A Novel Deep Hole Etching in NLD Plasma Low GWP Gases

As for etching of quartz or glass, CF₄ and C₃F₈ and C₄F₈ are mainly used. And, much SF₆ gas is used for etching of silicon. The case that uses together a C₄F₈-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 C₃F₇I. Furthermore, the method of performing anisotropic deep silicon etching by introducing a sputtering system into DRIE technology was invented, and C₄F₈ 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.