Filled Stadium Trench Layout for Continuous 3D Memory Tier Access
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Solution Overview
Problem
Conventional staircase structure fabrication techniques in microelectronic devices, such as 3D memory arrays, result in discontinuous conductive paths requiring multiple switching devices, complicating electrical connections and increasing fabrication complexity and cost.
Innovation Solution
A method involving the formation of stadium structures with opposing staircase structures and central regions, followed by filling trenches with dielectric materials, to create continuous conductive paths and simplify electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional staircase structure fabrication techniques are used, then electrical connections between conductive material and control logic devices can be established, but discontinuous conductive paths are formed requiring multiple switching devices to drive voltages across tiers
Solution Approach 1:
The patent applies preliminary action by forming a dielectric barrier liner on the stack structure before forming the conductive material. This preliminary protective layer prevents contamination and damage to the conductive material during subsequent fabrication steps, ensuring continuous conductive paths can be formed without defects that would require additional switching devices to compensate for unreliable connections.
Solution Approach 2:
The dielectric barrier liner acts as an intermediary between the stack structure and the conductive material. This intermediate layer provides a controlled interface that enables the conductive material to be properly positioned and connected across tiers, forming continuous conductive paths while reducing the need for multiple switching devices.
2Power
If multiple switching devices are used to drive voltages across tiers, then complete voltage coverage is achieved, but fabrication complexity and cost increase
Solution Approach 1:
The dielectric barrier liner is formed in advance to establish a proper foundation for the conductive material. This preliminary structure enables the conductive material to extend continuously across tier edges without requiring multiple discrete switching devices, simplifying fabrication while maintaining voltage driving capability.
Solution Approach 2:
The patent merges the functions of multiple switching devices into a single continuous conductive path by properly forming the conductive material to extend across tier edges. This consolidation reduces fabrication complexity while maintaining the ability to drive voltages across all tiers.
3Ease of manufacture
If conductive material is segmented by staircase structures, then contact regions are defined, but discontinuous conductive paths result requiring additional switching devices
Solution Approach 1:
The dielectric barrier liner serves as an intermediary that allows the conductive material to maintain continuity across the staircase structure interfaces. This intermediate layer enables the conductive material to bridge between segmented contact regions without breaking the conductive path, eliminating the need for additional switching devices.
Solution Approach 2:
By forming the dielectric barrier liner before depositing the conductive material, the patent establishes a prepared surface that guides continuous conductive path formation. This preliminary action ensures that the conductive material can span across segmented regions while maintaining reliability.
Data Source
AI summary
A microelectronic device includes a stack structure including blocks separated from one another by dielectric slot structures and each including a vertically alternating sequence of conductive structures and insulative structures arranged in tiers. The blocks including a stadium structure including opposing staircase structures each having steps comprising edges of the tiers. The blocks further include a filled trench vertically overlying and within horizontal boundaries of the stadium structure. The filled trench includes dielectric liner structures and additional dielectric liner structures having a different material composition than that of the dielectric liner structures and alternating with the dielectric liner structures. The filled trench also includes dielectric fill material overlying an alternating sequence of the dielectric liner structures and additional dielectric liner structures.