A Novel Deep Hole Etching in NLD Plasma Low GWP Gases
As for etching of quartz or glass, CF<sub>4</sub> and C<sub>3</sub>F<sub>8</sub> and C<sub>4</sub>F<sub>8</sub> are mainly used. And, much SF<sub>6</sub> gas is used for etching of silicon. The case that uses together a C<sub>4</sub>F<sub>8</sub>-CVD method is also in sidewall protection film formation. However, these gases have a very large GWP. Since a MEMS market becomes larger in the future, the gas used by DRIE needs the reduction in GWP. This research is developing quartz etching technology, and succeeded in etching of the GWP free etching of Pyrex glass via using C<sub>3</sub>F<sub>7</sub>I. Furthermore, the method of performing anisotropic deep silicon etching by introducing a sputtering system into DRIE technology was invented, and C<sub>4</sub>F<sub>8</sub> free etching anisotropic etching was also successful. Therefore, the NLD etching in the MEMS field is very useful equipment, which can realize drastic GWP reduction and can propose highly efficient etching technology.
Deep reactive ion etching of Pyrex glass using SF6 plasma
Abstract Deep reactive ion etching of Pyrex glass has been characterized in sulfur hexafluoride plasma (SF6). High etch rate (∼0.6 μm/min) was demonstrated under a condition of low pressure (0.2 Pa) and high self-bias (−390 V) by using a magnetically enhanced inductively coupled plasma reactive ion etching. Vertical etch profile (taper angle ∼88°), high aspect ratio (>10) and through-wafer etching of Pyrex glass (200 μm in thickness) were achieved under the condition by using thick (20 μm) and vertical electroplated nickel film as mask. The vertical etch profile was achieved when the mask opening is narrower than 20 μm because the deposition of nonvolatile product on the sidewall is reduced. A novel etching technique “scoop-out etching” was demonstrated by using the present etching characteristics.
A Study on Greenhouse Automatic Control System Based on Wireless Sensor Network
The system proposed in this paper collects temperature of leaves and humidity on leaves of crop. As well as greenhouse environmental information such as temperature, humidity, etc. Crop diseases, especially, have deep relationship not only with indoor environmental factors but also with humidity lasting time on leaves and temperature of leaves. Accordingly, monitoring crop itself is as important as monitoring indoor environments. Using these collected greenhouse environmental data, indoor environments can be more effectively controlled, and monitoring crop itself can contribute to improve productivity and to prevent crops from damages by blight and harmful insects. In addition, it will be possible for farmers to do control plant growth through closely studying relationship between indoor environmental information and monitored information on crop itself. Collected data can be stored to database either in server installed in greenhouse or to remote server. It is made possible to collect information and control effectively and automatically greenhouse in the site or from a remote place through web browser. System components are: temperature sensor, humidity sensor, leaf temperature sensor, leaf humidity sensor, Zigbee based wireless sensor node, relay nodes for automatic control, and data server to store greenhouse information. The system is implemented using low power wireless components, and easy to install.