Process conditions and precursors for atomic layer deposition (ALD) of AL2O3

• US 6,620,670 B2
• Filed: 01/18/2002
• Issued: 09/16/2003
• Est. Priority Date: 01/18/2002
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ravi, Jallepally, Song, Kevin, Chen, Liang-Yuh, Li, Shih-Hung
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): HO, TU TU V
• Application Number:
  US10/053,009
• Publication Number:
  US 20030139005A1
• Time in Patent Office: 606 Days
• Field of Search: 438/240, 438/216, 257/310, 257/410
• US Class Current: 438/216
• CPC Class Codes: C23C 16/403 of aluminium, magnesium or beryllium
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• 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 21/31616 Deposition of Al2O3
• CPC Class Codes: H01L 21/31683 of metallic layers, e.g. Al deposited on the body, e.g. formation of multi-layer insulating structures

Abstract

A semiconductor processing chamber has been utilized to perform sequential deposition of high-K Al₂O₃ thin films on a substrate disposed in the chamber employing low viscosity precursors. The method commences with introduction of an aluminum precursor into the processing chamber. In this manner, a monolayer of aluminum precursor is chemisorbed onto the substrate surface. Thereafter, non-chemisorbed aluminum precursor is purged from the processing chamber, followed by introduction of an oxygen precursor. The oxygen precursor reacts with the chemisorbed layer, resulting in a monolayer of Al₂O₃. Finally, excess oxygen precursor and by-products of the reaction are purged completing the sequential deposition cycle. The sequential deposition cycle can be repeated to grow the Al₂O₃ film to a desired thickness.

Claims

1. A method for depositing an aluminum-containing layer on a substrate disposed in a processing chamber, said method comprising:

forming an aluminum-containing monolayer upon said substrate by flowing an aluminum-containing compound and a liquid solvent into a vaporizer and then delivering the aluminum-containing process gas onto said substrate;

reacting oxygen with said aluminum-containing monolayer by exposing said aluminum-containing monolayer to an oxygen-containing precursor to produce a layer of Al₂O₃; and

repeating forming said aluminum-containing layer and reacting oxygen with said aluminum-containing monolayer to form said layer of Al₂O₃ with a desired thickness.

2. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor selected from the set of precursors consisting essentially of Triisopropoxyaluminum-Tetrahydrofuran, Aluminumtrichloride, Dimethylaluminumhydride:

Dimethylethylamine and Ethylpiperidine;

Dimethylaluminumhydride and reacting oxygen further includes vaporizing water to produce said oxygen-containing precursor.

3. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor selected from the set of precursors consisting essentially of Triisopropoxyaluminum-Hexane, Triisopropoxyaluminum-Tetrahydrofuran, Dimethylaluminumhydride:

Dimethylethylamine and Ethylpiperidine;

Dimethylaluminumhydride, by flowing said liquid aluminum-containing precursor into a vaporizer.

4. The method as recited in claim 1 wherein reacting oxygen further includes flowing an oxygen-containing compound, selected from a set of compounds consisting essentially of ozone, water vapor, oxygen radical and oxygen ions into said processing chamber.

5. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes heating said substrate to a temperature in a range of 100°

C. to 500°

C., inclusive and establishing a pressure within said processing chamber to be in a range of 0.1 Torr to 500 Torr.

6. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes vaporizing a liquid Triisopropoxyaluminum-Hexane having a weight ratio of Triisopropoxyaluminum to Hexane in a range of 10:

90 to 60;

40, by flowing said liquid Triisopropoxyaluminum-Hexane into a vaporizer.

7. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes vaporizing a liquid Triisopropoxyaluminum-Tetrahydrofuran having a weight ratio of Triisopropoxyaluminum to Tetrahydrofuran in a range of 10:

90 to 60;

40, by flowing said liquid Triisopropoxyaluminum-Tetrahydrofuran into a vaporizer.

8. The method as recited in claim 1 wherein forming an aluminum-containing monolayer upon said substrate further includes flowing said aluminum-containing process gas into said processing chamber at a rate in a range of 1 mg/minute to 200 mg/minute, inclusive.

9. The method as recited in claim 1 wherein forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor by heating liquid Aluminumtrhichloride to a temperature above a sublimation temperature that is associated with said liquid Aluminumtrichloride to produce Aluminumtrichloride gas and introducing said Aluminumtrichloride gas into said processing chamber at a rate in a range of 20 sccm to 1000 sccm, inclusive.

10. The method as recited in claim 1 wherein reacting oxygen further includes dissociating an oxygen-containing gas to form reactive species by impinging microwave frequencies on said oxygen-containing gas in a range of 100 Watts to 3000 Watts, and flowing said reactive species over said substrate.

11. The method as recited in claim 1 further including purging, after forming said aluminum-containing layer, said processing chamber of said aluminum-containing process gas before reacting oxygen with said aluminum-containing monolayer, and removing, after reacting oxygen and before repeating forming said aluminum-containing layer, said oxygen-containing precursor from said processing chamber.

12. The method of claim 1, wherein the aluminum-containing compound and the liquid solvent are flowed into the vaporizer in a weight ratio between about 10:

90 and about 60;

40.

13. A method for depositing an aluminum-containing layer onto a substrate disposed in a processing chamber, said method comprising:

heating said substrate to a temperature in a range of 100°

C. to 500°

C., inclusive;

establishing a pressure within said processing chamber in a range of 0.1 Torr to 500 Torr;

forming an aluminum-containing monolayer upon said substrate by flowing an aluminum-containing compound and a liquid solvent into a vaporizer and then delivering the aluminum-containing process gas onto said substrate;

reacting oxygen with said aluminum-containing monolayer by exposing said aluminum-containing monolayer to an oxygen-containing precursor to produce a layer of Al₂O₃ and by-products; and

repeating forming said aluminum-containing layer and reacting oxygen with said aluminum-containing monolayer to form said layer of Al₂O₃ with a desired thickness.

14. The method as recited in claim 13 wherein heating said substrate further includes heating said substrate to a processing temperature no less than 150°

C. and forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor selected from the set of precursors consisting essentially of Triisopropoxyaluminum-Hexane and Triisopropoxyaluminum-Tetrahydrofuran, by flowing said liquid aluminum-containing precursor into a vaporizer and reacting oxygen further includes flowing an oxygen-containing compound, selected from a set of compounds consisting essentially of ozone, oxygen radical and oxygen, ions into said processing chamber.

15. The method as recited in claim 13 wherein heating said substrate furthering includes heating said substrate to a processing temperature having a range no greater than 300°

C. and, forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor selected from the set of precursors consisting essentially of Triisopropoxyaluminum-Tetrahydrofuran, Dimethylaluminumhydride;

Dimethylethylamine and Ethylpiperidine;

Dimethylaluminumhydride and reacting oxygen further Includes flowing an oxygen-containing compound, selected from a set of compounds consisting essentially of water vapor, ozone, oxygen radicals and oxygen ions into said processing chamber.

16. The method as recited in claim 13 wherein heating said substrate furthering includes heating said substrate to a processing temperature having a range of 100°

C. to 300°

C., inclusive and forming said aluminum-containing monolayer further includes vaporizing a liquid aluminum-containing precursor selected from the set of precursors consisting essentially of, Aluminumtrichloride, Dimethylaluminumhydride;

Dimethylethylamine and Ethylpiperidine;

Dimethylaluminumhydride and reacting oxygen further includes flowing water vapor into said processing chamber.

17. The method as recited in claim 13 further including purging, after forming said aluminum-containing layer, said processing chamber of said aluminum-containing process gas before reacting oxygen into said aluminum-containing monolayer, and removing, after reacting oxygen and before repeating forming said aluminum-containing layer, said oxygen-containing precursor from said processing chamber.

18. The method of claim 13, wherein the aluminum-containing compound and the liquid solvent are flowed into the vaporizer in a weight ratio between about 10:

90 and about 60;

40.

19. A processing system for forming an aluminum-containing layer on a substrate, said system comprising:

a body defining a processing chamber;

a cover disposed over the body and adapted to deliver gases into the processing chamber;

a holder disposed within said processing chamber to support said substrate;

an oxygen-containing precursor source mounted on the cover;

an aluminum-containing precursor in fluid communication with the cover;

a temperature control system in thermal communication with said processing chamber;

a pressure control system in fluid communication with said processing chamber;

a controller in electrical communication with the cover, said temperature control system, and said pressure control system; and

a memory in data communication with said controller, said memory comprising a computer-readable medium having a computer-readable program embodied therein, said computer-readable program including a first set of instructions for controlling the cover, said pressure control system and said temperature control system to form an aluminum-containing monolayer upon said substrate by chemisorption of said aluminum-containing precursor, and a second set of instructions to control said gas delivery system, said pressure control system and said temperature control system to chemisorb oxygen into said aluminum-containing monolayer by exposing said aluminum-containing monolayer to said oxygen-containing precursor to produce a layer of Al₂O₃ and by-products, and a third set of instructions to control the cover, said pressure control system and said temperature control system to repeat forming said aluminum-containing layer and chemisorbing oxygen into said aluminum-containing monolayer to form said layer of Al₂O₃ with a desired thickness.

20. The system as recited in claim 19 wherein said computer-readable program further includes a fourth set of instructions to control the cover to purge said aluminum-containing precursor and by-products from said processing chamber before introduction of said oxygen-containing precursor into said processing chamber and a fifth set of instructions to remove said oxygen-containing precursor after chemisorbing said oxygen into said aluminum-containing monolayer and before execution of said third set of instructions.

21. The processing system of claim 19, wherein the oxygen-containing precursor source comprises a remote plasma source.