SGER: Exploratory Study of Imbedded Carbon Nanotubes to Improve Thermal Performance of Flexible Electronics Packages

在高性能微电子中，大热负荷通常需要高导热材料来保持电子设备的健康和性能。在柔性电路中，对灵活性的需求限制了金刚石等高导电性但刚性材料的使用，热通孔或焊料凸起只能略微提高聚合物基板的热性能。最近的研究表明，碳纳米管（CN）可以显著改善挠性电路的热管理。初步结果表明，高导电性CN的纳米级直径和高纵横比（轴向~ 3000 W/mK）使CN/聚合物复合材料获得了与传统微尺度颗粒复合材料不同的高导热性。在我们的实验室进行的初步测试中，用1 wt%随机分散的CN合成的商用环氧树脂的导热系数提高了1.7倍，而理论预测，如果CN排列整齐，这个数字可以达到100。基于我们有限的实验结果，我们提出了两种不同类型的CN (a)随机取向和(b)垂直取向的CN/聚酰亚胺复合材料的制备和热性能评估。拟建项目高风险高收益。它特别适合SGER资助，因为CN的物理性质还没有得到很好的理解，微电子工业可以从该项目开发的高导电性聚合物复合材料中获益良多。拟议活动的智力价值拟议的项目对纳米技术和微电子领域很重要。它不仅影响了未来电子封装的设计，而且大大提高了我们目前对CN材料的了解。提议的工作是非常新颖的、原创的和有组织的，并且提议团队完全有资格执行所需的工作。PI在MEMS，模拟和传热等不同但互补的领域拥有丰富的经验。此外，该团队还可以在校园洁净室中使用完整的微加工设备。拟议活动的更广泛影响拟议的项目将为大学和高中的学生提供重要的教育机会。亚利桑那大学的研究生和本科生在这项努力下将从进行拟议的纳米技术研究的经验中受益匪浅。为该项目招募的K-12学生和教师将更加了解纳米技术，这可能导致更多K-12学生将科学和工程作为职业道路。PI将通过他目前作为女性和少数族裔工程学生导师的角色，积极招募代表性不足的学生。为该项目开发的加工技术和购买的设备将大大提高UA多用户微型制造设施的能力。

Large heating loads in high performance microelectronics often require high thermal conductivity materials to maintain the health and performance of the electronics. In flex-based circuitry, where the need for flexibility limits the use of such highly conductive but stiff materials like diamond, thermal vias or solder bumps can only slightly enhance the thermal performance of the polymeric substrates. Recent studies suggest that carbon nanotubes (CN) can dramatically improve the thermal management of flex circuits. Preliminary results indicate that the nanoscale diameter and high aspect ratio of the highly conductive CN (~ 3000 W/mK in the axial direction) allow CN/polymer composites to achieve unusually high thermal conductivities, unlike polymers composited with the traditional microscale particles. Initial tests performed at our laboratory on a commercial epoxy composited with 1 wt% of randomly dispersed CN showed that the thermal conductivity was enhanced by a factor of 1.7, while theory predicts this number to reach 100 if the CN were aligned.Based on the results of our limited experiments, we propose to fabricate and evaluate the thermal performance of two different types of CN/Polyimide composites with (a) randomly oriented and (b) vertically aligned CN. The proposed project is both high-risk and high-payoff. It is especially suitable for SGER funding due to the fact that the physical properties of CN are not well understood and the microelectronics industry can potentially benefit tremendously from the highly conductive polymer composite developed by the project. Intellectual Merit of Proposed ActivityThe proposed project is important to the fields of nanotechnology and microelectronics. It not only impacts the design of future electronics packaging but also significantly enhances our current knowledge of CN materials. The proposed work is very novel, original, and organized, and the proposal team is well qualified to perform the required work. The PI's have extensive experience in such diverse but complementary areas as MEMS, simulation, and heat transfer. Additionally, the team has access to a complete line of micro fabrication facilities in an on-campus cleanroom. Broader Impacts of Proposed ActivityThe proposed project will generate significant educational opportunities for students at both the college and high school levels. The UA graduate and undergraduate students supported under this effort will benefit greatly from the experience of carrying out the proposed nanotechnology research. The K-12 students and teachers recruited for the project will become more aware of nanotechnology, which can lead to more K-12 students pursuing science and engineering as a career path. The PI will actively recruit underrepresented students through his current role as a mentor for women and minority engineering students. The processing techniques developed and equipment purchased for the project will significantly enhance the capability of the multi-user micro fabrication facilities at UA.