| 摘要 |
PURPOSE:To enable a layer-shaped electric charge accumulation electrode which is electrically connected to an element region through an opening of any size formed on the upper-part side surface of a trench and is along the inner wall of the trench by selectively etching the upper part of a conductive thin film along the inner wall of the trench which is continuous to the element region with a thermal oxide film as a mask. CONSTITUTION:After forming a first thin film 4, a first conductive thin film 5, and a second thin film 10 in sequence on the entire surface for a trench 3, the second thin film 10 on an element isolation region 1 is eliminated and a first conductive thin film 5 on the element isolation region 1 is selectively oxidized with the second thin film 10 as a mask. After that, the second thin film 10 and the first conductive thin film 5 on the element region and the continuous trench sidewall are eliminated and then the first thin film 4 on the upper part of the trench which is continuous to the element region is etched, thus forming an undercut at the first thin film 4 which is adjacent to the upper-edge part of a first conductive thin film 6. After that, by forming a second conductive thin film 8 at the undercut part of the first thin film 4 selectively, an electric charge accumulation electrode 13 which is electrically connected to the element region of the periphery of trench is formed. |
