Extended metallization reliability testing: Combining standard wafer level with product tests to increase test sensitivity

For future semiconductor technologies with larger interconnect aspect ratios, metallization is more prone to stress and electro migration. Therefore, metallization reliability is expected to become increasingly important. However, challenges arise if test structures and test methodologies are not accommodated to trace reliability issues with sufficient sensitivity. In such cases long test times and high volume tests are required to guaranty the metallization reliability. An extended test method is presented which addresses these problems by directly investigating the product at wafer level instead of a limited set of test structures. The method will be demonstrated for the example of stress migration in aluminum filled vias.