Avoiding burnt probe tips: Practical solutions for testing internally regulated power supplies

A new industry-wide trend is the presence of multiple on-die power-supplies that are not directly connected to external supplies. Examples are internally-regulated supplies and power-gated supplies. This trend has brought to fore, the problem of testing for shorts between such internal supply grids and other (internal or external) supply grids. Today, presence of such shorts often results in excessive current draw from the tester and eventually results in burnt probe-tips adding to the overall cost of test. This paper proposes a classification of shorts defects involving internally regulated supplies. Two classes of solutions for mitigating or eliminating the problem are described. Methods for maximizing sensitivity of the solutions under leakage and probe-tip constraints are also described.