MRAM Capping Layer Step Difference Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The etching process in manufacturing magnetoresistive random access memory (MRAM) devices creates differences in height between the cell and peripheral regions, leading to step differences that can result in reliability and wiring defects.

Innovation Solution

A MRAM device design that includes a first insulating interlayer, lower electrode contacts, and a structure with a magnetic tunnel junction, where the capping layer has a uniform thickness and the upper surface of the insulating interlayer in the peripheral region is higher than in the cell region, reducing the step difference between the two areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the etching process is used to form MTJ structure in the cell region, then the magnetic tunnel junction structure can be created, but step differences occur between the cell region and peripheral region

Engineering Contradiction:

ImproveMTJ structure formationVSAvoidsurface height uniformity

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The patent applies local quality by making the first insulating interlayer have different heights in different regions: the first height in the cell region and the second height in the peripheral region. This localized structural differentiation compensates for the step differences caused by etching, allowing the MTJ structure to be formed with precise height control while maintaining overall surface uniformity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-forming the first insulating interlayer with differentiated heights before the etching process. This advance preparation ensures that when the MTJ structure is subsequently formed through etching, the step differences are already compensated, preventing reliability and wiring defects.

Inventive Principle:

Principle #10Preliminary action

2Area of stationary object

If the capping layer is formed to cover the first insulating interlayer and first structure, then surface coverage is achieved, but uniform thickness is difficult to maintain due to height differences

Engineering Contradiction:

Improvecapping layer coverage areaVSAvoidcapping layer thickness uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a non-uniform first insulating interlayer structure that compensates for the uniform capping layer. The different heights of the first insulating interlayer in cell and peripheral regions ensure that when the capping layer is formed with uniform thickness, the overall surface remains substantially flat, achieving both complete coverage and thickness uniformity.

Inventive Principle:

Principle #3Local quality

3Shape

If the first insulating interlayer is formed with different heights in cell and peripheral regions, then step differences are reduced, but the insulating interlayer structure becomes more complex

Engineering Contradiction:

Improvesurface height uniformityVSAvoidinsulating interlayer structure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the height parameter of the first insulating interlayer in different regions. By controlling the first height in the cell region and the second height in the peripheral region, the patent achieves substantially flat overall surface and reduced step differences without fundamentally changing the insulating interlayer material composition or structure.

Inventive Principle:

Principle #35Parameter changes

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

This design reduces the step difference between the cell and peripheral regions, thereby minimizing reliability and wiring defects, and improves the manufacturing process by maintaining a uniform capping layer thickness.

Implementation Method 1

a magnetic tunnel junction structure... including a first magnetic pattern, a tunnel barrier pattern, and a second magnetic pattern sequentially stacked

Methodology Applied

Scientific EffectQuantum tunneling:

Implementation Method 2

Magnetoresistive random access memory (MRAM) device... lower electrode, a magnetic tunnel junction structure and an upper electrode sequentially stacked

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentUS11417833B2Method of manufacturing magnetoresistive random access memory device

Publication Date: 2022.08.16 SAMSUNG ELECTRONICS CO LTD

AI summary

A MRAM device includes a first insulating interlayer on a substrate including a cell region and a peripheral region, lower electrode contacts extending through the first insulating interlayer of the cell region, a first structure on each of the lower electrode contacts, the first structure including a lower electrode, a magnetic tunnel junction structure, and an upper electrode sequentially stacked, and a capping layer covering surfaces of the first insulating interlayer and the first structure in the cell and peripheral regions, wherein an upper surface of the capping layer on the first insulating interlayer in the peripheral region is higher than an upper surface of the capping layer on the first insulating interlayer between the first structures in the cell region.