A New Method to Make Programmable Transducers in Microelectromechanical Systems (P-MEMS)

现代技术极大地受益于微型机电系统(MEMS)开发的微型传感器。磁性微器件是一类在微机器人学、微流体学、芯片实验室等领域显示出巨大应用潜力的MEMS。例如，磁性微流控芯片在基因组探索和用于癌症诊断的单细胞阵列分析中可以极大地降低成本和提高DNA测序的吞吐量。然而，尽管磁性材料具有巨大的潜力，但在微加工过程中集成磁性材料仍然是一个昂贵、省时的问题，因此仍然是一个开放的研究课题。例如，通过蚀刻沉积层制造的微型换能器的性能低于相同尺寸的块状磁体。即使是最有希望的微制造过程中集成磁性材料的解决方案，不幸的是，为整个芯片上的微设备提供相同的磁性特性，并且不能在以后单独调整。该项目将开发一个全面的解决方案来解决这些问题。它将分三个工作包(WP)交付。在WP1，该项目将开发一种新的微制造工艺，以实现MEMS(p-MEMS)中的片上可编程换能器(p-MEMS)。这一过程将把一系列磁性微型设备与单独的电热微型加热器集成在一起。在这项创新技术中，每个微型设备的温度随着施加到其相应加热器的电力而增加。然后，施加外部磁场，产生选择性磁退火。因此，将芯片上的整个磁性微器件暴露在外部磁场中，并将选定的加热器连接到电源，将仅在选定的微器件中导致永久磁性变化。因此，这项技术可以通过施加不同组合的外部磁场和选定的加热器，在单个芯片上形成各种磁极性图案。WP1将与BAE系统公司的专家密切合作，他们对未来的微米和纳米技术特别感兴趣。在WP2中，这项研究工作将开发一个新的综合微磁学模型(M-MAG)，以了解这些微型换能器的磁性行为。MEMS中铁磁性厚层(FM)的磁性能不同于薄膜和块体磁体。厚层磁体不同于块体磁体，因为厚层磁体沉积后的原子有序性。它们也不同于薄的沉积层，后者的几个原子的厚度施加了某些约束和假设，这些约束和假设对厚层不一定有效。新的M-MAG模型将用于开发一种计算机辅助设计(CAD)工具，用于将微型设备的磁性行为集成到现有的三维微机械建模工具中。这将为未来p-MEMS中微换能器的设计提供多物理有限元分析。在WP3中，将使用p-MEMS工艺开发一个微流控芯片原型，以测试和验证工艺的可靠性以及M-MAG模型和新CAD工具模拟的准确性。P-MEMS具有广泛的应用前景。将重点放在微流控应用上，将把拟议技术的跨学科优势扩展到工程学和物理学之外。就像可编程电子集成电路使更广泛的非专家用户社区一样，拟议中的p-MEMS研究将导致这些传感器在生物技术和化学等其他学科中得到更广泛的使用。因此，WP3将采用包括英国iGenomix专家在内的各种最终用户的反馈。P-MEMS设计工具包，包括层厚度、材料特性和布局设计规则，以及M-MAG模型和CAD工具，都将在项目网站上免费提供

Modern technologies have vastly benefitted from the miniaturised transducers developed in Micro-Electromechanical Systems (MEMS). Magnetic microdevices are one class of MEMS that demonstrate a significant potential for future applications in microrobotics, microfluidics, lab-on-chip, etc. For example, magnetic microfluidic chips can drastically reduce the costs and increase the throughput of DNA sequencing in genomic explorations and single-cell array analysis for cancer diagnosis. However, despite their great potential, the integration of magnetic material in microfabrication processes remains costly, time-inefficient and is therefore still an open research topic. For example, microtransducers manufactured by etching deposited layers have lower performance than bulk magnets of the same size. Even the most promising solutions for integrated magnetic materials in microfabrication processes, unfortunately deliver identical magnetic properties for the entire set of microdevices on a chip and cannot be individually tuned afterwards.This project will develop a comprehensive solution to these problems. It will be delivered in three work packages (WP). In WP1, this project will develop a new microfabrication process to realise on-chip programmable transducers in MEMS (p-MEMS). This process will integrate an array of magnetic microdevices with individual electrothermal microheaters. In this innovative technique the temperature of each microdevice increases in response to the applied electrical power to its corresponding heater. Applying an external magnetic field then produces the selective magnetic annealing. Therefore, exposing the entire magnetic microdevices on a chip to an external magnetic field and connecting selected heaters to electrical power will result in permanent magnetic changes only in the selected microdevices. Hence, this technique can develop various magnetic polarity patterns on a single chip by applying different combinations of external magnetic fields and selected heaters. WP1 will be carried out in close partnership with experts from BAE Systems who are particularly interested in the future micro and nano technologies. In WP2, this research work will develop a new comprehensive micromagnetism model (M-MAG) to understand the magnetic behaviour of these microtransducers. The magnetic behaviour of thick microfabricated ferromagnetic (FM) layers in MEMS is different from thin films and bulk magnets. Thick layers are different from bulk magnets due to their atomic ordering after deposition. They are also different from thin deposited layers whose thicknesses of a few atoms impose certain constraints and assumptions that are not necessarily valid for thick layers. The new M-MAG model will be used to develop a computer aided design (CAD) tool for integrating the magnetic behaviour of microdevices into the available three dimensional micromechanical modelling tools. This will provide the multiphysics finite element analysis for the design of future microtransducers in p-MEMS. In WP3, a prototype microfluidic chip will be developed using the p-MEMS process to test and verify the reliability of the process as well as the accuracy of the M-MAG model and simulations in the new CAD tool. There is a wide variety of applications for p-MEMS. Focusing on microfluidic applications will extend the cross disciplinary benefits of the proposed technique beyond Engineering and Physics. Just as programmable electronic integrated circuits enabled a wider community of non-expert users, the proposed research on p-MEMS will lead to a broader usage of these transducers emerging among other disciplines such as Biotechnology and Chemistry. Hence, WP3 will apply feedback from various end-users including experts from iGenomix UK. The p-MEMS design kit including the layer thicknesses, material properties and layout design rules as well as the M-MAG model and the CAD tool will all be made freely available on the project webs