Evaluation of Residual Stress in a Multilayer Ceramic Capacitor and its Effect on Dielectric Behaviors Under Applied dc Bias Field

Abstract

The residual stress in a multilayer ceramic capacitor (MLCC) has been evaluated by two‐dimensional finite element simulation in combination with X‐ray diffraction measurement. It is shown that there is a compressive in‐plane stress in the active layers of the MLCC, which increases with increases in the number of dielectric layers when both dielectric layer thickness and electrode thickness are kept constant. A good order of magnitude agreement between the residual stresses obtained from two approaches is found. The ɛ–V response of the MLCC with different number of dielectric layers demonstrates that under a given or no applied field, the dielectric permittivity increases with increasing compressive stress. Additionally, under dc bias field, the higher the compressive in‐plane stress existing in the MLCC, the more significant the decrease of the dielectric permittivity. These results can be explained through a phenomenological thermodynamic model, including both elastic and electrostatic energy, based on the Ginsburg–Landau–Devonshire theory.

Finite Element Analysis and Design of Thermal–Mechanical Stresses in Multilayer Ceramic Capacitors

“…Numerical results reveal that thermal residual stresses in the dielectric ceramic show in‐plane compressive values of up to 52.14 MPa (as shown in Fig. d), which are consistent with values (60 MPa) obtained from X‐ray diffractometry measurements . Numerical results further indicate that the location of maximum tensile stress changes from the upperpart of the dielectric ceramic during the soldering process to the lower part throughout the board flex tests.…”

Thermal-Shock Testing and Fracturing of MLCCs Under Manual-Soldering Conditions

“…These stresses are responsible not only for structural failures such as cracks and delaminations, but also for modification of the dielectric behavior of ceramic materials [13]. Because coefficient of thermal expansion (CTE) of barium titanate ceramics is less than of nickel, during the cooling from sintering (∼1300 • C) to room temperature nickel electrodes contract more significantly than ceramic layers.…”

“…7(a)] and some decrease in capacitance, ∼3%, [ Fig. 7(b)] that was likely due to the effect of mechanical stresses [13] associated with exposure to extremely low temperatures.…”

Characterization of Domains Reorientation in Multilayer Piezoelectric Ceramic Actuators by Polarized Raman Spectroscopy

“…Figure (b) shows the mapping of the variation in the Raman shift of E(3TO + 2LO) + B 1 , and it moves upward around the crack tip and keeps relative stable in the region far away from the crack. In the multilayer piezoelectric/ferroelectric devices, such as MLPAs and multilayer ceramic capacitors (MLCCs), as the coefficients of thermal expansion for the internal metal electrodes is larger than that of the ceramic layers, compressive residual stresses are generated during manufacturing process . As observed in other perovskite ferroelectric/ferroelastic materials, tensile stress moves the Raman shift upward, whereas compressive stress has a reverse effect .…”