It is an object of the invention to provide a thin, lightweight, high
performance, and low in cost semiconductor device and a display device by
reducing an arrangement area required for a power supply wiring and a
ground wiring of a functional circuit and decreasing a drop in power
supply voltage and a rise in ground voltage.In the functional circuit of
the semiconductor device and the display device, a power supply wiring
and a ground wiring are formed in a comb-like arrangement, and the tips
thereof are electrically connected with a first wiring, a second wiring,
and a contact between the first wiring and the second wiring, thereby
forming in a grid-like arrangement. The drop in power supply voltage and
the rise in ground voltage can be decreased and the arrangement area can
be decreased in the grid-like arrangement.