Liquid crystal display device and manufacturing method thereof

• US 8,421,985 B2
• Filed: 04/12/2010
• Issued: 04/16/2013
• Est. Priority Date: 03/17/2000
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Hirakata, Yoshiharu
• Primary Examiner(s): DUONG, THOI V
• Application Number:
  US12/758,424
• Publication Number:
  US 20100195013A1
• Time in Patent Office: 1,100 Days
• Field of Search: 349/156, 349/153, 349/46, 349/130, 349/43, 349149-152, 349/139, 349/155, 349/123, 349/84
• US Class Current: 349/156
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/136204 Arrangements to prevent high voltage or static electricity failures
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• 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
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

An electro-optical device typified by an active matrix type liquid crystal display device, is manufactured by cutting a rubbing process, and in addition, a reduction in the manufacturing cost and an improvement in the yield are realized by reducing the number of process steps to manufacture a TFT. By forming a pixel TFT portion having a reverse stagger type n-channel TFT, and a storage capacitor, by performing three photolithography steps using three photomasks, and in addition, by having a uniform cell gap by forming wall-like spacers by performing one photolithography step, without performing a rubbing process, a multi-domain perpendicular orientation type liquid crystal display device having a wide viewing angle display, and in which a switching direction of the liquid crystal molecules is controlled, can be realized.

Claims

1. A liquid crystal semiconductor device comprising:

a TFT provided over a first substrate, the first substrate having a pixel portion;

a second substrate opposite to the first substrate;

a plurality of spacers formed over the second substrate and located between the first substrate and the second substrate, wherein the spacers are arranged in a stripe shape and each have a first surface facing the first substrate, a second surface facing the second substrate and a sloped surface having a curved portion, the second surface being larger than the first surface;

a sealing material bonding the first substrate and the second substrate, the sealing material holding a liquid crystal material and surrounding the pixel portion;

a pixel electrode formed over the first substrate and electrically connected to the TFT; and

an orientation film provided between the pixel electrode and the liquid crystal material;

wherein the plurality of spacers each have a straight line shape, and

wherein the first surface and the second surface are substantially parallel to each other.

2. The liquid crystal semiconductor device according to claim 1, wherein the plurality of spacers are formed in the pixel portion.

3. The liquid crystal semiconductor device according to claim 1, wherein each of the plurality of spacers comprises an organic material or an inorganic material.

4. The liquid crystal semiconductor device according to claim 1, further comprising a plurality of second spacers formed over the first substrate and located between the first substrate and the second substrate, wherein at least portions of the second spacers are arranged in a stripe shape and each have a third surface facing the first substrate and a fourth surface facing the second substrate, the third surface being larger than the fourth surface.

5. The liquid crystal semiconductor device according to claim 4, wherein each of the plurality of second spacers comprises an organic material or an inorganic material.

6. The liquid crystal semiconductor device according to claim 1, further comprising a convex portion for orienting the liquid crystal material.

7. The liquid crystal semiconductor device according to claim 6, comprising at least a first region and a second region, wherein a tilt angle of the liquid crystal material in the first region and that in the second region are made symmetric by the convex portion.

8. The liquid crystal semiconductor device according to claim 1, wherein the pixel electrode comprises a material selected from the group consisting of indium oxide, zinc oxide, indium oxide zinc oxide alloy, indium oxide tin oxide alloy, and zinc oxide in which gallium is added.

9. The liquid crystal semiconductor device according to claim 1, wherein each of the spacers is a wall-like spacer.

10. The liquid crystal semiconductor device according to claim 1, wherein the spacers are located in the pixel portion.

11. A liquid crystal semiconductor device comprising:

a TFT provided over a first substrate, the first substrate having a pixel portion;

a second substrate opposite to the first substrate;

a plurality of spacers formed over the second substrate and located between the first substrate and the second substrate, wherein the spacers are arranged in a stripe shape and each have a first surface facing the first substrate, a second surface facing the second substrate and a sloped surface having a curved portion, the second surface being larger than the first surface;

a sealing material bonding the first substrate and the second substrate, the sealing material holding a liquid crystal material and surrounding the pixel portion;

a pixel electrode formed over the first substrate and electrically connected to the TFT;

a first orientation film for vertical alignment provided between the pixel electrode and the liquid crystal material; and

a second orientation film for vertical alignment provided between the opposing electrode and the liquid crystal material,

wherein a gate electrode of the TFT is formed by etching a lamination film to have a lamination structure including a first layer, a second layer and a third layer, wherein the first layer comprises a material selected from the group consisting of Ti, Ta, W, Mo, Cr and Nd, the second layer comprises a material selected from the group consisting of Al and Cu, and the third layer comprises a material selected from the group consisting of Ti, Ta, W, Mo, Cr and Nd,

wherein the plurality of spacers each have a straight line shape, and

wherein the first surface and the second surface are substantially parallel to each other.

12. The liquid crystal semiconductor device according to claim 11, wherein the plurality of spacers are formed in the pixel portion.

13. The liquid crystal semiconductor device according to claim 11, wherein each of the plurality of spacers comprises an organic material or an inorganic material.

14. The liquid crystal semiconductor device according to claim 11, further comprising a plurality of second spacers formed over the first substrate and located between the first substrate and the second substrate, wherein at least portions of the second spacers are arranged in a stripe shape and each have a third surface facing the first substrate and a fourth surface facing the second substrate, the third surface being larger than the fourth surface.

15. The liquid crystal semiconductor device according to claim 14, wherein each of the plurality of second spacers comprises an organic material or an inorganic material.

16. The liquid crystal semiconductor device according to claim 11, further comprising a convex portion for orienting the liquid crystal material.

17. The liquid crystal semiconductor device according to claim 16, comprising at least a first region and a second region, wherein a tilt angle of the liquid crystal material in the first region and that in the second region are made symmetric by the convex portion.

18. The liquid crystal semiconductor device according to claim 11, wherein the pixel electrode comprises a material selected from the group consisting of indium oxide, zinc oxide, indium oxide zinc oxide alloy, indium oxide tin oxide alloy, and zinc oxide in which gallium is added.

19. The liquid crystal semiconductor device according to claim 11, wherein each of the spacers is a wall-like spacer.

20. The liquid crystal semiconductor device according to claim 11, wherein the spacers are located in the pixel portion.