Variable Resistive Memory Bottom Electrode Self-Alignment
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Solution Overview
Problem
Current methods for forming variable resistive memory devices face challenges in achieving precise alignment and efficient contact between the bottom electrodes and the variable resistive material patterns, leading to potential misalignment and reduced program efficiency.
Innovation Solution
A method involving the formation of a conductive pattern and insulation patterns on a substrate, where a sacrificial pattern is used as an etch mask to create a bottom electrode pattern, and subsequently replaced with a variable resistive pattern, ensuring self-alignment and minimizing contact areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form bottom electrode patterns and variable resistive material patterns, then the manufacturing process can be completed, but misalignment occurs between the patterns leading to reduced program efficiency
Solution Approach 1:
The sacrificial pattern is formed in advance on the substrate before forming the bottom electrode pattern. This preliminary placement allows the bottom electrode pattern to be formed using the sacrificial pattern as a mask, ensuring automatic alignment. The sacrificial pattern serves as a pre-positioned reference structure that guides subsequent pattern formation, eliminating alignment errors that would occur with conventional direct patterning methods.
Solution Approach 2:
The sacrificial pattern acts as an intermediary element between the substrate and the bottom electrode pattern. It is temporarily introduced to facilitate precise alignment during the patterning process, then removed after serving its alignment function. This intermediary structure enables the bottom electrode and variable resistive material patterns to be perfectly aligned without directly interfering with the final device structure.
2Reliability
If the contact area between bottom electrodes and variable resistive material is large, then easier electrical connection is achieved, but program efficiency is reduced due to insufficient electrical contact resistance
Solution Approach 1:
The contact area between the bottom electrode and variable resistive material is locally minimized by using the sacrificial pattern as an alignment mask. The sacrificial pattern defines precise contact regions where the bottom electrode touches the variable resistive material, ensuring that only the necessary minimal area contacts. This local optimization of contact area creates sufficiently high electrical contact resistance for effective memory cell programming while maintaining reliable electrical connection.
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 simplifies the process, prevents misalignment, and enhances the electrical contact resistance between the variable resistive material and the bottom electrodes, thereby improving the program efficiency of memory cells.
Implementation Method 1
etching the conductive pattern using the preliminary sacrificial pattern as an etch mask
Data Source
AI summary
A method of forming a variable resistive memory device includes forming a conductive pattern that alternates with a first insulation pattern along a first direction on a substrate that is parallel with a surface of the substrate, forming a preliminary sacrificial pattern on the conductive pattern that contacts a sidewall of the first insulation pattern, etching the conductive pattern using the preliminary sacrificial pattern as an etch masks to form a preliminary bottom electrode pattern, patterning the preliminary sacrificial pattern and the preliminary bottom electrode pattern to form a sacrificial pattern and a bottom electrode pattern that each include at least two portions which are separated from each other along a second direction intersecting the first direction, and replacing the sacrificial pattern with a variable resistive pattern.