Etch Stop Metal Plates for Reliable 3D Memory Backside Vias
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Solution Overview
Problem
Existing three-dimensional memory devices face challenges in providing efficient electrical connections for backside via structures, which are crucial for supporting write, read, and erase operations of memory cells in vertical NAND strings.
Innovation Solution
The implementation of etch stop metal plates that provide electrical connections for backside via structures through a method involving the formation of an alternating stack of insulating and conductive layers, memory openings, dielectric material portions, and contact via structures, along with integrated via and pad structures, and backside contact pad structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connection methods are used for backside via structures, then manufacturing is simpler, but electrical connection reliability is insufficient
Solution Approach 1:
The connection structure is divided into multiple functional segments: metal plates for electrical connection, dielectric material portions for isolation, contact via structures for vertical access, and integrated via and pad structures for signal routing. This segmentation allows each component to be optimized for its specific function, improving overall electrical connection reliability while maintaining manufacturability through modular fabrication processes.
Solution Approach 2:
The patent implements nested structures where contact via structures are formed within dielectric material portions, which themselves are positioned on metal plates. The integrated via and pad structures further nest within this hierarchy, creating a multi-level nested architecture that achieves complex electrical connections through systematic nesting of functional elements.
2Productivity
If complex multi-layer structures are implemented, then electrical connection efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
Metal plates are formed and positioned in advance before subsequent dielectric and via structures are created. This preliminary action establishes a stable foundation that simplifies later alignment operations, as subsequent layers can be precisely registered to the pre-formed metal plate patterns, reducing the cumulative precision requirements of multi-step processes.
Solution Approach 2:
Dielectric material portions serve as intermediary elements between metal plates and contact via structures. These intermediaries provide mechanical support and electrical isolation, allowing precise positioning of upper layers relative to lower layers without requiring direct contact or complex alignment between all components, thereby reducing overall manufacturing precision requirements.
Data Source
AI summary
A semiconductor structure includes an alternating stack of insulating layers and electrically conductive layers that is located on a front side of at least one semiconductor material layer; memory openings vertically extending through the alternating stack; memory opening fill structures; a dielectric material portion contacting sidewalls of the insulating layers of the alternating stack. In one embodiment, a connection via structure can vertically extend through the dielectric material portion, and a metal plate can contact the connection via structure. Alternately or additionally, an integrated via and pad structure may be provided, which includes a conductive via portion vertically extending through the dielectric material portion and a conductive pad portion located on an end of the conductive via portion.