Properties of joints realized by electrically conductive adhesives

摘要

Resistance and nonlinearity of current vs. voltage characteristics of joints manufactured of electrically conductive adhesives (ECA) were investigated. These measurements were completed with limited number of noise measurements. The joints were manufactured of six different types of adhesives by assembly of resistors with "zero" resistance (their measured resistance was 5 mΩ) on FR4 boards. The surface finish on the boards was either copper or gold-plated copper. The resistors were of a type 1206 recommended for assembly using ECA. Their nonlinearity and noise were very low in comparison with nonlinearity and noise of the joints. The measurements were performed using four-point connection of the resistors. The specimens were thermally aged at the temperature of 160 ℃. It was found that the resistance and nonlinearity of the joints increased after thermal aging and that this increase depends on the time of aging. A longer time of aging caused higher increase of investigated parameters. The burden of the work was to analyze especially nonlinearity of the joints as a quite new parameter for evaluation of their properties and therefore the measurements of the noise voltage were performed for limited number of joints only. It was found that the changes of noise voltage are similar to the changes of nonlinearity.