rolled copper foil and a method of manufacturing the same, as well as copper-clad laminate

摘要

Provided are a rolled copper foil which has excellent flexibility and has a surface with satisfactory etchability, a process for producing the copper foil, and a copper-clad laminate. The copper foil, after 0.5-hour annealing at 200ºC, has an I(200)/I0(200) of 50 or greater. When the copper foil is examined with a stylus type surface roughness tester and the average length of contour elements which is defined in JIS-B0601 is expressed by Rsm, then the ratio of the value thereof determined through a measurement made in a direction perpendicular to the rolling direction (RsmTD) to the value thereof determined through a measurement made in a direction parallel to the rolling direction (RsmRD), RsmTD/RsmRD, is 2.0 or greater. In the copper foil after 0.5-hour annealing at 200ºC, the areal proportion of crystal grains which have a major-axis length of 20 µm or shorter in a 0.5-mm-square region in the surface (rolled surface) is 20% or more. When a cross-section of the copper foil which is parallel to the rolling direction is examined with an SEM over a length of 0.5 mm along the rolling direction, then the areal proportion of crystal grains which are present across the center of the copper foil thickness and have a major-axis length of 20 µm or shorter is up to 20% of the field of view.