METALLIC INTERCONNECTION, METHOD OF FORMING THIN-FILM TRANSISTOR USING THE SAME, TFT LIQUID-CRYSTAL DISPLAY DEVICE AND METAL INTERCONNECTION

摘要

PURPOSE:To restrain the hillock of a metal interconnection from being generated by forming the metal interconnection which is composed of a laminated film of thin films patterned on a substrate and composed mainly of Al and in which the upper-layer film of the laminated film is composed of an Al thin film doped with Ta. CONSTITUTION:A glass substrate is used as a substrate 11, a pure Al thin film which is not doped with impurities is formed as a gate-electrode lower-layer part 13 and an Al thin film which is doped with Ta is formed as a gate-electrode upper-layer part 14 continuously without breaking a vacuum by a DC sputtering method in such a way that their film thicknesses are respectively at 250 and 100nm. After that, a working operation is performed by a photolithographic technique, and they are changed into a gate electrode 12. In addition, a cross-sectional taper angle theta1 which is formed by a lower-layer film at a pattern edge part for a laminated film with reference to the substrate is set at 30 deg. or higher and less than 90 deg., and a cross-sectional taper angle theta2 which is formed by an upper-layer film at a pattern edge part for the laminated film with reference to a flat part on the surface of the upper-layer film is set at 130 deg. or higher and less than 180 deg..