MRAM MTJ Protection via Segmented Nitride Layers
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Solution Overview
Problem
In the manufacturing of magnetic random access memory (MRAM) using magnetic tunnel junction (MTJ) structures, existing methods face challenges in protecting the MTJ stacked elements from excessive etching during the formation of contact structures, which can affect their performance.
Innovation Solution
A semiconductor structure is developed with a dielectric layer containing MTJ stacked elements and dummy MTJ stacked elements, where a first nitride layer covers the sidewalls and a thicker second nitride layer covers the top surfaces of the dummy MTJ elements, enhancing protection and allowing controlled penetration of contact structures without damaging the MTJ elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed on the MTJ stacked elements to prevent over-etching, then the protection effect is improved, but the contact structure formation becomes more difficult
Solution Approach 1:
The protective mask is divided into two distinct nitride layers with different thicknesses. The first nitride layer (thinner) allows contact structures to penetrate through easily, while the second nitride layer (thicker) provides enhanced protection against over-etching. This segmentation enables both protection and ease of contact formation simultaneously.
Solution Approach 2:
Different regions of the mask have different properties - the first nitride layer is thinner to facilitate contact structure penetration, while the second nitride layer is thicker to provide protection. This local differentiation of mask quality resolves the contradiction between protection and ease of manufacture.
2Reliability
If a thicker protective layer is formed on the MTJ elements, then the protection against over-etching is improved, but the electrical connection of contact structures becomes more difficult
Solution Approach 1:
The mask is segmented into two nitride layers with different thicknesses. The thinner first nitride layer ensures easy penetration for contact structures, while the thicker second nitride layer provides enhanced protection. This segmentation resolves the contradiction between protection thickness and connection ease.
Solution Approach 2:
Instead of using a single thick mask layer that would block contact formation, the solution adds a dimensional approach by stacking two layers with different thicknesses. The first layer (thinner) enables contact penetration, while the second layer (thicker) provides protection, solving the problem through dimensional differentiation.
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 prevents over-etching of MTJ elements while enabling easy electrical connection of contact structures, ensuring reliable performance and efficient manufacturing of MRAM devices.
Implementation Method 1
a mask consisting of a first nitride layer and a second nitride layer is formed on the top of each MTJ stacked element, so that the protection effect on the top of the MTJ stacked element can be enhanced
Implementation Method 2
Depending upon the orientations of the magnetic moments of the free layer and the fixed layer, the resistance of the MTJ device will change
Data Source
AI summary
The invention provides a semiconductor structure, the semiconductor structure includes a dielectric layer, a plurality of MTJ stacked elements and at least one dummy MTJ stacked element located in the dielectric layer, a first nitride layer covering at least the sidewalls of the MTJ stacked elements and the dummy MTJ stacked elements, a second nitride layer covering the top surfaces of the dummy MTJ stacked elements, the thickness of the second nitride layer is greater than the thickness of the first nitride layer, and a plurality of contact structures located in the dielectric layer and electrically connected with each MTJ stacked element.