Low temperature reactive ion etching for bulk micromachining

To make three dimensional micron structures, the directional deep etching techniques are very important. The directional wet etching technique is often used for the bulk micromachining. However, directions of the wet deep etching and profiles of products are restricted by the crystalline orientation of silicon substrate. To solve this problem, high speed and deep directional dry etching processes have been studied. The low temperature reactive ion etching (RIE) apparatus for the bulk micromachining was fabricated and the etching characteristics were investigated. The high etch rate of 0.022 /spl mu/m/s and the low normalized side etch ratio of 0.021 were realized at the cathode temperature of -80/spl deg/C. The etch rate is equal or a little higher than that of the directional wet etching.<>