A Fracture Mechanics Approach to Structural Reliability of Ceramic Capacitors

Physical defects, such as cracks, spa!Is, and delaminations, may be associated with a significant percentage of the multilayered capacitors produced for high reliability applications. These defects may lead to severe cracking of the capacitors and eventually to their electrical failure. This paper presents a fracture mechanics approach to the reliability assessment of physically defective capacitors used under high mechanical stress conditions. This approach requires both the characterization of the material properties (fracture toughness, elastic moduli, et cetera) of the multilayer capacitor and of the part´s application (environment and operational conditions). From these results the mechanical reliability of a capacitor can be estimated for different system applications and realistic limits can be determined for the allowable sizes and types of defects.