| 摘要 |
PURPOSE:To stably form a storage electrode buried type memory cell by not exposing silicon nitride contained in a capacity insulating film with a groove opening. CONSTITUTION:With silicon nitride 102 as a mask silicon oxide 103 for isolating elements is formed by thermally oxidizing on a single crystal silicon substrate 101. After a groove is formed on a capacity, a capacity insulating film made of two layers of silicon oxide 105 and silicon nitride 106 is formed on the inner wall of the groove. Then, the groove is completely buried with polycrystalline silicon 107, etched to a depth of approx. 0.5 micron from the groove opening, and the silicon nitride 106 is further removed by selectively etching to expose the silicon oxide 105 on the sidewall of the groove near the groove opening. Then, a photoresist 108 is formed on the whole surface of the substrate in which part of the groove is removed, the silicon oxide 105 is etched to expose the substrate 101 only at the part of the sidewall of the groove. Thereafter, after the photoresist 108 is removed, the groove is further completely buried with polycrystalline silicon 109. |
