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

在高性能微电子产品中，大量的热负荷往往需要高导热材料来维持电子产品的健康和性能。在基于柔性的电路中，对灵活性的需求限制了钻石、热孔或焊料凸块等高导电性但坚硬材料的使用，因此只能略微增强聚合物基板的热性能。最近的研究表明，碳纳米管(CN)可以显著改善柔性电路的热管理。初步结果表明，与传统微米级粒子复合的聚合物不同，高导电性CN(轴向约3000W/MK)的纳米尺度直径和高长径比使得CN/聚合物复合材料具有异常高的导热系数。在我们实验室对含有1wt%随机分散CN的商业环氧树脂进行的初步测试表明，如果CN排列，导热系数提高了1.7倍，而理论预测这个数字将达到100。基于我们有限的实验结果，我们建议制备和评价(A)随机取向和(B)垂直排列CN的两种不同类型的CN/聚酰亚胺复合材料的热性能。拟议的项目既是高风险的，也是高回报的。由于CN的物理性质尚未得到很好的了解，而且微电子行业可能会从该项目开发的高导电聚合物复合材料中获得巨大利益，因此它特别适合为SGER提供资金。拟议活动的智力价值拟议中的项目对纳米技术和微电子领域具有重要意义。它不仅影响了未来电子封装的设计，而且极大地提高了我们目前对CN材料的认识。建议的工作非常新颖、原创和有组织，提案团队完全有资格执行所需的工作。PI在MEMS、模拟和传热学等不同但互为补充的领域拥有丰富的经验。此外，该团队还可以使用校园洁净室中的一整套微型制造设施。拟议活动的更广泛影响拟议的项目将为学生提供大量的大学和高中教育机会。在这项努力下支持的亚利桑那大学研究生和本科生将从开展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，这可以导致更多的K-12学生将理工科作为职业道路。PI将通过他目前担任的女性和少数族裔工程专业学生导师的角色，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的多用户微制造设施的能力。

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.