Thermal resistance evaluation in high heat flux electronics

In recent years, heat flux is becoming much higher according to the downsizing of electronics, and accurate thermal design and high efficient cooling technique are required for higher reliability of electronics. Heat spreader is one of the key technology of high heat flux electronics. Conventionally, heat spreading angle in the heat spreaders is assumed as 45 degrees. However, the angle depends on surrounding condition. Additionally, for efficient use of the heat spreaders, contact thermal resistance is also important. However, heat spreading angle and contact thermal resistance under high heat flux condition have not been discussed in details. In this paper, contact thermal resistance and heat spreading angle in the heat spreaders under high heat flux condition are discussed.