IN-SITU ATOMIC LAYER DEPOSITION

• US 20070037412A1
• Filed: 08/03/2006
• Published: 02/15/2007
• Est. Priority Date: 08/05/2005
• Status: Abandoned Application

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Dip, Anthony, Sasaki, Sadao, Reid, Kimberly, Toeller, Michael
• Application Number:
  US11/462,234
• Publication Number:
  US 20070037412A1
• Time in Patent Office: Days
• US Class Current: 438/785
• CPC Class Codes: C23C 16/0236 by etching with a reactive gas
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45546 specially adapted for a substrate stack in the ALD reactor
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02312 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02318 post-treatment
• CPC Class Codes: H01L 21/02323 introduction of oxygen
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2

Abstract

An in situ method for forming a HfO₂ high-k dielectric layer in a batch wafer processing system. The method comprises first loading a plurality of wafers into a process chamber, and then pre-treating the plurality of wafers in the process chamber with a first oxidizer. After pre-treating the wafers, and without removing the wafers from the process chamber, the method then comprises depositing HfO₂ on the plurality of wafers by atomic layer deposition, which comprises a plurality of deposition cycles, each cycle comprising alternating exposure of the plurality of wafers in the process chamber to a second oxidizer and a hafnium precursor. The hafnium precursor is selected from hafnium tert-butoxide (HTB) or hafnium tetra-diethylamide (TDEAH).

Claims

1. An in situ method for forming a HfO₂ high-k dielectric layer in a batch wafer processing system, comprising:

loading a plurality of wafers into a process chamber;

pre-treating the plurality of wafers in the process chamber with a first oxidizer selected from an oxygen-containing gas or an oxygen- and nitrogen-containing gas;

after the pre-treating, and without removing the plurality of wafers from the process chamber, depositing HfO₂ on the plurality of wafers by atomic layer deposition comprising a plurality of deposition cycles, each cycle comprising alternating exposure of the plurality of wafers in the process chamber to a second oxidizer and a hafnium precursor with optional purging in-between, wherein the second oxidizer is selected from an oxygen-containing gas or an oxygen- and nitrogen-containing gas, and wherein the hafnium precursor is selected from hafnium tert-butoxide (HTB) or hafnium tetra-diethylamide (TDEAH); and

unloading the plurality of wafers from the process chamber.

2. The method of claim 1 wherein the process chamber is purged between each alternating exposure and between each deposition cycle with an inert gas.

3. The method of claim 1 wherein the inert gas is H₂ or Ar.

4. The method of claim 1 wherein the first oxidizer is different than the second oxidizer, and each are selected from O₂, O₃, N₂O, NO, or H₂O vapor.

5. The method of claim 1 wherein the pre-treating is performed at a wafer temperature in the range of about 500-1000°

C. for a period of about 30 seconds to about 30 minutes.

6. The method of claim 1 wherein the pre-treating is performed at a wafer temperature in the range of about 600-850°

C. for a period of about 5-20 minutes.

7. The method of claim 1 wherein the depositing is performed at a wafer temperature in the range of about 25-800°

C. for 5-50 deposition cycles, with each alternating exposure being for a period of about 5 seconds to about 5 minutes.

8. The method of claim 1 wherein the depositing is performed at a wafer temperature in the range of about 175-350°

C. for 10-25 deposition cycles, with each alternating exposure being for a period of about 15 seconds to about 2 minutes.

9. The method of claim 8 wherein the period of exposure to the second oxidizer is twice as long as the period of exposure to the hafnium precursor.

10. The method of claim 1 further comprising, prior to unloading the plurality of wafers from the process chamber, annealing the plurality of wafers at a temperature in the range of about 250-1000°

C. to densify the HfO₂.

11. The method of claim 1 further comprising, prior to unloading the plurality of wafers from the process chamber, annealing the plurality of wafers to densify the HfO₂ wherein the annealing is selected from one or any sequential combination of:

(a) a high temperature bake at a temperature in the range of about 500-1000°

C. with no gaseous environment;

(b) a high temperature oxidation anneal at a temperature in the range of about 500-1000°

C. in the presence of a third oxidizer selected from an oxygen-containing gas or an oxygen- and nitrogen-containing gas;

or

(c) a high temperature anneal at a temperature in the range of about 500-1000°

C. in the presence of a non-oxidizing gas.

12. The method of claim 11 wherein the temperature in (a), (b), or (c) is 550-800°

C.

13. The method of claim 11 wherein the annealing is (b) at a temperature of 600°

C. and the third oxidizer is NO.

14. The method of claim 11 wherein the annealing is (c) at a temperature of 800°

C. and the non-oxidizing gas is N₂.

15. The method of claim 1 further comprising, prior to unloading the plurality of wafers from the process chamber, annealing the plurality of wafers to densify the HfO₂ wherein the annealing is selected from one or any sequential combination of:

(a) a low temperature bake at a temperature in the range of about 250-450°

C. with no gaseous environment;

(b) a low temperature oxidation anneal at a temperature in the range of about 250-450°

C. in the presence of a third oxidizer selected from an oxygen-containing gas or an oxygen- and nitrogen-containing gas;

or

(c) a low temperature anneal at a temperature in the range of about 250-450°

C. in the presence of a non-oxidizing gas.

16. An in situ method for forming a HfO₂ high-k dielectric layer in a batch wafer processing system, comprising:

loading a plurality of wafers into a process chamber;

pre-treating the plurality of wafers in the process chamber at a wafer temperature in the range of about 600-850°

C. with a first oxidizer selected from O₂, O₃, N₂O, NO, or H₂O vapor;

after the pre-treating, and without removing the plurality of wafers from the process chamber, depositing HfO₂ on the plurality of wafers by atomic layer deposition comprising a plurality of deposition cycles, each cycle comprising alternating exposure of the plurality of wafers in the process chamber at a wafer temperature in the range of about 175-350°

C. to a second oxidizer and a hafnium precursor with optional purging in-between, wherein the second oxidizer is selected from O₂, O₃, N₂O, NO, or H₂O vapor, and wherein the hafnium precursor is selected from hafnium tert-butoxide (HTB) or hafnium tetra-diethylamide (TDEAH);

after the depositing, and without removing the plurality of wafers from the process chamber, annealing the plurality of wafers at a temperature in the range of about 550-800°

C. to densify the HfO₂, wherein the annealing is selected from one or any sequential combination of a bake with no gaseous environment, an oxidation anneal in the presence of a third oxidizer selected from O₂, O₃, N₂O, NO, or H₂O vapor;

or an anneal in the presence of a non-oxidizing gas; and

unloading the plurality of wafers from the process chamber.

17. The method of claim 16 wherein the third oxidizer is NO, and the non-oxidizing gas is N₂.

18. The method of claim 16 wherein the period of exposure to the second oxidizer is twice as long as the period of exposure to the hafnium precursor.

19. The method of claim 16 wherein the annealing includes the oxidation anneal, the first and third oxidizers are NO, the second oxidizer is O₂, and the hafnium precursor is HTB.

20. The method of claim 16 wherein the annealing includes the anneal in the presence of a non-oxidizing gas, the first oxidizer is NO, the second oxidizer is water vapor, the hafnium precursor is TDEAH, and the non-oxidizing gas is N₂.