Apparatus and method for improving target erosion in hollow cathode magnetron sputter source

A hollow cathode magnetron sputtering source comprising:

• a vacuum chamber having an inlet for introducing a plasma-forming gas into said vacuum chamber;
• a hollow cathode target disposed within said vacuum chamber, said hollow cathode target comprising a particle confining container having a wall disposed about a vertical axis of said hollow cathode target, a closed end surface and an open side;
• an anode;
• an electrical potential source coupled to said hollow cathode target;
• a plasma forming region disposed in said vacuum chamber between said closed end surface of said hollow cathode target and said anode;
• a magnetic field source, said magnetic field source emanating from a region surrounding exterior of said wall, said magnetic field source comprises a stack of magnets, said stack of magnets being separated by variable thickness spacers, said spacers increasing in thickness monotonically from a spacer closest to said closed end surface of said hollow cathode target to a spacer closest to said open side of said hollow cathode target;
• and
• a pole plate, said pole plate positioned adjacent to said closed end surface of said hollow cathode target.

A hollow cathode magnetron sputtering source comprising:

• a vacuum chamber having an inlet for introducing a plasma-forming gas into said vacuum chamber;
• a hollow cathode target disposed within said vacuum chamber, said hollow cathode target comprising a particle confining container having a wall disposed about a vertical axis of said hollow cathode target, a closed end surface and an open side;
• an anode;
• an electrical potential source coupled to said hollow cathode target;
• a plasma forming region disposed in said vacuum chamber between said closed end surface of said hollow cathode target and said anode;
• a magnetic field source, said magnetic field source emanating from a region surrounding exterior of said wall, said magnetic field source further comprises a tapered field magnet, said tapered field magnet having maximum magnetic field strength closest to said closed end surface of said hollow cathode target and monotonically decreasing magnetic field strength approaching said open side of said hollow cathode target;
• and
• a pole plate, said pole plate positioned adjacent to said closed end surface of said hollow cathode target.

A hollow cathode magnetron sputtering source comprising:

• a vacuum chamber having an inlet for introducing a plasma-forming gas into said vacuum chamber;
• a hollow cathode target disposed within said vacuum chamber, said hollow cathode target comprising a particle confining container having a wall disposed about a vertical axis of said hollow cathode target, a closed end surface and an open side;
• an anode;
• an electrical potential source coupled to said hollow cathode target;
• a plasma forming region disposed in said vacuum chamber between said closed end surface of said hollow cathode target and said anode;
• a magnetic field source, said magnetic field source emanating from a region surrounding exterior of said wall, said magnetic field source comprises a stack of variable strength magnets decreasing in magnetic field strength monotonically from a magnet closest to said closed end surface of said hollow cathode target to a magnet closest to said open side of said hollow cathode target;
• and
• a rotating magnet positioned adjacent to said closed end surface of said hollow cathode target.

A hollow cathode magnetron sputtering source comprising:

• a vacuum chamber having an inlet for introducing a plasma-forming gas into said vacuum chamber;
• a hollow cathode target disposed within said vacuum chamber, said hollow cathode target comprising a particle confining container having a wall disposed about a vertical axis of said hollow cathode target, a closed end surface and an open side;
• an anode;
• an electrical potential source coupled to said hollow cathode target;
• a plasma forming region disposed in said vacuum chamber between said closed end surface of said hollow cathode target and said anode;
• a magnetic field source, said magnetic field source emanating from a region surrounding exterior of said wall, said magnetic field source comprises a stack of magnets, said stack of magnets being separated by variable thickness spacers, said spacers increasing in thickness monotonically from a spacer closest to said closed end surface of said hollow cathode target to a spacer closest to said open side of said hollow cathode target;
• and
• a rotating magnet positioned adjacent to said closed end surface of said hollow cathode target.

A hollow cathode magnetron sputtering source comprising:

• a vacuum chamber having an inlet for introducing a plasma-forming gas into said vacuum chamber;
• a hollow cathode target disposed within said vacuum chamber, said hollow cathode target comprising a particle confining container having a wall disposed about a vertical axis of said hollow cathode target, a closed end surface and an open side;
• an anode;
• an electrical-potential source coupled to said hollow cathode target;
• a plasma forming region disposed in said vacuum chamber between said closed end surface of said hollow cathode target and said anode;
• a magnetic field source, said magnetic field source emanating from a region surrounding exterior of said wall, said magnetic field source further comprises a tapered field magnet, said tapered field magnet having maximum magnetic field strength closest to said closed end surface of said hollow cathode target and monotonically decreasing magnetic field strength approaching said open side of said hollow cathode target;
• and
• a rotating magnet positioned adjacent to said closed end surface of said hollow cathode target.

A hollow cathode magnetron sputtering source comprising:

• a means for creating a plasma, said plasma consisting of an inert gas held at low pressure;
• a hollow cathode target, said hollow cathode target comprising a particle confining container having an open end, a wall, and a closed end surface, said hollow cathode target confining said plasma within a hollow region, said hollow cathode target comprising a selected target material;
• a means to apply a voltage across said hollow cathode target, said voltage creating an electrical field within said hollow region of said hollow cathode target;
• a means for generating a magnetic field, said magnetic field emanating from an area surrounding exterior of said wall of said hollow cathode target, said magnetic field creating a magnetic null region adjacent to said open end of said hollow cathode target, said magnetic field having looping magnetic field lines which intersect said wall of said hollow cathode target, said means for generating a magnetic field comprises stacking variable strength magnets about the exterior of said wall of said hollow cathode target to alter profile of the magnetic field within said hollow region of said hollow cathode target, said variable strength magnets decreasing in magnetic field strength monotonically from a magnet closest to said closed end surface of said hollow cathode target to a magnet closest to said open side of said hollow cathode target;
• a means for altering direction of said looping magnetic field lines, said means for altering the direction resulting in increased uniformity of erosion throughout the surface area of said hollow cathode target;
• a means for intensifying said plasma on the order of at least about 1013 particles/cc, said plasma containing a percent of ions of said selected target material greater than 2.0 percent;
• a means for extracting ions from said plasma through said magnetic null region;
• a means for focusing the path of extracted ions toward a remote surface to be deposited on;
• and
• a means for creating an electrical sheath potential between said plasma and said remote surface to be deposited on, said electrical sheath potential allowing for said target material particles to contact said surface to be deposited on at near normal angles of incident.

A hollow cathode magnetron sputtering source comprising:

• a means for creating a plasma, said plasma consisting of an inert gas held at low pressure;
• a hollow cathode target, said hollow cathode target comprising a particle confining container having an open end, a wall, and a closed end surface, said hollow cathode target confining said plasma within a hollow region, said hollow cathode target comprising a selected target material;
• a means to apply a voltage across said hollow cathode target, said voltage creating an electrical field within said hollow region of said hollow cathode target;
• a means for generating a magnetic field, said magnetic field emanating from an area surrounding exterior of said wall of said hollow cathode target, said magnetic field creating a magnetic null region adjacent to said open end of said hollow cathode target, said magnetic field having looping magnetic field lines which intersect said wall of said hollow cathode target, said means for generating a magnetic field comprises stacking, alternately, equal strength magnets and spacers of varying thickness about the exterior of said wall of said hollow cathode target to alter profile of the magnetic field within a confining region of said hollow cathode target, said spacers increasing in thickness monotonically from a spacer closest to said closed end surface of said hollow cathode target to a spacer closest to said open side of said hollow cathode target;
• a means for altering direction of said looping magnetic field lines, said means for altering the direction resulting in increased uniformity of erosion throughout the surface area of said hollow cathode target;
• a means for intensifying said plasma on the order of at least about 1013 particles/cc, said plasma containing a percent of ions of said selected target material greater than 2.0 percent;
• a means for extracting ions from said plasma through said magnetic null region;
• a means for focusing the path of extracted ions toward a remote surface to be deposited on;
• and
• a means for creating an electrical sheath potential between said plasma and said remote surface to be deposited on;
• said electrical sheath potential allowing for said target material particles to contact said surface to be de-posited on at near normal angles of incident.

A hollow cathode magnetron sputtering source comprising:

• a means for creating a plasma, said plasma consisting of an inert gas held at low pressure;
• a hollow cathode target, said hollow cathode target comprising a particle confining container having an open end, a wall, and a closed end surface, said hollow cathode target confining said plasma within a hollow region, said hollow cathode target comprising a selected target material;
• a means to apply a voltage across said hollow cathode target, said voltage creating an electrical field within said hollow region of said hollow cathode target;
• a means for generating a magnetic field, said magnetic field emanating from an area surrounding exterior of said wall of said hollow cathode target, said magnetic field creating a magnetic null region adjacent to said open end of said hollow cathode target, said magnetic field having looping magnetic field lines which intersect said wall of said hollow cathode target, said means for generating a magnetic field comprises the use of a tapered field magnet positioned about the exterior of said wall of said hollow cathode target to alter profile of the magnetic field within the confining region of said hollow cathode target, said tapered field magnet having maximum magnetic field strength closest to said closed end surface of said hollow cathode target and monotonically decreasing magnetic field strength approaching said open side of said hollow cathode target;
• a means for altering direction of said looping magnetic field lines, said means for altering the direction resulting in increased uniformity of erosion throughout the surface area of said hollow cathode target;
• a means for intensifying said plasma on the order of at least about 1013 particles/cc, said plasma containing a percent of ions of said selected target material greater than 2.0 percent;
• a means for extracting ions from said plasma through said magnetic null region;
• a means for focusing the path of extracted ions toward a remote surface to be deposited on;
• and
• a means for creating an electrical sheath potential between said plasma and said remote surface to be deposited on;
• said electrical sheath potential allowing for said target material particles to contact said surface to be deposited on at near normal angles of incident.

A method for physical vapor deposition of a thin film comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises stacking variable strength magnets about an exterior wall of said hollow cathode target to alter profile of the magnetic field within a confining region of said hollow cathode target, said variable strength magnets decreasing in magnetic field strength monotonically from a magnet closest to said closed end surface of said hollow cathode target to a magnet closest to said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• introducing a plasma forming gas into a vacuum chamber and holding said plasma forming gas at low pressure;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a [the] hollow region of said hollow cathode target;
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target into said plasma;
• ionizing said plasma;
• extracting ions of said plasma through said magnetic null region;
• directing a flow of extracted ions within said plasma toward a remote surface requiring thin film coverage;
• creating an electrical field sheath potential between said plasma and said remote surface;
• and
• depositing said target material particles on said remote surface, said target material particles contacting said remote surface at an angle generally normal to said remote surface requiring thin film coverage.

A method for physical vapor deposition of a thin film comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises stacking, alternately, equal strength magnets and spacers of varying thickness about an exterior wall of said hollow cathode target to alter profile of said magnetic field within a confining region of said hollow cathode target, said spacers increasing in thickness monotonically from a spacer closest to said closed end surface of said hollow cathode target to a spacer closest to said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• introducing a plasma forming gas into a vacuum chamber and holding said plasma forming gas at low pressure;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a [the] hollow region of said hollow cathode target;
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target into said plasma;
• ionizing said plasma;
• extracting ions of said plasma through said magnetic null region;
• directing a flow of extracted ions within said plasma toward a remote surface requiring thin film coverage;
• creating an electrical field sheath potential between said plasma and said remote surface;
• and
• depositing said target material particles on said remote surface, said target material particles contacting said remote surface at an angle generally normal to said remote surface requiring thin film coverage.

A method for physical vapor deposition of a thin film comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises using a tapered field magnet positioned about an exterior wall of said hollow cathode target to alter profile of the magnetic field within a confining region of said hollow cathode target, said tapered field magnet having maximum magnetic field strength closest to said closed end surface of said hollow cathode target and monotonically decreasing magnetic field strength approaching said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• introducing a plasma forming gas into a vacuum chamber and holding said plasma forming gas at low pressure;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a hollow region of said hollow cathode target;
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target into said plasma;
• ionizing said plasma;
• extracting ions of said plasma through said magnetic null region;
• directing a flow of extracted ions within said plasma toward a remote surface requiring thin film coverage;
• creating an electrical field sheath potential between said plasma and said remote surface;
• and
• depositing said target material particles on said remote surface, said target material particles contacting said remote surface at an angle generally normal to said remote surface requiring thin film coverage.

A method for physical vapor deposition of a thin film comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target;
• said producing magnetic field further comprising using an extender magnet positioned atop and offset from a main magnetic field source, said extender magnet serving to extend said magnetic field beyond said opening in said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• dispersing said magnetic field throughout a confining region of said hollow cathode target;
• introducing a plasma forming gas into a vacuum chamber and holding said plasma forming gas at low pressure;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a hollow region of said hollow cathode target;
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target into said plasma;
• ionizing said plasma;
• extracting ions of said plasma through said magnetic null region;
• directing a flow of extracted ions within said plasma toward a remote surface requiring thin film coverage;
• creating an electrical field sheath potential between said plasma and said remote surface;
• and
• depositing said target material particles on said remote surface, said target material particles contacting said remote surface at an angle generally normal to said remote surface requiring thin film coverage.

A method for uniform erosion of a hollow cathode target comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises stacking variable strength magnets about an exterior wall of said hollow cathode target to alter profile of the magnetic field within a confining region of said hollow cathode target, said variable strength magnets decreasing in magnetic field strength monotonically from a magnet closest to said closed end surface of said hollow cathode target to a magnet closest to said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a hollow region of said hollow cathode target;
• and
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target.

A method for uniform erosion of a hollow cathode target comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises stacking, alternately, equal strength magnets and spacers of varying thickness to alter profile of said magnetic field within a confining region of said hollow cathode target, said spacers increasing in thickness monotonically from a spacer closest to said closed end surface of said hollow cathode target to a spacer closest to said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a hollow region of said hollow cathode target;
• and
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target.

A method for uniform erosion of a hollow cathode target comprising:

• producing a magnetic field, said magnetic field looping through an opening in a hollow cathode target, said magnetic field resulting in a magnetic null region adjacent to said opening in said hollow cathode target, said producing a magnetic field step comprises using a tapered field magnet positioned about an exterior wall of said hollow cathode target to alter profile of the magnetic field within a confining region of said hollow cathode target, said tapered field magnet having maximum magnetic field strength closest to said closed end surface of said hollow cathode target and monotonically decreasing magnetic field strength approaching said open side of said hollow cathode target;
• drawing said magnetic field toward a closed end surface of said hollow cathode target by using a pole plate to draw and direct said magnetic field toward the closed end surface of said hollow cathode target;
• applying an electrical potential across said hollow cathode target;
• creating an electrical potential difference between said hollow cathode target and an anode resulting in an electrical field;
• interacting said magnetic field and said electrical field to create magnetron action which generates a plasma within a hollow region of said hollow cathode target;
• and
• ejecting target material particles uniformly from all interior surfaces of said hollow cathode target.