guidelines exist to mitigate void formation during reflow processing, the presence of a microvia in a PWB pad can contribute significantly to void formation. It is believed that the depression in the pad caused by the microvia traps air during the stencil printing process, and the air cannot fully escape during reflow.
A process of filling the vias with copper at the board fabrication phase, thereby eliminating the depression that contributes to voids, was tested for its effectiveness in void mitigation during assembly. The test compares the voiding results of filled vias with those of unfilled vias and flat pads with no vias at all. The test vehicle and methods, as well as the results of the tests are presented and discussed in detail.