Polycrystalline liquid crystal display device having large width channel and method of fabricating the same

• US 20050139918A1
• Filed: 06/25/2004
• Published: 06/30/2005
• Est. Priority Date: 12/29/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Lee, Seok-Woo
• Granted Patent: US 6,998,287 B2
• Time in Patent Office: Days
• US Class Current: 257/347
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate 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 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/78603 characterised by the insulating substrate or support H01L29/78657 takes precedence

Abstract

A polysilicon liquid crystal display (LCD) device having a large width channel includes a buffer layer formed on a substrate, an active layer formed on the buffer layer and having a plurality of heat releasing parts, a gate line formed in a width direction of the active layer, at least one heat releasing path formed in each of the plurality of heat releasing parts, source and drain electrodes symmetrically formed at both sides of the active layer, and a contact hole connecting the source and drain electrodes and the active layer.

Claims

1. A polysilicon liquid crystal display (LCD) device having a large width channel, comprising:

a buffer layer formed on a substrate;

an active layer formed on the buffer layer and having a plurality of openings serving as heat releasing parts;

a gate line formed in a width direction of the active layer across the plurality of openings;

at least one heat releasing path formed in one of the plurality of openings;

source and drain electrodes respectively formed at both sides of the active layer; and

contact holes for connecting the source and drain electrodes to the active layer.

2. The LCD device of claim 1, wherein the buffer layer includes a first buffer layer formed of a silicon nitride film and a second buffer layer formed of a silicon oxide film.

3. The LCD device of claim 1, wherein the active layer is divided into a plurality of sub-channels by the plurality of openings.

4. The LCD device of claim 1, further comprising:

a passivation layer formed of a silicon nitride film on the source and drain electrodes.

5. The LCD device of claim 4, wherein the passivation layer is connected to the buffer layer along the heat releasing path.

6. The device of claim 5, wherein the buffer layer connected to the passivation layer is a first buffer layer formed of the silicon nitride film.

7. A method for fabricating a polysilicon LCD device, comprising:

forming a buffer layer on a substrate;

forming an active layer having at least one opening in the buffer layer for serving as a heat releasing part;

forming a first/insulation layer on the active layer;

forming a gate line on the first insulation layer;

forming a second insulation layer on the gate line;

forming at least one hole as a heat releasing path in an opening of the second insulation layer;

forming at least one contact hole in the second insulation layer;

forming source and drain electrodes connected to the active layer through the contact hole; and

forming a passivation layer in the hole to connect to the buffer layer along the heat releasing path.

8. The method of claim 7, wherein forming the active layer comprises:

forming an amorphous silicon layer on the buffer layer;

crystallizing the amorphous silicon layer; and

patterning the crystallized silicon layer in such a manner that the silicon layer includes the at least one opening.

9. The method of claim 7, wherein forming the buffer layer comprises:

forming a first buffer layer of silicon nitride film on the substrate; and

forming a second buffer layer of silicon oxide film on the first buffer layer.

10. The method of claim 7, wherein forming the heat releasing path and the contact hole in the second insulation layer comprises:

forming a photoresist film on the second insulation layer;

forming a heat-releasing-path forming region by partially removing the photoresist film to expose the second insulation layer;

forming a contact-hole forming region by diffraction-exposing the photoresist film;

removing the exposed second insulation layer and the diffraction-exposed photoresist film; and

removing portions of the buffer layer and the first insulation layer that correspond to the heat-releasing-path forming region.

11. The method of claim 10, wherein the exposed second insulation layer and the diffraction-exposed photoresist film are removed through dry etching.

12. The method of claim 10, wherein removing portions of the buffer layer and the first insulation layer is performed at the same time as removing portions of the first insulation layer and the second insulation layer, which corresponding to the contact-hole forming region, to expose the active layer.

13. The method of claim 10, wherein the portions of the buffer layer and the first insulation layer that correspond to the heat-releasing-path forming region are removed through wet etching.

14. The method of claim 10, wherein forming a heat-releasing path forming region and forming a contact hole forming region are formed simultaneously by diffraction exposing method using mask including patter for full exposure and pattern for diffraction exposure.

15. The method of claim 10, wherein removing portions of the buffer layer is performed by removing silicon oxide layer of the buffer layer.

16. A method for fabricating a polysilicon LCD device, comprising:

forming a buffer layer on a substrate;

forming an active layer having at least one heat releasing part on the buffer layer;

forming a first insulation layer on the active layer;

forming a gate line on the first insulation layer;

forming a second insulation layer on the gate line;

forming a photoresist film on the second insulation layer;

forming a heat-releasing-path forming region by partially removing the photoresist film to expose the second insulation layer;

forming a contact-hole forming regions by diffraction-exposing the photoresist film;

removing the exposed second insulation layer and the diffraction-exposed photoresist film to form contact holes;

removing portions of the buffer layer and the first insulation layer that correspond to the heat-releasing-path forming region; and

forming source and drain electrodes connected to the active layer through the contact holes.

17. The method of claim 16, wherein the exposed second insulation layer and the diffraction-exposed photoresist film are removed through dry etching.

18. The method of claim 16, wherein removing portions of the buffer layer and the first insulation layer is performed at the same time as removing portions of the first insulation layer and the second insulation layer, which corresponding to the contact-hole forming region, to expose the active layer.

19. The method of claim 16, wherein the portions of the buffer layer and the first insulation layer that correspond to the heat-releasing-path forming region are removed through wet etching.

20. The method of claim 16, wherein forming a heat-releasing-path forming region and forming a contact hole forming region are formed simultaneously by diffraction exposing method using mask including patter for full exposure and pattern for diffraction exposure.

21. The method of claim 16, wherein removing portions of the buffer layer is performed by removing silicon oxide layer of the buffer layer.