Slotted electrostatic shield modification for improved etch and CVD process uniformity

• US 7,232,767 B2
• Filed: 03/18/2004
• Issued: 06/19/2007
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area), BeiJing E-Town Semiconductor Technology Co., Ltd.
• Original Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area)
• Inventors: Zajac, John, Devine, Daniel J., Savas, Stephen E., George, Rene, Kadavanich, Andreas, Shan, Hongching
• Primary Examiner(s): GHYKA, ALEXANDER G
• Application Number:
  US10/803,453
• Publication Number:
  US 20040244691A1
• Time in Patent Office: 1,188 Days
• Field of Search: 438/710, 438/714, 438/795, 118/723.R, 118/723.I, 156/345
• US Class Current: 438/714
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32431 Constructional details of the reactor
• CPC Class Codes: H01L 21/02104 Forming layers deposition in general C23C; crystal growth in general C30B
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

A more uniform plasma process is implemented for treating a treatment object using an inductively coupled plasma source which produces an asymmetric plasma density pattern at the treatment surface using a slotted electrostatic shield having uniformly spaced-apart slots. The slotted electrostatic shield is modified in a way which compensates for the asymmetric plasma density pattern to provide a modified plasma density pattern at the treatment surface. A more uniform radial plasma process is described in which an electrostatic shield arrangement is configured to replace a given electrostatic shield in a way which provides for producing a modified radial variation characteristic across the treatment surface. The inductively coupled plasma source defines an axis of symmetry and the electrostatic shield arrangement is configured to include a shape that extends through a range of radii relative to the axis of symmetry.

Claims

1. In a processing chamber that uses an inductively coupled plasma source defining an axis of symmetry which produces a plasma density having a given radial variation characteristic across a treatment surface of a treatment object therein using a given electrostatic shield, a method comprising:

configuring an electrostatic shield arrangement to replace said given electrostatic shield in a way which provides for producing a modified radial variation characteristic across said treatment surface which is different than said given radial variation characteristic and said electrostatic shield arrangement is further configured to include at least a sidewall arrangement having a shape that extends through a range of radii relative to said axis of symmetry having a modified slot arrangement that is made up of a plurality of elongated modified slots, each of which includes a length in said sidewall that extends through at least a portion of said range of radii and each of which includes a width that varies at least partially along said length for producing said modified radial variation characteristic.

2. The method of claim 1 including using the electrostatic shield arrangement to produce said modified radial variation characteristic as being more constant across said treatment surface than the given radial variation characteristic.

3. The method of claim 1 wherein said electrostatic shield arrangement is at least generally conical in configuration.

4. The method of claim 1 wherein said electrostatic shield arrangement is at least generally frustoconical in configuration.

5. The method of claim 1 wherein said electrostatic shield arrangement is at least generally dome-shaped in configuration.

6. The method of claim 1 wherein said electrostatic shield arrangement includes a plate-like upper surface that is arranged to intersect said axis of symmetry and each of said elongated modified slots extends from the sidewall and at least partially across said plate-like upper surface.

20. The method of claim 1 including using a semiconductor wafer as said treatment object.

7. In a processing chamber that uses an inductively coupled plasma source that defines an axis of symmetry and which produces a plasma density having a given radial variation characteristic across a treatment surface of a treatment object therein using a given electrostatic shield, a method comprising:

configuring an electrostatic shield arrangement to include at least a sidewall arrangement having a shape that extends through a range of radii relative to said axis of symmetry to replace said given electrostatic shield to provide for producing a modified radial variation characteristic across said treatment surface which is different than said given radial variation characteristic by arranging said electrostatic shield arrangement to include at least a first, inner shield member and a second, outer shield member, said inner shield member defining a first aperture pattern and said outer shield member defining a second aperture pattern, and supporting the outer shield member outside of and adjacent to the inner shield member and rotating the outer shield member relative to the inner shield member to cause the first aperture pattern to cooperate with the second aperture pattern in a way which provides a range in said modified radial variation characteristic across said treatment surface.

8. The method of claim 7 including a rotation arrangement for sensing the modified radial variation characteristic and for rotating one of the inner shield member and the outer shield member responsive to a sensed value of the modified radial variation characteristic.

9. The method of claim 7 wherein said electrostatic shield arrangement is configured such that each of the inner shield member and the outer shield member are frustoconical in configuration, said inner shield member including an inner shield sidewall and said outer shield member including an outer shield sidewall such that the inner shield sidewall and the outer shield sidewall are adjacent to one another.

10. In a processing chamber that uses an inductively coupled plasma source that defines an axis of symmetry and which produces a plasma density having a given radial variation characteristic across a treatment surface of a treatment object therein using a given electrostatic shield, a method comprising:

configuring an electrostatic shield arrangement to include at least a sidewall arrangement having a shape that extends through a range of radii relative to said axis of symmetry to replace said given electrostatic shield to provide for producing a modified radial variation characteristic across said treatment surface which is different than said given radial variation characteristic by arranging said electrostatic shield arrangement to include at least a first shield member and a second shield member, said first shield member defining a first aperture pattern, and supporting said second shield member outside the first shield member for linear movement in relation to the first shield member in a way which produces a range in said modified radial variation characteristic across said treatment surface.

11. The method of claim 10 wherein said first shield member is frustoconical in configuration having a narrowed end and said second shield member is supported for movement toward and away from the narrowed end of the first shield member.

12. The method of claim 11 including forming said narrowed end having a through opening and said second shield member moves toward and away from said through opening.

13. The method of claim 11 wherein the frustoconical configuration of the first shield member includes a conical sidewall having an upper peripheral edge and a top wall having an outer peripheral edge that is connected with the upper peripheral edge of the conical sidewall.

14. The method of claim 13 wherein said conical sidewall and said top wall cooperate to define an overall aperture pattern that carries in a continuous manner from the conical sidewall to the top wall.

15. The method of claim 14 including forming said overall aperture pattern as a circumferential arrangement of wedge-shaped apertures each defined as having a base edge in the conical sidewall and an apex in said top wall.

16. In a processing chamber that uses an inductively coupled plasma source that defines an axis of symmetry and which produces a plasma density having a given radial variation characteristic across a treatment surface of a treatment object therein using a given electrostatic shield, a method comprising:

configuring an electrostatic shield arrangement to include at least a sidewall arrangement having a shape that extends through a range of radii relative to said axis of symmetry to replace said given electrostatic shield in a way which provides for producing a modified radial variation characteristic across said treatment surface which is different than said given radial variation characteristic by arranging said electrostatic shield arrangement to include at least a first shield member and a second shield member, said first shield member defining a first aperture pattern and said second shield member defining a second aperture pattern, and supporting said second shield member outside the first shield member for rotational movement about said axis of symmetry and in relation to the first shield member in a way which produces a range in said modified radial variation characteristic across said treatment surface by rotating the second shield member relative to the first shield member.

17. The method of claim 16 wherein said first shield member is frustoconical in configuration having a conical sidewall and a narrowed end that is closed by an upper surface, and said conical sidewall and said upper surface cooperate to define said first aperture pattern as a plurality of spaced apart openings that carry in a continuous manner from the conical sidewall into the upper surface, and said second shield member is formed to include a major surface that is arranged in a confronting relationship with said upper surface of the first shield member, said major surface defining a plurality of slots, as the second aperture pattern, complementing said spaced apart openings, as defined in the upper surface of the first shield member, and arranging the second shield member for rotation about said axis of symmetry such that rotation of the second shield member relative to the first shield member modifies said radial variation characteristic.

18. The method of claim 17 wherein said spaced apart openings of the first aperture pattern and said slots of the second aperture pattern are each configured as wedge-shaped such that each of the openings in the first shield member includes a base edge in the conical sidewall and an apex in said upper surface.

19. The method of claim 17 including forming said second shield member to include a skirt that extends from an outermost edge of said major surface in a confronting relationship with said conical sidewall of the first shield member and at least a portion of said second aperture pattern is defined in said skirt.