Continuous electrical resistance monitoring, pull strength, and fatigue life of isotropically conductive adhesive joints

Abstract

Four isotropically conducting adhesives were used to form lap joints between copper fingers which had been prepared with four surface metallizations (Cu, Au, Pd, and PdNi). A micromechanical tester was used to perform pull and fatigue tests on the 16 adhesive/finish combinations. The micro-ohm resistance change was measured during both the pull and fatigue tests. The similarities and differences between the mechanical strength, fatigue life, and resistance change for the 16 adhesive/finish combinations have been reported, and conclusions were made about relative motion between silver particles, and the fracture interfaces.

Influence of Temperature and Dwelling Time on Low-Cycle Fatigue Characteristic of Isotropic Conductive Adhesive Joint

“…Therefore, for electronic devices, the evaluation of the fatigue life of the interconnects is important. [7][8][9][10] However, fatigue characteristics of the conductive adhesive and its fatigue damage mechanism have not been elucidated. For practical applications, the fatigue characteristics of the conductive adhesive must be elucidated.…”

1/f noise as a diagnostic tool to investigate the quality of isotropic conductive adhesive bonds

“…Another possible mechanism for the decrease in while remains about constant is the wearing away of the smallest contact asperity spots as the particles slide relative to one another as they are strained to form larger contact spots that have less noise. The so-called coalescence is discussed in [12] and [13]. These mechanisms can be considered as a kind of annealing.…”

“…This is an indication for a reduction of the electrical (internal) contact area by a factor one (no reduction at all); 10 ; and 3 for DM, Polysolder, and Ablebond, respectively. This will be explained by (13) in the next section.…”

“…For a region II contact we find from (7) and (8) that holds, and hence for the ratio between the maximum value and the minimum value for the relative noise after a degradation process, we have (12) We choose for the notation where the maximum amount of noise corresponds with the minimum value of electrical contact area and vice versa. Thus from noise measurements we can quantitatively express the degree of delamination by a -factor defined as (13) In Fig. 7(a), versus and versus are plotted for the region II multispot contact with an onset of delamination by -reduction only.…”

Electrical Reliability of a Film-Type Connection during Bending

“…In general, a dedicated connector or anisotropic conductive film (ACF) is used to connect FPCs to printed circuits and other electronic components. When using a connector, conduction between the facing FPC electrode and the connector electrode relies on a mechanical normal force [3]; thus, mechanical designs for miniaturized connectors are limited by the requirement for a sufficient normal force.…”