Magnetic Memory Device Using Metal-Assisted Chemical Etching
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Solution Overview
Problem
Current magnetic memory devices face challenges in achieving high-density integration and efficient domain wall shifting with existing etching methods, which lead to increased manufacturing costs and potential shape defects.
Innovation Solution
The magnetic memory device employs a configuration with alternately stacked semiconductor layers, a magnet structure including a pillar and terrace portion, and the use of metal-assisted chemical etching (MaCE) for etching, allowing for the formation of thin wire magnets and reducing shift current requirements, while also using a catalyst metal to etch holes and lines simultaneously, thereby minimizing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used, then manufacturing process is simpler, but manufacturing precision deteriorates due to shape defects
Solution Approach 1:
The patent introduces a catalyst layer as an intermediary substance that mediates between the etching solution and the magnet wire structure. This catalyst layer enables metal-assisted chemical etching (MaCE) to achieve precise wire shape formation without the complexity of conventional multi-step etching processes, directly resolving the contradiction between etching precision and process complexity
Solution Approach 2:
The patent changes the chemical parameters of the etching process by introducing a catalyst layer and using specific etching solutions that react with the catalyst. This parameter change enables the MaCE process to achieve superior etching precision compared to conventional methods, while the overall process remains manageable despite the added chemical complexity
2Quantity of substance
If magnet wire thickness is reduced for high-density integration, then memory density improves, but manufacturing precision deteriorates due to etching difficulties
Solution Approach 1:
The catalyst layer serves as a mediator that enables precise formation of thin magnet wires. By depositing the catalyst layer before magnet formation, the MaCE process can etch extremely thin wires with high precision, enabling high-density integration while maintaining manufacturing quality
Solution Approach 2:
The patent adds a temporal dimension to the etching process by using a two-stage MaCE approach with different etching solutions applied at different times. This dimensional change in the process allows sequential removal of materials to achieve the desired thin wire structure with high precision
3Manufacturing precision
If multiple etching steps are used for holes and lines, then manufacturing precision improves, but productivity deteriorates
Solution Approach 1:
The patent merges the etching of holes and lines into a single unified MaCE process step. By using the catalyst layer pattern to guide the etching, both features are formed simultaneously in one process, dramatically improving productivity while maintaining the shape accuracy needed for functional devices
Solution Approach 2:
The catalyst layer serves multiple functions: it guides the etching process, defines the pattern geometry, and enables selective removal of materials. This multi-functionality allows a single etching step to achieve what would traditionally require multiple specialized steps, improving manufacturing efficiency
4Speed
If domain wall shifting uses higher current, then shifting speed improves, but use of energy worsens
Solution Approach 1:
The patent creates local quality variations in the magnet wire structure through the MaCE process, forming regions with different magnetic properties. These localized structural features reduce the overall current needed for domain wall shifting while maintaining fast switching speeds, resolving the energy-speed trade-off
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 configuration enhances memory density, reduces shift errors, and lowers manufacturing costs by using MaCE for etching, resulting in improved reliability and efficient domain wall shifting with reduced power consumption.
Implementation Method 1
a first magnetoresistance effect element coupled to the first terrace portion of the first magnet
Implementation Method 2
the use of metal-assisted chemical etching (MaCE) for etching, allowing for the formation of thin wire magnets
Data Source
AI summary
According to one embodiment, a magnetic memory device includes: a plurality of first films and a plurality of second films stacked alternately; a first insulating layer passing through the plurality of first and second films; a second insulating layer passing through the plurality of first and second films and in contact with a surface of the first insulating layer; a first magnet including a first pillar portion provided between the second insulating layer and the plurality of first and second films, and a first terrace portion coupled to one end of the first pillar portion; a first interconnect layer coupled to the other end of the first pillar portion of the first magnet; and a first magnetoresistance effect element coupled to the first terrace portion of the first magnet.