A novel non-destructive evaluation method of inductively excited lock-in thermography (called InduLIT in this paper) is investigated for crack detection on PCB-vias. Previous publications already showed the working principle. Now the crack inspection of PCB-vias using flat inductors is investigated in detail. FE-models were created to get a better understanding of the process and to find optimum excitation parameters. Planar coil prototypes were produced and InduLIT experiments were performed on test samples. A comparison of the FE-simulations and experiments showed a good correlation.