Aluminum bulk micromachining through an anodic oxide mask by electrochemical etching in an acetic acid/perchloric acid solution

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• 作者：Tatsuya Kikuchi ; Yuhta Wachi ; Masatoshi Sakairi ; Ryosuke O. Suzuki
• 关键词：Bulk micromachining ; Aluminum ; Anodizing ; Electrochemical etching ; Laser irradiation
• 刊名：Microelectronic Engineering
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：111
• 期：Complete
• 页码：14-20
• 全文大小：2060 K

文摘

A well-defined microstructure with microchannels and a microchamber was fabricated on an aluminum plate by four steps of a new aluminum bulk micromachining process: anodizing, laser irradiation, electrochemical etching, and ultrasonication. An aluminum specimen was anodized in an oxalic acid solution to form a porous anodic oxide film. The anodized aluminum specimen was irradiated with a pulsed Nd-YAG laser to locally remove the anodic oxide film, and then the exposed aluminum substrate was selectively dissolved by electrochemical etching in an acetic acid/perchloric acid solution. The anodic oxide film showed good insulating properties as a resist mask during electrochemical etching in the solution. A hemicylindrical microgroove with thin free-standing anodic oxide on the groove was fabricated by electrochemical etching, and the groove showed a smooth surface with a calculated mean roughness of 0.2-0.3 ¦Ìm. The free-standing oxides formed by electrochemical etching were easily removed from the specimen by ultrasonication in an ethanol solution. Microchannels 60 ¦Ìm in diameter and 25 ¦Ìm in depth connected to a microchamber were successfully fabricated on the aluminum.