Investigating the Use for Solderless Assembly for Electronics of Some Electrically Conductive Composite Materials

Solderless assembly for electronics is a new paradigm aimed to solve the problems resulting from contradictory contemporary trends: the ban of the lead by the EU RoHS Directive led to an increase of the energy consumption and cost of the electronic products, but to a degradation of reliability; hence, an increase in wastes that comes in contradiction with the depletion of materials for the electronics industry. The increase in demand for electronic products due to an expanding IoT industry requires increased reliability. In a particular approach that tried to be both simple, i.e. using mostly existing electronic assembly line equipment, and disruptive, i.e. manufacturing the entire assembled electronic module in one location, it turned out that new materials were needed. Another electrically conductive substance is needed to avoid the electrochemical process of copper deposition. The paper describes the findings of a study on two electrically conductive composite materials, as well as a method for qualifying them for use in the production of solderless electronic modules capable of handling ultra high-frequency and microwave signals. A practical solution is to compare the frequency behavior of two identical test structures, one made by the electrically conductive composite material, and the other by copper. The comparative analysis revealed that electrically conductive adhesives perform slightly better at high frequencies than copper in terms of insertion loss and return loss in the range of 0 to 10 GHz; the adhesive is a good substitute for solder alloy to connect temperature-sensitive components operating at high frequency.