Silicon etching characteristics for the TMAH based solution with additives

In this study, the anisotropic etching properties of single crystal silicon were examined using the TMAH solution. The effect of IPA additive was also examined. As the THAM concentration (10~25 wt.%) decreased, the etching rate increased from 10 μm/h to 70 μm/h at temperatures between 70 and 90°C. On the other hand, the etched surface roughness became degraded as the hillock density and corner undercut ratio increased. Additive of IPA affected the morphology of the etched surface to be flat. Also, the PA additive improved the etched surface significantly by decreasing the hillock density on the surface.