Method of manufacturing a semiconductor device

• US 7,402,467 B1
• Filed: 03/24/2000
• Issued: 07/22/2008
• Est. Priority Date: 03/26/1999
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamauchi, Yukio, Yamazaki, Shunpei, Kitakado, Hidehito, Kadono, Masaya
• Primary Examiner(s): COLEMAN, WILLIAM D
• Application Number:
  US09/535,233
• Time in Patent Office: 3,042 Days
• Field of Search: 156/345, 438/151, 438/704, 204/192.5, 257/1, 65/605
• US Class Current: 438/151
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• 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 27/1222 with a particular composition, shape or crystalline structure of the active layer
• 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 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1274 using crystallisation of amorphous semiconductor or recrystallisation of crystalline semiconductor
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• 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 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/846 comprising getter material or desiccants
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/873 Encapsulations
• CPC Class Codes: H10K 59/874 including getter material or desiccant

Abstract

A reduction in contaminating impurities in a TFT, and a TFT which is reliable, is obtained in a semiconductor device which uses the TFT. By removing contaminating impurities residing in a film interface of the TFT using a solution containing fluorine, a reliable TFT can be obtained.

Claims

1. A method of manufacturing a semiconductor device, comprising steps of:

forming a semiconductor film over a substrate having an insulating surface;

forming a patterned resist mask over said semiconductor film;

patterning said semiconductor film to form at least one semiconductor island;

removing the patterned resist mask located over said semiconductor island;

spinning the substrate after removing the patterned resist mask;

applying an etching solution to a surface of said semiconductor island and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the semiconductor island by the step of applying the etching solution; and

then

forming a gate insulating film in contact with the semiconductor film from the surface of which the contaminating impurity has been removed.

2. A method according to claim 1, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

3. A method according to claim 1, wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

4. A method according to claim 1, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

5. A method according to claim 1, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄F₂) and ammonium fluoride (NH₄F) (LAL500).

6. A method of manufacturing a semiconductor device, comprising steps of:

forming a semiconductor film over a substrate having an insulating surface;

forming a patterned resist mask over said semiconductor film;

patterning said semiconductor film to form at least one semiconductor island;

removing the patterned resist mask located over said semiconductor island;

spinning the substrate after removing the patterned resist mask;

applying an etching solution to a surface of said semiconductor island and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the semiconductor island by the step of applying the etching solution;

forming a gate insulating film over said semiconductor island after the contaminating impurities are removed from the surface of the semiconductor island;

spinning the substrate having the gate insulating film;

applying an etching solution to a surface of said gate insulating film and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the gate insulating film by the step of applying the etching solution; and

then

forming a gate electrode over said gate insulating film after the contaminating impurities are removed from the surface of the gate insulating film.

7. A method according to claim 6, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄HF₂) and ammonium fluoride (NH₄F) (LAL500).

8. A method according to claim 6, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

9. A method according to claim 6, wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

10. A method according to claim 6, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

11. A method of manufacturing a semiconductor device, comprising steps of:

forming a semiconductor film over a substrate having an insulating surface;

crystallizing said semiconductor film;

forming a patterned resist mask over said crystallized semiconductor film;

patterning the crystallized semiconductor film to form at least one semiconductor island over said substrate;

removing the patterned resist mask located over said semiconductor island;

spinning the substrate after removing the patterned resist mask;

applying an etching solution to a surface of said semiconductor island and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the semiconductor island; and

then

forming a gate insulating film over said semiconductor island after the contaminating impurities are removed from the surfaces by the step of applying the etching solution; and

forming a gate electrode over said gate insulating film.

12. A method according to claim 11, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄HF₂) and ammonium fluoride (NH₄F) (LAL500).

13. A method according to claim 11, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

14. A method according to claim 11, wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

15. A method according to claim 11, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

16. A method according to claim 11, wherein the step of crystallization is performed by irradiating the semiconductor film with a laser light.

17. A method of manufacturing a semiconductor device, comprising steps of:

forming a gate wiring over a substrate having an insulating surface;

spinning the substrate;

applying an etching solution to surfaces of said substrate and said gate wiring and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the wiring and the insulating surface by the step of applying the etching solution; and

then

forming a gate insulating film and a semiconductor film over said gate wiring after the contaminating impurities are removed from the surfaces.

18. A method according to claim 17, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄HF₂) and ammonium fluoride (NH₄F) (LAL500).

19. A method according to claim 17, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

20. A method according to claim 17, wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

21. A method according to claim 17, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

22. A method of manufacturing a semiconductor device, comprising steps of:

forming a gate wiring over a substrate having an insulating surface;

spinning the substrate;

applying an etching solution to surfaces of said substrate and said gate wiring and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the wiring and the insulating surface by the step of applying the etching solution; and

then

forming a gate insulating film and a semiconductor film over said gate wiring, continuously after the contaminating impurities are removed from the surfaces.

23. A method according to claim 22, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄HF₂) and ammonium fluoride (NH₄F) (LAL500).

24. A method according to claim 22, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

25. A method according to claim 22 wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

26. A method according to claim 22, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

27. A method of manufacturing a semiconductor device, comprising steps of:

forming a semiconductor film over a substrate having an insulating surface;

crystallizing said semiconductor film;

forming a patterned resist mask over said crystallized semiconductor film;

patterning the crystallized semiconductor film to form at least one semiconductor island over said substrate;

removing the patterned resist mask located over said semiconductor island;

spinning the substrate after removing the patterned resist mask;

applying an etching solution to a surface of said semiconductor island and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the semiconductor island; and

then

forming a gate insulating film over said semiconductor island after the contaminating impurities are removed from the surfaces by the step of applying the etching solution;

spinning the substrate having the gate insulating film;

applying an etching solution to a surface of said gate insulating film and scattering the etching solution during said spinning, thereby contaminating impurities are removed from the surface of the gate insulating film by the step of applying the etching solution; and

then

forming a gate electrode over said gate insulating film after the contaminating impurities are removed from the surface of the gate insulating film.

28. A method according to claim 27, wherein said etching solution is selected from the group consisting of hydrofluoric acid, dilute hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid (BHF), hydrofluoric acid and aqueous hydrogen peroxide (FPM), and a solution mixture including ammonium hydrofluoride (NH₄F₂) and ammonium fluoride (NH₄F) (LAL500).

29. A method according to claim 27, wherein the contaminating impurity is at least one element selected from periodic table group 1 elements or periodic table group 2 elements.

30. A method according to claim 27, wherein the contaminating impurity element is at least one element selected from the group consisting of Na, K, Mg, Ca, and Ba.

31. A method according to claim 27, wherein the contaminating impurity is removed by an acidic solution containing fluorine.

32. A method according to claim 27, wherein the step of crystallization is performed by irradiating the semiconductor film with a laser light.