| 摘要 |
PURPOSE:To prevent the disconnection and shortcircuit of wirings which crosses a stepwise difference by smoothly burying the step of a groove and the end of a pattern. CONSTITUTION:After an MOS capacitor is formed, a thin SiO2 film 16 is accumulated, a polycrystalline Si of the thickness equal to or larger than 1/2 of the width of a recess is then accumulated to bury the recess. Then, when the entire surface is etched by plasma etching for the thick film of the polycrystalline Si, the remaining etched part 18 at the center of the groove and the remaining etched part 19 at the end of a pattern are formed, and the surface is smoothly formed. Since the same polycrystalline Si as the electrode material is selected as the material to be buried for flattening in this manner, the surface of the polycrystalline Si is thermally oxidized, and an interlayer insulating film is formed selectively on the capacitor electrode. Since the thermal expansion coefficients of the polycrytalline Si and the substrate Si 1 are substantially equal, no stress is produced in the groove and no crystal defect is produced in the substrate 1 at the heat treating time. |
