Beyond direct-write: Dynamically reconfigurable holographic multibeam interference lithography for high-throughput nanomanufacturing

在制造任何类型的电子器件时，都需要图案化来实现小的特征，例如具有不同功能的材料的不同区域。现代电子学和光子学的不断增加的复杂性已经导致过多的衬底图案化方法。对于这些方法中的每一种，总是存在图案化速度（写入速度）、最小特征尺寸、多功能性和成本之间的折衷。在这里，要被图案化的芯片被涂上一层被称为“抗蚀剂”的光敏材料，光线通过一个故意放置孔的掩模照射到抗蚀剂上。穿过孔的光引起抗蚀剂的化学变化，因此图案从掩模转移到芯片上。缺点是每个光刻掩模仅适用于一种特定类型的芯片设计，并且不能重新配置用于制造其他芯片设计，并且掩模设计和制造耗时且成本高。替代图案化技术，称为直写光刻，使器件设计的灵活性很大，但在缓慢的图案化速度的代价，往往是巨大的资本和运营costs. There，我们提出了一种新的工艺光刻，我们命名为全息多光束干涉光刻（HMBIL）。HMBIL承诺具有亚波长分辨率的大面积图案化以及快速写入速度、短开发时间、低成本和曝光图案的动态可重构选择。使用HMBIL，我们将展示在大面积上以高产量（在1小时内>25 cm^2器件面积）对任意形状的100 nm特征尺寸进行图案化，这是目前直写光刻技术无法实现的。作为原理证明，我们将展示HMBIL制造示例器件结构的能力：多光谱滤波器阵列。这些滤波器阵列，当与图像传感器集成时，将允许采集光谱，用于从医学成像到遥感的各种应用。HMBIL多光谱滤光片阵列的制造将为安全、工业或医疗应用的定制探测器和成像传感器开辟一系列途径。我们设想这种多功能的新HMBIL工艺主要在制造链中的两个位置：首先，作为纳米制造设计的快速原型制作手段，其次，作为大规模生产个性化定制组件的手段。这将彻底改变广泛应用领域的制造工艺，包括集成光电子、多功能即时诊断设备、显示器和图像传感器、片上光子学（波导和光子晶体）、等离子体、纳米/微机电机器、微流体、嵌入式系统和物联网等等。

When manufacturing any kind of electronic device, patterning is required to achieve small features, such as different regions of materials with different functions. The ever-increasing complexity of modern electronics and photonics has led to a plethora of approaches to substrate patterning. For each of these approaches, there are always compromises between the speed of patterning (write speed), the minimum feature size, versatility and cost.The most dominant patterning process in electronics and photonics manufacturing is mask-based photolithography. Here, the chip to be patterned is coated with a light-sensitive material known as a "resist," and light is shone onto the resist through a mask with deliberately placed holes. Light that passes through the holes causes a chemical change in the resist, and thus the pattern is transferred from the mask onto the chip. The disadvantage is that each photolithography mask is only suitable for a one particular type of chip design and cannot be reconfigured for the manufacture of other chip designs, and mask design and fabrication is time-consuming and costly. Alternative patterning techniques, known as direct-write lithography, do enable great flexibility in device design, but at the expense of slow patterning speeds, and often large capital and operating costs.Here, we propose a novel process for photolithography, which we name holographic multi-beam interference lithography (HMBIL). HMBIL promises large area patterning with sub-wavelength resolution as well as fast write speeds, short development times, low costs and a dynamically reconfigurable choice of exposure pattern. Using HMBIL, we will demonstrate patterning of arbitrarily-shaped 100 nm feature sizes over large areas with high throughput (>25 cm^2 device area in under 1 hour), which is currently unachievable with direct-write lithography techniques.As a proof-of-principle, we will demonstrate the capability of HMBIL for manufacturing an example device structure: multispectral filter arrays. These filter arrays, when integrated with an image sensor, will allow the acquisition of light spectra for applications as diverse as medical imaging to remote sensing. HMBIL manufacture of multispectral filter arrays will open up a range of avenues for custom detectors and imaging sensors for security, industrial or medical applications.We envisage this versatile new HMBIL process primarily in two locations in the manufacturing chain: Firstly, as a means of rapid prototyping of nanofabricated designs and secondly, as a means of large scale production of individually customised components. This will revolutionise manufacturing processes across a broad range of application areas including miniaturised optoelectronics, versatile point-of-care diagnostic devices, displays and image sensors, on-chip photonics (waveguides and photonic crystals), plasmonics, nano/micro-electromechanical machines, microfluidics, embedded systems and the internet of things, and many more.