MTJ Dummy Fill Gradient for Embedded MRAM Density
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Solution Overview
Problem
Current methods for producing MRAM devices result in wasted space due to non-active dummy magnetic cells and fail to meet metal tunnel junction density requirements, especially in embedded MRAM cell technology.
Innovation Solution
A method is developed to form a gradient of MTJ dummy fill density from near-active-MRAM-cell periphery to far-outside-MRAM logic regions, using different minimum space and distance rules for high-density and low-density MTJ dummy structures without top or bottom electrodes, based on specific metal layer configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dummy magnetic cells are placed at the perimeter of the memory array to produce a uniform magnetic environment, then magnetic uniformity is improved, but the overall MRAM cell dimensions increase, wasting valuable space
Solution Approach 1:
The patent applies local quality by creating different dummy fill densities in different regions: high-density MTJ dummy structures in the near-active-MRAM-cell periphery logic region and low-density MTJ dummy structures in the far-outside-MRAM logic region. This localized differentiation achieves uniform magnetic environment near the active cells while minimizing space consumption in outer regions.
2Ease of manufacture
If standard via dummy fill solution is used with dummy fill in common regions of top and below metal dummy regions, then manufacturing simplicity is improved, but MTJ density requirement for MRAM design is not met, especially in near-active-MRAM-cell periphery logic regions
Solution Approach 1:
The patent implements local quality by forming high-density MTJ dummy structures specifically in the near-active-MRAM-cell periphery logic region where MTJ density requirements are critical, while using low-density structures in far-outside regions. This satisfies both the density requirement and manufacturing simplicity.
Solution Approach 2:
The patent changes the density parameter of MTJ dummy structures based on location: high-density in near-active regions and low-density in far-outside regions. This parameter differentiation meets the MTJ density requirement in critical areas while maintaining ease of manufacture through standardized formation processes.
3Quantity of substance
If high-density MTJ dummy structures are formed in near-active-MRAM-cell periphery logic region without top electrode or bottom electrode, then MTJ density requirement is met, but device complexity increases due to different formation rules
Solution Approach 1:
The patent applies local quality by using simplified MTJ dummy structures (without top electrode or bottom electrode) specifically in the near-active-MRAM-cell periphery logic region where density is critical, while using different structures in other regions. This meets density requirements with manageable complexity through localized simplification.
Data Source
AI summary
Methods of forming a MTJ dummy fill gradient across near-active-MRAM-cell periphery and far-outside-MRAM logic regions and the resulting device are provided. Embodiments include providing an embedded MRAM layout with near-active-MRAM-cell periphery logic and far-outside-MRAM logic regions; forming a MTJ structure within the layout based on minimum space and distance rules relative to a first metal layer, a second metal layer, and/or both the first and second metal layers; forming a high-density MTJ dummy structure in the near-active-MRAM-cell periphery logic region based on second minimum space and distance rules relative to a first metal layer, a second metal layer, and/or both the first metal layer and the second metal layer; and forming a low-density MTJ dummy structure in the far-outside-MRAM logic region based on third minimum space and distance rules relative to a first metal layer, a second metal layer, and/or both the first metal layer and the second metal layer.