| Electronic packages tend to advance toward higher power, more functions and more leads. Due to the high power, one of the serious problems of electronic packages is heat generated from chip. As die power increases, the spatial fluctuation of temperature in a die is expected to increase. At higher temperatures some components in the die may start malfunctioning. Therefore, use of average temperature of the die would prevent us from assessing the exact high temperature at certain locations within the die. This necessitates us in design a new temperature sensor with high spatial resolution.; In this study, there are two different goals; (1) to measure the die temperatures with high spatial resolution and reduce the disturbance due to the existence of the temperature sensors, and (2) to evaluate some thermal interface material (TIM), compare them to each other, and construct the best way to transfer heat from die to heatsink.; To achieve the first goal, thin film thermocouples (TFTCs) made with T-type (copper-constantan) thermocouples are used. A thin aluminum nitride (AlN) layer of 100nm thickness is deposited on a silicon wafer and acts not only as an electrical insulator but thermal conductor between a silicon wafer and thin film thermocouples. Copper thin film with a thickness of 50 nm and constantan thin film with the same thickness are deposited on the AlN layer. The sensor array has 10 x 10 junctions within 9mm x 9mm, and each junction has a 100mum x 100mum. Simulation results are compared with temperatures measured by thin film thermocouple (TFTC) using 2-dimensional (2-D) steady-state heat conduction. Simulation results show good agreement with experimental measurements.; To achieve the second goal, some thermal interface materials are tested. Based on ASTM D5470, a new device to measure thermal impedance and resistance is developed using thermometer principles. This new device consists of an alumina substrate, titanium tungsten (TiW) layers, gold layers, and thin alumina layers. Newly developed thermal interface materials are tested by this new device, and thermal impedance of the thermal interface material is almost half of other commercial ones. |
