Depth and profile control in plasma etched MEMS structures

• Published in: Sensors and actuators. A. Physical. Vol. 82; no. 1; pp. 234 - 238
• Main Authors: Kiihamäki, J., Kattelus, H., Karttunen, J., Franssila, S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-05-2000; Elsevier Science
• Subjects: Dry etching; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; Micromachining; Micromechanical devices and systems; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications; Profile; Uniformity; Wet etching; Wet etching; Dry etching; Uniformity; Profile; Micromachining; Micromechanical devices; Electromechanics; Inductively coupled plasma; Wet process; Line shape; Dry process; Plasma etching; Experimental study
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(99)00336-2

We have achieved uniform etched depth regardless of feature size by employing a combination of anisotropic plasma etching in inductively coupled plasma (ICP) followed by wet etching. In our approach, the original feature is divided into small elementary features in a mosaic-like pattern. These individual small features are all the same size and thus exhibit identical etch rates and sidewall profiles. Final patterns are completed by wet etching: the ridges between the elementary features are removed in TMAH. In this paper, we present the results obtained using this dry/wet etching sequence. The benefits and limitations of this method are described. Extensions to more complex multidepth structures are discussed.