Liquid crystal display device and a manufacturing method of the same
A four-mask process and a three-mask process proposal are constructed for a TN-type liquid crystal display device and an IPS-type liquid crystal device in which the formation of a passivation insulating layer is not required by streamlining the formation of a scan line and a pseudo-pixel element, both comprising a laminate made of a transparent conductive layer and a metal layer, at the same time and the formation of the transparent conductive pixel electrode by removing the metal layer on the pseudo-pixel electrode at the time of the formation of the opening in the gate insulating layer, by streamlining the treatment of the formation process of the contact and the formation process of the protective insulating layer using one photomask due to the introduction of half-tone exposure technology, and the formation of source-drain wires for etch-stop type insulating gate-type transistor using a photosensitive organic insulating layer and leaving the photosensitive organic insulating layer unchanged on source-drain wires or on the source wire (signal line), or by forming an anodized layer, which is an insulating layer, on source-drain wires.
1. A liquid crystal display device having an etch-stop type insulating gate-type transistor, which has a protective insulating layer on a channel thereof, the liquid crystal display device comprising:
1) a first insulating substrate in which unit pixels are arranged in a 2-dimensional matrix on a principal plane, wherein the first insulating substrate comprises:
a) the insulating gate-type transistor,
b) a scan line doubling as a gate electrode and signal line doubling as a source wire of the insulating gate-type transistor,
c) a pixel electrode connected to a drain of the insulating gate-type transistor,
d) a counter electrode formed at a specified distance from the pixel electrode;
2) a second insulating substrate or a color filter that faces the first insulating substrate; and
3) liquid crystal filled between the first insulating substrate and the second insulating substrate or a color filter;
wherein at least the signal line is insulated with an insulating layer;
wherein an opening that self aligns with the protective insulating layer is defined on the scan line outside an image display area, at least in a gate insulating layer and, such that part of the scan line is exposed in the opening, and
wherein the scan line exposed in the opening is a single-layered transparent conductive layer.
2. The liquid crystal display device as in claim 1 , wherein the scan line and the counter electrode, comprising a first metal layer of one or more layers, are formed on a main surface of the first insulating substrate,
a first semiconductor layer absent or near absent of impurities is formed in an island form through a gate insulating layer of one or more layers above the gate electrode,
the protective insulating layer is formed narrower than the gate electrode on the first semiconductor layer above the gate electrode,
the source and the drain wire, comprising a laminate of a second semiconductor layer including impurities and a second metal layer of one more layers including a heat-resistant metal layer, are formed on part of the protective insulating layer and on the first semiconductor layer,
the photosensitive organic insulating layer is formed on the signal line except for an electrode terminal of the signal line, which is part of the signal line, and
an electrode terminals of the scan line comprising a second metal layer is formed in a gate insulating layer on the scan line outside an image display area.
3. The liquid crystal display device as in claim 1 , wherein
the scan line and the counter electrode, each comprising a first metal layer of one or more layers, are formed on a main surface of the first insulating substrate,
a first semiconductor layer with absence or near absence of impurities is formed in an island form through a gate insulating layer of one or more layers above the gate electrode,
the protective insulating layer is formed narrower than the gate electrode on the first semiconductor layer above the gate electrode,
the source wire and the drain wire comprising a laminate of a second semiconductor layer including impurities and a heat-resistant metal layer of one or more layers are formed on part of the protective insulating layer and on the first semiconductor layer,
the photosensitive organic insulating layer is formed on the signal line except for on an electrode terminal of the signal line, which is part of the signal line, and
an electrode terminal of the scan line comprising a second semiconductor layer and a second metal layer is formed containing an opening, which is formed in a gate insulating layer on the scan line outside an image display area and self aligns with the protective insulating layer.
4. The liquid crystal display device as in claim 1 , wherein
the scan line and the counter electrode, comprising a first metal layer of one or more layers, are formed on a main surface of the first insulating substrate,
a first semiconductor layer not including impurities is formed in an island form through a gate insulating layer of one or more layers above the gate electrode,
the protective insulating layer is formed narrower than the gate electrode on the first semiconductor layer above the gate electrode,
the source wire and the drain wire comprising a laminate of a second semiconductor layer including impurities and an anodizable metal layer of one or more layers including a heat-resistant metal layer are formed on part of the protective insulating layer and on the first semiconductor layer,
an anodized layer is formed on the surface of a source-drain wire except for on an electrode terminal of the signal line, which is part of the signal line,
an electrode terminal of the scan line comprising a second semiconductor layer and an anodizable metal layer is formed containing an opening, which is formed in a gate insulating layer on the scan line outside an image display area.
5. The liquid crystal display device as in claim 1 , wherein
the scan line and the counter electrode, comprising a first metal layer of one or more layers, are formed on a main surface of the first insulating substrate,
a first semiconductor layer not including impurities is formed in an island form through a gate insulating layer of one or more layers above the gate electrode,
the protective insulating layer is formed narrower than the gate electrode on the first semiconductor layer above the gate electrode,
the source wire and the drain wire comprising a laminate of a second semiconductor layer including impurities and an anodizable metal layer of one or more layers including a heat-resistant metal layer are formed on part of the protective insulating layer and on the first semiconductor layer,
an anodized layer is formed on the surface of a source-drain wire except for on an electrode terminal of the signal line, which is part of the signal line,
an electrode terminal of the scan line comprising a second semiconductor layer and an anodizable metal layer is formed containing an opening, which is formed in a gate insulating layer on the scan line outside an image display area and self aligns with the protective insulating layer.