Self-Aligned Variable Resistance Memory via Protruding Contact Plug
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Solution Overview
Problem
Current semiconductor memory devices face challenges in achieving reliable storage elements due to issues with variable resistance pattern formation, such as inclined sidewall profiles and etch process limitations, which affect the reliability and performance of next-generation memory devices.
Innovation Solution
The proposed solution involves forming a semiconductor memory device with a self-isolated variable resistance pattern using a lower contact plug that protrudes over an inter-layer dielectric layer, allowing for vertical sidewalls without the need for an etch process, and incorporating a second variable resistance pattern to improve the characteristics of the magnetic tunnel junction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etch process is used to form variable resistance patterns, then the patterns can be created, but inclined sidewall profiles occur reducing reliability
Solution Approach 1:
The patent replaces the mechanical etch process with a deposition-based self-aligned formation method. The lower contact plug protruding over the inter-layer dielectric layer serves as a physical mask during deposition, automatically defining the variable resistance pattern boundaries without requiring etching, thereby eliminating inclined sidewall profiles and improving both manufacturing precision and reliability
Solution Approach 2:
The lower contact plug structure serves dual functions: as an electrical contact and as a self-aligned mask for pattern formation. The protruding portion automatically defines the pattern boundaries during deposition, eliminating the need for separate etch processes and masks, thus improving reliability through self-alignment
2Ease of manufacture
If conventional memory structures are used, then fabrication is simpler, but magnetic tunnel junction characteristics are insufficient
Solution Approach 1:
The patent divides the variable resistance structure into two separate patterns: a first variable resistance pattern for data storage and a second variable resistance pattern surrounding the lower contact plug for magnetic field generation. This segmentation allows each pattern to be optimized for its specific function, improving magnetic tunnel junction characteristics while maintaining fabrication feasibility
Solution Approach 2:
The second variable resistance pattern is formed to surround the lower contact plug, creating a nested structure where the contact plug is positioned within the second pattern. This nested configuration enables the second pattern to generate magnetic fields that improve the magnetic tunnel junction characteristics of the first pattern
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 approach enhances the reliability and performance of semiconductor memory devices by preventing etch-related problems and improving the magnetic tunnel junction characteristics, leading to improved data storage characteristics and easier fabrication processes.
Implementation Method 1
a magnetic structure formed over the substrate and located below top portions of lower contact plugs so as to be separated from the first variable resistance patterns, the magnetic structure producing a magnetic field at the first variable resistance patterns
Data Source
AI summary
An electronic device includes a semiconductor memory that includes: an inter-layer dielectric layer which is formed over a substrate; a contact plug which is coupled with the substrate by passing through the inter-layer dielectric layer and has a protruding portion over the inter-layer dielectric layer; a first variable resistance pattern which is formed over the contact plug; and a protective layer which covers the first variable resistance pattern and a portion of sidewalls of the contact plug in such a manner that the sidewalls of the contact plug are exposed.