Vertical Memory Staircase Layout for Continuous Tier Conduction
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Solution Overview
Problem
Conventional staircase structure fabrication techniques in vertical memory arrays lead to discontinuous conductive paths, requiring multiple switching devices to drive voltages across tiers, which increases complexity and reduces efficiency.
Innovation Solution
A method of forming microelectronic devices with a stack structure comprising conductive and insulative materials, where sacrificial material is replaced with conductive material, and additional dielectric slot structures are used to segment bridge regions, reducing the need for multiple switching devices by maintaining continuous conductive paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional staircase structure fabrication techniques are used, then electrical connections between conductive material and control logic devices can be established, but the conductive material of an individual tier is segmented resulting in discontinuous conductive paths requiring multiple switching devices
Solution Approach 1:
The patent introduces an intermediary material (e.g., conductive paste, metal layer, or doped semiconductor region) that is deposited or formed over the staircase structure to bridge the segmented conductive paths. This intermediary material acts as a mediator that connects the discontinuous conductive regions, allowing a single switching device to drive voltages across the entire tier without requiring multiple switching devices.
Solution Approach 2:
The patent merges the segmented conductive paths by forming a continuous conductive layer that spans across multiple tiers and connects the previously discontinuous conductive regions. This combining of separate conductive elements into a unified continuous path reduces the number of switching devices needed from multiple to just one per string driver.
2Device complexity
If the number of switching devices is reduced by maintaining continuous conductive paths, then device complexity and manufacturing simplicity improve, but new fabrication processes are required
Solution Approach 1:
The patent performs preliminary actions by pre-forming the staircase structure with properly positioned contact regions and conductive material segments before depositing the continuous conductive layer. This preliminary preparation ensures that when the continuous conductive path is formed, it automatically aligns and connects to the underlying conductive regions, simplifying the overall fabrication process despite the additional step.
Solution Approach 2:
The continuous conductive layer serves multiple functions simultaneously: it provides electrical connection between tiers, bridges segmented conductive paths, acts as a routing structure, and enables voltage driving across the entire tier. This multi-functionality reduces the need for separate structures and switching devices, simplifying both device complexity and fabrication.
3Quantity of substance
If vertical memory array architectures are used to increase memory density, then more switching devices can be located in a unit of die area, but discontinuous conductive paths require multiple switching devices per tier
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of conductive paths to a three-dimensional vertical stack structure with continuous conductive paths that extend through multiple tiers. By utilizing the vertical dimension and forming continuous conductive paths that span multiple levels, the architecture achieves high memory density while requiring only one switching device per string driver regardless of the number of tiers.
Solution Approach 2:
The patent ensures continuity of the conductive path through the vertical stack, allowing electrical signals and voltages to flow continuously from one end of the tier to the other without interruption or segmentation. This continuous conductive path maintains the useful action of voltage driving across the entire memory tier with a single switching device, eliminating the need for multiple switching devices that would be required with discontinuous paths.
Data Source
AI summary
A microelectronic device comprises a stack structure comprising a vertically alternating sequence of conductive material and insulative material arranged in tiers. The stack structure has blocks separated from one another by first dielectric slot structures. Each of the blocks comprises two crest regions, a stadium structure interposed between the two crest regions in a first horizontal direction and comprising opposing staircase structures each having steps comprising edges of the tiers of the stack structure, and two bridge regions neighboring opposing sides of the stadium structure in a second horizontal direction orthogonal to the first horizontal direction and having upper surfaces substantially coplanar with upper surfaces of the two crest regions. At least one second dielectric slot structure is within horizontal boundaries of the stadium structure in the first horizontal direction and partially vertically extends through and segmenting each of the two bridge regions. Memory devices, electronic systems, and methods of forming microelectronic devices are also described.