Contact alignment for read only memory devices.

摘要

A layout and fabrication technique for EPROMs and similar devices includes a preferred technique for partially self-aligning bit line contacts. In addition, a self-aligned, buried Vss line is provided which is in contact with the substrate for its entire length. This provides a highly conductive Vss line, allowing the size of such line to be diminished. The use of a buried Vss contact line and a partially self-aligned bit line contact contributes to a device layout having minimum cell sizes for a given feature size.