Wiring board, manufacturing method thereof, semiconductor device and manufacturing method thereof

摘要

The invention provides a wiring board having a small-scale and high-performance functional circuit while realizing a multi-layer wiring with a small number of steps. In addition, the invention provides a semiconductor device in which a display device is integrated with such high-performance functional circuit on the same substrate. According to the invention, first to third wirings, first and second interlayer insulating films and first and second contact holes are formed over a substrate having an insulating surface. The second wiring is wider than the first wiring, or the third wiring is wider than the first wiring or the second wiring. The second contact hole has a larger diameter than the first contact hole.