| 摘要 |
PURPOSE:To form excellent apertures of the contact parts and prevent a gate oxide film from contamination by a method wherein, in the contact photolithography process, an Al film is formed after the apertures of the contact parts are formed using a polycrystalline silicon film as a mask. CONSTITUTION:A polycrystalline silicon film 7 is deposited on an oxide film 3 by CVD and a resist 5 is applied on the film 7. After development, apertures 5a of the contact parts are formed by removing the polycrystalline silicon film 7 using the resist 5 as a mask. At that time, even if the polycrystalline silicon film 7 is etched by an etchant containing nitric acid, fluoric acid or the like, as the thickness of the polycrystalline silicon film 7 is thin, sidewise extension of the etchant hardly occurs. Then, after the resist 5 is removed, the oxide film 3 is etched by a fluoric acid system etchant using the polycrystalline silicon film 7 as a mask. At that time, because the polycrystalline silicon film 7 deposited by CVD works as a mask, insoak of the etchant is completely avoided. Then, an Al film 6 is formed by sputtering or deposition. |
