Effect of Temperature Shocks on the Resistance of Joints Formed of Conductive Adhesives

Abstract

Conductive adhesive joints were climatically aged with temperature pulses in the range of -40 to 115 °C. The joints were made of two types of electrically conductive adhesives with isotropic electrical conductivity. The insulating matrix of the adhesives was bis-phenol formaldehyde epoxy resin, and the conductive filler was silver flakes. One adhesive was two-component and the other one-component. Adhesives were applied to the printed circuit board by stencil printing, and then zero-value resistors were mounted by adhesive mounting. Thus, adhesion bonds were formed. The joints were first exposed for 15 minutes in the hot chamber of the thermal pulse testing device, then moved within 8 seconds to the cold chamber and exposed again for 15 minutes. This cycle was repeated two hundred times and five hundred times. The connection resistance was measured using the four-point method. Exposure to temperature pulses was found to cause small changes only in junction resistance.