Elimination of flow and pressure gradients in low utilization processes

• US 20060029747A1
• Filed: 08/09/2004
• Published: 02/09/2006
• Est. Priority Date: 08/09/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Cruse, James P., Hegedus, Andreas G., Kuppurao, Satheesh
• Granted Patent: US 7,955,646 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45557 Pulsed pressure or control pressure
• CPC Class Codes: C23C 8/10 Oxidising
• CPC Class Codes: C23C 8/36 using ionised gases, e.g. ionitriding
• CPC Class Codes: C30B 25/14 Feed and outlet means for the gases; Modifying the flow of the reactive gases
• CPC Class Codes: C30B 29/06 Silicon
• 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 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 21/28525 the conductive layers comprising semiconducting material H01L21/28518, H01L21/28537 take precedence
• CPC Class Codes: H01L 21/3115 Doping the insulating layers
• CPC Class Codes: H01L 21/3144 on silicon

Abstract

The amount of atoms diffused into a substrate may be made uniform or the thickness of a thin film may be made uniform in a low species utilization process by stopping the flow of gas into a reaction chamber during the low species utilization process. Stopping the flow of gas into a reaction chamber may entail closing the gate valve (the valve to the vacuum pump), stabilizing the pressure within the reaction chamber, and maintaining the stabilized pressure while stopping the gas flowing into the chamber. Low species utilization processes include the diffusion of nitrogen into silicon dioxide gate dielectric layers by decoupled plasma nitridation (DPN), the deposition of a silicon dioxide film by rapid thermal processing (RTP) or chemical vapor deposition (CVD), and the deposition of silicon epitaxial layers by CVD.

Claims

1. A method, comprising:

flowing a gas into a chamber;

stopping the gas flowing into the chamber; and

performing a low species utilization process within the chamber after minimizing pressure and flow gradients within the chamber.

2. The method of claim 1, wherein stopping the gas flowing into the chamber comprises stabilizing the pressure within the chamber, closing a gate valve of the chamber, and maintaining the pressure within the chamber while stopping the gas flowing into the chamber.

3. The method of claim 1, wherein performing the low species utilization process comprises depositing a film having a thickness of less than 30 angstroms.

4. The method of claim 1, wherein performing the low species utilization process comprises diffusing atoms into a substrate in the approximate range of 1×

e¹⁴ atoms/cm² and 1×

e¹⁶ atoms/cm².

5. The method of claim 1, wherein performing the low species utilization process comprises a decoupled plasma nitridation.

6. The method of claim 1, wherein performing the low species utilization process comprises a rapid thermal process to deposit a film.

7. The method of claim 1, wherein performing the low species utilization process comprises a chemical vapor deposition.

8. The method of claim 7, wherein the chemical vapor deposition comprises growing an epitaxial layer on a substrate.

9. The method of claim 1, wherein performing the low species utilization process comprises atomic layer deposition.

10. A method, comprising:

flowing a gas into a plasma chamber;

stopping the gas flowing into the plasma chamber; and

striking a plasma after stopping the gas flowing into the plasma chamber.

11. The method of claim 10, further comprising stabilizing the pressure within the plasma chamber before striking the plasma.

12. The method of claim 10, further comprising maintaining a stable pressure within the plasma chamber while striking the plasma.

13. The method of claim 10, further comprising diffusing the gas into a substrate while striking the plasma.

14. The method of claim 13, wherein diffusing a gas into a substrate comprises diffusing nitrogen gas into a silicon dioxide gate.

15. A method, comprising:

flowing a nitrogen gas into a decoupled plasma nitridation chamber, the decoupled plasma nitridation chamber having an internal pressure;

closing the gate valve of the decoupled plasma nitridation chamber;

stabilizing the internal pressure of the decoupled plasma nitridation chamber to obtain a stabile pressure;

maintaining the stable pressure within the decoupled plasma nitridation chamber while stopping the gas flowing into the decoupled plasma nitridation chamber; and

striking a plasma after stopping the nitrogen gas flowing into the chamber and after stabilizing the internal pressure of the chamber.

16. The method of claim 15, wherein striking a plasma comprises implanting nitrogen in the approximate range of 1×

10¹⁴ atoms/cm² and 8×

10¹⁴ atoms/cm² into a silicon dioxide film on a 300 mm wafer.

17. The method of claim 15, wherein striking a plasma comprises providing a coil about a roof of the plasma nitridation chamber and energizing the coil with radio frequency (RF) power.

18. The method of claim 15, wherein stabilizing the internal pressure of the decoupled plasma nitridation chamber comprises bringing the internal pressure to within approximately 5 mTorr and 95 mTorr.

19. The method of claim 15, wherein stabilizing the internal pressure of the decoupled plasma nitridation chamber comprises bringing the internal pressure to approximately 20 mTorr.

20. The method of claim 15, further comprising maintaining the stabilized internal pressure while striking a plasma

21. The method of claim 15, wherein maintaining the stable pressure within the decoupled plasma nitridation chamber comprises ramping down the nitrogen gas flow at a rate in the approximate range of 10 sccm/second and 50 sccm/second.

22. The method of claim 15, wherein implanting nitrogen into a substrate comprises applying an effective radio frequency in the approximate range of 30 W to 300 W.

23. The method of claim 15, wherein implanting nitrogen into a substrate comprises applying an effective radio frequency of approximately 150 W.

24. A method, comprising:

flowing a reactant gas into a rapid thermal processing chamber containing a substrate;

stopping the gas flowing into the rapid thermal processing chamber at a first temperature that is not sufficient to cause a reaction of the reactant gas; and

ramping the first temperature to a second temperature after stopping the gas flowing into the rapid thermal processing chamber, the second temperature sufficient to cause a reaction of the reactant gas; and

forming a film on the substrate at the second temperature.

25. The method of claim 24, wherein flowing a reactant gas into the chamber comprises flowing a mixture of hydrogen (H₂) and oxygen (O₂) gases into the chamber.

26. The method of claim 24, wherein flowing a reactant gas into the chamber comprises flowing oxygen gas into the chamber.

27. The method of claim 24, wherein flowing a reactant gas into a rapid thermal processing chamber comprises flowing an amount of reactant gas sufficient to grow a film having a thickness in the approximate range of 5 angstroms and 50 angstroms.

28. The method of claim 24, further comprising stabilizing an internal pressure within the rapid thermal processing chamber before stopping the gas flowing into the rapid thermal processing chamber at a first temperature that is not sufficient to cause a reaction of the reactant gas.

29. The method of claim 24, wherein forming the film on the wafer comprises depositing a silicon dioxide film.

30. The method of claim 24, wherein the second temperature comprises a temperature in the approximate range of 800°

C. and 1100°

C.

31. A method, comprising:

flowing a reactant gas into a chemical vapor deposition chamber containing a substrate;

stopping the gas flowing into the chemical vapor deposition chamber at a first temperature that is not sufficient to cause a reaction of the reactant gas;

ramping the first temperature to a second temperature after stopping the gas flowing into the chemical vapor deposition chamber, the second temperature sufficient to cause a reaction of the reactant gas; and

forming a film on the substrate at the second temperature.

32. The method of claim 31, wherein flowing a reactant gas into a chemical vapor deposition chamber comprises flowing a mixture of a silicon containing gas, hydrogen gas, and a marker into the chemical vapor deposition chamber.

33. The method of claim 31, wherein flowing a reactant gas into a chemical vapor deposition chamber comprises flowing an amount of reactant gas sufficient to grow a film having a thickness in the approximate range of 5 angstroms and 500 angstroms.

34. The method of claim 31, wherein flowing a reactant gas into a chemical vapor deposition chamber comprises flowing an amount of reactant gas sufficient to grow a film having a thickness of approximately 100 angstroms.

35. The method of claim 31, further comprising stabilizing an internal pressure within the chemical vapor deposition chamber before stopping the gas flowing into the chemical vapor deposition chamber at a first temperature that is not sufficient to cause a reaction of the reactant gas.

36. The method of claim 31, wherein forming the film on the substrate comprises growing an epitaxial silicon layer on a silicon wafer.

37. The method of claim 31, wherein forming the film on the substrate comprises growing an epitaxial polysilicon layer on a silicon wafer.

38. The method of claim 31, wherein forming the film on the substrate comprises growing an amorphous silicon layer on a silicon wafer.

39. The method of claim 31, wherein forming the film on the substrate comprises growing a silicon dioxide layer on the wafer.

40. The method of claim 31, wherein forming the film on the substrate comprises growing a silicon nitride layer on the wafer.

41. A substrate processing system, comprising:

a process chamber;

a system controller for controlling the process chamber;

a machine-readable medium coupling to the controller, the machine-readable medium has a memory that stores a set of instructions that controls operations of a pressure stabilization of the process chamber; and

wherein the set of instructions further controls all parameters of the pressure stabilization within the process chamber by ramping down a gas flow rate of gas flowing into the process chamber, stabilizing the pressure within the process chamber before closing a gate valve of the process chamber, and maintaining the pressure within the process chamber while stopping the gas flowing into the process chamber.

42. The substrate processing system of claim 41, wherein the process chamber is a decoupled plasma nitridation chamber.

43. The substrate processing system of claim 41, wherein the process chamber is a rapid thermal processing chamber.

44. The substrate processing system of claim 41, wherein the process chamber is a chemical vapor deposition chamber.

45. The substrate processing system of claim 41, wherein the set of instructions further controls all parameters of the pressure stabilization within the process chamber by performing a low species utilization process after stopping the gas flowing into the process chamber.