Patent ID: 7338716
Filing Date: 2008-03-04
Classification: B32B,H05K,Y10T

Abstract:
1. A laminate comprising a metal foil and an insulating resin layer, wherein the insulating resin layer comprises (1) at least one polyimide resin layer (A) of low thermal expansion with a coefficient of linear thermal expansion of 30×10 wherein the metal foil is in contact with the polyimide resin layer (B) and the bonding strength between the metal foil and the polyimide resin layer (B) in contact therewith is 0.5 kN/m or more, wherein the polyimide resin layer (B) intervenes between the metal foil and the polyimide resin layer (A), wherein the average rate of etching of the insulating resin layer by a 50 wt % aqueous solution of potassium hydroxide at 80° C. is 0.5 μm/min or more, wherein the insulating resin layer comprises a ratio in thickness of polyimide resin layer (A)/polyimide resin layer (B) in the range of 2-100 based on the total polyimide resin layers constituting the insulating resin layer, wherein the polyimide resin layer (A) comprises a rate of etching 1 to 30 times that of the polyimide resin layer (B) in contact with the metal foil, wherein the rates of etching of the polyimide resin layers (A) and (B) by a 50 wt % aqueous solution of potassium hydroxide at 80° C. is 2 μm/min or more and 0.5 μm/min or more, respectively, wherein the polyimide resin layer (B) comprises a polyimide resin obtained by the reaction of a diamine with a tetracarboxylic acid dianhydride, and wherein 50 mol % or more of the diamine in use is at least one kind of diamine selected from the group consisting of 2,4-diaminotoluene, 1,3-bis(3-aminophenoxy)benzene, 4,4′-diamino-2′-methoxybenzanilide, and diamines represented by the following general formula (2)  wherein Z-Z3 are independently hydrogen atoms and alkyl groups containing 1-3 carbon atoms and Y is a divalent straight-chain or branched aliphatic hydrocarbon group containing 1-5 carbon atoms and optionally a substituent.