ReRAM Plug-Groove Structure for Height and Contact Control
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Solution Overview
Problem
The height difference between resistive switching cells and logic units in ReRAM devices leads to yield deterioration and poor contact between resistive switching cells and conductive plugs, affecting the fabrication process.
Innovation Solution
A method is introduced where a lower conductive plug is etched back to create a groove, allowing a resistance switching element to be formed within this groove, and an upper conductive plug is formed to electrically contact the resistance switching element, reducing the height difference and improving contact quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resistive switching cell is formed with a certain thickness in the ILD, then the memory device can achieve proper electrical characteristics, but a height difference is created between the memory area and logic area, deteriorating the yield of subsequent processes
Solution Approach 1:
The patent introduces an etched groove dimension into the ILD structure, allowing the resistive switching cell to be positioned at a lower depth level while the ILD surface remains planar. This vertical dimensional adjustment resolves the height difference conflict while preserving the electrical characteristics of the memory device.
Solution Approach 2:
The patent applies local quality by creating a groove only in the memory area where resistive switching cells are formed, while the logic area remains unaffected. This localized structural modification allows different regions to have different vertical profiles, solving the height mismatch between memory and logic areas.
2Reliability
If the resistive switching cell is formed with a certain thickness, then the memory function is achieved, but poor contact is caused between the resistive switching cell and the conductive plug
Solution Approach 1:
The patent uses vertical dimensional adjustment by etching a groove into the ILD, allowing the resistive switching cell to extend upward from the groove. This creates better vertical alignment and contact interface with the conductive plug, solving the poor contact problem while maintaining memory functionality.
3Manufacturing precision
If the height difference between memory area and logic area is reduced, then the yield of subsequent processes is improved, but the contact between resistive switching cell and conductive plug must be ensured
Solution Approach 1:
The patent resolves this contradiction by using vertical groove depth adjustment - the groove provides the necessary height reduction for planarity, while the resistive switching cell material fills and extends from the groove to ensure proper contact with the conductive plug, simultaneously achieving both goals.
Data Source
AI summary
A ReRAM device includes an interlayer dielectric (ILD), a lower conductive plug, a resistance-switching element (RSE) and an upper conductive plug. The ILD has an upper surface. The lower conductive plug is disposed in the ILD, and has a top surface lower than the upper surface. The RSE is disposed above the top surface and electrically contacts with the top surface. The upper conductive plug is disposed above the RSE and electrically contacts with the RSE.