Microplasma for Dry Etching: New Approaches for Micro and Nano Systems

0100366 Gianchandani等离子体处理通常用于半导体处理应用，并且是硅蚀刻的主导技术。传统的蚀刻器旨在在硅晶片所在的处理室中产生均匀的等离子体。然而，在微机械加工和纳米技术的应用中，替代范例可能证明是有用的。例如，目前的制造技术对于制造具有100个不同深度的沟槽阵列是不实际的，这将需要100个光刻步骤。这样的阵列可能是有用的应用，如生物细胞sorting.This建议解决的问题，有关的科学和技术的空间限制的反应等离子体（微等离子体）和它们的应用，硅和其他材料的蚀刻。特别是，它专注于原位微等离子体，这是由硅晶片本身上的电极图案产生的。这一概念的可行性，从根本上不同于其他最近的工作在微等离子体，已被证明的初步实验中，在原位直流微等离子体被用来完全蚀刻通过硅晶片在不到一个小时。本研究将探讨反应性微电浆蚀刻矽及其他材料的物理、技术与诊断，并将探讨各种蚀刻组态对电浆限制、蚀刻速率、各向异性、遮罩选择性与电极磨损的影响。将探索有前途的电极结构，包括静电控制离子流以局部调整蚀刻速率和侧壁轮廓的选项。将评估各种电极材料、供电方案和气体化学。将开发和使用原位和非原位诊断工具（包括薄膜朗缪尔探针）。将进行光谱分析。的Paschen击穿曲线，周围气体的分子行为，电离率和电子能量的依赖关系，以及这些参数的蚀刻速率和配置文件的关系将explored.Theoretical模型将开发的反应性微等离子体的精炼全球等离子体分析。这包括结合实际的基本数据和考虑放电几何形状和电极材料。理论模型将用于缩放研究，以确定等离子体是否可以减少到纳米尺寸。支持实验将进行探索的缩放限制和验证的theory.The建议的反应微等离子体有潜力不仅为传统的蚀刻应用作出贡献，但也有利于以前不可行的微结构的制造。使用微等离子体，只需两个掩模步骤就可以构建100个不同深度的沟槽阵列。此外，如果所提出的研究是成功的，不仅将有可能单独指定阵列中的每个沟槽的轮廓，而且还可以在由辅助电极控制的局部电场的帮助下偏斜蚀刻的方向。从长远来看，拟议的研究可能会带来其他研究途径，包括通过溅射或等离子体增强化学气相沉积（PECVD）进行局部沉积。

0100366GianchandaniPlasma processing is routinely used in semiconductor processing applications, and is the dominant technique for silicon etching. Conventional etchers aim to create a uniform plasma across the process chamber in which the silicon wafers are located. However, there are applications in micromachining and nanotechnology in which alternative paradigms may prove useful. For example, present fabrication techniques are not practical for manufacturing an array of trenches with 100 different depths, which would require 100 lithography steps. Such a array could be useful for applications like biological cell sorting.This proposal addresses questions pertaining to the science and technology of spatially confined reactive plasmas (microplasmas) and their application to the etching of silicon and other materials. In particular, it focuses on in-situ microplasmas, which are generated by electrodes patterned on the silicon wafer itself. The viability of this concept, which differs radically from other recent work in microplasmas, has been demonstrated by preliminary experiments in which in-situ DC microplasmas were used to etch completely through a silicon wafer in less than one hour. The proposed effort will explore the physics, technology, and diagnostics for reactive microplasmas for etching silicon and other materials.A number of etching configurations will be examined for their impact on plasma confinement, etch rates, anisotropy, mask selectivities, and electrode wear. Promising electrode structures will be explored, including options in which the ion flux is electrostatically controlled to locally adjust the etch rate and sidewall profile. Various electrode materials, powering schemes, and gas chemistries will be evaluated. Both in-situ and ex-situ diagnostic tools (including thin-film Langmuir probes) will be developed and used. Spectroscopic analysis will be performed. The dependencies of the Paschen breakdown curve, the molecular behavior of the ambient gas, the ionization rates and the electron energies, as well as the relationship of these parameters to the etch rates and profiles will be explored.Theoretical models will be developed for the reactive microplasmas by refining global plasma analysis. This includes the incorporation of realistic basic data and consideration of discharge geometry and electrode material. The theoretical models will be used for scaling studies to determine if the plasmas can be reduced to nanometer dimensions. Supporting experiments will be carried out to explore the scaling limits and validate the theory.The proposed reactive microplasmas have the potential not only for making a contribution to traditional etching applications, but also facilitating the fabrication of microstructures that were previously infeasible. Using microplasmas, an array of 100 trenches with different depths could be built with just two masking steps. In addition, if the proposed research is successful, not only will it be possible to individually specify the profile of every trench in the array, but also to skew the direction of the etch with the help of local electric fields controlled by secondary electrodes. In the longer term, the proposed research could lead to other avenues of research, including localized deposition by sputtering or plasma enhanced chemical vapor deposition (PECVD).