Cost effective and high quality processes are needed for further development of flexible electronic systems Applications of these structures are e. g. in the field of high density interconnection foils or polymer electronics. In this paper a lithography process for patterning copper on flexible foils using reel-to-reel methods is presented. The process allows the fabrication of well defined copper structures with typical feature sizes from 15 to 40 μm using either etching or electro plating technology. Properties of the dry film photoresist used in the process as well as details of the technology are described. Influences of photolithography and etching on dimensional accuracy and resolution are given and some consequences on design rules are shown.