the present invention has an object to provide an active - matrix liquid crystal display device that realizes the improvement in productivity as well as in yield . in the present invention , a laminate film comprising the conductive film comprising metallic material and the second amorphous semiconductor film containing an impurity element of one conductivity type and the amorphous semiconductor film is selectively etched with the same etching gas to form a side edge of the first amorphous semiconductor film 1001 into a taper shape . thereby , a coverage problem of a pixel electrode 1003 can be solved and an inverse stagger type tft can be completed with three photomask . selected figure is fig . 15 .