3D Memory Contact Plug Structure for Smaller Hookup Area
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Solution Overview
Problem
Existing memory devices with three-dimensionally disposed memory cells face challenges in minimizing the area required for the hookup area, leading to increased space usage and potential instability during manufacturing due to high aspect ratios in the stacked structure.
Innovation Solution
The memory device employs a staggered array of contact plugs and support pillars, with the support pillars not centered on the contact plugs, reducing the area needed for the hookup area and maintaining low resistance between the contact plugs and conductors, and in the second embodiment, contact plugs are arranged in a hexagonal shape to further stabilize the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If contact plugs are arranged in a dense grid pattern to minimize hookup area, then area is reduced, but manufacturing stability deteriorates due to high aspect ratios in the stacked structure
Solution Approach 1:
The patent applies asymmetry by positioning support pillars at offset locations relative to contact plugs rather than in a symmetric centered arrangement. Specifically, support pillars are located at coordinates that are shifted from the contact plug centers, creating an asymmetric configuration that reduces the required hookup area while maintaining structural stability during manufacturing processes.
Solution Approach 2:
The patent transitions from a two-dimensional grid arrangement to a three-dimensional staggered configuration by vertically offsetting support pillars from contact plug positions. This dimensional change allows the structure to achieve compact footprint while distributing stress more effectively across multiple layers, thereby maintaining manufacturing stability.
2Reliability
If support pillars are centered on contact plugs for structural support, then stability is improved, but hookup area increases
Solution Approach 1:
The patent deliberately positions support pillars asymmetrically relative to contact plugs, with horizontal and vertical offsets that prevent direct alignment. This asymmetric arrangement reduces the bounding box area of the hookup region while the support pillars still provide adequate structural support through their offset positioning.
Solution Approach 2:
The patent segments the structural support function from the contact plug centers by placing support pillars at separate, offset locations. This segmentation allows the support function to be distributed across multiple offset positions rather than concentrated at centered locations, reducing the overall area requirement.
Data Source
AI summary
Contact plugs extend along a first axis. Each contact plug includes a second conductor and a first insulator. A first insulator is between the first conductors and the second conductor. A lower face of each contact plug is in contact with an upper face of a unique one of the first conductors. A first one and second one of the contact plugs are adjacent along a second axis that crosses the first axis. A third one of the contact plugs is between the first and second contact plugs on the second axis, and is at a different position from positions of the first and second contact plugs on a third axis orthogonal to the first and second axes.