Electrolytic copper foil with low roughness surface and process for producing the same

Abstract

An electrolytic copper foil with low roughness surface whose surface roughness (Rz) is 2.0 μm or less, the surface uniformly provided with low roughness without uneven surge, which electrolytic copper foil exhibits a percent elongation of 10.0% or higher at 180° C. This electrolytic copper foil with low roughness surface can be obtained by a process for producing an electrolytic copper foil, comprising passing a direct current between an insoluble anode consisting of a titanium plate coated with a Platinum Group element or oxide thereof and a titanium drum as a cathode counter to the anode in an electrolyte of an aqueous solution of sulfuric acid / copper sulfate, wherein the electrolyte contains an oxyethylene surfactant a polyethyleneimine or derivative thereof, a sulfonate of active organosulfer compound and chloride ions.

Description

TECHNICAL FIELD [0001] The present invention relates to electrodeposited copper foil with low roughness surface and processes for producing the same, the copper foils having roughness surface uniformly provided with low roughness without uneven surge and being applicable in printed-wiring boards or cathode collectors of lithium secondary battery. BACKGROUND ART [0002] One conventional process for producing an electrodeposited copper foil well known in the art includes passing a direct current between an insoluble anode consisting of a titanium plate coated with a Platinum Group element or oxide thereof and a titanium drum as a cathode counter to the anode in an electrolyte of an aqueous solution of sulfuric acid / copper sulfate to allow electrodeposited copper to precipitate on the surface of the titanium drum, while peeling off the precipitated electrodeposited copper from the surface of the titanium drum rotating at a constant speed and continuously winding up the same. [0003] In t...

AI Technical Summary

Benefits of technology

[0014] That is, the present invention is directed to an electrodeposited copper foil with low roughness surface, wherein surface roughness (Rz) is 2.0 μm or less, surface uniformity is provided with low roughness without uneven surge, and a percent elongation is 10.0% or higher at 180° C.

Problems solved by technology

However, it is difficult to reduce the difference in roughness between gloss surface and roughness surface, while satisfying various practicable mechanical characteristics.

The resultant electrodeposited copper foil had low roughness on the roughness surface of the electrodeposited copper foil, however, moderate uneven surge still occurred on the roughness surface (see FIG. 7 below).

The moderate uneven surge occurring on the roughness surface of the electrodeposited copper foil (electrodeposited copper foil, without treatment) may induce abnormal precipitation of copper crystalline particles during the aforementioned step of providing roughness, and increase surface roughness (Rz) of a roughness surface of product.

In application of flexible printed-wiring board, a copper foil undergoes heat history in the step of adhesion with an insulating film, and when copper crystalline particles are small in size, they will grow and become bulky through this heat history.

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