Tin-whisker failure problem from lead-free solder in military electronics is target of Air Force research job

WRIGHT-PATTERSON AFB, Ohio, 20 March 2011. U.S. Air Force electronics researchers are asking industry to develop a set of requirements virtually to eliminate the risks of tin whiskers and other problems related to lead-free solder in integrated circuit and circuit board manufacturing for aerospace and defense electronics applications.The Air Force Research Laboratory (AFRL) at Wright-Patterson Air Force Base, Ohio, released a broad agency announcement (BAA-11-16-PKM) last Thursday for a program called Mitigating Reduction of Hazardous Substances (RoHS) Lead-Free Issues in Aerospace Circuit Board Manufacture, which seeks to develop guidelines to help military electronics manufacturers choose lead-free components, as well as control thermal degradation of lead-free solders at the component and materials level.Scientists at the Materials Integrity Branch of the AFRL Systems Support Division are asking industry experts to find ways of eliminating tin whiskers in lead-free solders to help reduce defects and field failures in aerospace and defense electronics. Tin whiskers, which can grow over time on lead-free solders, can cause short circuits and other defects in electronic systems.

Air Force researchers are interested in using a method that has been used on military-grade electronic parts since the mid-1960s to mitigate tin whisker problems: fusing the matte tin on lead-free parts and boards in a post processing step prior to board assembly, or by requesting a fused tin finish from parts vendors.

As more parts and materials are re-engineered to be compatible with the higher temperatures and longer dwell times necessary when using many lead-free alloys, the number of parts likely to be compatible with tin fusing should grow, Air Force officials explain. To come up with guidelines to achieve this, companies must identify component families normally only available with pure unfused matte tin finishes that are compatible with tin fusing.

For the program, the Air Force is asking companies to find ways to determine the suitability of electronic components or materials for soldering cycles during circuit card assembly, as well as ways to estimate time to failure due to this kind of soldering.

The program also asks companies to find the best ways of selecting components, materials, and vendors for design and manufacture of defense and aerospace electronics equipment using suitable lead-free solder alloys.

The Mitigating Reduction of Hazardous Substances (RoHS) Lead-Free Issues in Aerospace Circuit Board Manufacture program should be a 15-month, $1.7 million effort, with a contract to one company expected to be awarded as early as 30 June 2011.

Companies interested should mail hard-copy proposals no later than 2 May 2011 to Crystal Price, Det 1 AFRL/PKMD, Bldg. 167, 2310 8th St., Wright-Patterson AFB, OH 45433-7801. For questions or concerns, e-mail Crystal Price at [email protected].

More information is online at https://www.fbo.gov/spg/USAF/AFMC/AFRLWRS/BAA-11-16-PKM/listing.html.