Vertical Memory Structure With Bending Prevention Layer
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Solution Overview
Problem
VNAND flash memory devices with increased vertical gate electrodes are prone to bending, leading to non-uniform electrical characteristics.
Innovation Solution
Incorporation of a bending prevention layer on the insulating interlayer, extending parallel to the substrate surface, to stabilize the substrate and reduce bending, combined with a second substrate and gate electrodes perpendicular to the first substrate, and channels and contact plugs extending through these structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of gate electrodes stacked in a vertical direction increases, then the storage capacity of the VNAND flash memory device is improved, but the substrate becomes more prone to bending
Solution Approach 1:
A bending prevention layer is introduced as an intermediary component between the substrate and the stacked gate electrodes. This layer acts as a mediator that counteracts the bending forces generated by the heavy multi-layer gate electrode structure, thereby maintaining substrate stability while allowing high-density vertical stacking
Solution Approach 2:
The bending prevention layer modifies the mechanical parameters of the substrate structure by introducing a layer with specific stress characteristics. This layer changes the overall stress distribution and rigidity parameters of the device structure, enabling it to support the weight of multiple stacked gate electrodes without excessive bending
2Quantity of substance
If the number of gate electrodes stacked in a vertical direction increases, then the storage capacity is improved, but the electrical characteristics become non-uniform
Solution Approach 1:
The bending prevention layer serves as a mediator that not only prevents physical bending but also ensures uniform stress distribution across the substrate. This uniform stress distribution prevents variations in electrical characteristics that would otherwise arise from substrate deformation, thereby maintaining reliability across all memory cells
3Stability of the object's composition
If a bending prevention layer is added to stabilize the substrate, then substrate bending is reduced, but the device complexity increases
Solution Approach 1:
The bending prevention layer is implemented as a separate, distinct layer in the device structure, segmented from other components. This segmentation allows for independent optimization of the bending prevention function without complicating the design of other device components, making the overall system more manageable despite the added layer
Data Source
AI summary
A vertical memory device including: a circuit pattern on a first substrate; an insulating interlayer on the first substrate, the insulating interlayer covering the circuit pattern; a bending prevention layer on the insulating interlayer, the bending prevention layer extending in a first direction substantially parallel to an upper surface of the first substrate; a second substrate on the bending prevention layer; gate electrodes spaced apart from each other in a second direction on the second substrate, the second direction being substantially perpendicular to the upper surface of the first substrate; and a channel extending through the gate electrodes in the second direction.