Variable Resistance Memory Element Fabrication via Segmented Island-Line Structure

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Solution Overview

Problem

Existing semiconductor memory technologies face challenges in forming reliable variable resistance elements with vertical sidewalls, leading to deteriorated magnetic and electrical characteristics due to sloped profiles during etching, and require multiple masks increasing processing costs and time.

Innovation Solution

The proposed solution involves a semiconductor memory structure with a first portion having an island shape and a second portion with a line shape, where the second portion extends over the first, both including magnetization layers and a tunnel barrier layer, and using a single mask for patterning the second portion to reduce etching-induced slope effects and processing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional etching processes are used to form variable resistance elements, then the elements can be formed, but sloped profiles are created leading to deteriorated magnetic and electrical characteristics

Engineering Contradiction:

Improvevertical sidewall profileVSAvoidmagnetic and electrical characteristics

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The variable resistance element is divided into two portions: a first portion with an island shape and a second portion with a line shape extending over the first portion. This segmentation allows the first portion to maintain vertical sidewalls for reliable magnetic and electrical characteristics, while the second portion serves as a common structure that can be formed with a single mask, resolving the contradiction between precision and reliability.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If multiple masks are used for patterning variable resistance elements, then precise patterning can be achieved, but processing costs and time increase

Engineering Contradiction:

Improvepatterning precisionVSAvoidprocessing time and cost

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The second portion of the variable resistance element is designed as a line-shaped common structure that extends over multiple first portions. This allows the second portion to be patterned using a single mask process, while the first portions are formed separately. By merging the function of multiple patterns into a single line-shaped structure, the invention reduces the number of mask processes from multiple to one, thereby reducing processing time and cost while maintaining patterning precision.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If the variable resistance element structure is simplified, then fabrication becomes easier, but magnetic and electrical characteristics deteriorate

Engineering Contradiction:

Improvefabrication simplicityVSAvoidmagnetic and electrical characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention applies different structural qualities to different portions of the variable resistance element. The first portion has an island shape with vertical sidewalls to ensure reliable magnetic and electrical characteristics, while the second portion has a line shape to simplify fabrication. This local differentiation allows each portion to optimize its function: the first portion maintains high reliability, while the second portion provides fabrication ease, resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:

Principle #3Local quality

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 configuration improves the reliability and efficiency of data writing operations by maintaining vertical sidewalls and reducing the number of mask processes, thereby lowering processing costs and time while enhancing the magnetic and electrical characteristics of the variable resistance elements.

Implementation Method 1

a tunnel barrier layer interposed between the free layer and the pinned layer

Methodology Applied

Scientific EffectQuantum tunneling:

Implementation Method 2

including at least a free layer which has a variable magnetization direction

Methodology Applied

Scientific EffectMagnetization: Magnetism

Implementation Method 3

including at least a pinned layer which has a pinned magnetization direction

Methodology Applied

Scientific EffectPinned magnetization: Magnetism

Data Source

PatentUS10199433B2Electronic device and method for fabricating the same

Publication Date: 2019.02.05 SK HYNIX INC

AI summary

Provided is an electronic device including a semiconductor memory. The semiconductor memory may include: a first portion of a variable resistance element, the first portion having an island shape and including at least a free layer which has a variable magnetization direction; a second portion of the variable resistance element, the second portion having a line shape which extends in a direction over the first portion and including at least a pinned layer which has a pinned magnetization direction; and a tunnel barrier layer interposed between the free layer and the pinned layer.