Apparatus for low-temperature annealing of metallization microstructures in the production of a microelectronic device

• US 6,508,920 B1
• Filed: 08/31/1999
• Issued: 01/21/2003
• Est. Priority Date: 02/04/1998
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Inventors: Dundas, Curt, Stevens, E. Henry, Ritzdorf, Thomas L., Graham, Lyndon W., Chen, LinLin
• Primary Examiner(s): Valentine, Donald R.
• Assistant Examiner(s): Leader, William T.
• Application Number:
  US09/387,577
• Time in Patent Office: 1,239 Days
• Field of Search: 204/194, 204/198, 204/224.R, 204/241, 204/242, 205/123, 205/224, 118/58, 118/59, 118/69
• US Class Current: 204/194
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 5/022 using masking means
• CPC Class Codes: C25D 5/50 by heat-treatment
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/67173 in-line arrangement
• CPC Class Codes: H01L 21/6723 comprising at least one plating chamber electroless plating apparatuses C23C, electroplating apparatuses C25D
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material

Abstract

A method for filling recessed microstructures at a surface of a microelectronic workpiece, such as a semiconductor wafer, with metallization is set forth. In accordance with the method, a metal layer is deposited into the microstructures with a process, such as an electroplating process, that generates metal grains that are sufficiently small so as to substantially fill the recessed microstructures. The deposited metal is subsequently subjected to an annealing process at a temperature below about 100 degrees Celsius, and may even take place at ambient room temperature to allow grain growth which provides optimal electrical properties. Various novel apparatus for executing unique annealing processes are also set forth.

Claims

1. An apparatus for use in applying metallization in recessed microstructures of a microelectronic workpiece comprising:

at least one deposition station for depositing a metal into at least the recessed microstructures of the microelectronic workpiece; and

at least one annealing station for subjecting the microelectronic workpiece to an annealing temperature that is at or below about 250 degrees Celsius, wherein the at least one annealing station comprises;

a heat generator proximate a first side of the workpiece to heat the first side of the workpiece; and

a fluid flow system directing a flow of cooling fluid at a second side of the workpiece, opposite the first side, to thereby generate a temperature gradient between the first and second sides of the. workpiece.

2. An apparatus as set forth in claim 1 wherein the fluid flow system directs a cooling gas across the second side of the workpiece.

3. An apparatus as set forth in claim 1 wherein the fluid flow system comprises:

a cooling member proximate a second side of the microelectronic workpiece for cooling the second side of the workpiece; and

at least one channel associated with the cooling member for directing a flow of cooling gas therethrough to cool the cooling member.

4. An apparatus as set forth in claim 1 wherein the heat generator comprises a hot plate contacting the first side of the microelectronic workpiece.

5. An apparatus as set forth in claim 1 wherein the heat generator comprises an ultraviolet radiation source disposed to direct ultraviolet radiation toward the first side of the microelectronic workpiece.

6. An apparatus as set forth in claim 1 wherein the heat generator comprises a radiative heat source disposed at the first side of the microelectronic workpiece.

7. An apparatus as set forth in claim 1 wherein the heat generator comprises a laser source disposed to selectively direct laser radiation at selective portions of the first side of the microelectronic workpiece.

8. An apparatus as set forth in claim 1 and further comprising a programmable control system connected to control the magnitude of the temperature gradient.

9. An apparatus for use in fabricating metallization in recessed microstructures of a microelectronic workpiece comprising:

at least one deposition station for depositing a metal into at least the recessed microstructures of the microelectronic workpiece; and

at least one annealing station for subjecting the microelectronic workpiece to an annealing process in which the workpiece is subject to a controlled temperature gradient, wherein the at least one annealing station comprises;

a heat generator proximate a first side of the workpiece to heat the first side of the workpiece; and

a fluid flow system directing a flow of cooling fluid at a second side of the workpiece, opposite the first side, to thereby generate a temperature gradient between the first and second sides of the workpiece.

10. An apparatus as set forth in claim 9 wherein the fluid flow system directs a cooling gas across the second side of the workpiece.

11. An apparatus as set forth in claim 9 wherein the fluid flow system comprises:

a cooling member proximate a second side of the microelectronic workpiece for cooling the second side of the workpiece; and

at least one channel associated with the cooling member for directing a flow of cooling gas therethrough to cool the cooling member.

12. An apparatus as set forth in claim 9 wherein the heat generator comprises a hot plate contacting the first side of the microelectronic workpiece.

13. An apparatus as set forth in claim 9 wherein the heat generator comprises an ultraviolet radiation source disposed to direct ultraviolet radiation toward the first side of the microelectronic workpiece.

14. An apparatus as set forth in claim 9 wherein the heat generator comprises a radiative heat source disposed at the first side of the microelectronic workpiece.

15. An apparatus as set forth in claim 9 wherein the heat generator comprises a laser source disposed to selectively direct laser radiation at selective portions of the first side of the microelectronic workpiece.

16. An apparatus as set forth in claim 9 and further comprising a programmable control system connected to control the magnitude of the temperature gradient.

17. An apparatus for use in applying metallization in recessed microstructures of a microelectronic workpiece including at least one low-k dielectric layer comprising:

at least one deposition station for depositing metal into at least the recessed microstructures of the microelectronic workpiece; and

at least one annealing station for subjecting the microelectronic workpiece to an elevated temperature annealing process at a predetermined temperature that is below a temperature at which the low-K dielectric would substantially degrade, wherein the at least one annealing station comprises;

a heat generator proximate a first surface of the workpiece to heat the first surface of the workpiece; and

a cooling system disposed proximate a second surface of the workpiece that is spaced from the first surface, to thereby generate a temperature gradient between the first and second surfaces of the workpiece.

18. The apparatus of claim 17, wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid relative to a side of the workpiece.

19. The apparatus of claim 17 wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid such that the cooling fluid directly contacts the workpiece.

20. The apparatus of claim 17 wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid through a heat sink configured to draw heat away from the workpiece.

21. An apparatus for use in applying metallization in recessed microstructures of a microelectronic workpiece comprising:

at least one deposition station for depositing metal into at least the recessed microstructures of the microelectronic workpiece; and

at least one annealing station for subjecting the microelectronic workpiece to an annealing temperature, wherein the at least one annealing station comprises;

a heat generator proximate the workpiece to heat the workpiece during a heating cycle; and

a cooling system disposed proximate the workpiece and superimposed relative to the heat generator to cool the workpiece, wherein the cooling system generates a temperature gradient between first and second surfaces of the workpiece.

22. The apparatus of claim 21 wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid relative to a side of the workpiece.

23. The apparatus of claim 21 wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid such that the cooling fluid directly contacts the workpiece.

24. The apparatus of claim 21 wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid through a heat sink configured to draw heat away from the workpiece.

25. The apparatus of claim 21 wherein the heat generator comprises a hot plate, contacting a first side of the workpiece.

26. The apparatus of claim 21 wherein:

the heat generator comprises a hot plate at least proximate to a first side of the workpiece; and

the cooling system comprises a heat sink at least proximate to a second side of the workpiece.

27. The apparatus of claim 21 wherein the heat generator comprises a hot plate configured to subject the workpiece to an annealing temperature that is at or below 250°

C.

28. The apparatus of claim 21, further comprising a programmable control system operatively coupled to the heat generator and the cooling system to control the time and temperature of the heating and cooling cycles so that the workpiece is annealed at a temperature that is at or below 250°

C.

29. An apparatus for use in fabricating metallization in recessed microstructures of a microelectronic workpiece comprising:

at least one deposition station for depositing a metal into at least the recessed microstructures of the microelectronic workpiece; and

at least one annealing station for subjecting the microelectronic workpiece to an annealing process in which the workpiece is subject to a controlled temperature gradient, wherein the at least one annealing station comprises;

a heat generator proximate a first surface of the workpiece to heat the first side of the workpiece; and

a fluid flow system controlling a flow of cooling fluid to cool a second surface of the workpiece, spaced from the first surface, to thereby generate a temperature gradient between the first and second surfaces of the workpiece.

30. The apparatus of claim 29, further comprising a heat sink that is cooled by the cooling fluid.

31. An apparatus for use in forming metal components in recesses of a microelectronic workpiece, comprising:

at least one deposition station for depositing metal into the recesses; and

at least one annealing station for subjecting the microelectronic workpiece to an annealing temperature comprising;

a heat generator proximate the workpiece to heat the workpiece during a heating cycle, and

a cooling system comprising a heat sink proximate to the workpiece to cool the workpiece during a cooling cycle, wherein one of the heat sink or the heat generator (a) generates a temperature gradient between first and second surfaces of the workpiece and (b) defines a support member configured to support the workpiece in one position during the heating cycle and the cooling cycle.

32. The apparatus of claim 31 wherein the cooling system further comprises a fluid flow system that directs a flow of cooling fluid through the heat sink.

33. The apparatus of claim 31 wherein the heat generator comprises a hot plate contacting a first side of the workpiece.

34. The apparatus of claim 31 wherein:

the heat generator comprises a hot plate at least proximate to a first side of the workpiece; and

the heat sink is at least proximate to a second side of the workpiece.

35. The apparatus of claim 31 wherein the heat generator comprises a hot plate configured to subject the workpiece to an annealing temperature that is at or below 250°

C.

36. The apparatus of claim 31, further comprising a programmable control system operatively coupled to the heat generator and the cooling system to control the time and temperature of the heating and cooling cycles so that the workpiece is annealed at a temperature that is at or below 250°

C.

37. An apparatus for use in applying metallization in recessed micro structures of a microelectronic workpiece comprising:

an input/output station for receiving a microelectronic workpiece;

an enclosure disposed adjacent the input/output station;

at least one electrochemical deposition station disposed within the enclosure for depositing metal into at least the recessed microstructures of the microelectronic workpiece, the electrochemical deposition station including;

an electroprocessing chamber that receives the microelectronic workpiece and a processing solution;

an electrical contact assembly for contacting the microelectronic workpiece; and

an electrode disposed in contact with the processing solution;

a thermal annealing station disposed within the enclosure for receiving and subjecting the deposited metal on the microelectronic workpiece to an elevated temperature annealing process at a predetermined temperature, the annealing station including;

a heat generator disposed proximate the received workpiece and operable to heat the workpiece for annealing of the deposited metal; and

a cooling system disposed proximate the received workpiece and operable to cool the workpiece, wherein the cooling system generates a thermal gradient between first and second surfaces of the workpiece; and

a workpiece transfer system disposed at least partially within the enclosure for transferring the workpiece between the input/output station, the electrochemical deposition station and the thermal annealing station.

38. The apparatus of claim 37, wherein the heat generator heats a first side of the workpiece, and the cooling system cools a second side of the workpiece.

39. The apparatus of claim 37, further comprising a power supply for supplying power between the workpiece and the electrode and a controller for controlling the power supply to supply power at a first current density for a first time period and at a second current density that is greater than the first current density for a second time period.

40. The apparatus of claim 37, wherein the thermal annealing station is operated to subject a surface of the microelectronic workpiece to an annealing temperature that is at or below about 250 to 300 degrees Celsius.

41. The apparatus of claim 37, wherein the thermal annealing station is operated to subject a surface of the microelectronic workpiece to an annealing temperature that is at or below about 250 degrees Celsius.

42. The apparatus of claim 37, wherein the microelectronic workpiece includes at least one low-K dielectric layer and the thermal annealing station is operated to subject a surface of the microelectronic workpiece to an annealing temperature that does not exceed a temperature at which the low-K dielectric layer substantially degrades.

43. The apparatus of claim 37, further comprising at least one wet-chemical processing station.

44. The apparatus of claim 37, further comprising a rinsing/drying station.

45. The apparatus of claim 44, wherein the workpiece transfer system comprises a first transfer robot that transfers workpieces from the electrochemical deposition station to the rinsing/drying station and a second transfer robot that transfers workpieces from the rinsing/drying station to the thermal annealing station.

46. The apparatus of claim 37, wherein the workpiece transfer system comprises a transfer robot that transfers workpieces between the input/output station, the electrochemical deposition station, and the thermal annealing station.

47. The apparatus of claim 37, wherein the workpiece transfer system comprises a first transfer robot that transfers workpieces from the input/output station to the electrochemical deposition station and a second transfer robot that transfers workpieces from the electrochemical deposition station to the thermal annealing station.

48. The apparatus of claim 37, further comprising an intermediate staging door disposed within the enclosure between the electrochemical deposition station and the thermal annealing station.

49. The apparatus of claim 37, wherein the at least one electrochemical deposition station electrolytically deposits copper onto the microelectronic workpiece.

50. The apparatus of claim 37, wherein the cooling system comprises a fluid flow system that directs a flow of cooling fluid to cool a surface of the workpiece.

51. The apparatus of claim 50, wherein the cooling system comprises a heat sink that is cooled by the cooling fluid and that contacts the workpiece.

52. The apparatus of claim 50, further comprising a controller that controls flow of the cooling fluid.

53. An apparatus for use in applying metallization in recessed microstructures of a microelectronic workpiece comprising:

an input/output station for receiving a microelectronic workpiece;

an enclosure disposed adjacent the input/output station;

at least one electrochemical deposition station disposed within the enclosure for depositing metal into at least the recessed microstructures of the microelectronic workpiece, the electrochemical deposition station including;

an electroprocessing means for receiving the microelectronic workpiece and a processing solution;

an electrical contact means for establishing electrical contact with the microelectronic workpiece; and

an electrode disposed in contact with the plating solution;

thermal annealing means disposed within the enclosure for receiving and subjecting the deposited metal on the microelectronic workpiece to an elevated temperature annealing process at a predetermined temperature, the annealing station including;

heat generator means disposed proximate the received workpiece for heating the workpiece to anneal the deposited metal; and

cooling system means disposed proximate the received workpiece for cooling the workpiece, wherein the cooling system generates a thermal gradient between first and second surfaces of the workpiece; and

workpiece transfer means disposed at least partially within the enclosure for transferring the workpiece between the input/output station, the electrochemical deposition station and the thermal annealing station.