| 摘要 |
PURPOSE:To form grooves into a form suitable for the formation of trench capacitors and to contrive the stabilization of characteristics of the capacitors by a method wherein the grooves of capacitors are formed by isotropic etching using insulating regions as masks. CONSTITUTION:Insulating regions 2a for interelement isolation are formed in an Si semiconductor substrate 1. The parts, which surround capacitor forming regions 1a, of the regions 2a are formed in a trench structure. After a resist mask 6a, which exposes the regions 1a with a mask alignment margin in the regions 2a, is formed, grooves 11 are each formed in the regions 1a by isotropic etching. The inner side surfaces of the regions 2a are exposed on the side surfaces of the grooves 11, the bottom surfaces of the grooves are rounded and there exists no angularity and protrusion on the inner surfaces of the grooves. The mask 6a is removed and after an Si dioxide insulating film 12 is formed on the bottom surfaces of the grooves 11, a poly Si film is deposited on the whole surface and an impurity having a conductivity type opposite to that of the substrate 1 is diffused in this film to form a polychristalline Si conducting film 13. The film 13 is used as the electrode of one of trench capacitors, which are formed thereon. |
