Method of manufacturing semiconductor device having a circuit including thin film transistors

• US 7,501,653 B2
• Filed: 09/12/2005
• Issued: 03/10/2009
• Est. Priority Date: 04/06/2001
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Maekawa, Shinji, Arai, Yasuyuki
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US11/222,763
• Publication Number:
  US 20060006388A1
• Time in Patent Office: 1,275 Days
• Field of Search: 257/59, 257 71- 72, 257/347, 257/758
• US Class Current: 257/59
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02425 Conductive materials, e.g. metallic silicides
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02491 Conductive materials
• CPC Class Codes: H01L 21/02496 Layer structure
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02595 polycrystalline
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/02683 Continuous wave laser beam
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78633 : with a light shield
• CPC Class Codes: H01L 29/78675 : with normal-type structure, e.g. with top gate

Abstract

A grain size of a crystal grain in a crystalline semiconductor film obtained by a thermal crystallization method using a metallic element is reduced. Thus, the number of crystal grains in active regions of a device is made uniform. The thermal crystallization method using a metallic element is performed for a semiconductor film formed on an insulating film formed at a lower temperature than that at formation of the semiconductor film and that at crystallization of the semiconductor film. By thermal treatment in a step of crystallizing the semiconductor film, stress of the insulating film is applied to the semiconductor film, thus causing distortion in the semiconductor film. When the distortion is caused, surface energy and a chemical potential of the semiconductor film are changed to promote the generation of a natural nucleus. Therefore, since a generation density of the crystal nucleus is increased, a grain size of a crystal grain can be reduced.

Claims

1. A semiconductor device comprising:

a silicon nitride film on an insulating surface;

a light shielding film over the patterned silicon nitride film;

a silicon oxide film formed over the patterned light shielding film;

a semiconductor layer over the silicon oxide film;

a gate insulating film covering the semiconductor layer; and

a wiring formed over the gate insulating film, wherein the wiring is electrically connected to the light shielding film.

2. The semiconductor device according to claim 1, wherein the light shielding film comprises at least one of Ta, W, Cr and Mo.

3. The semiconductor device according to claim 1, wherein the semiconductor layer includes grains with size of 20 μ

m to 60 μ

m.

4. The semiconductor device according to claim 1, wherein the wiring comprises at least one of Ta, W, Ti, Mo, Al, Cu, Cr, and Nd.

5. The semiconductor device according to claim 1, wherein the wiring comprises a plurality of layers.

6. A semiconductor device comprising:

a silicon nitride film on an insulating surface;

a light shielding film over the silicon nitride film;

a silicon oxide film formed over the light shielding film;

a semiconductor layer including two channel forming regions and low concentration impurity regions over the silicon oxide film;

a gate insulating film covering the semiconductor layer; and

a wiring formed over the gate insulating film, wherein the wiring is electrically connected to the light shielding film.

7. The semiconductor device according to claim 6, wherein the light shielding film comprises at least one of Ta, W, Cr and Mo.

8. The semiconductor device according to claim 6, wherein the semiconductor layer includes grains with a size of 20 μ

m to 60 μ

m.

9. The semiconductor device according to claim 6, wherein the gate insulating film includes silicon.

10. The semiconductor device according to claim 6, wherein the wiring comprises at least one of Ta, W, Ti, Mo, Al, Cu, Cr, and Nd.

11. The semiconductor device according to claim 6, wherein the wiring comprises a plurality of layers.

12. A semiconductor device comprising:

a silicon nitride film on an insulating surface;

a first light shielding film over the silicon nitride film;

a silicon oxide film formed over the light shielding film;

a semiconductor layer including two channel forming regions and low concentration impurity regions over the silicon oxide film;

a gate insulating film covering the semiconductor layer;

a gate electrode over the gate insulating film;

an interlayer insulating film; and

a second light shielding film over the interlayer insulating film.

13. The semiconductor device according to claim 12, wherein the light shielding film comprises at least one of Ta, W, Cr and Mo.

14. The semiconductor device according to claim 12, wherein the semiconductor layer includes grains with a size of 20 μ

m to 60 μ

m.

15. The semiconductor device according to claim 12, wherein the gate insulating film includes silicon.