The Influence Of Electro-deposition Parameters On Microstructure And Mechanical Properties Of Electrolytic Copper Foils

Electrolytic copper foil is an important raw material in the electronic and electrical industries, which provides the primary substrate and conductive circuits in printed circuit boards (PCB) and printed wire boards (PWB). With the rapid developments occurred in the electronics industry over the past few decades, the electronic products become thinner, smaller, lighter and more functional, and the corresponding circuit designs become finer, denser and more intricate. The quality requirements of the electrolytic copper foil, such as tensile, elongation as well as anti-stripping property and oxidation Protection become much more demanding. Moreover, the microstructure and surface micro profile of copper foil are requested more fine.According to the actual condition of electrolytic copper foil industrialization production, the influence of different process parameters on the appearance structure and mechanical properties of electrolysis copper foil was studied in this article. The research results showed that:In CUSO4-H2SO4 electrolyte system, the microstructure and mechanical properties of copper foils were changed obviously with thickness changed. The morphology of matte surface changed with the increasing of thickness of copper foil, the (111) texture transformed to (220) texture simultaneous; The current density influenced copper foil appearance structure through enhancing the cathode polarization, then influence mechanical properties of copper foils; the copper concentration influenced the tensile and elongation by the Influence of crystallization uniformity, and had nothing to do with the growth pattern of crystal grain. Polyethylene glycol (PEG) can refine particles of the copper foil, resulting in reducing roughness and increasing the mechanical properties. But excessive PEG will reduce the mechanical properties. Above all, the optimum process conditions are the following:80g/L copper concentration,0.5A/cm2 current density,40L/min electrolyte flow rate.According to the problem of pinholes on the copper foil which produced by certain copper foil company, the main factors of causing pinhole were analyzed. In the premise of keeping the normal properties of the copper foil, the effective measure was found and applied to copper foil production. The research results showed that: The pinholes were formed because the lead anode dissolved in CUSO4-H2SO4 electrolyte. Pinhole is one of the major defects of copper foils, which affects both of the mechanical properties and the physical properties greatly. The addition of hydroxyethyl cellulose (HEC) in the electrolyte can prevent the formation of pinhole and promote fine crystallization; accordingly it improves the mechanical properties of copper foil.