Enhancing shear strength of terminal electrodes through glass phase evolution during copper paste sintering

Abstract The high shear strength of terminal electrodes in multilayer ceramic capacitors is crucial for ensuring device reliability. However, the specific factors governing the shear strength remain insufficiently elucidated, leaving the development of high‐adhesion copper pastes without adequate theoretical support. This study demonstrates that regulating the crystallization behavior of CaO‐BaO‐Al 2 O 3 ‐B 2 O 3 ‐SiO 2 glass and its interaction with CaZrO 3 ‐based ceramic substrates can optimize the glass composition during the terminal electrode sintering process, thereby enhancing the shear strength of the terminal electrode. As the CaO content in the glass increases, the shear strength of the terminal electrodes initially increases and then decreases. A maximum shear strength of 8.70 MPa is observed at a CaO content of 26.79 mol%. The reduction in shear strength is attributed to microcrack formation caused by localized stress concentrations from thermal expansion mismatch between the glass and ceramic phases at the interfacial layer. These findings clarify the decisive role of the glass phase composition evolution during sintering in determining the shear strength of terminal electrodes, providing valuable theoretical insights for the design of high‐adhesion terminal pastes.