STTR Phase I: Diamond Carbon Coated Graphite-Copper Material for Use in RF Power Amplifier Packaging

这项小型企业技术转让（STTR）第一阶段项目的重点是开发一种独特的金刚石碳涂层石墨铜复合材料。该复合材料将用于生产用于射频功率放大器的低热阻封装组件。在第一阶段的努力下，将展示一种低成本的金刚石碳涂层工艺。迫切需要具有改进热性能的先进材料，以满足当前和未来高功率射频放大器的热管理要求。由于封装、电路结构和半导体材料的进步，电子系统的散热率急剧增加。今天的高功率射频功率放大器器件的散热接近600至800 W/cm2，预计在几年内将达到1,000 W/cm2。本项目的研究目标是对用于生产金刚石碳涂层的聚合物前驱体的化学合成工艺进行细化，建立涂层工艺，将聚合物前驱体沉积在石墨-铜衬底上，并将聚合物前驱体热转化为高导热金刚石碳涂层。理想情况下，金刚石碳涂层石墨铜复合材料的导热系数应该在500到600 W/m-oK之间，热膨胀系数可以在5到10 ppm/oC之间进行调节，以最大限度地减少衬底和射频半导体器件之间的热膨胀。该研究项目的结果将使制造具有成本效益的金刚石碳涂层石墨铜复合材料成为可能，该复合材料可改善热性能，对下一代射频功率放大器的热管理解决方案至关重要。如果成功，这项研究将促进对以下方面的基本理解：(1)生产聚合物前体的化学合成过程；(2)在石墨-铜基体上制备金刚石碳涂层的方法；(3)复合材料变量（如碳纤维和铜基体体积分数、金刚石碳结构、金刚石碳热处理、金刚石碳涂层厚度等）对复合材料微观结构及其力学性能和热性能的影响。这些结果将为建立对金刚石碳包覆石墨-铜复合材料基本性质的经验认识提供基础。这种理解对于基于复合材料的电子封装的设计至关重要。电子系统中金刚石碳涂层石墨铜材料的采用和广泛使用将使基于更高效、更高功率半导体材料的商业产品成为可能，这将以更高效、更长寿的电子产品的形式为社会带来好处；减少能源消耗；改善环境质量。

This Small Business Technology Transfer (STTR) Phase I project is focused on the development of a unique diamond carbon coated graphite-copper composite material. The composite material will be used to produce low thermal resistance packaging components for use in RF power amplifiers. Under the Phase I effort, a low-cost diamond carbon coating process will be demonstrated. There is a critical need for advanced materials with improved thermal properties capable of meeting the thermal management requirements of current and future high power RF amplifiers. Due to advances in packaging, circuit architecture and semiconductor materials, the heat dissipation rate of electronic systems has increased dramatically. Today's high power RF power amplifier devices are approaching a heat dissipation of 600 to 800 W/cm2 and this level is projected to reach1,000 W/cm2 within several years. The research objective of this project is the refinement of the chemical synthesis process for the polymer precursor used to produce the diamond carbon coating and establish the coating process to deposit the polymer precursor onto the graphite-copper substrate, and thermally convert the polymer precursor to a high thermal conductivity diamond carbon coating. Ideally, the diamond carbon coated graphite-copper composite would have a thermal conductivity of from 500 to 600 W/m-oK and a coefficient of thermal expansion that can be adjusted from 5 to 10 ppm/oC in order to minimize the thermal expansion between the substrate and the RF semiconductor device that would be attached to it. The results of this research program will enable the manufacture of a cost effective diamond carbon coated graphite-copper composite that offers improved thermal properties critical to thermal management solutions for next generation RF power amplifier. If successful this research effort will advance the basic understanding of (1) the chemical synthesis process to produce the polymer precursor; (2) the methods to produce a diamond carbon coating on a graphite-copper substrate and (3) the impact of the composite material variables (e.g., carbon fiber and copper matrix volume fraction; diamond carbon structure; diamond carbon thermal processing; diamond carbon coating thickness; etc.) on the composite's microstructure, and its mechanical and thermal properties. These results will provide the basis for establishing an empirical understanding of the basic properties of the diamond carbon coated graphite-copper composite material. This understanding will be critical to the design of electronic packages based on the composite material. The adoption and wide-spread use of the diamond carbon coated graphite-copper material for electronic systems will enable commercial products based upon more efficient higher power semiconductor materials that will provide benefit to society in the form of more efficient, longer life electronics; reduced energy consumption; and improved environmental quality.