Magnetic Memory Cell Pillar Etching with Protective Sleeve
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Solution Overview
Problem
Conventional manufacturing methods for magnetic memory cells face challenges in producing high-yield cells due to the weak etching resistance of switching layers, leading to sidewall notches and shunting issues during the etching process.
Innovation Solution
A method involving depositing a magnetic memory element film stack and a selector film stack on a substrate, followed by etching with a mask to form pillars, and then using conformal dielectric layers to create protective sleeves around the switching layers, which prevents re-deposited material accumulation and facilitates the formation of memory cell pillars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching methods are used on switching layers, then the etching process can be completed, but sidewall notches and shunting issues occur due to weak etching resistance
Solution Approach 1:
A protective sleeve is formed around the switching layer before the etching process begins. This protective sleeve acts as a preliminary barrier that prevents etching damage to the sidewalls, eliminating sidewall notches and shunting issues while maintaining manufacturing yield
Solution Approach 2:
The protective sleeve serves as an intermediary layer between the etching process and the switching layer. It mediates the etching process by providing etching resistance to the sidewalls, allowing the etching to proceed without directly damaging the switching layer structure
2Manufacturing precision
If conventional etching processes are applied, then memory cell pillars can be formed, but re-deposited material accumulates on sidewalls causing defects
Solution Approach 1:
The harmful re-deposited material is prevented from accumulating on the switching layer sidewalls by the protective sleeve. The protective sleeve extracts the switching layer from the harmful etching environment, allowing precise pillar formation without contamination
Solution Approach 2:
The protective sleeve acts as an intermediary barrier that prevents re-deposited material from reaching and contaminating the switching layer sidewalls during the etching process, ensuring clean and precise pillar formation
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 method enhances the reliability and yield of magnetic memory cell production by preventing sidewall notches and shunting, ensuring consistent and efficient formation of memory cell pillars.
Implementation Method 1
depositing a first conforming dielectric layer over the selector pillar, including a sidewall thereof
Data Source
AI summary
The present invention is directed to a method for manufacturing a memory cell that includes a magnetic memory element electrically connected to a two-terminal selector. The method includes the steps of depositing a selector film stack on a substrate; depositing a magnetic memory element film stack on top of the selector film stack; etching the magnetic memory element film stack with an etch mask formed thereon to remove at least an insulating tunnel junction layer in the magnetic memory element film stack not covered by the etch mask, thereby forming a magnetic memory element pillar; depositing a first conforming dielectric layer over the magnetic memory element pillar, including a sidewall thereof, and surrounding surface; etching a portion of the first conforming dielectric layer covering the surrounding surface to form a first protective sleeve around at least the insulating tunnel junction layer of the magnetic memory element pillar; and etching the selector film stack using the etch mask and the first protective sleeve as a composite mask to form a memory cell pillar.