Device and method for the production of chlorotriflouride and system for etching semiconductor substrates using said device

• US 20060006057A1
• Filed: 03/27/2003
• Published: 01/12/2006
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Laermer, Franz
• Granted Patent: US 8,382,940 B2
• Time in Patent Office: Days
• US Class Current: 204/164
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 2219/0894 Processes carried out in the presence of a plasma
• CPC Class Codes: C01B 7/24 Inter-halogen compounds
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4652 using inductive coupling means, e.g. coils

Abstract

A device (6) and a method for generating chlorine trifluoride is described, a high-density plasma (105) being generated in the interior of a plasma reactor (100) using plasma generating means (110, 120, 130, 150, 155, 160, 170, 180), and a first gas and a second gas, which react with one another under the influence of the high-density plasma (105) in the plasma reactor (100) under the formation of chlorine trifluoride, being supplied to the plasma reactor (100) via gas supply means (21, 22, 25, 26). In addition, a gas outlet (20) is provided, via which the generated chlorine trifluoride can be removed from the plasma reactor (100). Finally, a system (5) for etching semiconductor substrates (30), silicon wafers in particular, is described including such an upstream device (6), the system (5) having a process chamber (10) which is connected to the plasma reactor (100) via the gas outlet (20), and the semiconductor substrate (30) being situated in the process chamber (10) and exposed to the gaseous chlorine trifluoride generated by the device (6).

Claims

1-13. -13. (canceled)

14. A device for generating chlorine trifluoride comprising:

a plasma reactor (100), plasma generating means (110, 120, 130, 150, 155, 160, 170, 180) via which a high-density plasma (105) can be generated in the interior of the plasma reactor (100), gas supply means (21, 25, 22, 26) via which a first gas and a second gas can be supplied to the plasma reactor (100), these gases reacting with one another under the influence of the high-density plasma (105) in the plasma reactor (100), forming chlorine trifluoride, and a gas outlet (20) via which the formed chlorine trifluoride can be removed from the plasma reactor (100).

15. The device according to claim 14, wherein the plasma generating means include a coil (110), an adaptation network (120), and a high-frequency generator (130).

16. The device according to claim 14, wherein the plasma generating means include a microwave hollow conductor (150), tuning elements (155), a magnetron (170), a circulator (160), and a hollow conductor terminating element (180).

17. The device according to claim 14, wherein the plasma reactor (100) includes a quartz tube or a hollow quartz body having a polished interior wall or a ceramic tube or a hollow ceramic body having a polished interior wall or being made of aluminum oxide.

18. The device according to claim 14, wherein the gas supply means (21, 22, 25, 26) include a first mass flow regulator (22) via which the quantity of the first gas, which is supplied to the plasma reactor (100), is adjustable, and the gas supply means (21, 22, 25, 26) include a second mass flow regulator (26) via which the quantity of the second gas, which is supplied to the plasma reactor (100), is adjustable.

19. A system for etching semiconductor substrates, comprising:

the device (6) according to claim 14, a process chamber (10), which is connected to the plasma reactor (100) via the gas outlet (20), being assigned to it, the semiconductor substrate (30) being situated in the process chamber (10) and being exposed to the gaseous chlorine trifluoride generated by the device (6) for generating chlorine trifluoride.

20. A method for generating chlorine trifluoride, comprising:

generating a high-density plasma (105) in a plasma reactor (100), and supplying to the plasma reactor (100) a first gas and a second gas, which react with one another under the influence of the high-density plasma (105) in the plasma reactor (100), forming chlorine trifluoride.

21. The method according to claim 20, wherein the high-density plasma (105) is generated using inductive high-frequency excitation or microwave excitation.

22. The method according to claim 20, wherein a gas which includes Cl₂ or HCl is used as the first gas, and a gas which includes NF₃, F₂, SF₆ is used as the second gas.

23. The method according to claim 20, wherein oxygen as an additional gas is supplied to the plasma reactor (100) or to a process chamber (10) downstream from the plasma reactor (100).

24. The method according to claim 20, wherein the generated chlorine trifluoride is separated from hydrogen fluoride and other gas components, using a filter downstream from the plasma reactor (100).

25. The method according to claim 20, wherein the first gas and the second gas are supplied to the plasma reactor (100) in such a way that fluoride atoms and chlorine atoms, in the form of radicals or reactive species, are present in the high-density plasma (105) at a 3:

1 ratio.

26. The method according to claim 20, wherein the high-density plasma (105) is generated having a density in radicals or reactive species of at least 10¹¹ particles per cm³, in particular at least 10¹² particles per cm³.