Sputtering apparatus

A sputtering system comprising:

• a chamber through which a substrate moves;
• a cathode assembly comprising:
• an elongated rotatable cylindrical tube mounted in the chamber and having a target surface;
• a magnetron assembly positioned within the elongated rotatable cylindrical tube, the magnetron assembly comprising:
• a plurality of magnets;
• and
• a yoke configured to hold all of the plurality of magnets within four straight, parallel, and independent linear arrays, the linear arrays comprising two outer linear arrays and two inner linear arrays;
• wherein the plurality of magnets is arranged in the yoke so as to form a pattern comprising an outer portion and an inner portion, wherein the outer portion substantially surrounds the perimeter of the inner portion;
• wherein the magnets used to form the outer portion are oriented to utilize a first polarity and the magnets used to form the inner portion are oriented to utilize a second polarity;
• wherein the outer portion of the pattern comprises:
• the outer linear arrays of the first polarity;
• and
• magnets at the ends of the inner linear arrays, the magnets at the ends of the inner linear arrays having the first polarity and the magnets that make up the majority of the inner linear arrays having the second polarity;
• and
• wherein magnets of the two inner linear arrays having the second polarity are laterally offset from each other so as to form a magnetic step.