Slotted electrostatic shield modification for improved etch and CVD process uniformity

• US 8,413,604 B2
• Filed: 11/28/2006
• Issued: 04/09/2013
• 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: George, Rene, Kadavanich, Andreas, Devine, Daniel J., Savas, Stephen E., Zajac, John, Shan, Hongching
• Primary Examiner(s): DHINGRA, RAKESH KUMAR
• Application Number:
  US11/564,134
• Publication Number:
  US 20070113979A1
• Time in Patent Office: 2,324 Days
• Field of Search: 118/723.I, 156/345.48
• US Class Current: 118/723.I
• 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 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, an apparatus comprising:

an electrostatic shield arrangement including 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 and where said electrostatic shield arrangement includes 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 the outer shield member nests proximate to the inner shield member with the inner and outer shield members being supported for rotation relative to one another such that the first aperture pattern cooperates with the second aperture pattern in a way which provides a range in said modified radial variation characteristic across said treatment surface by defining an effective aperture pattern that is made up of a plurality of effective apertures in which each effective aperture extends through at least a portion of the range of radii relative to the axis of symmetry and each effective aperture includes a width that varies at least partially along the length of that effective aperture to produce the modified radial variation characteristic, and 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.

2. The apparatus of claim 1 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.

3. The apparatus of claim 1 including using a semiconductor wafer as said treatment object.

4. In a processing chamber that uses an inductively coupled plasma source defining 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, an apparatus comprising:

an electrostatic shield arrangement including 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 and where said electrostatic shield arrangement includes at least a first, inner shield member and a second, outer shield member, said first shield member being frustoconical in configuration having a narrowed end and defining a first aperture pattern and said second shield member is supported for linear movement in relation to the first shield member toward and away from the narrowed end of the first shield member in a way which produces a range in said modified radial variation characteristic across said treatment surface.

5. The apparatus of claim 4 wherein said narrowed end is formed having a through opening and said second shield member moves toward and away from said through opening.

6. In a processing chamber that uses an inductively coupled plasma source defining 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, an apparatus comprising:

an electrostatic shield arrangement including at least a sidewall 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 and where said electrostatic shield arrangement includes at least a first, inner shield member and a second, outer shield member, and said first shield member is frustoconical in configuration and 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 which defines a first aperture pattern that is made up of a plurality of elongated slots, each of which includes a length in said conical sidewall that extends through a portion of said range of radii and each of which includes a width that varies at least partially along said length and said second shield member is supported for movement in relation to the first shield member to cooperate with the first aperture pattern in a way which produces a range in said modified radial variation characteristic across said treatment surface.

7. The apparatus of claim 6 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.

8. The apparatus of claim 7 wherein said overall aperture pattern is formed 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.

9. In a processing chamber that uses an inductively coupled plasma source defining 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, an apparatus comprising:

an electrostatic shield arrangement including 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 and where said electrostatic shield arrangement includes at least a first, inner shield member and a second, outer shield member, said first shield member defining a first aperture pattern and 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 defining a second aperture pattern, and said second shield member is supported 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 to define an effective aperture pattern that is made up of a plurality of effective apertures in which each effective aperture extends through at least a portion of the range of radii relative to the axis of symmetry and each effective aperture includes a width that varies at least partially along the length of that effective aperture to produce the modified radial variation characteristic 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, such that rotation of the second shield member relative to the first shield member produces said modified radial variation characteristic.

10. The apparatus of claim 9 wherein said apertures and said slots are configured as wedge-shaped such that each of the apertures in the first shield member includes a base edge in the conical sidewall and an apex in said upper surface.

11. The apparatus of claim 9 wherein said second shield member includes 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.