Electromigration Study on Micro-vias of Multi-layer Anodic Alumina Substrate with a Thermal Compensated on-line Measurement Scheme

The Kelvin structure was designed on alumina MCM-D substrate to evaluate the substrate electromigration (EM) reliability. The Median Time To Failure (t₅₀) and the resistance shift of the interconnection via of Kelvin structure were measured by applying different current (DC) under different ambient temperatures. A thermal compensation method was adopted which ensured the packaged test structures fail at the same condition. The test results show that the active energy and the current density exponent of anodic alumina substrate are 0.57 eV and 1.03 respectively. The failure of the Kelvin structure during EM test is caused by the void formation at the interconnection of lines and vias where the current bending in 90-degree corner accelerate the EM process.