Cross-Point Memory Interconnect Layout to Prevent Via Corrosion

The direct connection between word lines and lower conductive vias is segmented into two separate connection paths: one through upper conductive vias to bit lines and another through lower conductive vias to semiconductor devices. This segmentation prevents charge carrier buildup by eliminating the direct galvanic couple between dissimilar metals, thereby preventing transistor breakdown while maintaining manufacturing feasibility through systematic process integration.

Upper conductive vias and bit lines serve as intermediary elements that provide alternative current paths and isolate the word lines from direct contact with lower conductive vias. This intermediary structure prevents galvanic corrosion by breaking the direct electrical contact between dissimilar metals, while the overall interconnect architecture remains manufacturable through established semiconductor fabrication processes.

The offset between word lines and lower conductive vias is achieved by utilizing the vertical dimension through multiple interconnect layers. Word lines are positioned in one vertical level while lower conductive vias are positioned at a different vertical level, with upper conductive vias providing the vertical connection path. This dimensional separation prevents galvanic corrosion while relying on standard via alignment tolerances rather than requiring precise lateral offset alignment.

Upper conductive vias act as intermediary connection elements that bridge the vertical gap between word lines and upper bit lines, allowing the word lines to be offset from lower conductive vias without compromising electrical connectivity. This intermediary structure reduces the alignment precision requirement from lateral offset alignment to standard vertical via alignment, which is more readily achievable with existing manufacturing processes.

Charge carrier removal is performed as a preliminary action before forming the upper conductive vias. This preliminary charge removal prevents subsequent charge accumulation that would occur during later fabrication steps, thereby improving reliability. The process integrates seamlessly into the fabrication sequence by adding a charge removal step at the appropriate stage, without requiring fundamental changes to the overall manufacturing approach.

The fabrication process maintains continuity by integrating charge carrier removal as an inline step within the existing process flow, rather than as a separate discrete operation. The charge removal is performed continuously during the interconnect formation sequence, ensuring that no charge accumulation occurs while maintaining an efficient, uninterrupted manufacturing process that does not significantly increase overall process complexity.