The present invention relates to a copper interconnection comprising a copper or copper alloy layer, wherein at least 50% of crystal grains of copper or a copper alloy form twins. A copper interconnection of the present invention is, therefore, highly reliable, and, a production cost thereof is low.
An RF power transistor with a metal design (70) comprises a drain pad (72) and a plurality of metal drain fingers (74) extending from the drain pad, wherein at least one metal drain finger comprises one or more sections of metal (74-1, 74-2, 100-1, 100-2, 100-3), each section of metal including of one or more branch (54-1, 54-2, 116-1, 116-2, 116-11, 116-21, 116-41) of metal having a metal width maintained within a bamboo regime.
