Fatigue Behaviour and Ductility Determination for Rolled Annealed Copper Foil and Flex Circuits on Kapton

An adaptive Cu trace fatigue model based on average cross-section strain

“…1 shows a constitutive schematic, pointing out the various aspects of a material model and the differences between monotonic and cyclic values. Since Engelmaier's work using E = 82.7 GPa [14,15] has been used most, and falls in the middle of the field as far as the literature goes, the decision was made to use Engelmaier's values of E and n for Cu.…”

“…The existing literature does not have a consensus of Cu properties for electronics devices [14][15][16]. It is generally accepted that the Ramberg-Osgood elastic-plastic constitutive model [17] is the best representation of Cu stress-strain response:…”

Effects of Thickness and Crystallographic Orientation on Fatigue Life of Single-Crystalline Copper Foils

“…Further, fatigue behavior of copper foils has attracted much attention as they are used widely in flexible printed circuits. 1,2) Recently, thin copper foils are being employed as fine pitch wiring in highly miniaturized devices. Under these circumstances, a number of studies have been conducted to investigate the so-called size effect on mechanical properties of thin sheet metals with the thicknesses ranging from about 200 nm to 500 µm.…”