Etching oxide-nitride stacks using C4F6H2

Patent metadata

Field	Value
Publication number	US-9748366-B2
Application number	US-201414491828-A
Country	US
Kind code	B2
Filing date	Sep 19, 2014
Priority date	Oct 3, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An article having alternating oxide layers and nitride layers is etched by an etch process. The etch process includes providing a first gas comprising C 4 F 6 H 2 in a chamber of an etch reactor, ionizing the C 4 F 6 H 2 containing gas to produce a plasma comprising a plurality of ions, and etching the article using the plurality of ions.

First claim

What is claimed is:

1. A method comprising:
providing a first gas comprising C 4 F 6 H 2 into a chamber of an etch reactor;
providing a second gas comprising C 4 F 6 into the chamber, wherein a ratio of the C 4 F 6 H 2 to the C 4 F 6 is between 1:2 and 2:1;
ionizing the first gas comprising the C 4 F 6 H 2 and the second gas comprising the C 4 F 6 to produce a plasma comprising a plurality of ions; and
etching a substrate using the plurality of ions.

2. The method of claim 1 , wherein the substrate comprises a plurality of alternating oxide layers and nitride layers and wherein a first etch rate for the oxide layers differs by less than 20% from a second etch rate for the nitride layers.

3. The method of claim 2 , further comprising:
controlling a ratio between the first etch rate of the oxide layers and the second etch rate of the nitride layers by adjusting a ratio of the C 4 F 6 H 2 to the C 4 F 6 .

4. The method of claim 1 , further comprising:
providing a third gas comprising C 4 F 8 into the chamber.

5. The method of claim 1 , wherein the plasma comprises at least one of C 3 F 3 H 2 , CF 3 , C 4 F 3 H 2 , C 4 F 5 H 2 , C 3 F 2 H 2 , C 3 F 2 H, CF, CF 2 , CHF, C 2 F 2 H 2 or C 2 F 3 H.

6. The method of claim 1 , further comprising:
providing a third gas comprising CH 2 F 2 into the chamber.

7. The method of claim 1 , wherein the etching produces a cavity in the substrate having a depth to width aspect ratio ranging from 10:1 to 100:1.

8. The method of claim 1 , further comprising:
maintaining a plasma power of 150-350 W during the etching.

9. A method comprising:
providing a gas mixture comprising at least one of a) C 4 F 6 H 2 and C 4 F 6 at a ratio of between 1:2 and 2:1 or b) C 4 F 6 H 2 and C 4 F 8 at a ratio of between 1:1 and 1:3;
ionizing the gas mixture to form a plasma comprising 37-84% C 3 F 3 H 2 , 8-28% CF 3 , 8-14% C 4 F 5 H 2 , 0-11% C 3 F 2 H, 0-10% CF, and 0-3% CF 2 ; and
anisotropically etching a substrate comprising an alternating stack of oxide layers and nitride layers using the plasma.

10. The method of claim 9 , wherein an etch rate of the oxide layers is about 400-500 nm/min and an etch rate of the nitride layers is about 400-500 nm/min.

11. A method comprising:
providing a first gas comprising C 4 F 6 H 2 into a chamber of an etch reactor;
providing a second gas comprising C 4 F 8 into the chamber, wherein a ratio of the C 4 F 6 H 2 to the C 4 F 8 is between 1:1 and 1:3;
ionizing the first gas comprising the C 4 F 6 H 2 and the second gas comprising the C 4 F 8 to produce a plasma comprising a plurality of ions; and
etching a substrate using the plurality of ions.

12. The method of claim 11 , wherein the substrate comprises a plurality of alternating oxide layers and nitride layers and wherein a first etch rate for the oxide layers differs by less than 20% from a second etch rate for the nitride layers.

13. The method of claim 12 , wherein an etch rate of the oxide layers is about 400-500 nm/min and an etch rate of the nitride layers is about 400-500 nm/min.

14. The method of claim 12 , further comprising:
controlling a ratio between the first etch rate of the oxide layers and the second etch rate of the nitride layers by adjusting a ratio of the C 4 F 6 H 2 to the C 4 F 8 .

15. The method of claim 11 , wherein the plasma comprises at least one of C 3 F 3 H 2 , CF 3 , C 4 F 3 H 2 , C 4 F 5 H 2 , C 3 F 2 H 2 , C 3 F 2 H, CF, CF 2 , CHF, C 2 F 2 H 2 or C 2 F 3 H.

16. The method of claim 11 , further comprising:
providing a third gas comprising CH 2 F 2 into the chamber.

17. The method of claim 11 , wherein the etching produces a cavity in the substrate having a depth to width aspect ratio ranging from 10:1 to 100:1.

18. The method of claim 11 , further comprising:
providing a third gas comprising C 5 F 8 or C 6 F 6 into the chamber.

19. The method of claim 11 , further comprising:
providing a third gas comprising O 2 or Ar into the chamber.

20. The method of claim 11 , further comprising:
maintaining a plasma power of 150-350 W and a frequency of 100-200 MHz during the etching.

Assignees

• Applied Materials Inc

Inventors

• Kim Jong Mun
• Doan Kenny L
• Ling Li
• Payyapilly Jairaj
• Nemani Srinivas D
• Shimizu Daisuke
• Huang Yuju

Classifications

• H10P50/283

  by chemical means · CPC title

• H01L21/31116

  Electricity · mapped topic

• H01L29/66833 Primary

  Electricity · mapped topic

• H10D30/0413 Primary

  of FETs having charge-trapping gate insulators, e.g. MNOS transistors · CPC title