Abstract
Capability of high-speed and low-cost manufacturing makes the printing techniques a very promising approach for large-area flexible electronics mass manufacturing. Due to fast and intensive technology development, the lack of knowledge about the reliability and lifetime of printed electronics is obvious, requiring further investigation. Especially, the effect of torsional bending on lifetime is a mostly unexplored field of reliability testing. In this article, a torsional bending test of parallel printed silver conductors (0.3-, 0.5-mm pitch) on polymer substrate (polyethylene terephthalate, 125- \mu \text{m} thickness) was conducted and analyzed. According to the experimental results, torsional bending causes wear-out type failures in conductors and the length-to-width (LTW) ratio of the sample's substrate was observed to have a significant impact on reliability. If the LTW ratio is smaller than 3, the lifetime of printed conductor seems to collapse and samples lasted for approximately only 17 bending cycles on average. Lifetime was improved by increasing the LTW ratio and samples withstood over hundreds of cycles with LTW ratio of higher than 15. However, the distance of a conductor from the edge of the substrate was not observed to have any significant influence on the reliability under torsional bending.
| Original language | English |
|---|---|
| Article number | 9089357 |
| Pages (from-to) | 2522-2528 |
| Number of pages | 7 |
| Journal | IEEE Transactions on Electron Devices |
| Volume | 67 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Jun 2020 |
| MoE publication type | A1 Journal article-refereed |
Funding
Manuscript received March 25, 2020; revised April 19, 2020; accepted April 20, 2020. Date of publication May 7, 2020; date of current version May 21, 2020. This work was supported in part by the Business Finland under Project Dnro 3944/31/2014, in part by the Academy of Finland’s FIRI funding under Grant 320017, and in part by the European Regional Development Fund’s Novel Digitally Fabricated Materials for Electronics, Optics and Medical Applications under Grant A74080. The review of this article was arranged by Editor M. M. Hussain. (Corresponding author: Esa Hannila.) Esa Hannila, Kari Remes, and Tapio Fabritius are with the Optoelectronics and Measurement Techniques Research Unit, University of Oulu, 90570 Oulu, Finland (e-mail: [email protected]).
Keywords
- Accelerated lifetime
- Flexible electronics
- Large-area electronics
- Printed electronics
- Reliability testing