Method for etching a layer on a silicon semiconductor substrate

Patent metadata

Field	Value
Publication number	US-8946090-B2
Application number	US-45269208-A
Country	US
Kind code	B2
Filing date	Jul 2, 2008
Priority date	Jul 19, 2007
Publication date	Feb 3, 2015
Grant date	Feb 3, 2015

Abstract

A method for selective etching of an SiGe mixed semiconductor layer on a silicon semiconductor substrate by dry chemical etching of the SiGe mixed semiconductor layer with the aid of an etching gas selected from the group including ClF 3 and/or ClF 5 , a gas selected from the group including Cl 2 and/or HCl being added to the etching gas.

First claim

What is claimed is:

1. A method for etching an SiGe mixed semiconductor layer on a silicon semiconductor substrate, the method comprising:
adding a gas, which includes at least one of Cl 2 and HCl, to the etching gas, wherein the etching gas includes at least one of ClF 3 and ClF 5 ; and
dry chemical etching the SiGe mixed semiconductor layer with the aid of the etching gas and the added gas;
wherein a ratio of partial pressures of the etching gas to the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧1:5 to ≦5:1, and
wherein the etching is a plasma-less etch based on ClF 3 or ClF 5 and not a plasma etch, so that no plasma reaches a process chamber with the substrate.

2. The method of claim 1 , wherein a partial pressure of the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧0.5 Pa to ≦500 Pa.

3. The method of claim 1 , wherein a partial pressure of the etching gas, which includes at least one of ClF 3 and ClF 5 , is in the range of ≧0.5 Pa to ≦500 Pa.

4. The method of claim 1 , wherein a total pressure of the etching gas and added gas is in the range of ≧0.5 Pa to ≦1000 Pa.

5. The method of claim 1 , wherein the ClF 3 etching gas is produced by generating a high-density plasma in a plasma reactor, a first gas including at least one of Cl 2 and HCl, and a second gas including at least one of NF 3 , F 2 , and SF 6 , being supplied to the plasma reactor, and the gases reacting under the effect of the high-density plasma in the plasma reactor, forming chlorine trifluoride.

6. The method of claim 1 , wherein an excess of a first gas including at least one of Cl 2 and HCl with respect to a second gas is supplied to a plasma reactor, a ratio of the gas flows of the first gas to the second gas being in the range of ≧1:3 to ≦4:1.

7. The method of claim 1 , wherein the gas including at least one of Cl 2 and HCl is added to chlorine trifluoride, the chlorine trifluoride and the gas including at least one of Cl 2 and HCl being jointly supplied to a process chamber in which the etching takes place.

8. The method of claim 1 , wherein the gas including at least one of Cl 2 and HCl is supplied to a process chamber separately from chlorine trifluoride.

9. The method of claim 1 , wherein a ratio of partial pressures of the etching gas, which is ClF 3 , to the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧1:5 to ≦5:1.

10. The method of claim 1 , wherein a ratio of partial pressures of the etching gas, which is ClF 3 , to the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧1:2 to ≦4:1.

11. The method of claim 1 , wherein a ratio of partial pressures of the etching gas, which is ClF 3 , to the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧1:1 to ≦2:1.

12. The method of claim 1 , wherein a partial pressure of the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧1 Pa to ≦100 Pa.

13. The method of claim 1 , wherein a partial pressure of the added gas, which includes at least one of Cl 2 and HCl, is in the range of ≧20 Pa to ≦50 Pa.

14. The method of claim 1 , wherein a partial pressure of the etching gas, which includes at least one of ClF 3 and ClF 5 , is in the range of ≧1 Pa to ≦100 Pa.

15. The method of claim 1 , wherein a partial pressure of the etching gas, which includes at least one of ClF 3 and ClF 5 , is in the range of ≧20 Pa to ≦50 Pa.

16. The method of claim 1 , wherein a total pressure of the etching gas and added gas is in the range of ≧1 Pa to ≦200 Pa.

17. The method of claim 1 , wherein a total pressure of the etching gas and added gas is in the range of ≧20 Pa to ≦100 Pa.

18. The method of claim 1 , wherein the ClF 3 etching gas is produced by generating a high-density plasma in a plasma reactor, a first gas including at least one of Cl 2 and HCl, and a second gas including at least NF 3 , being supplied to the plasma reactor, and the gases reacting under the effect of the high-density plasma in the plasma reactor, forming chlorine trifluoride.

19. The method of claim 1 , wherein an excess of a first gas which includes at least one of Cl 2 and HCl with respect to a second gas, which is NF 3 , is supplied to a plasma reactor, a ratio of the gas flows of the first gas to the second gas being in the range of ≧1:5 to ≦6:1.

20. The method of claim 1 , wherein an excess of a first gas which includes at least one of Cl 2 and HCl with respect to a second gas, which is NF 3 , is supplied to a plasma reactor, a ratio of the gas flows of the first gas to the second gas being in the range of ≧1:2 to ≦2:1.

21. The method of claim 1 , wherein the ClF 3 etching gas is produced by generating a high-density plasma in a plasma reactor, a first gas including at least one of Cl 2 and HCl, and a second gas including at least one of NF 3 , F 2 , and SF 6 , being supplied to the plasma reactor, and the gases reacting under the effect of the high-density plasma in the plasma reactor, forming chlorine trifluoride, wherein an excess of a first gas including at least one of Cl 2 and HCl with respect to a second gas is supplied to a plasma reactor, a ratio of the gas flows of the first gas to the second gas being in the range of ≧1:3 to ≦4:1, and wherein the gas including at least one of Cl 2 and HCl is added to chlorine trifluoride, the chlorine trifluoride and the gas including at least one of Cl 2 and HCl being jointly supplied to a process chamber in which the etching takes place.

22. The method of claim 1 , wherein the ClF 3 etching gas is produced by generating a high-density plasma in a plasma reactor, a first gas including at least one of Cl 2 and HCl, and a second gas including at least one of NF 3 , F 2 , and SF 6 , being supplied to the plasma reactor, and the gases reacting under the effect of the high-density plasma in the plasma reactor, forming chlorine trifluoride, wherein an excess of a first gas including at least one of Cl 2 and HCl with respect to a second gas is supplied to a plasma reactor, a ratio of the gas flows of the first gas to the second gas being in the range of ≧1:3 to ≦4:1, and wherein the gas including at least one of Cl 2 and HCl is supplied to a process chamber separately from chlorine trifluoride.

Assignees

• Becker Volker
• Laermer Franz
• Fuchs Tino
• Leinenbach Christina
• Bosch Gmbh Robert

Inventors

• Becker Volker
• Laermer Franz
• Fuchs Tino
• Leinenbach Christina

Classifications

• H10P90/126

  by chemical etching · CPC title

• H10P50/266

  by vapour etching only · CPC title

• H10P50/246

  of Group III-V materials · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• B81C1/00595

  Control etch selectivity · CPC title