MRAM Manufacturing via Segmented FEOL Magnetic BEOL Stages
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Solution Overview
Problem
Current methods for manufacturing magnetic random access memory (MRAM) are costly, unreliable, and non-modular, leading to low memory-element-per-wafer yield and increased costs due to contamination and design complexity, which hinders its competitiveness against other memory technologies.
Innovation Solution
A multi-stage manufacturing process involving a front end on-line (FEOL) stage for logic and non-magnetic portions, a magnetic fabrication stage for the magnetic material, and a back end on-line (BEOL) stage for metal and contacts, allowing for modularity and independent processing of CMOS and magnetic components, with intermediate process control steps to ensure high yield and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current methods for manufacturing MRAM are used, then magnetic memory cells can be produced, but the manufacturing cost is high and reliability is low due to contamination and design complexity
Solution Approach 1:
The manufacturing process is divided into three distinct stages: FEOL (front end on-line) for logic and non-magnetic portions, magnetic fabrication stage for magnetic material deposition, and BEOL (back end on-line) for metal and contacts. This segmentation allows each stage to be optimized independently, reducing overall process complexity and improving reliability by preventing cross-contamination between different material types.
Solution Approach 2:
The magnetic fabrication stage is extracted as a separate, independent process from the CMOS manufacturing lines. By taking out the magnetic material deposition process and performing it in a dedicated facility, the patent eliminates contamination risks to CMOS devices and simplifies the overall manufacturing system by allowing independent optimization of each process.
2Ease of manufacture
If current manufacturing methods are used, then MRAM cells can be manufactured, but contamination occurs and costs increase
Solution Approach 1:
The manufacturing process is segmented into separate facilities: FEOL/BEOL stages can be performed in standard CMOS factories, while the magnetic fabrication stage requires a dedicated magnetic fabrication facility. This physical segmentation prevents contamination of CMOS devices by magnetic materials and processing chemicals, eliminating the need for expensive cleanroom modifications and reducing overall manufacturing costs.
Solution Approach 2:
The magnetic fabrication process is extracted from the CMOS manufacturing environment and performed in a separate facility. This extraction eliminates the harmful interaction between CMOS processing and magnetic material deposition, preventing contamination while allowing each process to be optimized for its specific requirements, thereby reducing manufacturing costs.
3Productivity
If modular processing is implemented, then reliability and yield are improved, but process coordination complexity increases
Solution Approach 1:
The manufacturing process is segmented into independent stages that can be performed in different facilities and timelines. The FEOL stage prepares the substrate with logic circuits, the magnetic fabrication stage deposits magnetic materials, and the BEOL stage completes the interconnect structure. This segmentation allows intermediate storage and transport of wafers between stages, improving yield by allowing rework at specific stages without scrapping entire wafers.
Solution Approach 2:
The FEOL stage performs preliminary actions by completing the logic circuit fabrication and preparing the substrate before magnetic material deposition. This preliminary preparation includes forming trenches, depositing seed layers, and creating the structural framework that will receive the magnetic materials. By performing these actions in advance in a controlled CMOS environment, the patent ensures high-yield substrate preparation that can be independently optimized.
Data Source
AI summary
In accordance with a method of the present invention, a method of manufacturing a magnetic random access memory (MRAM) cell and a corresponding structure thereof are disclosed to include a multi-stage manufacturing process. The multi-stage manufacturing process includes performing a front end on-line (FEOL) stage to manufacture logic and non-magnetic portions of the memory cell by forming an intermediate interlayer dielectric (ILD) layer, forming intermediate metal pillars embedded in the intermediate ILD layer, depositing a conductive metal cap on top of the intermediate ILD layer and the metal pillars, performing magnetic fabrication stage to make a magnetic material portion of the memory cell being manufactured, and performing back end on-line (BEOL) stage to make metal and contacts of the memory cell being manufactured.