Applied Research Of Hotspot Removal In Chip Using Thermoelectric Cooler

With the increasingly high miniaturization and integration of electronic components, the heat generated by the chip in unit area become more and more, and heat production in different parts of chip is not uniform,so the chip will inevitably produce a very high heat flux hotspot. Because of some inherent defects, traditional ways of cooling can’t remove hotspot in chip. However, the thermoelectric cooler(TEC) has unique advantages in the small and concentrated heat environment of chip with hotspot, but the current researches in this field mainly focus on the pursuit of performance, and has a distance from the practical application. This paper will study TEC’s working performance and application in removing hotspot in chip based on an existing TEC(RMT Ltd: 1md06-021-03).Firstly, this paper established the mathematical model of heat transfer process according to the working principle of TEC, and verified the accuracy of the model with numerical simulation. To improve the accuracy of the model and expand its application range,the temperature dependence of model parameters, such as Seebeck coefficient, thermal conductivity and resistance, was studied. The results showed that the accuracy of the model affected by Seebeck coefficient and thermal conductivity when the model temperature changes could be ignored, but the temperature dependence of resistance should be taken into account when the model temperature changes in a large range. In addition, the paper also studied the influence of the cold and hot ends boundary conditions on the performance of the TEC. It found that the increasing of heat transfer resistance in hot end would reduce the maximum operating current value of TEC, the maximum temperature difference between the cold and hot ends, maximum net heat absorption, and coefficient of performance lower. While the increasing of the heat load in cold end would also result in the maximum temperature difference and coefficient of performance decreasing, but the maximum operating current value of the TEC could larger.Then, with the established TEC model, the simulation research of hotspot removal of chips was performed. When thermal resistance, diameter of hotspot, and power density of hotspot were 0K/W, 0.5mm and 500W/cm2 respectively, TEC’s maximum operating current can be taken to about 6A, while the optimum operating current was 3A. With the current value of 3A, the hot spot can be just removed, and compared with no TEC in use, the maximum temperature difference of the chip was dropped from 13.9℃ to 3.2℃, where the temperature drop caused by the TEC active cooling was 4.9℃. However, with the increase of heat transfer resistance, the temperature of the entire model will rise, but the cooling capacity and working efficiency of TEC will suffer small effects, and when the heat transfer resistance is large, the increase of operating current does not significantly increase TEC’s cooling capacity, on the contrary, it will increase the overall temperature of the chip.In the last of the paper, an experimental platform was designed and built to remove the chip hotspot using TEC, and studied the effect of chip hotspot removal in the practical application, and proved TEC’s ability to remove hotspot in chip.