MTJ Memory Cell Shield Layout Against External Magnetic Fields
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Solution Overview
Problem
Magnetic memory devices are susceptible to external magnetic fields, which affect their performance and data integrity.
Innovation Solution
Incorporating a magnetic shield layer with a recessed top surface between data storage patterns to reduce the impact of external magnetic fields, combined with a simplified fabrication method using wet etching to form the shield layer without additional patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic shield layer is added to protect data storage patterns from external magnetic fields, then the reliability of the device is improved, but the device complexity and fabrication process become more complex
Solution Approach 1:
The magnetic shield layer is integrated with the existing capping dielectric layer structure, where the magnetic shield layer is formed between the capping dielectric layer and the data storage patterns. This merging approach allows the magnetic shielding function to be added without creating a completely separate fabrication process, thereby improving reliability while controlling the increase in device complexity
Solution Approach 2:
The magnetic shield layer acts as an intermediary component between the external magnetic field environment and the sensitive data storage patterns. This intermediate layer specifically targets and mitigates the harmful magnetic field effects without requiring fundamental changes to the overall device architecture or fabrication methodology
2Stability of the object's composition
If a magnetic shield layer is added to minimize external magnetic field influence, then the stability of magnetic tunnel junction patterns is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The magnetic shield layer is formed by depositing a metal layer and then selectively removing portions through wet etching to create a recessed top surface between data storage patterns. This parameter change in the formation method allows the magnetic shielding function to be achieved while using conventional wet etching processes already present in the fabrication workflow, thereby improving stability without significantly complicating manufacturing
3Object-affected harmful factors
If the magnetic shield layer completely covers the data storage patterns, then the protection from magnetic fields is maximized, but the fabrication process requires additional patterning steps
Solution Approach 1:
Instead of providing uniform magnetic shielding across all areas, the magnetic shield layer is selectively positioned with a recessed top surface between the data storage patterns. This local quality approach concentrates the magnetic shielding effect where it is most needed (around the lateral surfaces of data storage patterns) while reducing the overall material usage and simplifying the patterning requirements compared to a complete coverage structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The magnetic shield layer effectively minimizes the influence of external magnetic fields on the magnetic tunnel junction patterns, enhancing the reliability and stability of the semiconductor device while simplifying the fabrication process.
Implementation Method 1
a magnetic shield layer on the cell region and between the data storage patterns, the magnetic shield layer surrounding lateral surfaces of the data storage patterns
Implementation Method 2
wet-etching a portion of the metal layer to form a magnetic shield layer having a top surface that is recessed toward the substrate between the data storage patterns
Data Source
AI summary
A semiconductor device includes a substrate that includes a cell region and a peripheral region, a plurality of data storage patterns on the cell region and each including a bottom electrode, a magnetic tunnel junction pattern, and a top electrode that are sequentially stacked, and a magnetic shield layer at the cell region and between the data storage patterns. The magnetic shield layer has a top surface that is recessed toward the substrate between the data storage patterns.