Thermal/microwave remote plasma multiprocessing reactor and method of use

• US 4,913,929 A
• Filed: 04/21/1987
• Issued: 04/03/1990
• Est. Priority Date: 04/21/1987
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Moslehi, Mehrdad M., Saraswat, Krishna C.
• Primary Examiner(s): BUEKER, RICHARD R
• Application Number:
  US07/040,909
• Time in Patent Office: 1,078 Days
• Field of Search: 118/715, 118/723, 118/725, 427/39, 427/248.1, 427/255.2, 427/255.3, 427/255.4
• US Class Current: 427/564
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence
• CPC Class Codes: C23C 16/481 by radiant heating of the substrate
• CPC Class Codes: C23C 16/511 using microwave discharges
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/3244 Gas supply means

Abstract

A novel cold wall single wafer rapid thermal/microwave remote plasma multiprocessing reactor comprising a vacuum chamber having means for mounting a wafer in the chamber, means for providing optical flux mounted adjacent one wall facing the back side of the wafer for optical heating of the wafer, and ports for plasma injection such that remote plasma can be generated and pumped into the chamber. Ports are provided for gas injection both through the plasma generating chamber and for non-plasma injection. The plasma and non-plasma ports are connected through separate manifolds to a plurality of gas sources. The comprehensive reactor design is such that several wafer processing steps can be done sequentially in situ, while providing for optimization of each processing step.

Claims

1. A rapid thermal plasma multiprocessing reactor for in-situ growth and deposition of layers on a wafer comprising

a vacuum chamber including top, bottom and side walls,

means for supporting said wafer with a top surface of said wafer to be processed facing the bottom of said chamber,

at least one quartz discharge tube mounted in said bottom of said reactor facing said wafer top surface for conveying plasma gas from a remote plasma generating chamber located outside of said vacuum chamber to said vacuum chamber,

heating means mounted facing said wafer mount for heating said back side of said wafer, and

at least one non-plasma injector port connected through a non-plasma manifold to a plurality of gas sources for selectively conveying gas to said chamber whereby a plurality of processes affecting said wafer may be carried out without removing said wafer from said chamber.

2. A reactor as in claim 1 including a remote plasma generating microwave cavity having an output coupled to said vacuum chamber through said quartz tube, the input to said microwave cavity being coupled through a gas distribution manifold to a plurality of gas sources for growth and deposition of layers on said wafer.

3. A reactor as in claim 1 wherein said heating means comprise an array of lamps positioned outside said vacuum chamber and facing said wafer through a window in said top surface of said chamber to heat said wafer.

4. A reactor as in claim 3 wherein said lamps are tungsten-halogen lamps, said window comprising a quartz window for passing the optical flux to said wafer.

5. A reactor as in claim 1 comprising a plurality of said quartz discharged tubes arranged in a regularly radially spaced array facing said wafer top surface for conveying plasma gas evenly to said wafer surface.

6. A reactor as in claim 5 wherein said discharge tubes surround a sapphire window mounted in the bottom of said reactor whereby photon enhanced processing using laser or ultraviolet is achieved.

7. A reactor as in claim 1 including a gas distribution network comprising said plurality of gas sources selectively connected through a non-plasma manifold to said non-plasma injector port and through a plasma injector to said quartz discharge tube to selectively convey said gases to said vacuum chamber.

8. A reactor as in claim 1 including a plurality of quartz discharge tubes each having an exhaust end emptying into said chamber, the exhaust ends being arranged in a circle concentric with the center of said wafer to convey plasma in an even flow to the surface of said wafer, the non-exhaust end of each said discharge tube being connected to a plasma generating microwave chamber for creating plasma to be conveyed to said chamber.

9. A reactor as in claim 8 wherein said tubes are regularly radially spaced around said circle and mounted at an angle toward the center of said circle for conveying said plasma to said wafer.

13. Apparatus as claimed in claim 3 wherein said wafer rests on low thermal mass quartz pins.

10. In a rapid thermal plasma multiprocessing reactor for in situ growth and deposition of layers on a wafer comprising a vacuum chamber including top, bottom and side walls, means for supporting said wafer with a top surface of said wafer to be processed facing the bottom of said chamber, at least one quartz discharge tube mounted in said bottom of said reactor facing said wafer top surface for conveying plasma gas from a remote plasma generating chamber located outside of said vacuum chamber to said vacuum chamber, means mounted adjacent to the top surface of said chamber facing said wafer mount for heating said back side of said wafer, and at least one non-plasma injector port connected through a non-plasma manifold to a plurality of gas sources for selectively conveying gas to said chamber whereby a plurality of processes affecting said wafer may be carried out without removing said wafer from said chamber, a method of fabricating tungsten-gate MOS devices comprising the steps of in situ growth of a gate dielectric by rapid thermal oxidation and rapid thermal nitridation cycles followed by a non-selective tungsten deposition process to form the gate electrode.

11. A method as in claim 10 wherein the tungsten deposition step comprises the steps of injecting WF₆, or WF₆ +H₂ through said non-plasma port, and injecting H₂ plasma, Ar plasma or Ar+H₂ plasma through said plasma port to non-selectively deposit tungsten on insulating surfaces.

12. In a rapid thermal plasma multiprocessing reactor for in-situ growth and deposition of layers on a wafer comprising

a vacuum chamber including top, bottom and side walls,

means for supporting said wafer with a top surface of said wafer to be processed facing the bottom of said chamber,

at least one quartz discharge tube mounted in said bottom of said reactor facing said wafer top surface for conveying plasma gas from a remote plasma generating chamber located outside of said vacuum chamber to said vacuum chamber,

heating means mounted facing said wafer mount for heating said back side of said wafer, and

at least one non-plasma injector port connected through a non-plasma manifold to a plurality of gas sources for selectively conveying gas to said chamber whereby a plurality of processes affecting said wafer may be carried out without removing said wafer from said chamber, a method of selectively depositing tungsten on exposed silicon areas of said wafer comprising flowing any combination of WF/H₂ /Ar without plasma discharge into said vacuum chamber at temperatures up to 450°

C.

14. Apparatus as claimed in claim 12 wherein said wafer rests on low thermal mass quartz pins.