Plasma enhanced atomic layer deposition system having reduced contamination

• US 20060213439A1
• Filed: 03/25/2005
• Published: 09/28/2006
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Ishizaka, Tadahiro
• Granted Patent: US 7,422,636 B2
• Time in Patent Office: Days
• US Class Current: 118/715
• CPC Class Codes: C23C 16/4401 Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/4583 the substrate being supported substantially horizontally
• CPC Class Codes: H01L 21/67155 Apparatus for manufacturing or treating in a plurality of work-stations
• CPC Class Codes: H01L 21/67751 vertical transfer of a single workpiece

Abstract

A plasma enhanced atomic layer deposition (PEALD) system is described, wherein the system comprises a processing space and a high vacuum, ultra-clean transfer space. During processing, the substrate to which the thin conformal film is formed is exposed to the processing space. During substrate transfer, the substrate is exposed to the high vacuum space. Processing gases are introduced sequentially and alternately to the process chamber and the pressures and gas flows within, to and from, and between the process chamber and the high vacuum transfer space are controlled to keep the transfer space ultra-clean.

Claims

1. A deposition system for forming a thin film on a substrate comprising:

a processing chamber comprising a process space in an upper region of said processing chamber configured to facilitate said thin film deposition, and a transfer space in a lower region of said processing chamber configured to facilitate transfer of said substrate into and out of said processing chamber;

a substrate holder coupled to said processing chamber and configured to support said substrate and to translate vertically between a first position to locate said substrate in said transfer space and a second position to locate said substrate in said process space, said substrate holder comprising a sealing device configured to seal said substrate holder with said processing chamber when said substrate holder is in said second position;

a first pressure control system coupled to said transfer space and configured to provide a substantially contaminant-free environment in said transfer space;

a second pressure control system coupled to said process space and configured to evacuate said process space during processing;

a gas injection system coupled to said processing chamber, and configured to alternatingly introduce a first process material and a second process material to said process space;

a power source coupled to said processing chamber, and configured to couple power to said first process material, or said second process material, or both in said process space to facilitate the formation of plasma; and

a temperature control system coupled to said substrate holder, and configured to control a temperature of said substrate.

2. The deposition system of claim 1, wherein said deposition system is coupled to a transfer system configured to transport said substrate into said transfer space of said processing chamber through a gate valve coupled to said lower region of said processing chamber.

3. The deposition system of claim 1, wherein said sealing device comprises a labyrinth seal formed between an outer edge of said substrate holder and an inner edge of said upper region of said processing chamber.

4. The deposition system of claim 3, wherein said labyrinth seal comprises a first set of teeth coupled to said substrate holder and configured to mate with a second set of teeth coupled to said processing chamber when said substrate holder is located in said second position.

5. The deposition system of claim 1, wherein said sealing device comprises at least one O-ring seal coupled to said substrate holder, or said processing chamber, or both.

6. The deposition system of claim 1, wherein said substrate holder further comprises a clamping system configured to affix said substrate to said substrate holder.

7. The deposition system of claim 6, wherein said clamping system comprises a mechanical clamping system or an electrical clamping system.

8. The deposition system of claim 1, wherein said substrate holder further comprises a backside gas distribution system configured to supply a heat transfer gas to the backside of said substrate to improve the thermal conduction between said substrate and said substrate holder.

9. The deposition system of claim 1, wherein said first pressure control system comprises a first pumping system and a first valve, and said second pressure control system comprises a second pumping system and a second valve.

10. The deposition system of claim 1, wherein said first pressure control system comprises a cryogenic vacuum pumping system.

11. The deposition system of claim 1, wherein said second pressure control system comprises a turbomolecular vacuum pumping system.

12. The deposition system of claim 1, wherein said gas injection system is configured to alternatingly and cyclically introduce a tantalum containing halogen and a hydrogen containing gas.

13. The deposition system of claim 1, wherein said gas injection system is configured to alternatingly and cyclically introduce tantalum pentachloride and hydrogen.

14. The deposition system of claim 1, wherein said power source is configured to couple power to said second process material.

15. The deposition system of claim 1, wherein said power source is coupled to an electrode within said substrate holder.

16. The deposition system of claim 15, wherein said power source comprises a radio frequency (RF) generator and an impedance match network.

17. The deposition system of claim 1, further comprising:

an upper assembly coupled to said processing chamber, wherein said gas injection system is coupled to said upper assembly and said upper assembly opposes said substrate across said process space.

18. The deposition system of claim 17, wherein said power source is coupled to an electrode formed within said upper assembly.

19. The deposition system of claim 18, wherein a second power source is coupled to said substrate holder.

20. The deposition system of claim 1, further comprising:

a controller coupled to said processing chamber, said substrate holder, said power source, and said gas injection, and configured to perform at least one of monitoring, adjusting, or controlling said processing of said substrate in said process space.

21. A method of treating a substrate in a deposition system comprising:

locating a substrate holder at a first position within a transfer space of a processing chamber of said deposition system;

loading said substrate onto said substrate holder while said substrate holder is in said first position;

locating said substrate holder within said processing chamber at a second position within a process space of said processing chamber;

sealing said substrate holder with said processing chamber while said substrate holder is in said second position such that said process space is decoupled from said transfer space;

evacuating said transfer space using a first pressure control system;

evacuating said process space using a second pressure control system;

treating said substrate in said process space by alternatingly exposing said substrate to a first process material and a second process material, and forming plasma during said exposing said substrate to said second process material;

unsealing said substrate holder from said processing chamber and moving said substrate holder from said second position such that said process space is recoupled to said transfer space;

controlling the pressure and flow within the processing chamber and transfer space to reduce the tendency of contaminant producing materials from entering the transfer space from the process chamber;

locating said substrate holder at said first position; and

unloading said substrate when said substrate holder is at said first position.

22. The method of claim 21, further comprising:

purging said transfer space, or said process space, or both spaces during said locating of said substrate holder from said second position to said first position.

23. A deposition system for forming a thin film on a substrate comprising:

a processing chamber comprising a process space in an upper region of said processing chamber configured to facilitate said thin film deposition, and a transfer space in a lower region of said processing chamber configured to facilitate transfer of said substrate into and out of said processing chamber;

a substrate holder coupled to said processing chamber and configured to support said substrate, and configured to translate vertically between a first position to locate said substrate in said transfer space and a second position to locate said substrate in said process space, wherein said substrate holder comprises a sealing device configured to seal said substrate holder with said processing chamber when said substrate holder is in said second position;

means for controlling the pressure in said transfer space in order to provide a substantially contaminant-free environment in said transfer space;

means for controlling the pressure in said process space in order to evacuate said process space during processing;

means for alternatingly introducing a first process material and a second process material to said process space;

means for coupling power to said processing chamber in order to couple power to said first process material, or said second process material, or both in said process space to facilitate the formation of plasma; and

means for controlling the temperature of said substrate.