Semiconductor Device Interconnection Structure for MRAM
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Solution Overview
Problem
As the density of magnetic random access memory (MRAM) cells increases, the proximity of adjacent cells leads to manufacturing challenges and potential short circuits between interconnection structures, which affects the yield and reliability of semiconductor devices with magnetic tunnel junction (MTJ) structures.
Innovation Solution
A semiconductor device design featuring two magnetic tunnel junctions with an interconnection structure comprising different metal interconnections, where the second metal interconnection is distinct from the first, positioned between the MTJ structures to mitigate short circuits and enhance manufacturing yield by varying material compositions and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of MRAM cells is increased to reduce the distance between adjacent cells, then the memory capacity is improved, but the risk of short circuits between interconnection structures increases
Solution Approach 1:
The patent applies local quality by using different metal materials for different interconnection structures. Specifically, the first interconnection structure uses a first metal material while the second interconnection structure uses a second metal material with different properties. This localized differentiation allows each interconnection to be optimized for its specific function and position, reducing the risk of short circuits while maintaining high cell density.
Solution Approach 2:
The patent employs composite materials by combining different metal materials in the interconnection structures. The first interconnection structure contains a first metal material and the second interconnection structure contains a second metal material, creating a composite interconnection system that leverages the advantageous properties of each metal to prevent short circuits in high-density configurations.
2Reliability
If different metal interconnections are used to reduce short circuit risk, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the interconnection system into distinct first and second interconnection structures, each with its own metal material. This segmentation isolates potential failure modes and allows each segment to be independently optimized, improving overall reliability while keeping the complexity manageable through clear functional separation.
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
The distinct interconnection structure effectively reduces the risk of short circuits and improves the manufacturing yield by enhancing the electrical connection reliability between MTJ structures, even when they are closely spaced.
Implementation Method 1
MRAM uses magnetism instead of electrical charges to store data. The data layer is composed of a magnetic material and the magnetization of the data layer can be switched between two opposing states by an applied magnetic field for storing binary information.
Implementation Method 2
The reference layer can be composed of a magnetic material in which the magnetization is pinned so that the strength of the magnetic field applied to the data layer and partially penetrating the reference layer is insufficient for switching the magnetization in the reference layer.
Implementation Method 3
During the read operation, the resistance of the MRAM cell is different when the magnetization alignments of the data layer and the reference layer are the same or not, and the magnetization polarity of the data layer can be identified accordingly.
Data Source
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AI summary
A semiconductor device comprising: a substrate; a first magnetic tunnel junction (MTJ) structure disposed on the substrate; a second MTJ structure disposed on the substrate; and an interconnection structure disposed on the substrate and located between the first MTJ structure and the second MTJ structure in a first horizontal direction, wherein the interconnection structure comprises: a first metal interconnection; and a second metal interconnection disposed on and contacting the first metal interconnection.