Abstract: Copper and copper alloy comprises: a structure having fine crystal grains with grain size of 1 ?m or less after a final cold rolling with a reduction ?, wherein ? is expressed in the following formula and satisfying ??3; and an elongation of 2% or more in a tensile test. ?=ln(T0/T1) T0: plate thickness before rolling, T1: plate thickness after rolling.

Abstract: A copper-alloy foil used for a laminate sheet achieves 5.0N/cm or more of 180° peeling strength when thermally fusion-bonded with liquid crystal polymer. The copper-alloy foil contains one or more of from 0.01 to 2.0% of Cr and from 0.01 to 1.0% of Zr. An oxide layer and occasionally a rust-proof film present on the outermost surface is 10 nm or less. The electrical conductivity is 50% IACS.

Abstract: Conductors, which are formed on a suspension member of the hard-disc drive suspension, are subject to thermal expansion and shrinkage during the laminating process with a substrate via a polyimide binder. The tracking width of the suspension member is influenced by the thermal expansion and shrinkage. In order to provide a copper-alloy foil, which can attain improved tracking width, the following ratio of thermal expansion and shrinkage is adjusted in a range of from −0.1 to +0.1% &Dgr;(%)=(l−l0)/l0×100 where l0 the length of a specimen before heating at 330° C. for 2 hours, and l is the length of a specimen after heating at 330° C. for 2 hours. &Dgr;(%) is measured in the direction parallel to the rolling direction.

Abstract: A copper-alloy foil used for a laminate sheet achieves 5.0N/cm or more of 180° peeling strength when thermally fusion-bonded with liquid crystal polymer. The copper-alloy foil contains one or more of from 0.01 to 2.0% of Cr and from 0.01 to 1.0% of Zr. An oxide layer and occasionally a rust-proof film present on the outermost surface is 10 nm or less. The electrical conductivity is 50% IACS.

Abstract: Copper and copper alloy comprises: a structure having fine crystal grains with grain size of 1 &mgr;m or less after a final cold rolling with a reduction &eegr;, wherein &eegr; is expressed in the following formula and satisfying &eegr;≧3; and an elongation of 2% or more in a tensile test.

Abstract: The conductors, which are formed on a suspension member of the hard-disc drive suspension is subjected to thermal expansion and shrinkage during the laminating process with a substrate via polyimide binder 3. The tracking width of the suspension member is influenced by the thermal expansion and shrinkage. In order to provide a copper-alloy foil, which can attain improved tracking width, the following ratio of thermal expansion and shrinkage is adjusted in a range of from −0.1 to+0.

Abstract: A copper alloy foil to be used in a printed board comprising a polyimide substrate is provided. The copper foil is not subjected to roughening plating and has hence fine surface roughness and can be directly bonded with the polyimide substrate. The copper alloy contains (a) one or more of the additive elements of from 0.01 to 2.0% of Cr and from 0.01 to 1.0% of Zr, or (b) from 1.0 to 4.8% of Ni and from 0.2 to 1.4% of Si. The surface roughness in terms of the ten-point average surface-roughness (Rz) is 2 &mgr;m or less, the 180° peeling strength is 8.0 N/cm or more. The alloy (a) has 600 N/mm2 or more of tensile strength, and 50% ICAS or more of electric conductivity. The alloy (b) has 650 N/mm2 or more of tensile strength, and 50% ICAS or more of electric conductivity.

Abstract: Copper alloy foils are provided having far greater strength and heat resistance than conventional copper foils, and having better productivity, are characterized by a composition comprising, all by weight, from 0.01 to 0.4% Cr, from 0.01 to 0.25% Zr, from 0.02 to 2.0% Zn; and when necessary from 0.05 to 1.8% Fe and from 0.05 to 0.8% Ti; and when further necessary one or more elements selected from the group consisting of Ni, Sn, In, Mn, P, Mg, Al, B, As, Cd, Co, Te, Ag, and Hf in a total amount of from 0.005 to 1.5%; the balance being copper and unavoidable impurities. Inclusions in the copper foil not larger than 10 .mu.m in size, and the inclusions between 0.5 and 10 .mu.m in size number less than 100 pieces/mm.sup.2.