CAREER: Low Temperature Deposition of Thin Metal Films from Supercritical Carbon Dioxide Solution

摘要-沃特金斯-9734177目前和未来的微电子和光电子器件制造的需求对金属沉积方案提出了严格的要求。这包括高薄膜纯度、低温和快速、可控的沉积速率。PI假设可以通过化学流体沉积(CFD)来实现这些目标，这是一种新的金属沉积方法，涉及在超临界二氧化碳中在低温(40-80oC)下化学或热还原可溶性有机金属化合物，以在无机或有机衬底上生成连续的薄膜。CFD利用了超临界流体溶剂独特的、可调节的物理化学性质，它位于液体和气体溶剂的中间，以绕过气相和液态技术的限制。在CFD中，前体在溶液中的迁移和还原发生在比化学气相沉积(CVD)等气相技术低得多的温度和更高的试剂浓度。虽然CFD是一种基于溶液的过程，但超临界流体的“类似气体”的传输特性及其与氢气等气态还原剂的相容性使该过程不会受到与液相还原相关的传质和沉积速率差问题的阻碍。初步实验表明，可以在低于CVD温度170℃的条件下，从超临界流体溶液中在硅片和其他无机衬底上沉积高纯度、连续的铂和钯薄膜。研究计划将侧重于通过二甲基环辛烷铂(II)的氢解从二氧化碳溶液中沉积薄膜，以及通过还原铜(II)双(六氟乙酰丙酮)和copper(II)bis(2，2，6，6-tetramethyl-3，5-heptanedionate).来沉积铜薄膜选择前驱体是为了便于将CFD中的薄膜质量和还原动力学与现有技术的薄膜质量和还原动力学进行直接比较，以及金属沉积在微电子、铜和催化铂器件中的潜在用途。这项工作的教育部分是：(1)培训将从事工程和材料化学接口工作的研究生，(2)为本科生提供研究经验的机会，(3)开发两门课程的材料处理系列课程，以满足学生的兴趣，并因化学工程系不断扩大的材料研究努力而得到加强，以及(4)将研究问题和主动学习原则融入课堂，并协助在整个课程中实施互动教学工具。

Abstract - Watkins - 9734177 The demands of present and future microelectronic and optoelectronic device fabrication place stringent requirements on metal deposition schemes. These include high film purity, low temperatures and rapid, controllable deposition rates. The PI postulates that these objectives can be met via Chemical Fluid Deposition (CFD), a new approach to metal deposition that involves the chemical or thermal reduction of soluble organometallic compounds in supercritical carbon dioxide at low temperatures (40-80oC) to yield continuous films on inorganic or organic substrates. CFD exploits the unique, and adjustable, physicochemical properties of SCF solvents, which lie intermediate to those of liquids and gases, to circumvent the limitations of both vapor and liquid phase techniques. In CFD, precursor transport and reduction occurs in solution at significantly lower temperatures and higher reagent concentrations than those of vapor phase techniques such as chemical vapor deposition (CVD). While CFD is a solution-based process, the "gas-like" transport properties of the SCF and its miscibility with gaseous reducing agents such as hydrogen, render the process unencumbered by issues of poor mass transfer and poor deposition rates associated with liquid phase reductions. Preliminary experiments demonstrate that high-purity, continuous platinum and palladium films can be deposited from SCF solution onto silicon wafers and other inorganic substrates at temperatures up to 170oC below those employed in CVD. The research program will focus on the deposition of thin films from carbon dioxide solution by the hydrogenolysis of dimethylcyclooctadine platinum (II) and the deposition of copper films by reduction of copper(II)bis(hexafluoroacetylacetone) and copper(II)bis(2,2,6,6-tetramethyl-3,5-heptanedionate). The precursors were chosen to facilitate a direct comparison of film quality and reduction kinetics in CFD to those of existing techniques and the potential utility of the m etal deposits in microelectronics copper and catalytic platinum devices. The educational portion of the work are to: (1) train graduate students who will work at the interface of engineering and materials chemistry, (2) provide undergraduates with opportunities for research experience, (3) develop a two-course series in materials processing that addresses the interests of students and is reinforced by the expanding materials research efforts in the Department of Chemical Engineering, and (4) incorporate research problems and active learning principles into the classroom and assist in the implementation of interactive teaching tools across the curriculum.