Thermal management materials for electronic control unit: Trends, processing technology and R&D challenges

The development of advanced thermal management materials for Electronic Control Unit (ECU) is the key to achieving high reliability and thus safety critical operations in areas of ECU applications such as automotives and power systems. Thermal management issues associated with the operation of ECU at elevated temperature have accounted for some of the recent reliability concerns which have culminated in current systems failures in some automobiles. As the functions of ECU in systems have increased in recent times, the number of components per unit area on its board has also risen. High board density boosts internal heat generated per unit time in ECU ambient. The generated heat induces stress and strain at the chip interconnects due to variation in the Coefficient of Thermal Expansion (CTE) and thermal conductivity of different bonded materials in the assembly. Thermal degradation could become critical and impacts device's efficiency. The life expectancy of electronic components reduces exponentially as the operating temperature rises thus making thermal management pivotal in electronic system reliability. Since materials' properties vary with operating condition, material performance has become a major consideration in the design of heat dissipation mechanism in ECU. The development of advanced thermal management materials and hence improving the performance of ECU requires an in-depth understanding of the complex relationship between materials' properties and their behaviours at elevated temperatures. The paper presents an overview of thermal management materials, review trends in material and processing technology. In addition, the paper outlines the crucial challenges in materials, cost and composite formulations and the outstanding R & D issues.