| 摘要 |
PURPOSE:To perform anisotropic etching having high selective ratio and etching rate by using mixed gas having C2F5Cl and CF4. CONSTITUTION:When a poly Si 3 is provided on an Si substrate 1 providing SiO2 on the surface and etching is done by applying resists 4 with predetermined patterns, selective ratio and the etching rate of poly Si will be low if C2F5Cl gas only is used in the usual way. The etching rate of poly Si will be increased by using mixed gas of CF4(+O2 5%) and C2F5Cl and by reducing the partial pressure ratio of C2F5Cl and the etching rates of photoresist and SiO2 become low and the selective ratio reaches a maximum when the mixed ratio of CF4 and C2F5Cl is about 2:1. With the poly Si 3 etched by this gas, anisotropic etching will be noted and no flaws will occur under the resists 4 even if excessive etching is applied and a good and fine process can be done. |
