Very fine-grain voltage island integrated circuit

A method of providing power supply voltages to an integrated circuit, the method comprising:

• providing a filler cell comprising an n-well;
• providing a voltage routing wire in a first metal layer;
• providing a wire group comprising a first and a second voltage supply wire, each of the first and second voltage supply wires being formed in a respective metal layer selected from the group consisting of a second metal layer and a third metal layer;
• wherein the first and the second voltage supply wires are substantially parallel and have a separation distance substantially equal to the width of the voltage routing wire;
• wherein the first and the second voltage supply wires each has an edge substantially aligned with an edge of the voltage routing wire;
• and
• connecting the voltage routing wire to a wire in the wire group through a via.

An integrated circuit structure comprising:

• a filler cell comprising an n-well;
• an M1 voltage supply wire carrying a first voltage in a first metal layer and out of the filler cell;
• an M2 voltage supply wire carrying a second voltage in a second metal layer and inside the filler cell;
• a voltage routing wire in the first metal layer;
• wherein the M1 voltage supply wire and the M2 voltage supply wire are substantially parallel;
• wherein the voltage routing wire is coupled to one of the M1 voltage supply wire and the M2 voltage supply wire.

A method of providing voltage supply voltage to an integrated circuit, the method comprising:

• providing a filler cell comprising an n-well;
• providing an M1 voltage supply wire carrying a first voltage in a first metal layer, the M1 voltage supply wire being located substantially outside the filler cell boundary;
• providing an M2 voltage supply wire carrying a second voltage in a second metal layer, the M2 voltage supply wire being substantially inside the filler cell boundary, wherein the M1 voltage supply wire and the M2 voltage supply wire are substantially parallel;
• providing a voltage routing wire in the first metal layer and substantially inside the filler cell boundary;
• coupling the M1 voltage routing wire to one of the M1 voltage supply wire and the M2 voltage supply wire.