基于TSV的三维高功率芯片的散热特性研究

发布时间：2018-05-15 06:21

本文选题：3D封装 + 高功率芯片　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：三维封装通过在Z方向堆叠多个裸晶,实现了高密度封装,满足了电子产品的低成本、低功耗、小尺寸等方面的要求。然而,3D封装存在着非常严重的散热问题,因此,对3D高功率芯片进行散热性能研究具有十分重要的意义。针对3D高功率芯片,将微流道集成在转接板内,利用微流体的循环流动带走发热芯片工作时产生的热量,将芯片的工作温度维持在合适的范围内,是一种可行的散热方案。本文针对功耗为100W,热流密度为100W/cm2的3D高功率芯片,提出了一种内含TSV和微流道的三维叠层结构,采用微通道液冷技术对芯片进行散热,建立模型并进行相关研究。本文主要包括以下内容:1、对封装体内数量众多的焊点进行了等效,提出了焊点部分的等效方法,推导了等效热导率计算公式。建立了含有400个焊点的实际模型和对应的等效模型,在加入填料和不加填料两种情况下,针对不同的焊点直径和焊点间距,采用ANSYS Workbench软件仿真分析了等效方法的误差,得到结论:采用本文提出的焊点等效方法,Z方向的温度误差小于±1.0%,X-Y方向的温度误差小于±30.0%。而将焊点部分全部视为焊料的等效方法,Z方向的温度误差在±65.0%~±99.0%之间,X-Y方向的温度误差很大,在±97.85%~±99.94%之间。2、由于3D封装体内部TSV尺寸微小且数量众多,因此对含有TSV的转接板进行了等效,推导了等效热导率计算公式,分析了转接板的等效热导率随TSV直径、间距、深宽比的变化规律。建立了包含100个TSV的转接板的实际模型和对应的等效模型,采用ANSYS Workbench软件进行稳态热分析,并对比分析了等效方法的误差,得到结论:转接板的等效热导率随着TSV直径的增大而增大,随着TSV间距的增大而减小,随着TSV深宽比的增大而减小。采用本文提出的转接板等效方法,其Z方向和X-Y方向的温度误差均低于±10%。3、基于焊点阵列和含有TSV的转接板的等效方法对整体模型进行了简化,建立了不加散热器的仿真模型;建立了含有0.2mm,0.4mm,0.6mm,0.8mm和1.0mm五组不同宽度的微流道的仿真模型,在冷却液入口流速分别为0.1m/s,0.5m/s,1m/s和2m/s时,采用ANSYS CFX软件进行了流体动力学仿真,对比分析了微流道内流体的压力场和芯片上的温度场,得到结论:不加散热器时,芯片上的温度高达1219.6K,而含有0.6mm宽的微流道在入口流速为1m/s时,对应的芯片上的最高温度降为334.1K;同一冷却液入口流速下随着微流道宽度的减小,其换热能力有所提高,相对压差有所增加;同一宽度的微流道的散热能力和相对压差均随着冷却液入口流速的增加而增大。4、在冷却液入口流速为1m/s时,0.6mm宽的微流道不能满足微泵的微型化需求,通过对微流道进行结构优化,将肋片的占空比由1调整为0.5,仿真后得到结论:在冷却液入口流速为0.5m/s时,芯片上的最高温度降为63.5℃,微流道出入口的压差为0.50441bar,能够满足系统热设计和微泵尺寸微型化的要求。随后,对散热系统整体封装结构进行了初步的设计,从理论上计算得到了系统的流量和压降分别为258.75mL/min和0.53142bar,并据此进行了微泵的选型。最后,对所有部件进行组装,得到系统整体的体积约为60mm?60mm?85mm。
[Abstract]:By stacking a number of bare crystals in the direction of Z, 3D Packaging realizes high density packaging and meets the requirements of low cost, low power consumption and small size of electronic products. However, 3D packaging has a very serious heat dissipation problem. Therefore, it is of great significance to study the heat dissipation performance of 3D high power chips. For the high power chip of 3D, In this paper, a 3D high power chip with a power consumption of 100W and a heat flux density of 100W/cm2 is proposed. A kind of TSV and microfluidic channel is proposed. The three dimensional layer structure, using microchannel liquid cooling technology to heat the chip, set up the model and carry on the related research. This article mainly includes the following contents: 1, the equivalent of the number of solder joints in the package is equivalent, the equivalent method of the solder joint part is put forward, the calculation formula of the equivalent thermal conductivity is derived. The practice of the 400 solder joints is established. The model and the corresponding equivalent model are used to analyze the error of the equivalent method by using ANSYS Workbench software to analyze the difference in the diameter of solder joint and the distance between the solder joint without adding two kinds of filler. The conclusion is that the temperature error of the Z direction is less than 1% and the temperature error of the X-Y direction is small by using the equivalent method of the solder joint proposed in this paper. The temperature error in the direction of Z is within + 65.0%~ + 99%, and the temperature error in the direction of X-Y is very large. The temperature error of the X-Y direction is very large. The temperature error of the direction is between + 97.85%~ + 99% and.2. As the TSV size in the 3D package is small and numerous, the equivalent of the switch plate containing TSV is equivalent, and the equivalent thermal conductivity meter is derived. The equivalent thermal conductivity with the TSV diameter, distance and the ratio of depth to width is analyzed. The actual model and corresponding equivalent model of the connecting plate with 100 TSV are established. The steady-state thermal analysis is carried out by ANSYS Workbench software, and the error of the equivalent square method is compared and analyzed. The conclusion is that the equivalent thermal conductivity of the connecting plate is followed by the equivalent thermal conductivity. With the increase of TSV diameter, it decreases with the increase of TSV spacing and decreases with the increase of the ratio of TSV depth to width. The temperature error of the Z direction and X-Y direction is less than + 10%.3 by the equivalent method proposed in this paper, and the integral model is simplified by the same effect method based on the solder joint array and the TSV transfer plate. The simulation model of the radiator is added, and the simulation models with five different widths with different widths of 0.2mm, 0.4mm, 0.6mm, 0.8mm and 1.0mm are established. When the inlet flow velocity of the coolant is 0.1m/s, 0.5m/s, 1m/s and 2m/s, the fluid dynamics simulation is carried out by ANSYS CFX software, and the pressure field and the temperature on the chip are analyzed. In the degree field, it is concluded that the temperature of the chip is up to 1219.6K without the radiator, and the maximum temperature on the corresponding chip is 334.1K when the inlet velocity is 1m/s at the inlet velocity of the 0.6mm wide. With the decrease of the width of the microfluidic channel at the inlet velocity of the same coolant, the relative pressure difference is increased and the width of the relative pressure is increased; the same width is increased. The heat dissipation capacity and relative pressure difference of the microfluidic channel increased with the increase of the inlet flow velocity of the coolant. When the inlet velocity of the coolant was 1m/s, the microchannel of 0.6mm wide could not meet the microminiaturization demand of the micropump. By optimizing the structure of the microfluidic channel, the space ratio of the ribs was adjusted from 1 to 0.5. The result of the simulation was that the cooling solution was entered. When the flow velocity is 0.5m/s, the maximum temperature on the chip is 63.5 C and the pressure difference of the inlet of the micro channel is 0.50441bar. It can meet the requirements of the system thermal design and micro pump size miniaturization. Then, the overall package structure of the heat dissipation system is preliminarily designed. The flow and pressure drop of the system are calculated to be 258.75mL/min, respectively. And 0.53142bar, and based on this, the selection of the micro pump was carried out. Finally, all the components were assembled and the volume of the whole system was about 60mm? 60mm? 85mm..

【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN405

【参考文献】