MMAE Seminar by John D. Williams: Flexible Hybrid Electronics—Process Development and Applications

Armour College of Engineering’s Department of Mechanical, Materials, and Aerospace Engineering will welcome John D. Williams, an associate technical fellow at Boeing Research and Technology, to present a lecture, “Flexible Hybrid Electronics—Process Development and Applications.”

The virtual seminar will take place on Wednesday, November 10, 2021, from 3:30–4:30 p.m. Contact Elena Magnus at magnus@iit.edu for the seminar details and a link to join.

Abstract

Boeing is actively engaged in the development of Flexible Hybrid Electronics. We began with single layer processes and have expanded rapidly prototype development of multilayer flexible printed circuit boards (Flex-PCBs) for size, weight, power, and cost-saving applications. Flex PCBs allow electronics to be wrapped onto cylindrical or bi-axial curved surfaces. Conventional Flex PCBs contain one to four copper layers with limited electronic packaging. Most devices are bonded to rigid boards that contain complex packaged electronics. Boeing’s processes, however, apply copper clad or printed inks on polyimide substrates to build fully functional Flex-PCBs up to eight conductive layers thick—thus, allowing antennas, sensors, communication links, and radars to be placed directly onto the surface of a vehicle. Similarly, power routing and microcontrollers can conform to surfaces or interior cavities. This technology represents a transformative approach to packaging PCBs in aerospace applications. Our team has demonstrated this capability on RF boards with no less than 500 through vias, 100 buried vias, and 50 electronically packaged components. Complex boards can be turned in days without electroplating. Pyralux AP polyimide substrates from DuPont, Taconic, and 3M bonding adhesive achieves alignment errors of 2 mil or less over an 8 x 10 square inch area. Kapton substrates can also be used with additional alignment error. Patterning can be completed with either copper clad material or silver ink. Vias are filled using conductive inks. Electronic packaging is currently performed using anisotropic conductive epoxy, but industrially standard solder attach is also available for copper clad and plated devices. Cost models have been completed for printed silver devices, documenting the manufacturability from Manufacturing Readiness Levels (MRL) four to six. We are currently examining pilot capability of different suppliers to manufacture devices at volumes needed for commercial activities. Note: The research is conducted in collaboration with Ted Dabrowski, Tim Messer, Michael Mitchell, Adriana Jara, Preston Bushey, and Kalsi Kwan at Boeing Research and Technology in Huntsville, Alabama.

Biography

John D. Williams received his Ph.D. in engineering science from Louisiana State University in 2004, and became a Boeing associate technical fellow and NextFlex Fellow in 2019. He has 15 years of principal investigator experience in device fabrication and is currently the principal investigator on numerous NextFlex contracts focused on antenna arrays and multilayer printing on curved surfaces. Williams is currently developing Additive Electronics Technologies (AET) for use on Boeing platforms. From 2004 to 2014 he served as a senior member of the technical staff at Sandia National Laboratories and as an assistant professor of electrical, optical, and material engineering at the University of Alabama in Huntsville (UAH). Williams joined Boeing in 2014 to found the Boeing Research and Technology AET effort in Huntsville, where his team performs novel research in microwave filters, antennas, and flexible hybrid electronic (FHE) sensors by maturing manufacturing capabilities, implementing modeling and simulation, and developing prototype demonstrators. Williams is the principal/co-principal investigator for four concurrent NextFlex MII Projects. He has led or co-led seven other NextFlex projects, serves on the NextFlex Technical Council, and is an industry co-lead for the NextFlex Materials Technical Working Group. Williams also serves as an industrial committee member for the ManTech JDMTP Electronics Subpanel. In 2021 he served on the organizing committee for the IEEE International Flexible Electronics Technologies Conference (IFETC). Williams has published more than 30 peer-reviewed articles, has more than 30 United States patents, 17 international patents, four Boeing trade secrets, and dozens of pending patents. His Boeing-related inventions on microwave filters, conformal antennas, hyperspectral metrology, and cryogenic cooling of MW class EMI filters are currently being developed for multiple BR&T efforts.