Analysis and Testing of Ceramic Column Grid Array Component
for Space Applications, 15-R8315
Principal Investigators
James Noll
Kelly Smith
Inclusive Dates: 05/25/12 – 09/25/12
Background — High-connection density, large lead-count ceramic column grid array (CCGA) packaged components bring new and improved capabilities to electronic systems for space applications. Prior SwRI efforts have qualified specific CCGAs for spaceflight use, but these devices had at most 624 leads with 1.27 mm pitch spacing. This project tested SwRI's capability to install a 1,752 lead, 1.00 mm pitch CCGA on a printed wiring assembly (PWA), and have those connections survive typical vibration and thermal loading for a space application.
Approach — Analysis of the environmental loading was performed to predict joint stresses for various CCGA installation locations and different stiffener designs. A test board emulating the mechanical and thermal properties of the predicted next version of the IRB (engineering model and flight model) was designed and fabricated. Two test CCGAs were installed in two different locations. One location minimized solder joint stresses, and the other provided the greatest flexibility for connections routing. The test board was subjected to environmental testing, including vibration and thermal cycling, to validate the analysis and manufacturing process.
Accomplishments — Analysis of the vibration-induced solder joint stresses predicted the CCGA could be installed safely near the board center with a reinforcing cross stiffener attached to the PWA. The assembled PWA passed vibration and thermal testing as predicted by analysis. Both installation locations passed testing. The CCGA was installed successfully, demonstrating the capability to meet the more challenging requirements of this larger CCGA: greatly increased column count, finer positioning requirements, and larger overall footprint. The quantity of solder paste required for successful installation was determined. The thermal profile needed to form the solder fillets was developed. This research effort uncovered a need for improved pick and place tooling to handle large CCGA installation. Mitigating this manufacturing risk has given SwRI a stronger technical position for proposed builds of IRB and DARPA System F6 flight components.
