Transreflection-type liquid crystal display device and method of fabricating the same

• US 20040207784A1
• Filed: 12/30/2003
• Published: 10/21/2004
• Est. Priority Date: 04/15/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Lim, Byoung Ho, Nam, Chul, Park, Jong Woo, Kim, Gyu Bong, Kim, Seong Hee
• Granted Patent: US 7,161,648 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps

Abstract

A transreflection-type liquid crystal display (LCD) device includes a plurality of gate and data lines on a substrate crossing each other defining a plurality of pixel regions, a plurality of storage lines parallel to the gate lines, each storage line positioned between the gate lines, a plurality of thin film transistors disposed at the crossings of the gate and data lines, each thin film transistor having source and drain electrodes and a U-shaped channel region, a negative-type organic insulating layer within the pixel region except for a transmission part, the negative type organic insulating layer having at least one of concave and convex patterns thereon, a reflective electrode on the negative-type organic insulating layer within the pixel region except for the transmission part, and a transparent electrode within the pixel region in electrical contact with the drain electrode.

Claims

1. A transreflection-type liquid crystal display (LCD) device, comprising:

a plurality of gate and data lines on a substrate crossing each other defining a plurality of pixel regions;

a plurality of storage lines parallel to the gate lines, each storage line positioned between the gate lines;

a plurality of thin film transistors disposed at the crossings of the gate and data lines, each thin film transistor having source and drain electrodes and a U-shaped channel region;

a negative-type organic insulating layer within the pixel region except for a transmission part, the negative type organic insulating layer having at least one of concave and convex patterns thereon;

a reflective electrode on the negative-type organic insulating layer within the pixel region except for the transmission part; and

a transparent electrode within the pixel region in electrical contact with the drain electrode.

2. The device according to claim 1, wherein each of the gate and data lines have a pad disposed at one extending end portion and includes a pad terminal formed of a same material as the transparent electrode.

3. The device according to claim 1, wherein the thin film transistor includes an active layer disposed beneath the data line and the source and drain electrodes.

4. The device according to claim 1, wherein the source electrode protrudes from each of the data lines and overlaps a gate electrode of the thin film transistor.

5. The device according to claim 1, wherein the negative-type organic insulating layer includes a negative-type photoacryl.

6. The device according to claim 1, wherein the concave and convex patterns of the negative-type organic insulating layer are formed using a stamping process.

7. The device according to claim 1, further comprising a passivation layer disposed between the reflective electrode and the transparent electrode.

8. The device according to claim 7, wherein the passivation layer includes one of SiO_x and SiN_x.

9. A method for fabricating a transreflection-type liquid crystal display (LCD) device, comprising:

forming a gate line and a storage line on a substrate using a first mask;

forming a gate insulating layer on the substrate;

forming a data line and a thin film transistor having source and drain electrodes using a second mask by depositing a semiconductor layer and a metal layer on the substrate including the gate line and the storage line, the data line being perpendicular to the gate line to define a pixel region;

forming a negative-type organic insulating layer having at least one of concave and convex patterns therein using a third mask, the concave and convex patterns formed within the pixel region except for a transmission part;

forming a reflective electrode on the negative-type organic insulating layer formed within the pixel region except for the transmission part, using a fourth mask;

forming a contact hole on a drain electrode using a fifth mask; and

forming a transparent electrode within the pixel region using a sixth mask to be connected with the drain electrode through the contact hole.

10. The method according to claim 9, wherein the thin film transistor includes a U-shaped channel region.

11. The method according to claim 9, further comprising:

forming a gate pad at one end portion of the gate line during forming of the gate line;

forming a data pad at one end portion of the data line during forming of the data line;

forming a contact hole in each of the gate pad and the data pad during forming of the contact hole in the drain electrode; and

forming a pad terminal in each of the gate pad and the data pad using a same material as the transparent electrode during forming of the transparent electrode.

12. The method according to claim 9, wherein the forming of the data line and the thin film transistor includes:

depositing a photo-resist layer on the metal layer;

patterning the photo-resist layer during a diffraction exposure using a second mask to reduce a thickness portion of the photo-resist layer corresponding to the channel region of the thin film transistor;

etching the semiconductor layer and the metal layer by using the patterned photo-resist layer as a mask;

ashing the photo-resist layer to remove the portion corresponding to the channel region; and

etching the metal layer using the photo-resist layer as a mask.

13. The method according to claim 9, wherein the negative-type organic insulating layer includes a negative-type photoacryl.

14. The method according to claim 9, wherein the concave and convex patterns of the negative-type organic insulating layer are using a stamping process.

15. The method according to claim 9, further comprising hardening the negative-type organic insulating layer using UV light.

16. The method according to claim 9, further comprising re-curing the negative-type organic insulating layer.

17. The method according to claim 16, wherein the re-curing process is performed at a temperature between about 160°

C. and about 240°

C. during a period of about 40 to about 80 minutes.

18. The method according to claim 9, further comprising forming a passivation layer between the reflective electrode and the transparent electrode.

19. The method according to claim 18, wherein the passivation layer includes one of SiO_x and SiN_x.

20. The method according to claim 18, wherein the passivation layer is formed at a temperature between about 180°

C. and about 220°

C.

33. The method according to claim 9, further comprising:

forming an inorganic insulating layer on the substrate before forming the negative-type organic insulating layer.

21. A method for fabricating a transreflection-type liquid crystal display (LCD) device, comprising:

forming a plurality of gate lines and a plurality of storage lines on a substrate, each gate line having a gate electrode protruding therefrom and each storage line is disposed between the gate lines in parallel to the gate lines;

forming a plurality of data lines and a plurality of drain electrodes on the substrate;

forming a semiconductor layer on a portion of the substrate including the gate lines, the plurality of data lines, and the plurality of drain electrodes, each data line perpendicular to the gate line on the semiconductor layer to define a pixel region;

forming a negative-type organic insulating layer having at least one of concave and convex patterns along an entire surface of the substrate including the data lines, the negative-type organic insulating layer including a contact part and a transmission part therein;

forming a reflective electrode corresponding to the pixel region except for the contact part and the transmission part;

forming an inorganic insulating layer along an entire surface of the substrate except for the contact part; and

forming a transparent electrode corresponding to the pixel region including the transmission part to be connected with the drain electrode within the contact part.

22. The method according to claim 21, wherein the forming of the semiconductor layer, the source and drain electrodes, and the data lines includes:

depositing a gate insulating layer, an amorphous silicon layer, an impurity layer, a metal layer, and a photo-resist layer along an entire surface of the substrate including the gate lines;

patterning the photo-resist layer to reduce a thickness portion of the photo-resist layer corresponding to a channel region of a thin film transistor by a diffraction exposure using a diffraction mask;

etching the amorphous silicon layer, the impurity layer, and the metal layer using the patterned photo-resist layer as a mask;

ashing the photo-resist layer to remove the portion corresponding to the channel region; and

etching the metal layer and the impurity layer using the photo-resist layer as a mask.

23. The method according to claim 22, wherein the diffraction mask includes a closed part corresponding to portions for forming the data lines and the source and drain electrodes, and a semi-transmission part corresponding to a portion for forming the channel region.

24. The method according to claim 21, wherein the source electrode includes in a U-shape.

25. The method according to claim 21, wherein the drain electrode overlaps the storage line.

26. The method according to claim 21, wherein the forming of the negative-type organic insulating layer includes:

depositing a negative-type organic insulating material along an entire surface of the substrate including the data lines;

patterning the at least one of the concave and convex patterns on the surface of the negative-type organic insulating layer to a predetermined thickness using a stamping method; and

forming the contact part and the transmission part by selectively removing the negative-type organic insulating layer.

27. The method according to claim 26, further comprising hardening the negative-type organic insulating layer using UV light after the forming of the negative-type organic insulating layer.

28. The method according to claim 26, further comprising re-curing the negative-type organic insulating layer after the selectively removing of the contact part and the transmission part of the negative-type organic insulating layer.

29. The method according to claim 28, wherein the re-curing process is performed at a temperature between about 160°

C. and about 240°

C. during a period of about 40 to about 80 minutes.

30. The method according to claim 21, wherein the negative-type organic insulating layer includes a negative-type photoacryl.

31. The method according to claim 21, wherein the inorganic insulating layer includes one of SiO_x and SiN_x.

32. The method according to claim 21, wherein the inorganic insulating layer is formed at a temperature between about 180°

C. and about 220°

C.