METHOD AND APPARATUS OF DISTRIBUTED PLASMA PROCESSING SYSTEM FOR CONFORMAL ION STIMULATED NANOSCALE DEPOSITION PROCESS

• US 20080026574A1
• Filed: 08/07/2007
• Published: 01/31/2008
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Brcka, Jozef
• Granted Patent: US 8,092,658 B2
• Time in Patent Office: Days
• US Class Current: 438/676
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates

Abstract

A deposition system and method of operating thereof is described for depositing a conformal metal or other similarly responsive coating material film in a high aspect ratio feature using a high density plasma is described. The deposition system includes a plasma source, and a distributed metal source for forming plasma and introducing metal vapor to the deposition system, respectively. The deposition system is configured to form a plasma having a plasma density and generate metal vapor having a metal density, wherein the ratio of the metal density to the plasma density proximate the substrate is less than or equal to unity. This ratio should exist at least within a distance from the surface of the substrate that is about twenty percent of the diameter of the substrate. A ratio that is uniform within plus or minus twenty-five percent substantially across the surface of said substrate is desirable. The ratio is particularly effective for plasma density exceeding 10¹² cm⁻³, and for depositing film on substrates having nanoscale features with maximum film thickness less than half of the feature width, for example, at ten percent of the feature width.

Claims

1-55. -55. (canceled)

56. A method of depositing in a high aspect ratio nano-feature on a substrate a thin film having a thickness of less than half of the width of the feature, the method comprising:

coupling RF energy from a distributed plasma source into a process chamber having a substrate holder therein configured to support a substrate thereon to form a plasma adjacent to a substrate supported on the substrate holder that has an electron density of at least 10¹² cm<sup>−

3</sup>;

introducing metal into to said process chamber from a distributed metal source; and

depositing a metal film on sidewall surfaces of the feature while controlling the coupling of RF energy and the introducing of metal such that, whenever metal is being deposited on the substrate, the density of the plasma at a plasma boundary adjacent a plasma sheath proximate the substrate is greater than the density of metal at said boundary.

57. The method of claim 56, further comprising:

maintaining a ratio between said metal density and said plasma density substantially uniform across said surface of said substrate.

58. The method of claim 56, further comprising:

maintaining a ratio between said metal density and said plasma density that varies as a function of time.

59. The method of claim 56 wherein said plasma source includes one or more plasma generating elements.

60. The method of claim 56, wherein said metal source includes a distributed metal source configured to perform at least one of adjusting or controlling a spatial distribution of said metal density above said substrate.

61. The method of claim 56, further comprising:

coupling a buffer device to said process chamber and controlling the buffer device to adjust at least one of said metal density or said plasma density proximate said substrate in said process chamber.

62. The method of claim 61, further comprising electrically biasing said buffer device to control said buffer device.

63. The method of claim 61, further comprising:

coupling a magnet system to said buffer device to adjust at least one of said metal density or said plasma density proximate said substrate in said process chamber.

64. The method of claim 63, wherein said magnet system includes at least one of a permanent magnet array, an electromagnet, a rotating magnet, a translatable magnet or a stationary magnet.

65. The method of claim 63, wherein said buffer device is translatable, in a direction substantially perpendicular to said substrate to adjust at least one of said metal density or said plasma density proximate substrate in said process chamber.

66. A method of depositing a thin film in a high aspect ratio feature on a substrate comprising:

disposing said substrate on a substrate holder in a deposition system;

providing said deposition system with a coating material source of a coating material having a coating material ionization potential;

introducing into said deposition system a processing gas having an ionization potential greater than said coating material ionization potential;

forming with said processing gas a plasma having a plasma density within said deposition system using a plasma source;

introducing coating material at a coating material density that is maintained at less than or equal to said plasma density within said deposition system using said coating material source;

maintaining a ratio of said coating material density to said plasma density above said substrate at not more than unity while performing within said feature a conformal deposition of said coating material having a uniformity of plus or minus twenty-five percent.

67. The method of claim 66, wherein said ratio is substantially uniform across said surface of said substrate.

68. The method of claim 66, wherein said plasma source is configured to produce a plasma density exceeding 10¹² cm⁻

3.

69. The method of claim 66, wherein said depositing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than half the width of the feature.

70. The method of claim 66, wherein said depositing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than approximately one-tenth of the width of the feature.

71. A method of depositing a thin metal film boundary layer or seed layer having a thickness of 6.25 nanometers or less and a conformality of 25% or less in a high aspect ratio feature on a substrate comprising:

disposing said substrate on a substrate holder in a deposition system;

forming a plasma having a plasma density of at least 10¹² electrons per cubic centimeter within said deposition system using a plasma source;

introducing metal having a metal density maintained less than the plasma density within said deposition system using a metal source; and

performing within said feature on said substrate a conformal deposition having a thickness of less than or equal to 6.25 nanometers and having a uniformity of plus or minus twenty-five percent while establishing and maintaining a ratio of said metal density to said plasma density proximate said substrate that is equal to or less than unity for the entire time while performing said deposition.

72. The method of claim 71 further comprising establishing said ratio by adjusting said plasma density using said plasma source.

73. The method of claim 71 further comprising establishing said ratio by adjusting said metal density using said metal source.

74. The method of claim 71, wherein said performing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than half the width of the feature.

75. The method of claim 71, wherein said performing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than approximately one-tenth of the width of the feature.