3D ReRAM Memory Device With Replacement Word Lines
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Solution Overview
Problem
Current three-dimensional ReRAM memory devices face challenges in achieving efficient data storage and retrieval due to limitations in the design of contact via structures and support pillars, which affect the continuity and conductivity of electrically conductive layers across array regions.
Innovation Solution
The proposed solution involves forming an alternating stack of insulating and sacrificial material layers over a substrate, creating resistive memory elements and support pillars, and etching connecting via cavities with different depths to replace sacrificial material layers with electrically conductive layers, while maintaining structural support through support pillars, allowing for continuous conductive paths between array regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If support pillars are formed in the contact region to provide structural support, then structural stability is improved, but continuity of electrically conductive layers is disrupted
Solution Approach 1:
The contact region is divided into multiple contact via structures at different depths, each contacting different electrically conductive layers. This segmentation allows support pillars to be positioned between these contact via structures, providing structural support while maintaining electrical continuity through the distributed contact points.
Solution Approach 2:
Contact via structures serve as intermediary elements that bridge the gap between support pillars and electrically conductive layers. These contact via structures are positioned between the support pillars and the conductive layers, allowing the support pillars to provide mechanical stability while the contact via structures ensure electrical continuity.
2Productivity
If contact via structures are formed at different depths to contact different electrically conductive layers, then data storage efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extends the contact via structures into the vertical dimension at different depths, allowing them to contact different electrically conductive layers. This three-dimensional arrangement enables multiple data storage locations within the same contact region, improving data storage efficiency while the regular patterning keeps fabrication manageable.
Solution Approach 2:
Contact via structures at different depths are nested vertically within the same contact region, with each contact via structure contacting a different electrically conductive layer. This nesting approach allows multiple storage elements to be packed into a compact volume, improving data storage efficiency without requiring proportional increases in lateral device dimensions.
3Reliability
If sacrificial material layers are removed to form lateral recesses, then continuity of electrically conductive layers is improved, but structural support is reduced
Solution Approach 1:
Support pillars are formed in the contact region before the sacrificial material layers are removed to form lateral recesses. This preliminary action ensures that structural support is already in place to maintain the integrity of the alternating stack during the subsequent removal of sacrificial material, preventing collapse while enabling continuity of electrically conductive layers.
Solution Approach 2:
Support pillars act as intermediary structural elements that provide mechanical support during the formation of lateral recesses. These pillars are positioned to support the alternating stack of insulating and sacrificial material layers while the sacrificial material is removed, ensuring structural stability is maintained even as continuity of electrically conductive layers is improved.
Data Source
AI summary
A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, resistive memory elements located in the alternating stack in first and second array regions and contact via structures located in a contact region between the first and the second array regions. The contact via structures have different depths and contact different electrically conductive layers. Support pillars are located in the contact region and extending through the alternating stack. At least one conduction channel area is located between the contact via structures in the contact region. The conduction channel area contains no support pillars, and all electrically conductive layers in the conduction channel area are continuous from the first array region to the second array region.