Stepped Semiconductor Stack Etching With Passivation Barrier
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Solution Overview
Problem
The integration of semiconductor devices is limited by the area occupied by unit memory cells, and existing three-dimensional structures face challenges in maintaining a stable and reliable structure due to uneven surfaces and increased area issues during manufacturing.
Innovation Solution
A method of manufacturing a semiconductor device involving the formation of stacked structures with stepped surfaces, where a passivation layer is used as an etching barrier to prevent uneven surfaces and maintain a flat profile, thereby preventing area expansion and ensuring structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If three-dimensional stacked structures are formed to improve integration density, then integration density is improved, but structural stability deteriorates due to uneven surfaces and area expansion
Solution Approach 1:
The manufacturing process is segmented into multiple sequential etching steps with intermediate planarization stages. The stack is divided into different height regions (first stepped structure, second stepped structure) that are processed separately, allowing each region to be stabilized before proceeding to the next level of integration.
Solution Approach 2:
A preliminary stepped structure is formed before final device assembly, and planarization layers are applied in advance to create flat surfaces. This preliminary action ensures that subsequent processing steps occur on stable, uniform surfaces, preventing structural instability during final device formation.
2Ease of manufacture
If conventional etching processes are used without etching barriers, then manufacturing process is simpler, but uneven surfaces are created causing area expansion
Solution Approach 1:
An etching barrier layer is introduced as an intermediary between the etching process and the underlying stack structure. This barrier layer controls the etching process to prevent lateral undercutting and uneven surface formation, thereby preventing area expansion while maintaining reasonable manufacturing complexity.
Solution Approach 2:
The etching process parameters are changed by introducing the etching barrier layer, which modifies the etching rate and selectivity. This allows precise control over the etching depth and profile, preventing the formation of uneven surfaces that would lead to area expansion.
3Shape
If multiple etching steps are performed without etching barriers, then stepped structures can be formed, but uneven surfaces cause reliability issues
Solution Approach 1:
The etching barrier layer serves as a mediator that enables the formation of precise stepped structures while simultaneously protecting against reliability issues. It provides a controlled interface that ensures uniform etching and prevents the formation of problematic uneven surfaces between different stepped structures.
Solution Approach 2:
The mechanical/physical process of direct etching is replaced by a chemically-controlled process using the etching barrier layer. This substitution allows for more precise and uniform material removal, creating reliable stepped structures without the defects that would compromise operational reliability.
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 enhances the integration density and operational reliability of semiconductor devices by maintaining a stable structure and preventing area increases due to uneven surfaces, improving the overall performance of the semiconductor device.
Implementation Method 1
forming a passivation layer that fills the opening and covers the first stepped structure; and forming a third stepped structure by etching the second stepped structure using the passivation layer as an etching barrier
Data Source
AI summary
A method of manufacturing a semiconductor device is provided. The method may include forming a stack, forming a preliminary stepped structure by patterning the stack, forming a first stepped structure, a second stepped structure, and an opening located between the first stepped structure and the second stepped structure by etching the preliminary stepped structure, forming a passivation layer that fills the opening and covers the first stepped structure, and forming a third stepped structure by etching the second stepped structure using the passivation layer as an etching barrier.