| 摘要 |
PURPOSE:To improve the density of integration, reliability and yield preventing a disconnection and a shortcircuit from happening by a method wherein both perfect filling with polysilicon and surface flattening are performed regardless of the shape of U-shaped groove. CONSTITUTION:After successive forming of an SiO2 film 22 and an Si3N4 film 23 on an Si substrate 21, a U-shaped groove 24 is formed conforming to specified depth and opening width. Firstly after forming an SiO2 film 25 on the groove wall, a poly Si 26 is grown. Secondly after coating the poly Si 26 with a resist 27 to fill a cavity 29 with the same 27, the overall surface is dry control-etched partly etching the poly Si 26a upon the top of the opening to form a poly Si 26b with wide-open shape. A poly Si 26c is grown again to fill the U-shaped groove 24. The U-shaped groove may be filled with poly Si completely without leaving any part of the cavity 29 since the initially grown poly Si 26b is wide-open. The surface may be flattened by means of polishing process as usual. |
