Integrated Circuit Cell Layout With N-PPNN-P Dopant Stacking
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing the footprint of integrated circuits (ICs) due to limitations in transistor placement and pitch, leading to increased space usage and inefficiencies in chip design.
Innovation Solution
The implementation of an N-PPNN-P dopant-stack architecture in ICs, where transistors are relocated to previously empty spaces above and below standard cells, allowing for a narrower cell width and increased height without significant disadvantage, thereby reducing the overall footprint by optimizing the arrangement of semiconductor cell regions and active regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If transistors are placed in traditional standard cell regions, then transistor functionality is maintained, but chip footprint increases
Solution Approach 1:
The patent applies dimensionality change by moving transistors from the traditional planar standard cell region into the vertical dimension of the trench structure. Transistors are placed in the trench bottom region and sidewall regions, utilizing the third dimension (depth) to reduce the horizontal footprint of the logic circuit while maintaining transistor functionality and electrical connections.
Solution Approach 2:
The patent implements nesting by placing transistors within the trench structure itself. The trench contains multiple transistor regions including bottom transistors and sidewall transistors, effectively nesting functional elements within the structural feature. This nested arrangement allows transistors to occupy space that would otherwise be structural, reducing overall chip area.
2Quantity of substance
If transistor pitch is reduced to increase density, then transistor density increases, but manufacturing precision requirements worsen
Solution Approach 1:
The patent resolves the pitch precision problem by transitioning from two-dimensional planar spacing to three-dimensional spatial arrangement. Transistors are distributed in multiple levels within the trench structure (bottom and sidewall regions), allowing high transistor density without requiring extremely tight horizontal pitch control, as the vertical dimension provides additional spacing.
Solution Approach 2:
The patent segments the transistor array into distinct spatial zones within the trench: bottom transistors in the trench bottom region and sidewall transistors in the sidewall regions. This segmentation allows independent optimization of each group's pitch and spacing, reducing the overall manufacturing precision requirements compared to a uniform high-density planar array.
3Area of stationary object
If cell width is narrowed to reduce footprint, then chip area decreases, but cell height must increase significantly
Solution Approach 1:
The patent uses nesting to place multiple transistor regions within the trench structure, allowing the cell width to be narrowed while the increased height is compensated by the vertical utilization of the trench. The trench sidewalls and bottom provide additional transistor placement areas that offset the reduced horizontal dimension.
Solution Approach 2:
The patent transforms the area-height tradeoff by utilizing the vertical dimension of the trench. Instead of simply increasing cell height in the planar direction, the design extends into the depth dimension, placing transistors at different vertical levels within the trench structure, thereby reducing the effective horizontal footprint without proportionally increasing the planar cell height.
4Area of stationary object
If standard cell layout is used, then design simplicity is maintained, but cumulative footprint across multiple ICs increases
Solution Approach 1:
The patent reduces cumulative footprint by transitioning from two-dimensional standard cell stacking to three-dimensional trench-based arrangements. Multiple logic circuits utilizing trench structures can be packed more efficiently in the horizontal plane, and the vertical stacking of trenches provides additional density without requiring complex interconnections between layers.
Solution Approach 2:
The patent merges the structural function of the trench with the functional elements of the transistors. The trench structure simultaneously serves as the mechanical feature and the transistor housing, eliminating the need for separate standard cell structures and reducing the overall footprint when multiple circuits are combined on the chip.
Data Source
AI summary
An integrated circuit (IC) includes a first, second and third semiconductor cell regions. The first cell region includes a first active region having a first dopant type. The second semiconductor cell region abuts the first cell region in a second direction, and includes second and third active regions having correspondingly a second dopant type and the first dopant type. The second active region is between the first and third active regions. The third cell region abuts the second cell region in the second direction, and includes a fourth active region having the second dopant type. The third active region is between the fourth active region and the second active region. The second semiconductor cell region has a height 2H, and the first, second and third semiconductor cell regions collectively have a height 3H.