There is provided a light emitting device in which low power consumption
can be realized even in the case of a large screen. The surface of a
source signal line or a power supply line in a pixel portion is plated to
reduce a resistance of a wiring. The source signal line in the pixel
portion is manufactured by a step different from a source signal line in
a driver circuit portion. The power supply line in the pixel portion is
manufactured by a step different from a power supply line led on a
substrate. A terminal is similarly plated to made the resistance
reduction. It is desirable that a wiring before plating is made of the
same material as a gate electrode and the surface of the wiring is plated
to form the source signal line or the power supply line.