Fracture analysis of interface delamination in Metal-Insulator-Metal capacitor device

It is well known that the Metal-Insulator-Metal (MIM) capacitor device can be a match circuit or a noise filter in RF circuit and be a loading device in digital circuit. The MIM capacitor devices are becoming most popular structures that have been massively used in system circuit designs to perform capacitors in IC and PCB processes. Because the characteristics of system will be changed and electrical performances will be impaired if large deformations or stresses are resulted in MIM capacitor device, the concerns of reliability for MIM capacitor devices are important issues. The critical stresses in MIM capacitor device may induce the phenomenon of interface delamination. For the purpose of realizing the stress distributions in MIM capacitor device, the finite element analysis (FEA) is adopted. The highly accelerated stress testing (HAST) of reliability test is also employed. The reliability test results show that the delamination occurs along the Si₃N₄ layer. Through FEA simulation results, the maximum stress is found to take place at the layer of Si₃N₄ or its corresponding interfaces. These stress concentration areas are critical places to be fractured, which are well agreed with the results of reliability test. Moreover, to have better geometric parameters in MIM capacitor device to reduce the critical stresses, the designs of experiments (DOE) analysis is also used. This study is expected to be useful design guidelines to prevent the delamination in MIM capacitor device.