The wiring of the present invention has a layered structure that includes
a first conductive layer (first layer) having a first width and made of
one or a plurality of kinds of elements selected from W and Mo, or an
alloy or compound mainly containing the element, a low-resistant second
conductive layer (second layer) having a second width smaller than the
first width, and made of an alloy or a compound mainly containing Al, and
a third conductive layer (third layer) having a third width smaller than
the second width, and made of an alloy or compound mainly containing Ti.
With this constitution, the present invention is fully ready for
enlargement of a pixel portion. At least edges of the second conductive
layer have a taper-shaped cross-section. Because of this shape,
satisfactory coverage can be obtained.