Sabine Penka

Size Effects and Temperature Dependence of Stress-Induced Voiding

In this investigation the stress-induced voiding (SIV) behavior of via structures with different geometries was tested. A variation of via sizes, aspect ratios, and widths of connected metal lines was studied. The resistance drift and its temperature dependence behavior showed sensitivity to the structure size. This can be explained by the size-dependence of mechanical stress in the metallization

Qualification of extrinsics in BEOL - the new challenge

Extrinsic failure behavior of vias and dielectrics in the backend of line (BEOL) has been studied using dedicated test structures on a large scale. Via fails after (unbiased) stress were detected utilizing a test set-up and program that allows the readout of more than 109 individual vias per wafer. The isolation behavior of intra and inter level BEOL dielectrics was studied by performing breakdown tests on various types of complex via/metal line structures covering layout areas above 1cm2 per wafer. Extrinsic failures of vias and dielectrics were linked to process or design marginalities. The study of both, resistance and isolation related defects allows a comprehensive assessment of the electrical defect density (eDD) in the BEOL to enable process and design improvements to ensure a “zero defect” product roadmap.