Gould Electronics Inc.

Jx Nippon Mining Metals Corporation

Harish D Merchant

Sidney J Clouser

Charles A Poutasse

Chin-Ho Lee

In one embodiment, the present invention relates to a flexible laminate, comprising a first flexible polymeric film; a copper layer having a microcracking prevention layer on at least one side the microcracking prevention layer sufficient to prevent microcracks in a copper layer having a thickness of up to about 18 &mgr;m during at least 50,000,000 bending cycles and/or a copper layer having a thickness of up to about 35 &mgr;m during at least 20,000,000 bending cycles of the flexible laminate; and a second flexible polymeric film.

Surface treatment of copper to prevent microcracking in flexible circuits

This invention relates to an improved high performance flexible laminate, comprising: a layer of electrodeposited copper foil overlying a layer of a flexible polymeric material, said copper foil being characterized by an ultimate tensile strength at 23.degree. C. of at least about 60,000 psi, a loss of ultimate tensile strength at 23.degree. C. of no more than about 15% after being annealed at 180.degree. C. for 30 minutes, an average grain size of up to about 1 micron, and a fatigue performance characterized by at least about 5000 cycles to failure when the strain amplitude is about 0.05% to about 0.2%. In one embodiment, the copper foil is electrodeposited using an electrolyte solution characterized by a free chloride ion concentration of up to about 4 ppm and an organic additive concentration of at least about 0.3 ppm.

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Hinckley, OH, United States of America

Harish D Merchant