Vertical Memory Gate Electrode Support for Structural Stability
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Solution Overview
Problem
The increasing integration degree of memory devices poses challenges in fabricating three-dimensional memory devices, particularly in forming reliable and efficient vertical semiconductor structures with high electrical characteristics and high integration degree.
Innovation Solution
A vertical memory device is fabricated using a substrate with a memory cell region and a contact region, featuring gate electrodes with step-shaped pad portions, contact plugs, and supporters below the pad portions, where at least one supporter vertically overlaps with the contact plug and others do not, formed through an alternating stack of dielectric and sacrificial layers and etched to create a supporter-embedded step structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the integration degree of memory devices is increased to achieve higher capacity, then the storage capacity is improved, but the fabrication difficulty increases
Solution Approach 1:
The patent transitions from planar memory structure to three-dimensional vertical structure by stacking multiple gate electrodes and channel structures vertically. This dimensional change allows significantly higher storage capacity within the same footprint while maintaining manufacturability through systematic formation processes for the stacked components including gate electrodes, channel structures, and interlayer dielectric layers.
Solution Approach 2:
The memory device is divided into multiple functional segments stacked vertically, including alternating layers of gate electrodes and channel structures, with interlayer dielectric layers separating each segment. This segmentation allows each layer to be formed and processed independently, simplifying the overall fabrication process while achieving high integration through vertical stacking.
2Reliability
If gate electrodes are extended to contact region to improve electrical connection, then the electrical characteristics are improved, but structural stability deteriorates due to bending
Solution Approach 1:
Support structures are formed in advance within the interlayer dielectric layer at positions that will later align with contact plugs. These pre-positioned support structures provide mechanical reinforcement to the extended gate electrodes in the contact region, preventing bending and maintaining structural stability while allowing the gate electrodes to extend for improved electrical connection.
Solution Approach 2:
The support structures act as intermediary elements between the extended gate electrodes and the contact plugs. These support structures provide mechanical support to the gate electrodes in the contact region, enabling the gate electrodes to extend further for better electrical connection without compromising structural stability, thus mediating between the conflicting requirements.
3Reliability
If contact plugs are formed to connect gate electrodes to external contacts, then the electrical connection is improved, but punch-through of gate electrodes occurs reducing reliability
Solution Approach 1:
Support structures are formed in advance within the interlayer dielectric layer at positions that will align with the contact plugs. These pre-positioned support structures provide mechanical reinforcement to prevent punch-through of the gate electrodes when contact plugs are formed, ensuring both good electrical connection and maintained reliability.
4Stability of the object's composition
If supporters are formed below all pad portions to prevent bending, then structural stability is improved, but manufacturing complexity increases
Solution Approach 1:
Support structures are formed only in specific local regions where gate electrodes extend into the contact region and where contact plugs will be formed, rather than uniformly below all pad portions. This localized approach provides structural stability exactly where needed to prevent bending and punch-through, while maintaining manufacturing efficiency by avoiding unnecessary support structures in other regions.
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 electrical characteristics and integration degree of the vertical memory device by preventing structural bending and punch-through, while maintaining reliability and improving manufacturing efficiency.
Implementation Method 1
The supporters include a dielectric material having an etch selectivity with respect to the sacrificial layers
Data Source
AI summary
A vertical memory device includes: a substrate including a memory cell region and a contact region; a plurality of gate electrodes that extend from the memory cell region to the contact region and include pad portions which are end portions stacked in a step shape in the contact region; a plurality of contact plugs coupled to the pad portions of the gate electrodes; and a plurality of supporters formed below the pad portions of the gate electrodes.