Unbalanced plasma generating apparatus having cylindrical symmetry
AssigneeIsoflux, Inc.
InventorsDavid A. Glocker, Mark M. Romach
Life of this patent
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Abstract
Apparatus for creating subatmospheric high plasma densities in the vicinity of a substrate in a work space for use in magnetron sputter deposition aided by ion bombardment of the substrate. Unbalanced flux lines emanating from cylindrical or frusto-conical targets cannot be captured across the work space, because the energizing magnets are cylindrical, and instead converge toward the axis of the apparatus to provide a high flux density, and therefore a high plasma density, in the vicinity of a substrate disposed in this region. The plasma profile and the coating material profile within the work space are both cylindrically symmetrical, resulting in a consistent and predictable coating on substrates.
Claims22
Apparatus for generating a plasma having cylindrical symmetry in a working gas environment, comprising:
- a) first electrode means wherein the shape of said first electrode means is selected from the group consisting of cylinder and conical frustum, said first electrode means having a surface;
- b) means for generating an unbalanced magnetic field adjacent said first electrode means, said means for generating providing excess magnetic pole strength of one polarity, a first portion of said magnetic field forming a magnetic trap adjacent said electrode surface and a second portion of said magnetic field extending away from said surface;
- and
- c) means for providing a voltage on said first electrode for cooperating with said magnetic field to form a plasma in said working gas,
- wherein said means for generating a magnetic field includes first and second ring magnets having opposite radial polarities and being disposed coaxially with said first electrode means and axially adjacent each other, one of said first and second ring magnets having excess pole strength relative to the other of said magnets.
Apparatus for generating a plasma having cylindrical symmetry in a working gas environment, comprising:
- a) a first electrode which is cylindrical in shape and electrically isolated;
- b) at least one auxiliary electrode which overlies one end of said first electrode;
- and
- c) magnetic field generating means for forming a magnetic trap on the surface of said first electrode to partially confine secondary electrons emitted from the surface of said first electrode, said magnetic field generating means being unbalanced and having excess pole strength of one polarity such that some open field lines created by said magnetic field generating means project from said overlying portion of said auxiliary electrode.
Dependencies are inferred from the claim text.