MRAM Interconnect Layout to Protect MTJ Electrical Integrity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional MRAM fabrication processes damage the MRAM structure and affect its electrical properties due to the formation of metal interconnections.

Innovation Solution

The MRAM structure is divided into memory and logic circuit regions, with a conductive plug having a smaller diameter than the MTJ, and a first metal interconnect structure is embedded in the logic circuit region, ensuring precise alignment and protection of the MTJ during etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal interconnections are formed using conventional fabrication processes, then electrical connectivity is achieved, but the MRAM structure is damaged and electrical properties are affected

Engineering Contradiction:

Improveelectrical properties of MRAMVSAvoiddamage to MRAM structure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the fabrication process into separate stages: first forming the MRAM structure, then creating contact holes, and finally forming metal interconnections. This segmentation allows each component to be optimized independently, preventing damage to the MRAM structure during interconnection formation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary protective actions by forming a protective layer over the MRAM structure before metal interconnection deposition. This preliminary protection prevents damage during subsequent fabrication steps while maintaining electrical connectivity.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If the conductive plug diameter is reduced to fit within the MTJ boundary, then MRAM structure protection is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvedamage to MRAM structureVSAvoidalignment precision of conductive plug

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary protective layer between the conductive plug and the MTJ. This intermediary structure allows the conductive plug to be positioned close to the MTJ boundary without direct contact, reducing the risk of damage while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent forms a protective buffer layer around the MTJ structure before depositing metal interconnections. This beforehand cushioning provides a safety margin that protects the MRAM structure from damage during fabrication while allowing precise positioning of the conductive plug.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS20250386738A1MRAM structure and fabricating method of the same

Publication Date: 2025.12.18 UNITED MICROELECTRONICS CORP

AI summary

An MRAM structure includes a first dielectric layer, and the first dielectric layer is divided into a memory region and a logic circuit region. An MRAM is embedded in the memory region of the first dielectric layer. The MRAM includes a bottom electrode, an MTJ and a top electrode stacked in sequence from bottom to top. A conductive plug is disposed on the top electrode and contacts the top electrode. The diameter of the conductive plug is smaller than the diameter of the MTJ. The conductive plug overlaps only one MRAM. A first metal interconnect structure is embedded in the logic circuit region of the first dielectric layer. The first metal interconnect structure includes a contact plug and a conductive line. The conductive line is disposed on the contact plug, and the top surface of the conductive line is aligned with the top surface of the conductive plug.