Semiconductor device and manufacturing method thereof

• US 8,823,004 B2
• Filed: 08/29/2013
• Issued: 09/02/2014
• Est. Priority Date: 05/09/2000
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Lee, Kyoung
• Application Number:
  US14/013,443
• Publication Number:
  US 20140001476A1
• Time in Patent Office: 369 Days
• Field of Search: None
• US Class Current: 257/59
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/1337 Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• 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: G02F 2203/03 scattering
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 25/18 : the devices being of types provided for in two or more different subgroups of the same main group of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N
• CPC Class Codes: H01L 27/12 : the substrate being other than a semiconductor body, e.g. an insulating body
• 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
• CPC Class Codes: H01L 27/1248 : with a particular composition or shape of the interlayer dielectric 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 29/78669 : with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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
• CPC Class Codes: H01L 2924/07811 : Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 33/0041 : characterised by field-effect operation

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.

Claims

1. A display device comprising:

a transistor comprising;

a gate electrode;

a first insulating film over the gate electrode;

a semiconductor film over the first insulating film, the semiconductor film comprising a first portion, a second portion, and a recessed portion interposed between the first portion and the second portion, wherein a thickness of the first portion is larger than a thickness of the recessed portion and a thickness of the second portion is larger than the thickness of the recessed portion;

a source electrode over and electrically connected to the semiconductor film; and

a drain electrode over and electrically connected to the semiconductor film;

a pixel electrode over and electrically connected to one of the source electrode and the drain electrode,

a second insulating film over the semiconductor film,

wherein the second insulating film comprises a region located between the source electrode and the drain electrode, and the region is in contact with a top surface of the first portion, a top surface of the second portion and a top surface of the recessed Portion,

wherein the gate electrode overlaps with the recessed portion, and

wherein a gap between the source electrode and the drain electrode is larger than a width of the recessed portion.

2. The display device according to claim 1,

wherein the source electrode overlaps with the first portion,

wherein, in a channel direction, a width of the first portion is larger than a width of the source electrode.

3. The display device according to claim 1, wherein the semiconductor film extends beyond an edge of one of the source electrode and the drain electrode.

4. The display device according to claim 1, further comprising:

a first color filter overlapping with the transistor; and

a second color filter overlapping with the transistor,

wherein the second color filter overlaps with the first color filter, and

wherein the first color filter and the second color filter transmit different colors.

5. The display device according to claim 1, wherein the pixel electrode has a convex portion.

6. The display device according to claim 1, wherein the semiconductor film comprises an amorphous silicon.

7. The display device according to claim 1, wherein each of the source electrode and the drain electrode comprises aluminum.

8. A display device comprising:

a transistor comprising;

a gate electrode;

an insulating film over the gate electrode;

a first semiconductor film over the insulating film, the first semiconductor film having a recessed portion;

a second semiconductor film over the first semiconductor film;

a third semiconductor film over the first semiconductor film;

a source electrode over and electrically connected to the second semiconductor film; and

a drain electrode over and electrically connected to the third semiconductor film;

a pixel electrode over and electrically connected to one of the source electrode and the drain electrode,

wherein the gate electrode overlaps with the recessed portion,

wherein a gap between the source electrode and the drain electrode is larger than a width of the recessed portion, and

wherein a gap between the second semiconductor film and the third semiconductor film is larger than the width of the recessed portion.

9. The display device according to claim 8,

wherein the first semiconductor film comprises a first region and a second region with the recessed portion interposed therebetween,

wherein the source electrode overlaps with the first region,

wherein, in a channel direction, a width of the first region is larger than a width of the source electrode.

10. The display device according to claim 8, wherein the first semiconductor film extends beyond an edge of one of the source electrode and the drain electrode.

11. The display device according to claim 8, further comprising:

a first color filter overlapping with the transistor; and

a second color filter overlapping with the transistor,

wherein the second color filter overlaps with the first color filter, and

wherein the first color filter and the second color filter transmit different colors.

12. The display device according to claim 8, wherein the pixel electrode has a convex portion.

13. The display device according to claim 8,

wherein the first semiconductor film comprises a first region and a second region with the recessed portion interposed therebetween,

wherein the second semiconductor film overlaps with the first region,

wherein, in a channel direction, a width of the first region is larger than a width of the second semiconductor film.

14. The display device according to claim 8, wherein the first semiconductor film extends beyond an edge of one of the second semiconductor film and the third semiconductor film.

15. The display device according to claim 8, wherein the first semiconductor film comprises an amorphous silicon.

16. The display device according to claim 8, wherein each of the source electrode and the drain electrode comprises aluminum.