Patent ID: 8742776

Claim:
A resistivity test structure on a substrate, comprising: a first bump, a second bump, and a third bump formed on the substrate, wherein the first, the second, and the third bumps are collectively formed on a corner of a die on the substrate, and wherein the first, the second, and the third bumps are not connected to active devices and are for resistivity measurement, and the first, the second and the third bumps form a triangle shape with the second bump disposed closest to a corner point of the die; a first conductive structure connecting the first and the second bumps; and a second conductive structure connecting the second and the third bumps, wherein a voltage drop is measured across the second bump by using the second and the third bumps when a current is applied between the first and the second bumps to calculate a resistivity of the second bump and underlying conductive layers of the second bump.