Screening method and apparatus for detecting deep trench isolation and SOI defects

A method of testing an integrated circuit device for buried insulator defects, comprising:

• forming a test circuit in the integrated circuit device comprising a dedicated ground bias pad connected across a high voltage electrostatic discharge clamp circuit to a well-driving ground pad, where the dedicated ground bias pad is electrically connected only to a wafer substrate in the integrated circuit device through a conductive structure in a deep trench isolation structure and is not connected to any other circuitry on the integrated circuit device, and where the well-driving ground pad is electrically connected to a well region in the integrated circuit device;
• applying a first voltage to the dedicated ground bias pad to bias the wafer substrate while simultaneously applying a second voltage to the well-driving ground pad to bias the well region, where the first and second voltages create a stressing voltage across a buried insulator layer in the integrated circuit device;
• and
• conducting a screening test to screen for a defect in the buried insulator layer by measuring a leakage current at the well-driving ground pad or dedicated ground bias pad.