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US 8,525,173 B2Granted
Semiconductor device and manufacturing method thereof
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei Yamazaki
Life of this patent
Estimating the term…
Abstract
A means of forming unevenness for preventing specular reflection of a pixel electrode, without increasing the number of process steps, is provided. In a method of manufacturing a reflecting type liquid crystal display device, the formation of unevenness (having a radius of curvature r in a convex portion) in the surface of a pixel electrode is performed by the same photomask as that used for forming a channel etch type TFT, in which the convex portion is formed in order to provide unevenness to the surface of the pixel electrode and give light scattering characteristics.
Claims64
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring comprises a same material as a material of the gate electrode,
- wherein each of the second wiring and the convex portion comprises a same material as a material of the source electrode and the drain electrode,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the convex portion is island-shaped, and
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode.
14 more elements
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring comprises a same material as a material of the gate electrode,
- wherein each of the second wiring and the convex portion comprises a same material as a material of the source electrode and the drain electrode,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the convex portion is island-shaped,
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode,
- wherein an size of the convex portion is 1 to 400 μm2, and
- wherein adjacent convex portions are isolated by 0.1 μm or greater.
16 more elements
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a terminal portion comprising a first layer and a second layer over the first substrate, the terminal portion electrically being connected to a flexible printed circuit,
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring comprises a same material as a material of the gate electrode,
- wherein each of the second wiring and the convex portion comprises a same material as a material of the source electrode and the drain electrode,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the first layer comprises a same material as a material of the gate electrode, and the second layer comprises a same material as a material of the pixel electrode,
- wherein the second layer covers at least one end of the first layer,
- wherein the convex portion is island-shaped, and
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode.
17 more elements
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a terminal portion comprising a first layer and a second layer over the first substrate, the terminal portion electrically being connected to a flexible printed circuit,
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring comprises a same material as a material of the gate electrode,
- wherein each of the second wiring and the convex portion comprises a same material as a material of the source electrode and the drain electrode,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the first layer comprises a same material as a material of the gate electrode, and the second layer comprises a same material as a material of the pixel electrode,
- wherein the second layer covers at least one end of the first layer,
- wherein the convex portion is island-shaped,
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode,
- wherein an size of the convex portion is 1 to 400 μm2, and
- wherein adjacent convex portions are isolated by 0.1 μm or greater.
19 more elements
A liquid crystal display device comprising:
- a first substrate,
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring and the gate electrode are concurrently formed by a first same patterning process step,
- wherein the second wiring, the convex portion, the source electrode, and the drain electrode are concurrently formed by a second same patterning process step,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the convex portion is island-shaped, and
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode.
14 more elements
A liquid crystal display device comprising:
- a first substrate,
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring and the gate electrode are concurrently formed by a first same patterning process step,
- wherein the second wiring, the convex portion, the source electrode, and the drain electrode are concurrently formed by a second same patterning process step,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the convex portion is island-shaped,
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode,
- wherein an size of the convex portion is 1 to 400 μm2, and
- wherein adjacent convex portions are isolated by 0.1 μm or greater.
16 more elements
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a terminal portion comprising a first layer and a second layer over the first substrate, the terminal portion electrically being connected to a flexible printed circuit;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring, the first layer and the gate electrode are concurrently formed by a first patterning process step,
- wherein the second wiring, the convex portion, the source electrode, and the drain electrode are concurrently formed by a second pattering process step,
- wherein the second layer and the pixel electrode are concurrently formed by a third patterning process step,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the second layer covers at least one end of the first layer,
- wherein the convex portion is island-shaped, and
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode.
17 more elements
A liquid crystal display device comprising:
- a first substrate;
- a thin film transistor over the first substrate, the thin film transistor comprising:
- a gate electrode over the first substrate;
- a semiconductor film having a channel forming region over the gate electrode;
- a source electrode and a drain electrode over the semiconductor film;
- a pixel electrode electrically connected to the thin film transistor;
- a first wiring over the first substrate;
- a second wiring over the first wiring;
- a convex portion overlapped with the first wiring;
- a terminal portion comprising a first layer and a second layer over the first substrate, the terminal portion electrically being connected to a flexible printed circuit;
- a second substrate opposite to the first substrate;
- and
- a light shielding portion located between the thin film transistor and the second substrate,
- wherein the first wiring, the first layer and the gate electrode are concurrently formed by a first patterning process step,
- wherein the second wiring, the convex portion, the source electrode, and the drain electrode are concurrently formed by a second pattering process step,
- wherein the second layer and the pixel electrode are concurrently formed by a third patterning process step,
- wherein the second wiring has a lamination structure comprising at least two conductive layers,
- wherein the second layer covers at least one end of the first layer,
- wherein the convex portion is island-shaped,
- wherein the channel forming region overlaps with the light shielding portion, and does not overlap with the pixel electrode,
- wherein a size of the convex portion is 1 to 400 μm2, and
- wherein adjacent convex portions are isolated by 0.1 μm or greater.
19 more elements
Dependencies are inferred from the claim text.