Thin film patterning method and method for manufacturing a liquid crystal display device
View Patent ↗A thin film patterning method comprising: depositing a first thin film and applying a photoresist layer on the first thin film; exposing and developing the photoresist layer to define first, second and third regions, wherein the photoresist layer in the first region is thicker than that in the second region, and no photoresist layer is left in the third region; over-etching to remove the first thin film in the third region and form an over-etched region in the peripheral region of the first region; removing a part of the photoresist layer to expose the first thin film in the second region; depositing a second thin film so that the first thin film contacts the second thin film in the second region; and lifting off the photoresist layer to remove the second thin film in the first region and exposing the substrate in the over-etched region of the first region.
1. A method for manufacturing a liquid crystal display device comprising
step 1 of depositing a common electrode transparent conductive layer on a substrate, and applying a photoresist layer on the common electrode transparent conductive layer;
step 2 of exposing and developing the photoresist layer using a dual tone mask to define a first region, a second region and a third region, wherein the photoresist layer in the first region is thicker than the photoresist layer in the second region and there is no photoresist layer left in the third region;
step 3 of over-etching the common electrode transparent conductive layer to remove the common electrode transparent conductive layer in the third region and form an over-etched region in the peripheral region of the first region;
step 4 of removing a part of the photoresist layer by ashing to expose the common electrode transparent conductive layer in the second region;
step 5 of depositing a gate metal layer so that the common electrode transparent conductive layer contacts the gate metal layer in the second region;
step 6 of lifting off the photoresist layer to remove the gate metal layer in the first region and exposing the substrate in the over-etched region of the first region, thereby forming gate lines, common electrode lines, and common electrodes contacting the common electrode lines;
step 7 of forming thin film transistors comprising a source/drain electrode metal layer on the substrate; and
step 8 of forming pixel electrodes on the substrate.
2. The thin film patterning method of claim 1 , wherein in step 3, a pattern composed of the common electrode transparent conductive layer is formed in a peripheral region of the first region adjacent to the second region.
3. The thin film patterning method of claim 1 , wherein in step 3, the substrate is exposed in a peripheral region of the first region adjacent to the third region.
4. The thin film patterning method of claim 1 , wherein in step 3, the common electrode transparent conductive layer is over-etched by a wet etching process.
5. The thin film patterning method of claim 4 , wherein in step 3, the common electrode transparent conductive layer has a bias of 3 μm or more by said over-etching.