IN SITU SILICON AND TITANIUM NITRIDE DEPOSITION

• US 20080286981A1
• Filed: 05/14/2007
• Published: 11/20/2008
• Est. Priority Date: 05/14/2007
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Hasper, Albert
• Granted Patent: US 7,629,256 B2
• Time in Patent Office: Days
• US Class Current: 438/762
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45578 Elongated nozzles, tubes with holes

Abstract

A method of processing semiconductor wafers is provided, comprising loading a batch of semiconductor wafers into a processing chamber; depositing titanium nitride (TiN) onto the wafers in the processing chamber; and depositing silicon onto the wafers in the processing chamber, without removing the wafers from the processing chamber between said depositing steps. In preferred embodiments, the TiN and silicon depositing steps are both conducted at temperatures within about 400-550° C., and at temperatures within 100° C. of one another.

Claims

1. A method of processing semiconductor wafers, comprising:

loading a batch of semiconductor wafers into a processing chamber;

depositing titanium nitride (TiN) onto the wafers in the processing chamber; and

depositing silicon onto the wafers in the processing chamber, without removing the wafers from the processing chamber between said depositing steps.

2. The method of claim 1, wherein said step of depositing silicon occurs after said step of depositing TiN.

3. The method of claim 1, wherein said step of depositing TiN occurs after said step of depositing silicon.

4. The method of claim 1, wherein the TiN depositing step is conducted at a first average temperature and the silicon depositing step is conducted at a second average temperature, the first and second temperatures being within 100°

C. of one another.

5. The method of claim 4, wherein the first and second temperatures are within 50°

C. of one another.

6. The method of claim 1, wherein the TiN and silicon depositing steps are both conducted at temperatures within about 400-550°

C.

7. The method of claim 6, wherein the TiN and silicon depositing steps are both conducted at temperatures within about 450-500°

C.

8. The method of claim 1, wherein depositing silicon comprises flowing trisilane through the processing chamber.

9. The method of claim 1, wherein loading the batch of wafers comprises providing an arrangement of generally parallel wafers spaced from one another, and wherein depositing TiN and silicon comprises flowing precursor gases through gas injector tubes each positioned within the processing chamber and oriented substantially perpendicular to the wafers, each injector tube extending along a majority of a length of the arrangement of wafers, each tube having a plurality of gas injector holes along its length.

10. The method of claim 9, wherein loading the batch of wafers comprises providing an arrangement of generally horizontal wafers spaced vertically from one another, each injector tube being oriented substantially vertically and extending along a majority of a height of the arrangement of wafers.

11. The method of claim 9, wherein depositing TiN comprises:

flowing a plurality of separate pulses of a titanium precursor gas through a first of the injector tubes; and

flowing a plurality of separate pulses of a nitrogen precursor gas through a second of the injector tubes, each of the nitrogen precursor gas pulses occurring temporally between two successive ones of the titanium precursor gas pulses.

12. The method of claim 11, wherein depositing TiN further comprises, during each of a plurality of separate time intervals, one of (1) flowing a purge gas into the processing chamber and (2) evacuating the processing chamber, each said time interval being after a pulse of one of the precursor gases and before an immediately following pulse of the other of the precursor gases.

13. The method of claim 11, wherein depositing TiN further comprises flowing an additional pulse of the nitrogen precursor gas through the second injector tube after a last of the titanium precursor gas pulses, said additional nitrogen precursor gas pulse not being followed by another titanium precursor gas pulse.

14. The method of claim 9, wherein depositing TiN comprises:

flowing a nitrogen precursor gas through a first of the injector tubes; and

while flowing the nitrogen precursor gas, flowing a plurality of separate pulses of a titanium precursor gas through a second of the injector tubes.

15. The method of claim 9, wherein depositing TiN comprises flowing nitrogen and titanium precursor gases in accordance with a cycle comprising the following steps:

flowing a pulse of the nitrogen precursor gas through a first of the injector tubes during a first time interval;

flowing a pulse of the titanium precursor gas through a second of the injector tubes during the first time interval; and

flowing a pulse of the nitrogen precursor gas through the first injector tube during a second time interval after the first time interval, wherein the titanium precursor gas is not delivered to the processing chamber during the second time interval.

16. The method of claim 15, wherein the cycle further includes the following steps:

temporally between the first and second time intervals, one of (1) purging the processing chamber with a purge gas and (2) evacuating the processing chamber; and

temporally after the second time interval, one of (1) purging the processing chamber with the purge gas and (2) evacuating the processing chamber.

17. The method of claim 15, wherein the titanium precursor gas comprises titanium tetrachloride (TiCl₄), and the nitrogen precursor gas comprises ammonia (NH₃).

18. An apparatus comprising:

a processing chamber configured to contain a plurality of semiconductor wafers;

a titanium precursor source connected to the chamber to deliver a vapor of the titanium precursor into the chamber;

a nitrogen precursor source connected to the chamber to deliver a vapor of the nitrogen precursor into the chamber;

a silicon precursor source connected to the chamber to deliver a vapor of the silicon precursor into the chamber; and

a valve system configured to allow selective control of delivery of the vapors into the chamber.

19. The apparatus of claim 18, wherein the titanium precursor comprises titanium tetrachloride (TiCl₄), the nitrogen precursor comprises ammonia (NH₃), and the silicon precursor source comprises trisilane (Si₃H₈).

20. The apparatus of claim 18, further comprising a deposition control system configured to control the valve system and temperature inside the chamber, the deposition control system programmed to deliver all of the precursor vapors into the chamber at temperatures within about 100°

C. of one another.

21. The apparatus of claim 20, wherein the deposition control system is programmed to deliver all of the precursor vapors into the chamber at temperatures within about 50°

C. of one another.

22. The apparatus of claim 18, further comprising a deposition control system configured to control the valve system and temperature inside the chamber, the deposition control system programmed to deliver all of the precursor vapors into the chamber at temperatures within about 400-550°

C.

23. The apparatus of claim 22, wherein the deposition control system is programmed to deliver all of the precursor vapors into the chamber at temperatures within about 450-500°

C.

24. The apparatus of claim 18, further comprising a deposition control system configured to control the valve system and programmed to deliver into the chamber alternating pulses of the titanium precursor vapor and the nitrogen precursor vapor.

25. The apparatus of claim 24, wherein the deposition control system is further programmed to, temporally between the alternating pulses of the titanium precursor vapor and the nitrogen precursor vapor, either purge the chamber with a purge gas or substantially evacuate the chamber.

26. The apparatus of claim 18, further comprising a deposition control system configured to control the valve system and programmed to deliver into the chamber a substantially constant flow of the nitrogen precursor vapor and a series of pulses of the titanium precursor vapor during the flow of the nitrogen precursor vapor.

27. The apparatus of claim 18, further comprising a deposition control system configured to control the valve system and programmed to deliver the precursor vapors into the chamber in multiple cycles of the following sequence:

substantially simultaneous pulses of the titanium and nitrogen precursor vapors; and

after the simultaneous pulses, an additional pulse of the nitrogen precursor vapor.

28. The apparatus of claim 27, wherein the deposition control system is further programmed to, in each cycle of the sequence:

either purge the chamber with a purge gas or substantially evacuate the chamber after the simultaneous pulses and before the additional pulse; and

either purge the chamber with a purge gas or substantially evacuate the chamber after the additional pulse and before a next cycle of the sequence.

29. The apparatus of claim 18, further comprising:

a wafer boat inside the processing chamber, the boat configured to support a stack of spaced apart wafers that are generally parallel to one another; and

a plurality of gas injector tubes each positioned within the processing chamber and oriented substantially perpendicular to the wafers, each injector tube extending along a majority of a length of the stack of wafers, each tube having a plurality of gas injector holes along its length, each of the injector tubes being in fluid communication with one of the precursor sources to deliver one of the precursor vapors into the reaction chamber.