Hybrid printed electronics (HPE) combines advantages of conventional electronics manufacturing technologies such as surface mount technology with those of printed electronics in order to realize more complex electronic systems. To realize the final product, such HPE subassemblies have to be connected to higher-level assemblies. So far interconnection techniques for the so-called level 3 interconnection between printed subsystems and standard electronics have not yet been considered adequately in scientific research. In this paper, alternative detachable level 3 interconnection technologies, i.e. spring loaded contact pins, zero insertion force (ZIF) as well as Non-ZIF connectors are investigated systematically regarding their electrical behaviour against the background of printed electronics. Screen-printed silver filled polymer thick film paste is used to realize printed conductor patterns on flexible polymer substrates, which are connected later on with the alternatives mentioned above. Transition resistance is measured using the four wire method as produced, after repeated mating cycles as well as after accelerated aging tests. The various electrical contacts are subjected to thermal stress in temperature cycling testing and during aging at a constant high temperature. As a result it can be stated, that the sping-loaded contact pins used in this investigation show superior behavior compared with the selected connectors in terms of resistance increase after mating cycles. Concerning long-term behavior after thermal cyling and high temperature storage, all investigated alternaives reveal convincing results.

In this work, on different substrate materials thermally cured polymer thick-film pastes are connected to Surface Mount Technology resistors using a SnBiAg solder alloy. The effect of substrate pre-treatment with atmospheric plasma and thermal cycling on the shear strength of these interconnection is investigated, and the shear forces obtained are graded using MIL-STD 883. In particular, the build-up of solder interconnections on conductive structures made of commercially available copper-containing polymer thick-film pastes and their mechanical characterization is novel. As well as the mechanical characterization of conductive structures, made of polymer thick-film, on plasma-treated substrates and their grading using the MIL-STD 883. In addition, interconnections with silver-containing conductive structures are realized for comparison. Depending on the interconnection system, component mean shear forces of up to 31 N are achieved. While some systems meet the 1.25 x criterion of MIL-STD 883, the majority of the systems investigated do not meet the 1.00 x criterion. Hereby, the adhesion between the conductive structure and the substrate usually fails. Plasma pre-treatment shows an adhesion-increasing effect only for a proportion of substrate materials used, as does thermal aging. Thermal loads can also impair the adhesive strength.