MRAM Device Fabrication with MTJ Damascene Contacts
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Solution Overview
Problem
Existing MRAM devices face issues such as high chip area, high cost, high power consumption, limited sensitivity, and susceptibility to temperature variations.
Innovation Solution
A method for fabricating a MRAM device involving the formation of metal interconnect structures using damascene processes, MTJ stacks, and etching techniques to create precise MTJ structures with slanted sidewalls and cap layers, along with specific material choices for improved electrical connectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic field sensor technologies (AMR, GMR, MTJ sensors) are used, then data storage capability is achieved, but chip area increases and cost increases
Solution Approach 1:
The patent combines the magnetic tunneling junction (MTJ) structure with metal interconnect structures into a single integrated device. The MTJ stack is formed directly on the substrate with metal interconnects, eliminating the need for separate sensor components and reducing overall chip area while maintaining data storage functionality.
Solution Approach 2:
The MTJ structure serves multiple functions simultaneously: it acts as both the magnetic memory element for data storage and the sensing element for magnetic field detection. This multi-functionality reduces the number of separate components needed, thereby reducing chip area and manufacturing cost.
2Reliability
If conventional magnetic field sensor technologies are used, then data storage is achieved, but power consumption increases
Solution Approach 1:
The patent optimizes the TMR ratio (tunneling magnetoresistance ratio) by adjusting material composition and layer thickness parameters in the MTJ structure. Higher TMR ratios enable lower read currents, directly reducing power consumption while maintaining reliable data storage and retrieval operations.
3Reliability
If conventional magnetic field sensor technologies are used, then sensing capability is achieved, but sensitivity is limited
Solution Approach 1:
The patent enhances sensitivity by optimizing key parameters including increasing the TMR ratio through material selection and thickness control, minimizing damping ratios through careful layer composition, and optimizing the magnetic anisotropy of the free layer. These parameter optimizations collectively improve the sensor's ability to detect weak magnetic fields.
4Ease of operation
If conventional magnetic field sensor technologies are used, then operation is achieved, but temperature stability deteriorates
Solution Approach 1:
The patent improves temperature stability by selecting materials with appropriate thermal characteristics and optimizing layer thicknesses to compensate for temperature-induced variations. The MTJ structure parameters are tuned to maintain consistent magnetic and electrical properties across a wide temperature range, ensuring stable operation.
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 method reduces chip area, lowers costs, enhances sensitivity, and improves resistance to temperature variations, resulting in a more efficient and reliable MRAM device.
Implementation Method 1
Magnetoresistance (MR) effect has been known as a kind of effect caused by altering the resistance of a material through variation of outside magnetic field. The physical definition of such effect is defined as a variation in resistance obtained by dividing a difference in resistance under no magnetic interference by the original resistance.
Implementation Method 2
the characterization of utilizing GMR materials to generate different resistance under different magnetized states
Implementation Method 3
anisotropic magnetoresistance (AMR) sensors
Data Source
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AI summary
A method for fabricating semiconductor device includes the steps of: forming a substrate having a magnetic tunneling junction (MTJ) region and a logic region; forming a MTJ on the MTJ region; forming a top electrode on the MTJ; forming an inter-metal dielectric (IMD) layer around the MTJ; removing the IMD layer directly on the top electrode to form a recess; forming a first hard mask on the IMD layer and into the recess; removing the first hard mask and the IMD layer on the logic region to form a contact hole; and forming a metal layer in the recess and the contact hole to form a connecting structure on the top electrode and a metal interconnection on the logic region.