SNM: Massively Parallel Nanopatterning by Print and Repeat Nanopantography with Reusable Stencil Masks

对越来越小的电子和光子设备的需求没有停止的迹象，事实上它正在加速。制造尺寸小于10纳米（100亿分之一米，或比人类头发小1万倍）的图案对于制造速度和功能远远超过当前能力的未来集成电路至关重要，这可能会给计算机、信息存储和清洁能源设备带来革命性的变化。生物应用如快速DNA测序也需要如此小的尺寸。虽然技术已经证明了这种解决方案，但它们与制造业的结合受到严重的技术和/或经济问题的阻碍。此前，研究人员展示了一种纳米成像方法，可以解决这些问题。在该工艺中，通过将一束正离子指向衬底，在衬底（如硅片）上形成图案。离子被聚焦，在数十亿个位置同时书写小至3纳米的图案。过去的研究受限于聚焦结构（一组透镜聚焦离子，就像玻璃透镜聚焦光一样）必须集成在基板上，这导致了低吞吐量。新的研究将通过允许透镜阵列分离来解决这个问题，这样它就可以在多个基板上使用。这将使先进电子设备的许多应用受益于现代生活的各个方面，特别是能源和卫生行业，具有明显的社会效益。这个具有挑战性的项目将带来新的知识，并将推动这一重要科学技术领域的教育。静电微透镜采用标准的微电子制造方法建立在衬底上。施加在透镜阵列上的电压导致离子束进入数十亿微透镜中的每一个，并聚焦在基板上。利用纳米摄影技术，300纳米直径的静电透镜阵列可以在硅中产生小至3纳米的纳米图案。虽然纳米摄影可以形成非常高分辨率的复杂图案，但该技术依赖于在每个基板上制造微透镜阵列，这增加了工艺的复杂性。为了解决这个问题，pi计划将微透镜阵列与衬底分离，以便它可以重复用于后续衬底的图案。这涉及到一个包含微透镜阵列的模板掩模的制造，它将被放置在顺序基板上，以演示打印和重复过程。采用这种方法将大大提高产量，使纳米照相成为一种有制造价值的工艺。实验工作将辅以离子轨迹模拟，以实现最佳聚焦，作为模板掩模与衬底之间间隙的函数，以及等离子体束条件。分子动力学模拟将用于研究O+和O2+在SiO2上对石墨烯的纳米特征蚀刻，重点研究离子能量和质量对特征尺寸的影响。质量控制措施将在潜在的中试生产线上进行演示。这项工作将展示一种大规模并行的方法，在衬底上重复写入二维材料（石墨烯和WS2）的纳米图案，使用可重复使用的模板掩模透镜阵列，其分辨率优于目前最先进的3纳米。在二维层中形成的纳米孔、点和带将被表征为等离子体和其他光电特性。纳米圆盘将从大面积的WS2薄膜中切割出来。微光致发光将用于表征其发光特性。

The demand for ever-smaller electronic and photonic devices shows no sign of stopping, and in fact it is accelerating. Fabricating patterns with sizes less than 10 nanometers (10 billionths of a meter, or about 10,000 times smaller than a human hair) is essential for the manufacturing of future integrated circuits with speeds and functionality far exceeding current capabilities, that could revolutionize computers, information storage, and clean energy devices. Biological applications such as rapid DNA sequencing also require such small dimensions. Although techniques have demonstrated this resolution, their integration into manufacturing is hampered by serious technical and/or economic issues. Previously, the researchers demonstrated a nanopantography method that could address these issues. In this process, patterns are formed on a substrate such as a silicon wafer by directing a beam of positive ions at the substrate. Ions are focused to write patterns at sizes as small as 3 nanometers simultaneously at billions of locations. The past research was limited by the fact that the focusing structure (an array of lenses that focus ions much as glass lenses focus light) had to be incorporated on the substrate, which resulted in low throughput. The new studies will solve this problem by allowing the lens array to be separate, so that it can be used on multiple substrates. This will enable many applications for advanced electronic devices that benefit all aspects of modern life, especially the energy and health industries, with clear societal benefits. This challenging project will lead to new knowledge and will advance education in this important area of science and technology.The electrostatic microlenses were built on the substrate, using standard microelectronic manufacturing methods. Voltages applied to the lens array cause ion beamlets entering each of billions of microlenses to be focused on the substrate. Using nanopantography, arrays of 300 nm diameter electrostatic lenses create nano-patterns in Si with sizes as small as 3 nm. While nanopantography can form complex patterns with very high resolution, the technique relies on the fabrication of a microlens array on each substrate, adding complexity to the process. To address this issue, the PIs plan on separating the microlens array from the substrate, so that it can be reused for patterning of subsequent substrates. This involves the fabrication of a stencil mask, containing the microlens array, which will be placed on sequential substrates to demonstrate a print-and-repeat process. Following this approach will greatly improve throughput, making nanopantography a manufacturing-worthy process. Experimental work will be complemented by ion trajectory simulations to achieve best focus, as a function of gap between the stencil mask and the substrate, and plasma beam conditions. Molecular Dynamics simulations will be used to study nanofeature etching in graphene on SiO2 by O+ and O2+, with an emphasis on the effect of ion energy and mass on feature size. Quality control measures will be demonstrated for potential pilot line manufacturing. The work will demonstrate a massively parallel method to repeatedly write nanopatterns in 2-D materials (graphene and WS2) on a substrate with a better than the state-of-the-art resolution of 3 nm, using a reusable stencil mask lens array. Nano holes, dots, and ribbons formed in the 2D layers will be characterized for plasmonic and other optoelectronic properties. Nanodisks will be carved out of large area WS2 films. Micro-photoluminescence will be used to characterize their light emitting properties.