Study of low-temperature interconnection techniques for instant assembly of electronics on stretchable e-textile ribbons

This article addresses the research and development of a reliable interconnection technique for mounting surface mounted device components onto newly developed conductive stretchable textile ribbons. The alternative nonconductive adhesive bonding in which electrical contact is realized only by mechanical pressure and fixed by an adhesive and the conventional soldering technique were selected for examination. Assessment of the performance of these techniques and their usability for interconnecting components on conductive textile ribbons was also our research goal. Reliability tests of the electrical and mechanical properties of realized interconnections (dry heat, damp heat, washing, electrical current load, jerk, and stretch tests) were realized. The results show that the nonconductive adhesive technique results in good mechanical properties and acceptable median electrical resistance of less than 2 Ω even after 90 washing cycles. It is also very gentle and fully compatible with textile production due to the maximal processing temperature lower than 70°C, without the risk of short circuit occurrence. This technique is suitable for sensors, illumination or data transfer applications. While soldering results in excellent median electrical resistance of less than 20 mΩ, it is more complex and costly. Moreover, there is a risk of short circuits as well as of textile damage by the high thermal load over 150°C. Soldering is more suitable for power supply applications or heating. The above-mentioned results were also confirmed in a decision analysis with pairwise comparisons, involving company representatives considering introducing the above-mentioned interconnection techniques into their production. The nonconductive adhesive technique was evaluated as 15% better in overall decision analysis than the low-temperature soldering.