Method of manufacture thin film transistor

Claim 1

A method for manufacturing a thin-film transistor with a gate layer, and source and drain electrode layers, said method comprising the steps of: forming a metal film having a predetermined profile on a first surface of an electrically insulative substrate which permits radiation to be transmitted therethrough, said metal film preventing the transmission of radiation and serving as the gate layer; forming an electrically insulative film on the first surface of said substrate so as to cover the gate metal film, said insulative film being thin enough to allow the transmittance of radiation; forming an electrically conductive and transparent film on said insulative film; forming a negative photoresist film on said conductive film; irradiating radiation from a second surface side opposite the first surface of said substrate to expose said negative photoresist film with said gate metal film being directly used as a mask, thereby forming a shadow of said gate metal film on said negative photoresist film, and then performing an etching process to obtain an electrically conductive film pattern in which an opening, which coincides with said profile of said gate metal film, is formed to define the source and drain electrode layers which are prevented from overlapping said gate metal film and which are self-aligned with said gate metal film; and forming a first semiconductive film on said opening and partially overlapping said source and drain electrode layers, said first semiconductive film serving as a channel region of said transistor.

Claim 2

A method for manufacturing a thin-film transistor with a gate layer, and source and drain electrode layers, said method comprising the steps of: forming a metal film having a predetermined profile on a first surface of an electrically insulative substrate which permits radiation to be transmitted therethrough, said metal film preventing the transmission of radiation and serving as the gate layer; forming an electrically insulative film on the first surface of said substrate so as to cover the gate metal film, said insulative film being thin enough to allow the transmittance of radiation; forming an electrically conductive and transparent film on said insulative film; forming a negative photoresist film on said conductive film; irradiating radiation from a second surface side opposite the first surface of said substrate to expose said negative photoresist film with said gate metal film being directly used as a mask, thereby forming a shadow of said gate metal film on said negative photoresist film, and then performing an etching process to obtain an electrically conductive film pattern in which an opening, which coincides with said profile of said gate metal film, is formed to define the source and drain electrode layers which are prevented from overlapping said gate metal film and which are self-aligned with said gate metal film; and forming a first semiconductive film on said opening and partially overlapping said source and drain electrode layers, said first semiconductive film serving as a channel region of said transistor.

Claim 13

A method for manufacturing a thin-film transistor with a gate electrode layer, and source and drain electrode layers, said method comprising the steps of: forming a metal layer having a predetermined profile on an electrically insulative and transparent substrate permitting the transmission of radiation, said metal layer serving as the gate electrode layer; sequentially forming on said substrate an insulative layer which is thin enough to permit the transmission of the radiation, a double-layer having a conductive and transparent layer, and a first semiconductor layer which is thin enough to permit the transmission of the radiation, so as to cover said gate electrode layer; forming a negative photoresist layer on said semiconductor layer; irradiating the radiation from the substrate side to form a shadow of the gate electrode on said negative photoresist layer with said electrode being directly used as a mask; performing solvent treatment of said negative photoresist layer to form therein an opening having a shape corresponding to the profile of said gate electrode; partially etching off said conductive and transparent layer and said semiconductor layer simultaneously by using the negative layer with the opening as a resist mask, thereby forming double-layered source and drain electrodes having substantially no overlap with said gate electrode without using a lift-off techique.

Claim 14

A method for manufacturing a thin-film transistor with a gate electrode layer, and source and drain electrode layers, said method comprising the steps of: forming a metal layer having a predetermined profile on an electrically insulative and transparent substrate permitting the transmission of radiation, said metal layer serving as the gate electrode layer; sequentially forming on said substrate an insulative layer which is thin enough to permit the transmission of the radiation, a double-layer having a conductive and transparent layer, and a first semiconductor layer which is thin enough to permit the transmission of the radiation, so as to cover said gate electrode layer; forming a negative photoresist layer on said semiconductor layer; irradiating the radiation from the substrate side to form a shadow of the gate electrode on said negative photoresist layer with said electrode being directly used as a mask; performing solvent treatment of said negative photoresist layer to form therein an opening having a shape corresponding to the profile of said gate electrode; partially etching off said conductive and transparent layer and said semiconductor layer simultaneously by using the negative layer with the opening as a resist mask, thereby forming double-layered source and drain electrodes having substantially no overlap with said gate electrode without using a lift-off techique.