1. Field of the Invention
The present invention relates to the capacitor of dynamic random access memories (DRAMs), and more particularly to a method for forming a cylinder-shaped capacitor of the DRAMs using a dielectric hard mask.
2. Description of the Prior Art
As the semiconductor memory device becomes highly integrated, the area occupied by a capacitor of a DRAM storage cell shrinks, thus decreasing the capacitance of the capacitor owing to its smaller electrode surface area. However, a relatively large capacitance is required to achieve a high signal-to-noise ratio in reading the memory cell and to reduce soft errors (due to alpha particle interference). Therefore, it is desirable to reduce the cell dimension and yet obtain a high capacitance, which achieves both high cell integration and reliable operation.
One approach for increasing the capacitance while maintaining the high integration of the storage cells is directed toward the shape of the capacitor electrodes. In this approach, the cylinder-shaped capacitor has become to be widely used in DRAM devices. However, especially for giga bit DRAM using 0.18 micrometer technology and beyond, the manufacture of the cylinder-shaped capacitor of such a small size becomes very difficult, if not impossible.
For the foregoing reasons, there is a need for a method of forming a cylinder-shaped capacitor for the DRAMs, and for facilitating the manufacture of cylinder-shaped capacitors.