Increasing Reliability of Printed Electronics Using Hyperspectral Metrology
Boeing, in collaboration with the University of Connecticut and ChemCubed, has worked to mature the manufacturing readiness level (MRL) and technology readiness level (TRL) of flexible hybrid electronics (FHE) using direct-write printing processes. In an effort to increase the reliability and repeatability of printing passive components, Boeing developed a process to standardize the direct-write printing procedure. This process was then used to liquid dispense over one hundred individual resistors, capacitors, and inductors to observe the component performance and variability over day-to-day print cycles. Resistor, capacitor, and inductor components were printed with both a liquid dispense process and an inkjet process to determine which yielded more repeatable components. The individual components were characterized by a profilometer to determine the surface profile. With a controlled manufacturing process, the inks were mixed, characterized with rheology, and modeled to simulate each printing procedure, increasing the MRL from 3 to 6. In addition to printing components, Boeing conducted an environmental test to determine the effect of ramped temperature and humidity on liquid dispense and inkjet printed components. Lastly, a hyperspectral camera system was developed as a standalone metrology tool increasing the MRL to 5. The results from this project can be applied to a number of applications as advances in printed passives allow for lighter, more flexible products. This project is aligned with current projects where printed passives remove the need for various surface mount components, increasing the flexibility and functionality of the final product.