Method of manufacturing semiconductor device

• US 7,696,045 B2
• Filed: 08/18/2007
• Issued: 04/13/2010
• Est. Priority Date: 08/22/2006
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Kawahara, Minoru
• Primary Examiner(s): Coleman; W. David
• Assistant Examiner(s): SCARLETT, SHAKA S
• Application Number:
  US11/840,964
• Publication Number:
  US 20080050920A1
• Time in Patent Office: 969 Days
• Field of Search: 438/270, 438/770, 438/589, 438/719, 438/243, 438/248, 438/227, 438/226, 257/E21.564, 257/E21.384, 257/E21.419, 257/E21.428, 257/E29.321
• US Class Current: 438/270
• CPC Class Codes: H01L 29/66621 using etching to form a recess at the gate location etching of semiconductor bodies H01L21/302

Abstract

A method of manufacturing a semiconductor device according to an embodiment of the present invention includes: forming a first insulating film on a semiconductor substrate; forming a mask with an opening of a predetermined pattern in the first insulating film; performing anisotropic etching on the semiconductor substrate with the mask used as an etching mask to form a trench; forming a second insulating film on a surface of an inner wall of the trench with the mask used as a selective oxidation mask; removing the mask; forming a conductive film on the semiconductor substrate to fill the trench with the conductive film; and etching back the conductive film until at least a surface of the semiconductor substrate is exposed.

Claims

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

(a) forming a mask with an opening of a predetermined pattern which is made of a mask insulating film on a semiconductor substrates;

(b) forming a trench in the substrate using the mask as an etching mask;

(c) forming a gate insulating film on a surface of an inner wall of the trench with the mask used as a selective oxidation mask;

(d) removing the mask;

(e) forming a conductive film on the semiconductor substrate to fill the trench with the conductive film; and

(f) etching back the conductive film until at least a surface of the semiconductor substrate is exposed.

2. The method of manufacturing a semiconductor device according to claim 1, wherein an etchant that does not remove the gate insulating film is used upon removing the mask.

3. The method of manufacturing a semiconductor device according to claim 1, wherein the mask insulating film is made of silicon nitride and the gate insulating film is made of silicon oxide.

4. The method of manufacturing a semiconductor device according to claim 2, wherein the mask insulating film is made of silicon nitride and the gate insulating film is made of silicon oxide.

5. The method of manufacturing a semiconductor device according to claim 1, wherein an etching rate of the semiconductor substrate and an etching rate of the conductive film are substantially equal to each other.

6. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor substrate is made of single crystal silicon, and the conductive film is made of polycrystalline silicon.

7. The method of manufacturing a semiconductor device according to claim 5, wherein the semiconductor substrate is made of single crystal silicon, and the conductive film is made of polycrystalline silicon.

8. The method of manufacturing a semiconductor device according to claim 1, further comprising:

etching off a protrusion of the gate insulating film from the surface of the semiconductor substrate after etching back the conductive film.

9. The method of manufacturing a semiconductor device according to claim 2, further comprising:

etching off a protrusion of the gate insulating film from the surface of the semiconductor substrate after etching back the conductive film.

10. The method of manufacturing a semiconductor device according to claim 5, further comprising:

etching off a protrusion of the gate insulating film from the surface of the semiconductor substrate after etching back the conductive film.

11. The method of manufacturing a semiconductor device according to claim 1, wherein the gate insulating film is formed to a thickness of approximately 500 Å

.

12. The method of manufacturing a semiconductor device according to claim 1, wherein the mask is removed with a phosphoric acid.

13. The method of manufacturing a semiconductor device according to claim 1, wherein the mask insulating film is formed by chemical vapor deposition.

14. The method of manufacturing a semiconductor device according to claim 1, wherein the mask is formed by photolithography and etching.

15. The method of manufacturing a semiconductor device according to claim 1, wherein the gate insulating film is formed by thermal oxidation.

16. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is formed by chemical vapor deposition.

17. The method of manufacturing a semiconductor device according to claim 1, wherein the conductive film is etched back using dry etching.

18. The method of manufacturing a semiconductor device according to claim 1, wherein the removal of the mask exposes the surface of the semiconductor substrate.