Research advances of electrochemical micro/nanofabrication based on confined etchant layer technique
- 化学化工－已发表论文 
与机械加工相比, 电化学加工技术具有无刀具磨损、无热效应、无机械损伤、加工效率高等优点, 而且适用于柔性、脆性及超硬材料,; 具备传统方法难以实现的复杂结构加工能力, 因而在航空航天、汽车、微电子等领域有着重要应用, 日益成为一种重要的工业制造技术.; 随着超大规模集成电路(ULSI)、微机电系统(MEMS)、微全分析系统(mu-TAS)、现代精密光学系统等高技术产业的迅速发展,; 功能性结构/器件的微型化和集成化的要求越来越高. 由于传统电化学只适用于金属材料, 为了应对微纳制造的时代要求, 拓展电化学加工的材料普适性,; 1992年田昭武院士提出了具有我国自主知识产权的约束刻蚀剂层技术(CELT). 一般的, 约束刻蚀包括3个步骤:; (1)通过电化学、光化学或光电化学的方法在模板电极表面生成刻蚀剂;; (2)通过后续的均相化学反应或自由基衰变反应将刻蚀剂约束在微/纳米厚度的液层内; (3)将模板电极逼近加工基底,; 当约束刻蚀剂层接触被加工基底时, 通过刻蚀反应实现微纳加工. 最近, 联合课题组通过仪器、原理和方法3个方面的努力, 引入外部物理场调制技术,; 实现一维铣削、二维抛光、三维微/纳结构加工, 大幅提升了CELT的技术水平.Compared with mechanical machining, ECM has several advantages, such as; avoiding tool wear, none thermal or mechanical stress on machining; surfaces, as well as high removal rate. Moreover, ECM is capable of; making complex three-dimensional structures and is appropriate for; flexible, fragile, or fissile materials even materials harder than the; machining tool. Thus, ECM has been widely used for various industrial; applications in the fields of aerospace, automobiles, electronics, etc.; ECM methods can be classified usually as electrolytic machining based on; anodic dissolution and electroforming based on cathodic deposition of; metallic materials. Recently, high technology industry, such as; ultralarge scale integration (ULSI) circuits, microelectromechanical; systems (MEMS), miniaturized total analysis systems (mu-TAS) and; precision optics, has developed more and more rapidly, where; miniaturization and integration of functional components are becoming; significant. Nowadays, the feature size of interconnectors in ULSI; circuits has been down to 20 nanometers, predicted by Moore's law.; Confined etchant layer technique (CELT) was proposed in 1992 to; fabricate three-dimensional micro- and nanostructures (3D-MNS) on; different metals and semiconductors, which has been developed an; effective machining method with independent intellectual property; rights. Generally, there are three procedures in CELT: (1) generating; the etchant on the surface of the tool electrode by electrochemical or; photoelectrochemical reactions; (2) confining the etchant in a depleted; layer with a thickness of micro- or nanometer scale; (3) etching process; when the tool electrode is fed to the workpiece, which applicable for 1D; milling, 2D polishing, and 3D microfabrication with an accuracy at micro; or nanometer scale. External physical-field modulations have recently; been introduced into CELT to improve its machining precision. In this; review, the advances of CELT in principles, instruments and applications; will be addressed as well as the prospects.