Design And Fabrication Of Transparent Three-Dimensional Tunnel Structure Of MEMS

Micro-electro-mechanical systems(MEMS)generally use oxidation,coating,etching,epitaxy growth,bonding and other processes to prepare micro-sensors.The three-dimensional tunnel structure introduced in this paper is a special suspension micro-structure,which is used to prepare micro-fluidic pipes,micro-channel radiators and other devices in industry.With the deepening of scientific research,microfluidics are required to operate in biological research and chemical detection,so microfluidic pipelines are indispensable and important devices.Most MEMS technologies today use deep etching and bonding to fabricate micro-tunnel or microfluidic pipe structures.Since the silicon wafer itself is opaque,an external voltage circuit is required to detect the flow velocity and composition properties of the microfluid,and the process of deep etching and bonding is complicated,and the quality of the silicon substrate is high,and it is difficult to be affected by the mask.Meet the requirements of a variety of graphics in the industry.In this experiment,a new method of preparing micro-tunnels and micro-fluidic pipes by drilling corrosion is designed.Its innovation lies in the material selection of silica as a new material for structural layer.Because of its simple preparation,strong structure,and transparent material,it has good transparency.As a tunnel wall,it can let the detection light directly irradiate the internal micro-fluids.It is convenient to use optical methods to complete the detection,no need for external voltage and current,and improve the performance.The integration of micro-devices reduces the power consumption when they are used as micro-fluidic pipes.The complex bonding process is abandoned and the cheap wet etching method is chosen.In the selection of the etching solution,the 25% tetramethylammonium hydroxide aqueous solution and the 34% potassium hydroxide aqueous solution were selected and compared,and the effect of the additive on the etching solution wasanalyzed and the improvement effect of the standard cleaning solution on the corrosion result was analyzed..When the silicon substrate etched with potassium hydroxide was observed by a metallographic microscope,it was found that although the corrosion rate was high in the potassium hydroxide solution,the corrosion as a structural layer was not negligible,and the corrosion process was observed.It will introduce potassium ion impurities,which is difficult to be compatible with integrated circuit processes.When the aqueous solution of tetramethylammonium hydroxide is used,the effect on the silica encroaching is small,the corroded structural layer is smooth and flat,and the etching liquid does not generate excess metal impurities,which is beneficial to the integration with the integrated circuit process,so that the structure can Used in the front TFT driver of LCD and OLED,it can effectively improve the process steps and reduce the cost and production cycle.At the end of the experiment,a set of trapezoidal transparent three-dimensional tunnel structure arrays with upper side 15.5 ?m,lower side 40 ?m,height 16.5 ?m and length 20 ?m were successfully prepared.