MRAM Upper Electrode Protection Against Etch Redeposition
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Solution Overview
Problem
During the manufacturing of magnetoresistive random access memory (MRAM) devices, physical etching processes can lead to electrical shorts due to conductive by-products redeposited on the sidewalls of magnetic tunnel junction (MTJ) structures, compromising device performance.
Innovation Solution
The implementation of an upper electrode protective structure that isolates the upper electrode from exposure during etching, using a combination of etching masks and spacer layers to prevent conductive by-products from being redeposited on the sidewalls, thereby reducing the likelihood of electrical shorts and improving MRAM device characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical etching process is used to etch MTJ layer, then etching efficiency is improved, but conductive by-products are redeposited on sidewalls causing electrical shorts
Solution Approach 1:
An upper electrode protective structure is introduced as an intermediary component between the upper electrode and the etching environment. This protective structure prevents conductive by-products from reaching and shorting the upper electrode while allowing the physical etching process to proceed efficiently on the MTJ layer.
Solution Approach 2:
The upper electrode protective structure is formed before the etching process to preemptively block the harmful redeposition of conductive by-products. By establishing this protective barrier in advance, the design prevents the electrical short problem before it can occur during etching.
2Reliability
If upper electrode protective structure is added, then electrical short prevention is improved, but device complexity increases
Solution Approach 1:
The upper electrode protective structure is implemented as a thin film or spacer layer rather than a bulky three-dimensional structure. This approach provides effective protection against conductive by-product redeposition while minimizing the increase in device complexity and maintaining a compact form factor.
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 effectively minimizes electrical shorts and enhances the manufacturing process for MRAM devices by ensuring that conductive by-products are easily removable, leading to improved device performance and characteristics.
Implementation Method 1
the upper electrode protective structure isolates the upper electrode from exposure during the patterning
Implementation Method 2
a magnetic tunnel junction (MTJ) layer may be etched by a physical etching process
Implementation Method 3
elements of the etched conductive layers may be re-deposited, as conductive by-products, on a sidewall of the MTJ structure
Data Source
AI summary
Manufacturing an MRAM device may include forming an upper electrode on a magnetic tunnel junction stack, where the stack may include a lower electrode layer, a magnetic tunnel junction layer and a middle electrode layer that are sequentially formed on an insulating interlayer and a lower electrode contact on a substrate. The upper electrode may be formed on the middle electrode layer. An upper electrode protective structure may be formed to cover at least a sidewall and an upper surface of the upper electrode. The middle electrode layer, the magnetic tunnel junction layer and the lower electrode may be patterned by an etching process to form a middle electrode, a magnetic tunnel junction pattern and a lower electrode, respectively. The upper electrode protective structure may isolate the upper electrode from exposure during the patterning, and the upper electrode protective structure may remain on the upper electrode subsequently to the patterning.