Non-destructive testing of a high dense small dimension through silicon via (TSV) array structures by using 3D X-ray computed tomography method (CT scan)

In the present study, high density TSV structures have been designed and fabricated with different diameter and depths, ranging from 2 to 60 µm and 50 to 100 µm respectively. The ratios of TSV diameter to space between TSVs are 1∶2, 1∶3 and 1∶4. Inspection of TSV structures at each processing step is very crucial to proceed to next step. 3D X-ray CT scan analysis has been employed to inspect TSV wafers at different processing steps. Detailed 3D X-ray CT scan analysis has been carried out on 20, 50 and 60 um TSV array structures. Using this method, it is possible to observe defect shape, size and distribution by conducting the virtual cross-section at desired location. Based on the detailed online failure analysis, TSV process development parameter are being fine-tuned and optimized.