基于相敏瞬态热反射系统的多层热界面材料的拟合研究

厚度微米级热界面材料的热物性参数,可通过相敏瞬态热反射测量法拟合得出。本文对该方法的原理进行了发展研究:基于数据测量过程中,不同调制频率区间对应在样品中的热穿透深度不同(高频区间内热穿透深度小,低频区间内热穿透深度大),提出针对多层材料,分频率段依次对各层热参数拟合的方法。本方法的途径是通过不同频率区间的选择,沿着热穿透方向依次对各层参数进行拟合,从而减少后层材料未知参数对当前层参数拟合的影响,同时减少对已知参数条件的要求,提高了拟合结果的质量。用本文方法对四层材料样品做了测量及拟合数据对比,结果表明拟合结果相对误差保持在±8%之内,同时对界面热导的信号敏感度进行了分析,发现拟合参数的信号敏感度依赖于频率的选择。

Study on the fitting of multilayered thermal interface materials based on the phase-sensitive transient thermal reflection system

The thermophysical parameters of micron-scale thermal interface materials can be fitted by phase-sensitive transient thermal reflection measurement.For transient measurement method,the thermal penetration depth is directly related to the modulation frequency of the heating pulse.Therefore,for multilayered structure,a layered probing method is proposed by carefully adjusting the modulation frequency range.By controlling the probing depth,the thermal properties of each layer along the direction of propagation of thermal wave can be determined sequentially.This method can effectively reduce the influence of unknown parameters of the rear layers on the probed layer,and thus limit the fitting parameters and improve the accuracy of the fitting results.In this work,a four-layer thermal interface structure(Cr/Au plated glass-indium-Cr/Au plated silicon oxide-silicon)is measured and the fitting results are compared with standard values.The fitting relative error is found to be within±8%.The signal sensitivity of interfacial thermal conductivity is analyzed,and it is found that the signal sensitivity of the parameters relies on the choice of frequency.