Methods of depositing a ruthenium film

• US 8,273,408 B2
• Filed: 10/14/2008
• Issued: 09/25/2012
• Est. Priority Date: 10/17/2007
• Status: Active Grant

• Current Assignee: ASM Korea Ltd. (ASM International NV)
• Original Assignee: Asm Genitech Korea Ltd. (ASM International NV)
• Inventors: Kim, Jong Su, Park, Hyung Sang
• Primary Examiner(s): Daniels, Matthew
• Assistant Examiner(s): SNELTING, ERIN LYNN
• Application Number:
  US12/250,827
• Publication Number:
  US 20090104777A1
• Time in Patent Office: 1,442 Days
• Field of Search: 427/255.29, 427/255.31
• US Class Current: 427/250
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 28/65 comprising a noble metal or a noble metal oxide, e.g. platinum (Pt), ruthenium (Ru), ruthenium dioxide (RuO2), iridium (Ir), iridium dioxide (IrO2)

Abstract

Cyclical methods of depositing a ruthenium layer on a substrate are provided. In one process, initial or incubation cycles include supplying alternately and/or simultaneously a ruthenium precursor and an oxygen-source gas to deposit ruthenium oxide on the substrate. The ruthenium oxide deposited on the substrate is reduced to ruthenium, thereby forming a ruthenium layer. The oxygen-source gas may be oxygen gas (O₂). The ruthenium oxide may be reduced by supplying a reducing agent, such as ammonia (NH₃) gas. The methods provide a ruthenium layer having good adherence to an underlying high dielectric layer while providing good step coverage over structures on the substrate. After nucleation, subsequent deposition cycles can be altered to optimize speed and/or conformality rather than adherence.

Claims

1. A method of depositing a ruthenium film, the method comprising:

loading a substrate into a reactor;

conducting a plurality of first and second deposition cycles, at least one of the first deposition cycles comprising steps of;

supplying a ruthenium precursor to the reactor;

supplying oxygen (O₂) gas to the reactor, wherein supplying the oxygen gas comprises supplying the oxygen gas simultaneously with supplying the ruthenium precursor; and

supplying ammonia (NH₃) gas to the reactor after supplying the ruthenium precursor and the oxygen gas without supplying the ruthenium precursor and the oxygen gas;

after the at least one of the first deposition cycles, conducting one or more second deposition cycles, wherein at least one of the second cycles comprises steps of;

supplying the ruthenium precursor the reactor; and

supplying oxygen gas to the reactor after supplying the ruthenium precursor, wherein ammonia gas is not supplied in the second cycles; and

supplying ammonia gas to the reactor subsequent to the one or more second cycles;

wherein the temperature of the reactor is maintained at about 200°

C. to about 400°

C.

2. The method of claim 1, wherein the at least one of the first deposition cycles further comprises purging the reactor after supplying the ruthenium precursor and the oxygen gas and before supplying the ammonia gas.

3. The method of claim 1, further comprising supplying a first purge gas before and/or after supplying the oxygen gas in the at least one of the first deposition cycle.

4. The method of claim 3, wherein a second purge gas is supplied after supplying the first purge gas, and before and/or after supplying the ammonia gas in the at least one of the first deposition cycle.

5. The method of claim 1, wherein the at least one of the first deposition cycles comprises one or more first sub-cycles before supplying the ammonia gas, each of the first sub-cycles comprising steps of:

supplying the ruthenium precursor and the oxygen gas simultaneously to the reactor; and

continuing to supply the oxygen gas to the reactor after stopping supply of the ruthenium precursor.

6. The method of claim 5, wherein each of the first sub-cycles further comprises increasing the flow rate of the oxygen gas during continuing to supply the oxygen gas and after supplying the ruthenium precursor.

7. The method of claim 6, further comprising supplying a first purge gas before and/or after increasing the flow rate of the oxygen gas.

8. The method of claim 7, wherein supplying the purge gas further comprises supplying a second purge gas after supplying the first purge gas, after increasing the flow rate of the oxygen gas, and before and/or after supplying the ammonia gas.

9. The method of claim 1, wherein the at least one of the second cycles further comprises supplying a purge gas after supplying the ruthenium precursor, and before and/or after supplying the oxygen gas.

10. The method of claim 1, further comprising supplying a purge gas after supplying the oxygen gas simultaneously with supplying the ruthenium precursor and before supplying the ammonia gas.

11. The method of claim 1, further comprising, after supplying the ammonia gas prior to the at least one second cycle, supplying a purge gas during:

a first time period before supplying the ruthenium precursor in the at least one second cycle;

a second time period after supplying the ruthenium precursor in the at least one second cycle and before supplying the oxygen gas in the at least one second cycle;

a third time period after supplying the oxygen gas in the at least one second cycle and before supplying the ammonia gas subsequent to the at least one second cycle; and

/or

a fourth time period after supplying the ammonia gas subsequent to the at least one second cycle.

12. The method of claim 1, wherein the ruthenium precursor comprises a compound represented by Ru(XaXb), wherein Xa and Xb are, respectively, any one of cyclopentadienyl (Cp), methylcyclopentadienyl (MeCp), ethylcyclopentadienyl (EtCp) and isopropylcyclopentadienyl (i-PrCp), or one or more of ruthenium octanedionate (Ru(OD)₃), ruthenium tetramethylheptadionate (Ru(thd)₃), or RuO₄.

13. The method of claim 1, wherein a ruthenium oxide layer is formed on the substrate by supplying the ruthenium precursor to the reactor and supplying the oxygen gas to the reactor, and wherein at least a portion of the ruthenium oxide layer is reduced to ruthenium by supplying the ammonia gas.

14. The method of claim 1, wherein supplying the ammonia gas comprises supplying the ammonia gas for a period of time equal to or less than 10 minutes.

15. A method of depositing a ruthenium film, the method comprising:

loading a substrate into a reactor; and

conducting a plurality of deposition cycles, at least one of the cycles comprising steps of;

supplying a ruthenium precursor to the reactor;

supplying an oxygen-source gas to the reactor to deposit oxidized ruthenium on the substrate, wherein supplying the oxygen-source gas comprises supplying the oxygen-source gas simultaneously with supplying the ruthenium precursor; and

reducing the oxidized ruthenium deposited on the substrate to ruthenium with non-plasma ammonia (NH₃) gas thereby forming greater than one complete monolayer of ruthenium; and

after supplying the ammonia gas, conducting one or more second cycles, wherein at least one of the second cycles comprises steps of;

supplying the ruthenium precursor the reactor; and

supplying oxygen-source gas to the reactor after supplying the ruthenium precursor, wherein ammonia gas is not supplied in the second cycles and

after the one or more second cycles, supplying ammonia gas to the reactor.

16. The method of claim 15, wherein the ruthenium precursor comprises a compound containing at least one ruthenium atom and one or more ligands bonding to the ruthenium atom.

17. The method of claim 15, wherein the oxygen-source gas comprises oxygen gas (O₂) and/or ozone (O₃) gas.

18. The method of claim 15, wherein the at least one of the cycles comprises a number of sub-cycles, each of the sub-cycles including supplying a ruthenium precursor to the reactor and supplying an oxygen-source gas to the reactor, wherein the number is selected such that a ruthenium film resulting from the plurality of deposition cycles is substantially free of pores therein.