The reliability investigation of capacitors embedded PCB

The reliability of the MLCC embedded PCB with Cu-filled via method was investigated and the finite element method (FEM) was conducted to simulate the stress distribution in the PCB. Due to the non-symmetrical of the MLCC embedded PCB and the CTE mismatch between the materials for the embedded PCB, all samples are non-flatness after test. For the PCB tested at Pb-free reflow, no failure could be observed until it was tested for 9 cycles, voids at the interface between the MLCC and the adhesive were observed. Failures were detected by the LCR tester when the PCB tested at thermal stress condition for 6 cycles and big delamination occurred between the component and the BT material. For the PCB tested at thermal cycling condition, no failure was observed even the samples tested for 1000 cycles. The FEM simulation results showed that the stress accumulated at the interface between the component and the BT material. When the ambient temperature reached 288°C, it is as high as 0.610 Gpa which leads to the delamination of the MLCC embedded PCB.