Multi-Level Contact Structure for Dense Semiconductor Wiring
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Solution Overview
Problem
Forming small-sized wiring structures in semiconductor devices is challenging and requires expensive processing equipment, and achieving proper electrical connections between these structures is difficult due to their minute size and close spacing.
Innovation Solution
The semiconductor device design includes specific configurations of contact plugs and conductive structures with varying heights and widths, allowing for electrical connections that are less prone to misalignment and interference, even when formed at different levels, using advanced lithography processes like EUV and ArF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If wiring structures are formed with minute size and small pitch, then device integration density is improved, but manufacturing difficulty and cost increase significantly
Solution Approach 1:
The patent introduces multiple vertical levels (first level, second level, third level) for conductive structures and contact plugs. By stacking wiring structures vertically rather than only horizontally, the design achieves higher integration density while maintaining manufacturable dimensions at each level. The multi-level architecture allows wiring to be distributed across different z-heights, reducing the pitch requirements at any single level.
Solution Approach 2:
The wiring structure is divided into multiple conductive structures at different levels (first conductive structure, second conductive structure, third conductive structure), each serving specific routing functions. Contact plugs are also segmented into multiple levels to connect between these structures. This segmentation allows each component to be optimized independently for manufacturing while achieving overall high density.
2Reliability
If contact plugs are formed at multiple levels with precise alignment, then electrical connection reliability is improved, but manufacturing complexity and misalignment risk increase
Solution Approach 1:
The patent utilizes the vertical dimension to create multiple levels of contact plugs and conductive structures. Instead of relying solely on precise lateral alignment in a single plane, the design distributes connections across different z-heights. This vertical stacking reduces the cumulative alignment complexity while maintaining reliable electrical pathways through each level.
Solution Approach 2:
The patent forms conductive structures and contact plugs in a predetermined sequence across multiple levels. By establishing the vertical architecture and lower-level connections before upper-level structures, the design simplifies subsequent manufacturing steps. Each level is prepared and positioned in advance, reducing the complexity of final alignment operations.
3Area of moving object
If contact plug size is reduced to match minute wiring structures, then wiring density is improved, but alignment tolerance decreases and manufacturing becomes more difficult
Solution Approach 1:
The patent compensates for reduced contact plug lateral dimensions by utilizing the vertical dimension. Contact plugs are formed at multiple levels with varying heights, allowing larger vertical footprint to compensate for smaller lateral size. This multi-level approach maintains alignment tolerance even as individual contact plug dimensions are reduced for higher density.
Solution Approach 2:
The conductive structures employ composite material systems including barrier layers, conductive layers, and capping layers. This composite structure allows optimization of each layer's properties - the barrier layer provides adhesion and diffusion prevention, the conductive layer provides low-resistance pathways, and the capping layer protects underlying structures. This material composition enables reliable electrical connections with reduced dimensional tolerances.
Data Source
AI summary
A semiconductor device may include a gate structure, first and second source/drain layers, first and second contact plugs, first and second conductive structures, and a third contact plug. The gate structure may be on a substrate. The first and second source/drain layers may be at upper portions, respectively, of the substrate on opposite sidewalls of the gate structure and adjacent thereto. The first and second contact plugs may be on the first and second source/drain layers, respectively, and each contact plugs may extend in a vertical direction. The first and second conductive structures may contact upper surfaces of the first and second contact plugs, respectively. The third contact plug may contact an upper surface of the second conductive structure. A height and a width of the second conductive structure may be greater than a height and a width of the first conductive structure.