Thermography-based imaging techniques for characterization of large-area electronics

In this thesis, novel thermography-based instrumentation and measurement techniques were developed for the characterization of selected large-area electronics (LAE) samples, including electrically conductive thin films, flexible hybrid electronics devices, and photovoltaics. Dedicated instrumentation suitable for LAE characterization is scarce. This applies especially to inline-compatible roll-to-roll (R2R) manufacturing monitoring systems. The need for such tools is obvious since LAE is an immature field of technology where manufacturing cannot be scaled up efficiently without proper quality assurance and process control.

Compatibility with R2R processing environments was prioritized in this research. Both physically contacting and contactless methods were developed and utilized. Contactless instrumentation based on inductive heating and infrared imaging was found to be superior for inline R2R characterization due to its versatility, e.g. the equipment can be inserted into a production line without major structural changes or even for ad hoc monitoring.

Developed methods were able to estimate the overall electrical uniformity of the samples and to detect and locate defects in all tested sample types. It was also shown that the resistance of conducting thin films can be analyzed by thermographic measurements. These quality monitoring techniques are expected to be widely applicable to other electronics materials and electronics devices by removing the bottlenecks of high-volume LAE production.