Pattern forming method and method of manufacturing thin film transistor
AssigneeNEC LCD Technologies, Ltd.
InventorShusaku Kido
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Abstract
After films composing a TFT are laminated on an insulating substrate, a resist mask having a plurality of regions with different film thicknesses is formed by patterning on the uppermost layer of the above-stated films. Then, a conductor film is formed by patterning with a liftoff method using this resist mask. Alternatively, using other resist mask having a plurality of regions with different film thicknesses as an etching mask, a plurality of material films among the laminated material films are processed in succession. By the above-stated new pattern forming method and the processing method, the liquid crystal display device, which has been manufactured by five photolitho processes in a conventional art is manufactured by two or three photolitho processes.
Claims11
A pattern forming method comprising the steps of:
- forming a first layer on a substrate;
- forming a second layer on the first layer;
- forming a mask layer on the second layer, the mask layer being patterned to have a first region and a second region such that the second region is thicker than the first region and the first region is provided with an opening;
- etching the second layer using the mask layer as an etching mask to form a contact hole reaching a surface of the first layer;
- removing at least the first region by etching to leave a liftoff pattern constituting a third region within the second region on the first layer;
- forming a third layer for covering the third region;
- and
- removing the third region to pattern the third layer by liftoff after forming the third layer.
A method of manufacturing a thin film transistor, comprising the steps of:
- patterning a first conductive film deposited on an insulating substrate to form a first conductive film pattern;
- depositing a first insulation layer covering the first conductive film, then depositing a second conductive film thereon, and forming a first mask on the second conductive film, the first mask having a plurality of regions with different film thicknesses and including a region as a first portion which is thin in a film thickness, and a region as a second portion which is thicker than the first portion in the film thickness;
- etching the second conductive film using the first mask as an etching mask, removing the first portion of the first mask to leave the second portion as a third portion, and subsequently etching the second conductive film using the third portion as a mask to process the second conductive film;
- after removing the third portion of the first mask, depositing a second insulation layer covering the second conductive film over the first insulation layer;
- forming a second mask on the second insulation layer, the second mask having a plurality of regions with different film thicknesses and including a region as a first portion which is thin in the film thickness, a region as a second portion which is thicker than the first portion in the film thickness, and an opening formed in the first portion;
- etching the second insulation layer and the first insulation layer using the second mask as an etching mask to partially form a first contact in the second insulation layer and the first insulation layer on the first conductive film and to partially form a second contact in the second insulation layer on the second conductive film;
- and
- removing the first portion of the second mask to make a remainder portion of the second portion a third portion, subsequently depositing a third conductive film on the second insulation layer, and removing the third portion together with the third conductive film deposited thereon to form an electrode or a wiring for a third conductive film.
Dependencies are inferred from the claim text.