Liquid crystal display having patterned insulating and semiconductor layers and a method of fabricating the same

• US 5,541,748 A
• Filed: 06/07/1994
• Issued: 07/30/1996
• Est. Priority Date: 06/07/1993
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Asuma, Hiroaki, Ono, Kikuo, Yamamoto, Hideaki, Konishi, Nobutake, Ohwada, Junichi
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): Abraham, Fetsum
• Application Number:
  US08/255,958
• Time in Patent Office: 784 Days
• Field of Search: 359/59, 359/87, 359/58, 359/79
• US Class Current: 349/42
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52

Abstract

A liquid crystal display provided with a matrix of inverted-stagger thin-film transistors has a plurality of gate insulating films formed over gate lines and including one insulating film formed in contact with gate electrodes of the thin-film transistors and in self-alignment with gate lines in the picture display area of the liquid crystal display. The rest of the gate insulating films not crossing the gate electrodes and in contact with a semiconductor layer are patterned in conformity with drain electrodes (data lines), and a semiconductor layer and an insulating film not crossing the drain electrode and crossing the gate electrodes are patterned at the same time. The method has less steps than the conventional method, is capable of fabricating a liquid crystal display capable of displaying pictures in a high picture quality at a high yield rate.

Claims

1. A method of fabricating a liquid crystal display comprising:

a substrate having a main surface, metal gate lines formed on the main surface of said substrate, data lines formed so as to intersect the gate lines, with respect to a plan view of the substrate main surface, at substantially right angles, thin-film transistors formed-near the intersections of the gate lines and the data lines, and pixel electrodes connected to the thin-film transistors to drive a liquid crystal material;

comprising the steps of;

anodizing upper and end side surfaces of the gate lines formed on the main surface of said substrate, respectively; and

continuously patterning insulating films and semiconductor layers stacked thereon, respectively, in a manner such that, with respect to a plan view of the substrate main surface, the patterns effected for each stacked pair of an insulating film and a semiconductor layer are substantially the same and coincide, each such stacked pair covering at least part of the anodized oxide film on respective ones of said gate lines.

2. A liquid crystal display comprising:

a substrate;

gate lines formed on said substrate;

data lines intersecting with said gate lines in a matrix shape;

thin-film transistors formed near the intersections of said gate lines and said data lines, respectively;

pixel electrodes connected to said thin-film transistors, respectively, to drive a liquid crystal material provided in said display, said pixel electrodes being formed on said substrate, respectively;

an insulating layer formed on said substrate along said data lines, respectively; and

a semiconductor layer formed on said insulating layer and having substantially a same pattern as that of said insulating layer,

wherein said data lines are formed on said semiconductor layer.

3. A liquid crystal display according to claim 2, wherein said insulating layer is disposed to be partially overlapping with said pixel electrodes.

4. A liquid crystal display according to claim 2, wherein said semiconductor layer is dimensioned to have a width which is greater than that of said data lines, respectively.

5. A liquid crystal display according to claim 2, wherein said semiconductor layer consists of an intrinsic type semiconductor layer.

6. A liquid crystal display according to claim 2, wherein said gate lines are coated with an anodic oxide film, respectively.

7. A liquid crystal display according to claim 2, wherein each of said thin-film transistors uses a corresponding one of said gate lines as a gate electrode, a corresponding said insulating layer being formed on said gate electrode and said semiconductor layer being formed on said insulating layer.

8. A liquid crystal display according to claim 7, wherein each of said thin-film transistors has a drain and a source electrode which are formed on said semiconductor layer.

9. A liquid crystal display according to claim 8, wherein said insulating layer and semiconductor layer formed on said gate electrode have substantially a same pattern.

10. A liquid crystal display according to claim 9, wherein said source electrode corresponding to each of said thin-film transistors is shaped to have a bending plane pattern.

11. A liquid crystal display according to claim 2, wherein an angle of inclination of an edge surface of said insulating layer is smaller than that of an edge surface of said semiconductor layer.

12. A liquid crystal display comprising:

a substrate;

gate lines formed on said substrate;

data lines intersecting with said gate lines in a matrix shape;

thin-film transistors formed near the intersections of said gate lines and said data lines, respectively, wherein each of said thin-film transistors uses a corresponding one of said gate lines as a gate electrode and each of said thin-film transistors has one of a drain and source electrode which is connected to a corresponding one of said data lines;

pixel electrodes each of which is electrically connected to the other of the drain and source electrode of a corresponding one of said thin-film transistors to drive a liquid crystal material provided in said display, said pixel electrodes being formed on said substrate, respectively;

an insulating layer formed on said substrate along said data lines, respectively, and on said gate electrode of each of said thin-film transistors corresponding thereto; and

a semiconductor layer formed on said insulating layer and having substantially a same pattern as that of said insulating layer,

wherein said data lines and said source and drain electrodes of each of said thin-film transistors are formed on said semiconductor layer, and

wherein said semiconductor layer is dimensioned to have a width which is greater than that of said data lines, respectively.

13. A liquid crystal display according to claim 12, wherein said insulating layer is disposed to be partially overlapping with said pixel electrodes.

14. A liquid crystal display according to claim 12, wherein said semiconductor layer consists of an intrinsic type semiconductor layer.

15. A liquid crystal display according to claim 12, wherein said gate lines are coated with an anodic oxide film, respectively.

16. A liquid crystal display according to claim 12, wherein an angle of inclination of an edge surface of said insulating layer is smaller than that of an edge surface of said semiconductor layer.

17. A liquid crystal display according to claim 12, wherein said source electrode corresponding to each of said thin-film transistors is shaped to have a bending plane pattern.

18. A liquid crystal display according to claim 12, wherein each of said gate lines consists of a single-metal layer and an anodized oxide film of metal formed on upper and side surfaces thereof.

19. A liquid crystal display according to claim 13, wherein said single-metal layer is formed of aluminum.

20. A liquid crystal display according to claim 18, wherein each of said data lines and said source and drain electrodes is constituted by a stacked arrangement of first and second metal layers.

21. A liquid crystal display according to claim 18, wherein each of said data lines consists of a single-metal layer.