MRAM Source Line Segmentation for Resistance Reduction

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Solution Overview

Problem

The manufacturing of Magnetic Random Access Memory (MRAM) faces challenges in reducing manufacturing costs and improving power conservation, particularly due to complex layouts and high resistance in current-carrying lines.

Innovation Solution

The implementation of a simplified source line design with a rectilinear shape and multiple parallel contacts in the MRAM apparatus, which reduces resistance and enhances manufacturability by simplifying the fabrication process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex source line design is used in MRAM, then current distribution can be improved, but manufacturing complexity and resistance increase

Engineering Contradiction:
Improvecurrent distributionVSAvoidsource line design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The source line is divided into multiple segmentsthat are connected in parallel between the bit line and word line. This segmentation allows current to be distributed through multiple paths, improving current distribution reliability while keeping each individual segment simple in structure, thus resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If traditional source line design is used, then manufacturability follows conventional processes, but resistance in current carrying lines is high

Engineering Contradiction:
Improvemanufacturing process compatibilityVSAvoidpower consumption
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

Multiple source line segments are merged in parallel configuration to create equivalent resistance reduction. The parallel arrangement combines the current-carrying capacity of multiple lines while maintaining compatibility with conventional MRAM manufacturing processes, thus reducing power loss without sacrificing ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If simplified source line design is implemented, then manufacturability improves, but layout complexity may increase

Engineering Contradiction:
Improvefabrication simplicityVSAvoidlayout complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The source line segments are designed to serve multiple functions: they provide current paths, define cell boundaries, and enable selective activation of memory cells. This multi-functionality reduces the need for separate structural elements, simplifying the overall layout while maintaining ease of manufacture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2471098B1System and method to manufacture magnetic random access memory
Publication Date: 2020.09.23 QUALCOMM INC
  • EP2471098B1 patent drawingFigure 1
  • EP2471098B1 patent drawingFigure 2
  • EP2471098B1 patent drawingFigure 3

AI summary

A system and method to manufacture magnetic random access memory is disclosed. In a particular embodiment, a method of making a magnetic tunnel junction memory system includes forming a portion of a metal layer into a branchless source line (120) having a substantially rectilinear portion. The method also includes coupling the source line, at the substantially rectilinear portion, to a first transistor (112) using a first via (116). The first transistor is configured to supply a first current received from the source line to a first magnetic tunnel junction device. The method includes coupling the source line to a second transistor using a second via, where the second transistor is configured to supply a second current received from the source line to a second magnetic tunnel junction device.