US Patent 7402914 Semiconductor device featuring overlay-mark used in photolithography process

In a semiconductor device, an insulating layer formed on a substrate and a wiring pattern layer is formed on the insulating layer. A lower mark element is defined as a groove formed in the insulating layer, and defines an overlay mark in conjunction with an upper mask element formed in a photoresist pattern coated on the insulating layer for the formation of the wiring pattern layer. The lower mark element features a width falling within a range from approximately 4 to 6 μm, and a depth of at most 1 μm.