The present invention provides a method for manufacturing a semiconductor
device having high characteristic and reliability. The etching damage
during dry etching after forming an electrode or a wiring over an
insulating film is prevented. The damage is suppressed by forming a
conductive layer so that charged particles due to plasma during dry
etching are not generated in a semiconductor layer. Accordingly, it is an
object of the invention to provide a method not for generating the
deterioration of the transistor characteristic especially in a thin film
transistor having a minute structure.