【作者】 王艳；

【导师】 丁桂甫；

【作者基本信息】 上海交通大学 ， 微电子学与固体电子学， 2009， 博士

【摘要】 从宏观器件的微小型化到功能化微小型器件的独立开发,结构的微型化使器件内部的物质和能量输运均受到了微小空间的限制,这使得部分高功率器件面临功率过高所带来高能量及快速热输运问题。另一方面,在微电子领域,随着芯片上器件集成度的快速增长,由微电子器件温度敏感性所带来的芯片热控制问题也不断突显。而具备高效率散热优势的微通道散热器为上述微小空间内的散热问题提供了良好的解决方案。传统的微通道散热器由平行排布的微通道散热单元组成,通过内部工质以强迫对流的方式散逸被冷却器件的热量。伴随着MEMS技术的不断成熟和发展,将MEMS技术应用于解决微小机构在特定时间和空间尺度范围内的热控制问题,使得微型化散热器件在散热性能和结构适应性方面得到了极大的提升和拓展。微通道散热器结构在经历了传统平行排布微通道结构布局后,开始出现许多变化的复杂结构形式。与此同时,这一趋势使得微通道散热器的设计理念获得了更多深层次的探讨和研究。也同时为研究不同微通道结构形式下的流动及传热机制问题提供了更多的实验经验。本文基于传统的微通道散热器结构和MEMS技术优势,提出了一种复合短程横向过流次级通道阵列和薄层散热板结构的新型复杂微通道散热器设计。在靠近热源器件的散热板下表面使用短程横向过流次级通道阵列一方面缩短了热源到工质的热传输路径,提高了散热效率;另一方面较短的通道长度使内部工质入口段在通道中所占比例提高,有效利用了工质入口段具有较高散热效率的优势;此外,与传统器件相比较,在纵向通道基础上引入该通道阵列增大了工质与散热板之间的热交换面积,创造了与工质高效热交换的良好条件。采用薄层散热板的设计为整体散热器提供了低阻传热通道,削弱了散热板对材料热导率的高要求。上述短程横向过流次级通道和薄层散热板结构相结合形成了本文新型微通道散热器的创新设计方法。本文同时运用ANSYS和CFX软件对创新方案与传统设计的关键性能进行了比较分析,确认了设计思想的合理性;在此基础上充分发挥MEMS技术在复杂微结构和多种材料兼容制造方面的优势,采用硅与非硅微加工技术相结合的集成制造流程,研制了新型微通道散热器样品,并搭建了红外测试平台对其进行了初步表征。在传统结构和新型结构的仿真比较分析中,新型结构在所采用的工况条件中都具备了较优的散热性能。实验测试表明,新型结构的微通道散热器在低工质流速6.79ml/min时,其整体热阻为1.87?С/W,当工质流速增大至800ml/min时,仿真预测的散热器整体热阻值低至0.09?С/W。基于仿真方法对上述结构进行了进一步的研究分析,在原有结构基础上加入了背面散热增强通道结构。通过参数化仿真方法,对不同结构参数下的微通道散热器进行了散热性能研究。分析发现对于微小空间的微通道散热器而言,通道结构几何参数的变化对整体微通道散热器散热性能的影响要小于拓扑变化所带来的影响。本文同时研究了复杂结构微通道散热器所涉及的MEMS工艺技术,确定了合适的工艺方案和工艺参数,选用合适的材料,涉及的基本工艺包括溅射、电镀、光刻、刻蚀、共晶键合技术等,并根据器件设计和实验要求,改进了一些常规工艺以保证器件的成功制作。更多还原

【Abstract】 With the trend from the microminiaturization of macro devices to the independent exploitation of micro devices, dimension of devices are brought into small space by MEMS technologies. Transition of matter and energy in devices are limited due to microminiaturization of structures, which results in difficulties of heat transformation in devices whose power consumption are so high. On the other hand, in the microelectronics filed, with the rapid development of the integrity of the devices in the chip, the problem of heat management of chips due to temperature sensitivity of microelectronic devices become more and more important. Microchannel heat sink with high heat transfer efficiency provides an effective solution for the problem mentioned above.Traditional microchannel heat sink comprises of parallel microchannels. Heat from the cooled device is transferred to the coolant with forced convection. With the development of MEMS technologies, applying MEMS technologies to solve the problem of heat management in micro system improves the structure adaptability and heat transfer characteristics of microchannel heat sink and the structure of microchannel heat sink become complicated compared with the traditional structure.A novel microchannel heatsink with short distance transverse channel array and thin heat spreader was investigated based on the traditional structure and MEMS technologies. The transverse channels near to the heat source provide a short heat transfer path. Short distance of transverse channel makes more coolant under the developing status, which increases the heat transfer efficiency. Compared to the traditional structure, transverse channel arrays increase the heat exchange area between the channel and coolant. On the other hand, using thin heat spreader provides a heat transfer path with low thermal resistance. The novel structure combined the transverse channel array and thin heat spreader to form a novel design. The key heat transfer performances of traditional and novel structure are compared employing ANSYS and CFX software packages. The relative analysis confirms the rationality of the design. Making use of superiority of MEMS technologies on complicated structure fabrication and different materials compatibility, a sample with novel structure was manufactured by integrating the silicon and Non-silicon microfabrication technologies. A test system including IR (infrared spectra) detector was set up to show the abecedarian characteristics of the novel microchannel heat sink.The novel structure had more efficient heat transfer performance than traditional structure under all of the conditions employed in simulation. Tests showed that the thermal resistance of the novel structure was about 1.87?С/W with the low coolant velocity 6.79ml/min. When the coolant velocity increased to 800ml/min, the result of the simulation showed that the whole thermal resistance was down to 0.09?С/W. Based on the above structure, a heat enhancement element was added at the back of the substrate. Applying the parameter simulation method, simulations of the microchannel heat sink with different structure were performed. The results showed that the effect of dimensions of the microchannels on the heat transfer characteristics was inconspicuous compared with the effect of channel conformation.The related micromachining technology has been studied for microchannel heat sink with complicated structure. Parameters and materials have been selected. The basic micromachining technologies were used including sputtering, electroplating, photolithography, etching and eutectic bonding. In order to ensure the devices being fabricated successfully, some normal micromachining technologies have been modified according to the design and actual requirement.更多还原