| 薄膜材料热物性多功能综合测试仪的研制及应用 | |
| Alternative Title | Development of Multifunctional Instrument for Thermophysical Properties Measurement of Films and Its Application |
| 陈新贵 | |
| Subtype | 博士 |
| Thesis Advisor | 王作明 |
| 2008-06-02 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 金属研究所 |
| Degree Discipline | 材料学 |
| Keyword | 薄膜热物性 仪器研制 Pi/sio2复合材料 Hdpe/mwcnt复合材料 快速传热 |
| Abstract | 薄膜材料广泛应用于微电子芯片，大规模集成电路，微机械、微器件等领域。在薄膜材料的使用过程中，热导率和热膨胀等热物理性能往往至关重要，但目前尚没有能够满足薄膜热物性测试需要的商业仪器产品。本论文工作中，在科学院仪器研制项目的支持下研制了一套薄膜热物性多功能综合测试仪，并利用建立的仪器设备开展了一些薄膜材料的热物性研究工作。 热物性多功能综合测试仪在一套设备上实现了薄膜热扩散率和热膨胀两个热物性参数的测量。其中薄膜热扩散率测量采用激光脉冲法，用8ns激光器和响应速度为40ns的碲镉汞(MCT)探测器以及500M带宽的示波器作为信号采集终端，具备了快速加热，快速探测的能力。该仪器能够实现包括金属、非金属、高分子材料在内的各种薄膜材料在-50oC~200oC之间的热扩散率测量，并可通过数学处理能够获得亚微米尺度涂层的热扩散率，经检验，系统的测量误差小于4%。热膨胀测量采用CCD(charge coupled device )非接触法，使用线阵CCD(光敏元间距4.7µm)作为图像测量器件，配合30倍的光学放大系统并对信号进行插值处理，可达到0.016µm的分辨率。使用特殊设计的试样架，既能保证薄膜试样在测试过程中保持平展，又能使薄膜在几乎不受外力的情况下自由膨胀。该仪器能在-140oC ~200oC之间对各种薄膜材料的热膨胀进行测量，经检验，测试误差小于5%。 对聚酰亚胺/纳米二氧化硅(PI/SiO2)复合材料薄膜的热物性研究发现：在SiO2添加量小于8%Wt时，PI/SiO2复合材料薄膜热扩散率随着添加量的增加而减小；当添加量高于8%Wt时，添加的SiO2使材料的热扩散率增加。添加SiO2能使PI/SiO2复合材料薄膜的热膨胀系数(CTE)下降，特别是在添加量较小的时候，作用非常明显，添加8%Wt的使室温时的CTE从49.9×10-6/oC下降到25.4×10-6/oC。得出了一个能对CTE实验结果进行描述的经验公式： 。 高密度聚乙烯/多壁纳米碳管(HDPE/MWCNT)复合材料是一种良好的正温度系数(PTC)材料。对HDPE/MWCNT复合材料薄膜的热导率研究发现，MWCNT在HDPE中形成的导热网络对材料的传热性能有重要影响。当MWCNT体积分数达到临界值VC1时，复合材料内开始有导热网络生成，此时随着MWCNT添加量的增加，导热网络迅速增加，热导率升高很快；当MWCNT体积分数进一步增大到临界值VC2时，形成完整的导热网络，此时再增加复合材料内的MWCNT只起增加导热网络分支结构的作用，热导率随MWCNT添加量增加而增加的速度变得相对缓慢。在HDPE/MWCNT PTC复合材料的工作温度范围内，HDPE/MWCNT复合材料具有比其他温度时大得多的热导率，证明HDPE/MWCNT PTC复合材料具有良好的温度响应性能。 对金属在脉冲激光作用下的传热行为进行的研究发现：采用脉冲宽度为8ns的Nd:YAG激光作为热源，在多种金属薄膜中观察到不同于正常热传导过程的快速传热现象。此现象无法根据现有的电子非平衡传热理论予以解释。; Nowadays，films were widely used in COMS chip, Large Scale Integrated circuit (LSI), MEMS and micro-device, and attracted more and more interest among researchers. The thermo-properties of films, such as thermal conductivity and thermal expansion, have played very important roles in these applications of films. However, there has no commercial instrument can satisfy the need of thermophysical properties measurement of films until now. In this dissertation, supported by the Instrument Development Fund, CAS, a multifunctional instrument for thermophysical properties measurement of films was developed. By this apparatus, thermophysical properties of some films have been studied. By this instrument, both thermal diffusivity and thermal expansion can be measured. Flash method (laser pulse method) is used to measure thermal diffusivity of films. An 8ns pulse Nd: YAG laser, a MCT detector which response time is 40ns and a 500M bandwidth oscillograph were adopt. Thermal diffusivity of metal, nonmetal and polymer films can be measured from -50oC~250oC, thermal diffusivity of submicron coating can be gained by mathematic method also. The error is determined to be less than 4%. CCD method is used to measure thermal expansion of films. The CCD, which space between two cells is 4.7µm, is used as the image detector. Enlarged by 30 multiples optical magnifying system, the special resolution of thermal expansion measurement system is well than 0.016µm. A special sample holder was designed, which may ensure the films not only keep from crispate, but also expand freely. The thermal expansion of films can be measured from -140oC ~250oC and the error is determined to be less than 5%. It is difficult to apply laser pulse method in the thermal diffusivity measurement of semitransparent materials, especially for those materials which were semitransparent both in the infra-red wave length of laser beam and detector. In this dissertation paper, a new method has been made up to solve this problem. The thermal expansion TE (ΔL/L0) of silica/polyimide (SiO2/PI) composite films with different SiO2 fractions i.e. 0, 1, 3, 5, 8 and 15 wt% prepared using the sol–gel technique was obtained in the temperature range of -120 to 200 oC using CCD method and the differential coefficient thermal expansion (CTE) can be deduced by ΔL/L0-temperature relation. The CTE of SiO2/PI composite films decreased with the increase of SiO2 content and the decrease of temperature. An empirical equation of CTE of SiO2/PI with SiO2 content has been educed. The thermal diffusivity of SiO2/PI composite films were also measured in the temperature range of -73oC-290oC. It was found that the thermal diffusivity increased with increasing SiO2 fraction when the SiO2 content below 8%Wt, while the SiO2 content above 8%Wt, it do the other way round. The thermal conductivities (TC) of HDPE/MWCNT composites films have been measured by laser pulse method. It is found that TC increased quickly with MWCNT fraction increased when the volume fraction of MWCNT below 3.35%Vol, but the increase rate became slower as the volume fraction of MWCNT above 3.35%Vol. Otherwise, TC varied slightly with temperature rise before HDPE melts, but increase swiftly with temperature rise during HDPE crystal melting. Considering the effect of MWCNT network, a new percolation model has been developed to simulate the TC of HDPE/MWCNT composites films; the results of model fit the experimental results well. An unusual ultra-fast heat transfer phenomenon was observed on various metal films excited by 8ns Nd: YAG laser pulse. Such phenomenon can not be interpreted by the existing non-equilibrium electrons theories. |
| Pages | 110 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/16933 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 陈新贵. 薄膜材料热物性多功能综合测试仪的研制及应用[D]. 金属研究所. 中国科学院金属研究所,2008. |
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