Redistribution metal and under bump metal interconnect structures and method

An integrated circuit die, comprising:

• a metal layer;
• a first passivation layer disposed above the metal layer;
• a conductive layer disposed above the first passivation layer;
• a polyimide layer disposed above the conductive layer;
• and
• an under bump metallization layer extended to the metal layer through the polyimide layer, the conductive layer, and the first passivation layer, wherein the under bump metallization layer directly contacts the metal layer and the conductive layer.

An integrated circuit die, comprising:

• a metal layer;
• a barrier layer above the metal layer;
• a first passivation layer disposed above the barrier layer;
• a redistribution layer disposed above the first passivation layer, wherein the redistribution layer does not contact the metal layer;
• and
• an under bump metallization layer plug coupled to the metal layer and disposed in a via that is provided through the first passivation layer, the redistribution layer, and the barrier layer, wherein a top surface of the redistribution layer plug is disposed above a top surface of the redistribution layer.

An integrated circuit die, comprising:

• a metal layer;
• a first passivation layer disposed above the metal layer;
• a first polyimide layer disposed above the first a passivation layer;
• and
• an under bump metallization layer coupled to the metal layer through the first polyimide layer, wherein the under bump metallization layer comprises at least one conductor extending across a top surface of the first polyimide layer and away from an area for a solder bump or pillar for the integrated circuit die, wherein the under bump metallization layer is directly connected between the solder bump or pillar and the metal layer.