Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China.
Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China; Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
Ultrasonics. 2020 Jan;100:105990. doi: 10.1016/j.ultras.2019.105990. Epub 2019 Aug 26.
Through-mask electrochemical micromachining (TMEMM) is the primary method to fabricate micro pits with controlled size, location, and density. In order to improve the machining localization and deep etching capability in TMEMM process, a novel method which combined megasonic vibration to TMEMM process is presented in this paper. Firstly, the coupling relationship between sound field, gas-liquid two-phase flow field and electrolytic process was theoretically analyzed. Theoretical analysis results indicate that acoustic wave agitation can promote the electrolytic process by increasing the conductivity of the electrolyte. Based on this theory, a numerical simulation method was used to predict anodic profiles under different megasonic intensity. The simulation results show that the addition of megasonic agitation can obviously improve the machining localization and deep etching capability in TMEMM process. Etching depth of the micro pit increased from 48.22 μm to 77.98 μm with megasonic agitation compared to the without megasonic one. Depth-diameter ratio of the micro pit increased from 0.30 to 0.45. Meanwhile, the etching factor (EF) increased from 1.55 to 2.10. Then, a megasonic electrolyser at 1 MHz was set up, micro pits were etched under different megasionc intensity. The experiment results show that megasonic assisted through-mask electrochemical micromachining (MA-TMEMM) had best process performance when it worked with the increase of megasionc intensity. When the megasonic intensity was 8 W/cm, micro pits with average diameter of 167.77 μm and 79.62 μm in depth were successfully fabricated. The average depth-diameter ratio of the micro pits was as high as 0.47, and the EF was as high as 2.35. The working mechanism of megasonic in MA-TMEMM process was analyzed too.
透掩膜电化学微机械加工（TMEMM）是制造具有可控尺寸、位置和密度的微孔的主要方法。为了提高 TMEMM 加工过程中的加工定位和深蚀能力，本文提出了一种将超声振动与 TMEMM 工艺相结合的新方法。首先，从理论上分析了声场、气液两相流场和电解过程的耦合关系。理论分析结果表明，声波搅拌可以通过增加电解液的电导率来促进电解过程。基于这一理论，采用数值模拟方法预测了不同超声强度下的阳极轮廓。模拟结果表明，超声搅拌的加入可以明显提高 TMEMM 加工过程中的加工定位和深蚀能力。与无超声搅拌相比，有超声搅拌时微坑的刻蚀深度从 48.22μm 增加到 77.98μm。微坑的深径比从 0.30 增加到 0.45。同时，刻蚀因子（EF）从 1.55 增加到 2.10。然后，建立了 1MHz 的超声电解槽，在不同的超声强度下刻蚀微坑。实验结果表明，超声辅助透掩膜电化学微机械加工（MA-TMEMM）在超声强度增加时具有最佳的工艺性能。当超声强度为 8W/cm 时，成功制备出平均直径为 167.77μm、深度为 79.62μm 的微坑。微坑的平均深径比高达 0.47，EF 高达 2.35。还分析了超声在 MA-TMEMM 工艺中的工作机制。
