Stadium Staircase Contacts for Isolated Vertical Memory Tiers
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Solution Overview
Problem
Conventional microelectronic device fabrication methods face challenges in forming conductive contacts to staircase structures without electrical shorting, particularly in vertical memory arrays, due to the complexity of etching through varying vertical heights of insulative material, which can lead to increased processing steps and potential short circuits.
Innovation Solution
The method involves forming conductive contact structures simultaneously with the conductive structures in the microelectronic device, using a stack structure with alternating insulative and conductive layers, and employing pillar structures to isolate and electrically connect the conductive layers, thereby reducing the number of processing steps and minimizing the risk of shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive contact structures are formed by etching through insulative material at varying vertical heights, then electrical connection to conductive tiers is achieved, but electrical shorting between neighboring conductive contact structures may occur
Solution Approach 1:
The patent introduces an intermediary material layer between neighboring conductive contact structures. This intermediary layer acts as a barrier that prevents electrical shorting while allowing the conductive contacts to maintain their electrical connection to the underlying conductive tiers. The intermediary material is positioned at the varying vertical heights where shorts would occur, effectively mediating between the need for electrical connection and the risk of shorting.
Solution Approach 2:
The patent segments the conductive contact structures by introducing intermediary material that divides and isolates adjacent contacts. This segmentation prevents the merging of electrical fields between neighboring structures, thereby eliminating the harmful effect of electrical shorting while preserving the individual electrical connection function of each contact structure.
2Ease of manufacture
If conventional etching methods are used to form conductive contacts through varying vertical heights, then contact to different tiers is achieved, but the number of processing steps increases
Solution Approach 1:
The patent applies preliminary action by forming the intermediary material layer before completing the conductive contact structure formation. This preliminary placement of the intermediary material prevents future shorting issues and guides subsequent processing steps, thereby reducing the total number of corrective or additional processing steps that would be needed if shorting occurred later in the manufacturing process.
3Reliability
If conductive contact structures are formed to access different vertical tiers, then electrical communication is established, but risk of inadvertent connection between neighboring structures increases
Solution Approach 1:
The intermediary material serves as a precision-isolation mechanism that maintains manufacturing precision by providing a physical and electrical barrier between neighboring conductive contact structures. This intermediary layer ensures that even when contacts are formed to different vertical tiers, the isolation between adjacent structures is maintained, thereby preserving manufacturing precision while enabling electrical communication.
Data Source
AI summary
A microelectronic device comprises a stack structure comprising a vertically alternating sequence of conductive structures and insulative structures arranged in tiers, the stack structure divided into block structures horizontally extending in parallel in a first direction and horizontally separated from one another in a second direction by dielectric slot structures. At least one of the block structures comprises a stadium structure comprising opposing staircase structures each having steps comprising edges of the tiers, and conductive contact structures vertically extending to and in contact with at least some of the conductive structures at the steps, the conductive contact structures positioned proximate horizontal boundaries of the stadium structure in the second direction. Related memory devices, electronic systems, and methods are also described.