Models for thermal contact resistance metal polymer interface models for friction and heat transfer for microchannels

所有微电子设备(如手机、笔记本电脑和高端服务器)在功能、速度和性能方面的进步导致在设备级产生的热量显著增加。热量必须穿过由不同材料(如金属/金属、金属/聚合物、聚合物/聚合物)形成的许多界面，然后才能通过散热器散失到环境中。为了确保连续运行，设备的温度必须保持在特定的临界水平以下。这需要降低从设备到环境的总热阻，并在较长时间内保持在低水平。总电阻由串联排列的几个扩展-收缩和接触电阻组成。散热器的热阻是总热阻预算的重要组成部分。正在进行实验研究，通过新的设计、新材料和冷却液的使用来降低散热器的热阻和压力降。提出用梯形或双梯形等非圆形截面微通道系统来代替传统的散热器，这些微通道被刻蚀到硅中。微通道的水力直径约为100微米，长度可达几毫米。微通道的初步实验结果表明，它们的性能比针翅式散热器高出2-3倍。然而，对于宏观通道的基本传输机制以及为宏观通道建立的摩擦和换热关联式是否适用于微通道，人们知之甚少。所有加拿大微电子公司都面临着这些严重的热和水力问题。实验和模型研究包括两部分：1)研究不同金属/聚合物界面的热扩散和接触电阻，为预测界面电阻提供准确的数据、关联式和模型。这些数据和相关性可以被行业用来对聚合物进行评级。2)对微通道内流体流动和换热的研究将产生热流体模型和关联式，以预测摩擦因数、压降和换热关联式。

Advances in functionality, speed, and performance of all microelectronic devices such as cell phones, notebooks, and high end servers have resulted in significant increases in heat which is produced at the device level. The heat must cross many interfaces formed by different materials (e.g. metal/metal, metal/polymer, polymer/polymer) before it is dissipated into the ambient through heat sinks. To ensure continuous functionality, the temperature of the devices must be maintained below certain critical levels. This requires the overall thermal resistance from the device to the ambient to be reduced and maintained at low levels over long periods of time. The overall resistance consists of several spreading-constriction and contact resistances in series arrangement. The thermal resistance of the heat sink is an important part of the overall resistance budget. Experimental research is being done to reduce the thermal resistance and the pressure drop of heat sinks by novel designs, and the use of new materials and cooling fluids. It is proposed to replace the conventional heat sinks with a system of microchannels of noncircular cross section such as trapezoidal or double trapezoidal which are etched into silicon. The hydraulic diameter of the microchannels is about 100 micrometers and the length may be several millimeters. Preliminary experimental results for microchannels show that they can outperform pin fin heat sinks by a factor of 2-3. However, little is known about the underlying transport mechanisms and whether the friction and heat transfer correlation equations developed for macrochannels are applicable for microchannels. All Canadian microelectronics companies are facing these severe thermal and hydraulic problems. The proposed experimental and modeling research has two parts: 1) Research on thermal spreading and contact resistances with different metal/polymer interfaces will yield accurate data, correlations and models for predicting the interface resistances. The data and correlations can be used by industries to rank the polymers. 2) Research on fluid flow and heat transfer in microchannels will produce thermofluids models and correlations to predict friction factor, pressure drop, and heat transfer correlations.