A method for fabricating a lead tab , comprising: supplying a lead tab ; forming concavo-convex patterns by emitting laser light onto a predetermined region of the lead tab ; coating the concavo-convex patterns with a coating solution; and bonding an insulating film to the concavo-convex patterns coated with the coating solution, wherein the forming of the concavo-convex patterns comprises forming first concavo-convex patterns by emitting first laser light onto a first region in a front surface of the lead tab , and forming second concavo-convex patterns by emitting second laser light having intensity different from that of the first laser light onto a second region in a rear surface of the lead tab , wherein the first and second concavo-convex patterns are formed so that the spacings between the respective concavo-convex patterns adjacent to each other gradually decrease from a central region toward either edge region in a predetermined region of the lead tab , while the depths of the concavo-convex patterns gradually increase from the central region toward either edge region in the predetermined region of the lead tab , an area occupied by the concavo-convex patterns ranges from 10% to 95% of the entire area of the predetermined region of the lead tab , the concavo-convex patterns are formed with a depth ranging from 1% to 80% of the thickness of the lead tab , an area occupied by the first concavo-convex patterns formed on the first region of the front surface of the lead tab is different from an area occupied by the second concavo-convex patterns formed on the second region of the rear surface of the lead tab , the first region in the front surface of the lead tab , in which the first concavo-convex patterns are formed, and the second region in the rear surface of the lead tab , in which the second concavo-convex patterns are formed, partially overlap each other, and the predetermined region of the lead tab is a region to which the insulating film is bonded. supplying a lead tab ; forming concavo-convex patterns by emitting laser light onto a predetermined region of the lead tab ; coating the concavo-convex patterns with a coating solution; and bonding an insulating film to the concavo-convex patterns coated with the coating solution, wherein the forming of the concavo-convex patterns comprises forming first concavo-convex patterns by emitting first laser light onto a first region in a front surface of the lead tab , and forming second concavo-convex patterns by emitting second laser light having intensity different from that of the first laser light onto a second region in a rear surface of the lead tab , wherein the first and second concavo-convex patterns are formed so that the spacings between the respective concavo-convex patterns adjacent to each other gradually decrease from a central region toward either edge region in a predetermined region of the lead tab , while the depths of the concavo-convex patterns gradually increase from the central region toward either edge region in the predetermined region of the lead tab , an area occupied by the concavo-convex patterns ranges from 10% to 95% of the entire area of the predetermined region of the lead tab , the concavo-convex patterns are formed with a depth ranging from 1% to 80% of the thickness of the lead tab , an area occupied by the first concavo-convex patterns formed on the first region of the front surface of the lead tab is different from an area occupied by the second concavo-convex patterns formed on the second region of the rear surface of the lead tab , the first region in the front surface of the lead tab , in which the first concavo-convex patterns are formed, and the second region in the rear surface of the lead tab , in which the second concavo-convex patterns are formed, partially overlap each other, and the predetermined region of the lead tab is a region to which the insulating film is bonded. <EOS>