Electron Beam Lithography Tool

电子束光刻是最灵活、最通用、高性能的光刻技术，用于实现低至亚10纳米范围的纳米结构。由于国家的最先进的仪器和适度的拥有成本相对较小的足迹，它非常适合学术纳米技术实验室，如中央实验室的微型和纳米技术，中央洁净室设施在RWTH亚琛大学提供微型和纳米加工技术的内部和外部用户。虽然目前在微纳米技术中心实验室有两个电子束光刻系统，但现有的工具无法满足当前和未来研究项目的需求。特别地，复杂掩模图案的（晶片级）制造以及跨越几个写入场的结构的图案化已经被证明是不合适的或者甚至不可能实现。其原因包括不适当的图案生成器不能处理复杂图案所需的大量数据和太大的拼接误差。此外，现有工具的受限加速电压（最大30千伏）限制了分辨率，并产生实质性的邻近效应。在许多情况下，后者不能被校正，因为必要的、精细的邻近校正导致图案生成器不能处理的这种复杂的掩模图案。最后，有限的加速电压还导致绝缘衬底的充电，从而导致预期图案的显著移位和失真。虽然可以用相当低的加速电压来实现减少邻近效应和消除绝缘衬底的充电，但这种情况下的光刻分辨率会严重退化，并且需要非常薄的抗蚀剂层，这些抗蚀剂层通常不适合蚀刻和剥离工艺。除了现有的两种电子束光刻工具的科学/技术问题之外，两者都基于不再制造的扫描电子显微镜柱。因此，只有在工具制造商有库存的情况下，才能保证获得备件。因此，微米和纳米技术中心实验室迟早将无法提供电子束光刻，即中心纳米图案化技术。因此，要求为一种新的、最先进的电子束光刻工具提供资金，该工具具有100千伏加速电压、最小的拼接误差并能够处理复杂的掩模图案，这为CMNT提供了必要的纳米级光刻能力，以便在未来几年开展研究项目。

Electron beam lithography is the most flexible, most versatile, high performance lithography technique for the realization of nanostructures down to the sub-10 nanometer regime. Due to a relatively small foot print of state-of-the-art instruments and moderate cost of ownership it is ideally suited for academic nanotechnology labs such as the Central Laboratory for Micro- and Nanotechnology, the central clean-room facility at RWTH Aachen University providing micro- and nanofabrication technologies for internal as well as external users. While there are two systems for electron beam lithography currently available at the Central Laboratory for Micro- and Nanotechnology, the existing tools cannot fulfil the demands of current and future research projects. In particular, the (wafer-scale) fabrication of complex mask patterns as well as the patterning of structures that straddle several write fields have been proven to be inappropriate or even impossible to achieve. The reasons for this include an inadequate pattern generator that cannot handle the large amount of data required for complex patterns and a too large stitching error. Moreover, the restricted acceleration voltage of the existing tools (a maximum of 30 kilovolts) limits the resolution and yields a substantial proximity effect. In many cases the latter cannot be corrected since the necessary, elaborate proximity correction results in such complex mask patterns that cannot be handled by the pattern generator. Finally, the limited acceleration voltage also leads to a charge-up of insulating substrates resulting in significant shifts and distortion of the intended patterns. While a reduced proximity effect and an obviation of the charge-up of insulating substrates can be achieved with rather low acceleration voltages, the lithographic resolution in this case is strongly degraded and requires very thin resist layers that are often unsuitable for etch- and lift-off processes. In addition to the scientific/technical issues of the existing two electron beam lithography tools, both are based on a scanning electron microscopy column which is not manufactured anymore. Thus, access to spare parts is only guaranteed as long as they are available and on stock of the tool manufacturer. Therefore, the Central Laboratory for Micro- and Nanotechnology will sooner or later be incapable of providing electron beam lithography, i.e. the central nanopatterning technique. As a result, funding for a new, state-of-the-art electron beam lithography tool with 100 kilovolts acceleration voltage, minimal stitching errors and capable of handling complex mask patterns is requested, that provides CMNT with the necessary nanoscale lithography capabilities to carry out research projects for the coming years.