Electronic Packaging Solution for 300°C Ambience

Abstract

Niche applications in automobile and aerospace industries such as the management of integrity and operation based on the inputs from the network of sensors (e.g. pressure, accelerometer, vibration etc.) that are strategically located close to the high temperature area of the engine, requires reliable packaging solution for higher temperature regime around $300^{\circ}\mathrm{C}$. A unique test vehicle involving different packaging scenarios including multi-layered ceramic capacitor (MLCC), sensor device, passive component and a voltage regulator was designed and fabricated. Different types of wire bond materials, wire bond pad metallization, substrate metallization, die attach materials both conductive and non-conductive types, lid attach materials were investigated and the prospective candidates are recommended for $300^{\circ}\mathrm{C}$ ambience Key finding of this work are NiAuAg substrate metallization could cater for both Au and Al wire bonds. Ag sintering material is the best suited candidate for conductive die attach application, since it does not induce any thermal stresses to the components, unlike the hard solders counterpart like Au-Sn eutectic or Au-Ge eutectic. Hermeticity of the rugged package involving ceramic substrate is guaranteed by seam welding approach. Functionality of the ruggedized packages is confirmed by pre and post reliability electrical measurements. Reliability tests were carried out to confirm the selected bill of materials (BOM), function reliably at $300^{\circ}\mathrm{C}$ ambience.