A structure and method for monitoring extrusion failures. The structure
includes: a test wire having first and second ends; first and second vias
contacting first and second ends of the test wire; a first monitor
structure electrically isolated from the test wire and surrounding a
periphery of the test wire; and a second monitor structure over the test
wire, the second monitor structure electrically isolated from the test
wire, the second monitor structure extending over at least the first end
of the test wire.