Manufacturing process for zero-capacitor random access memory circuits

Abstract

Embodiments of a manufacturing process flow for producing standalone memory devices that can achieve bit cell sizes on the order of 4F2 or 5F2, and that can be applied to common source/drain, separate source/drain, or common source only or common drain only transistor arrays. Active area and word line patterns are formed as perpendicularly-arranged straight lines on a Silicon-on-Insulator substrate. The intersections of the active area and spaces between word lines define contact areas for the connection of vias and metal line layers. Insulative spacers are used to provide an etch mask pattern that allows the selective etching of contact areas as a series of linear trenches, thus facilitating straight line lithography techniques. Embodiments of the manufacturing process remove first layer metal (metal-1) islands and form elongated vias, in a succession of processing steps to build dense memory arrays.