Patent ID: 7458335

Claim:
A magnetic field-enhanced plasma reactor, comprising: a reaction chamber adapted to apply a plasma to a substrate; and a first and second set of primary electromagnets having inner and outer perimeters disposed about said reaction chamber, said first set of primary electromagnets being provided with a first adjustable current and said second set of primary electromagnets being provided with a second adjustable current; and a secondary electromagnet nested within the inner perimeter of one of said primary electromagnets; wherein the reactor is adapted to maintain the ratio R=I 2 /I 1 during etching within the range −1<R<1, wherein I 1 is the current provided by the first current source, wherein I 2 is the current provided by the second current source, and wherein I 1 >I 2 , and comprising a plurality of secondary electromagnets, wherein each of the primary electromagnets of the first set has at least one secondary electromagnet nested within its inner perimeter.