Magnetic Tunnel Junction Etching Sidewall Byproduct Removal
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Solution Overview
Problem
The existing methods for manufacturing magnetic memory devices face challenges in effectively removing etch byproducts, which can lead to electrical shorts and reliability issues in magnetic tunnel junctions.
Innovation Solution
A method involving a two-step ion-beam etch process using alternating line mask patterns to form magnetic tunnel junctions in an island shape, where ion beams are continuously incident on the sidewalls to remove redeposited etch byproducts, enhancing electrical characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-step etching is used to form magnetic tunnel junctions, then the manufacturing process is simple, but etch byproducts remain on the sidewalls causing electrical shorts and reliability issues
Solution Approach 1:
The etching process is divided into multiple sequential steps with different mask patterns. First line mask patterns are formed and etching is performed, then the masks are removed and second line mask patterns are formed for additional etching. This segmentation allows each etching step to target specific regions, effectively removing etch byproducts from sidewalls while maintaining process control and improving reliability.
2Reliability
If multiple etching steps with alternating mask patterns are used, then etch byproducts are effectively removed, but the manufacturing process becomes more complex
Solution Approach 1:
Line mask patterns are formed in advance before the etching process begins. The first line mask patterns are formed on the substrate, followed by the etching step. After mask removal, second line mask patterns are formed for subsequent etching. This preliminary preparation of mask patterns enables precise control of the etching process, ensuring thorough removal of etch byproducts while maintaining manufacturing efficiency.
3Reliability
If ion beams are continuously incident on sidewalls during etching, then redeposited etch byproducts are removed, but the etching process requires more precise control
Solution Approach 1:
The etching process employs periodic action through alternating mask patterns. First line mask patterns guide the initial etching step, then after mask removal, second line mask patterns guide the subsequent etching step. This periodic application of different mask patterns ensures that ion beams systematically target different regions, thoroughly removing redeposited etch byproducts from sidewalls while maintaining precise process control through structured sequencing.
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 removes etch byproducts and improves the electrical characteristics and reliability of magnetic tunnel junctions, addressing the reliability issues in magnetic memory devices.
Implementation Method 1
etching the magnetic tunnel junction layer by a first ion-beam etch process using the first line mask patterns as an etch mask
Implementation Method 2
forming a magnetic tunnel junction layer including a first magnetic layer, a tunnel barrier layer, and a second magnetic layer that are sequentially stacked on a substrate
Data Source
AI summary
A method for manufacturing a magnetic memory device includes forming a magnetic tunnel junction layer that includes a first magnetic layer, a tunnel barrier layer, and a second magnetic layer sequentially stacked on a substrate. First line mask patterns are formed extending in a first direction and spaced apart from each other in a second direction crossing the first direction. The magnetic tunnel junction layer is etched by a first ion-beam etch process using the first line mask patterns as an etch mask to form preliminary magnetic tunnel junctions. Second line mask patterns are formed extending in the second direction and spaced apart from each other in the first direction. The preliminary magnetic tunnel junctions are etched by a second ion-beam process using the second line mask patterns as an etch mask to form magnetic tunnel junctions.