1. Field of the Invention
This invention relates to a Dynamic Random Access Memory cell and a method for its manufacture, and more particularly to a Dynamic Random Access Memory cell having a conducting layer located between a bit line and a word line for preventing the capacitive coupling occurred by the signal applied to the bit line and the word line and having self-aligned contacts, and a method for its manufacture.
2. Background of the Invention
In a bit line shielded capacitor cell in which a bit line is formed between a word line and a stacked capacitor, if the transient signal is applied to the word line during the operation of the cell, the potential of the adjacent bit line is affected by the capacitive coupling of the word line and the bit line. Therefore, it may result in the operation of the unwanted cell. Also, when the transient signal is applied to the bit line, the adjacent word line is also affected by the capacitive coupling of the word line and the bit line.
Also, in the manufacturing process of a Dynamic Random Access Memory cell, the bit line and the storage electrode are electrically coupled to the source and drain of a MOSFET, respectively, but they are electrically isolated from the word line.
Accordingly, for isolating the word line from the contacts, the layout should be made according to the design rule considering the critical dimension variation, misalignment tolerance and the thickness of the insulating layer.
However, when a Dynamic Random Access Memory cell is formed by self-aligned contacts according to the conventional method, high topology is formed so that the pattern of the conducting layer and insulating layer is not completely formed at the sidewall of the high topology during the patterning process of the conducting layer and insulating layer.