Method and apparatus for improving the uniformity ion bombardment in a magnetron sputtering system

A sputtering method for impacting a uniform ion flux upon a substrate, said method comprising the steps of:

• providing a cathode assembly including cathode magnet means;
• disposing a substrate having a surface in spaced relationship with and facing said cathode assembly;
• inducing a primary magnetic field closely adjacent to said cathode assembly with said cathode magnet means, said primary field including a fringe field portion extending to the vicinity of said substrate and including components perpendicular to the surface of said substrate near at least one inner portion thereof;
• impacting said substrate with an ion flux;
• disposing a countermagnet means adjacent to said substrate;
• and
• making said ion flux uniform across said substrate by generating a secondary magnetic field by means of said countermagnet means, said secondary field including field lines having components extending substantially perpendicular to the surface of said substrate at each said inner portion and in a direction opposite to the components of said primary magnetic field perpendicular to the substrate to substantially flatten the magnetic field in the vicinity of said surface substantially parallel thereto such that said ion flux is substantially uniform.

Apparatus for sputter coating a substrate, said apparatus comprising:

• a cathode assembly including a target composed of coating material and cathode magnet means for producing a primary magnetic field closely adjacent said target to enhance ion bombardment of said target with a primary ion flux, said primary magnetic field including a fringe field extending adjacent to said substrate and having a component substantially perpendicular to said surface of the substrate at at least one interior portion of said substrate;
• means for creating said primary ion flux and a secondary ion flux originating from within said primary magnetic field between said fringe field and said target;
• means for mounting said substrate spaced apart from and facing said cathode target;
• means including negative biasing means for impacting said secondary ion flux onto said substrate;
• and
• means for uniformly impacting said substrate with said secondary ion flux, including countermagnet means for producing a secondary magnetic field in the vicinity of said substrate, said secondary magnetic field having components perpendicular to the surface of said substrate, said components being substantially equal in magnitude and opposite in direction to said perpendicular components of said component of said fringe field at each portion of said substrate.

Apparatus for sputter coating a substrate, said apparatus comprising:

• a cathode assembly including target means composed of coating material and a cathode magnet means for producing a primary magnetic field closely adjacent said target means to enhance bombardment of said target means with a primary ion flux;
• means mounting said substrate spaced apart from and facing said cathode target means;
• means for directing a secondary ion flux bombardment upon said substrate;
• means for making said secondary ion flux upon said substrate uniform across its surface, said means including means for producing a secondary magnetic field in the vicinity of said substrate, and
• said countermagnet means having pole pieces of a number, size and spacing so selected to replicate the pole piece number, size and spacing of said cathode magnet means.

Apparatus for sputtering coating a substrate, said apparatus comprising:

• a cathode assembly including target means composed of coating material and a cathode magnet means for producing a primary magnetic field closely adjacent said target means to enhance ion bombardment of said target means, said primary magnetic field including fringe field lines extending adjacent to said substrate and having a component substantially perpendicular to said surface of the substrate, said fringe field lines tending to form a generally funnel shaped central boundary region;
• a means mounting said substrate spaced apart from and facing said cathode target means;
• and
• countermagnet means for producing a secondary magnetic field in the vicinity of said substrate, said secondary magnetic field having field lines with components perpendicular to the surface of said substrate, said perpendicular components being substantially opposite in direction to said perpendicular components of said primary magnetic fringe field lines and of such magnitude that the magnetic field in the vicinity of said substrate is substantially flattened in the vicinity of said surface and said funnel shaped central boundary region is substantially reduced in size.