CoMSaT: a single-chip fabrication technique for three-dimensional integrated fluid systems

A new micromachining process, i.e., Cover-on-Meshes technique for Single-ch ip fabrication of Three-dimensional structures (CoMSaT), is proposed and us ed for the fabrication of micro integrated-fluid systems (IFS). In this tec hnique, a two-stage etching process, including quick sacrificial layer etch ing and silicon anisotropic etching, is applied to the fabrication. Both us e the etching holes (meshes) on the anti-etching membranes through which th e etchant can pass freely. After the etching, an LTO layer is deposited usi ng low pressure chemical vapor deposition (LPCVD) to cover the opened meshe s. Real three dimensional structures with membranes suspended on deep cavit ies can be formed by use of such an single-chip fabrication. The technique makes it possible to produce 3D structures without wafer/chip bonding and a lignment, resulting in an easy integration of on-chip electric-circuits and an easy miniaturization of the 3D systems. Various micro-pumps, micro-valv es with pressure sensors, temperature sensors and micro-actuators have been on-chip integrated with electric-circuits within an area of 5.9 mm x 6.4 m m. The primary experiments show that this technique is promising in the fab rication of miniature integrated fluid systems. (C) 1999 Elsevier Science S .A. All rights reserved.