Standard Cell Dummy Areas Mitigate Local Layout Effects
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Solution Overview
Problem
The miniaturization of semiconductors increases the influence of peripheral structures on standard cells, leading to local layout effects (LLE) that affect the performance and operation of integrated circuits (ICs), which existing technologies have not adequately addressed.
Innovation Solution
Incorporating dummy areas adjacent to the cell areas in standard cells within integrated circuits, these dummy areas are electrically connected to power rails and actively biased to mitigate the local layout effects, thereby improving the performance and facilitating interconnection operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the size of standard cell patterns is reduced during miniaturization, then the integration density is improved, but the local layout effect from peripheral structures increases and degrades performance
Solution Approach 1:
Dummy areas are introduced as intermediary structures between the active cell area and peripheral structures. These dummy areas act as buffer zones that mediate the interaction between the standard cell and surrounding elements, reducing the direct influence of peripheral layouts on the active circuit region.
Solution Approach 2:
The dummy areas are strategically placed only in specific locations where local layout effects are most pronounced. By applying this principle, the patent selectively enhances protection in critical regions without unnecessarily increasing the overall cell area, thus maintaining integration density while mitigating LLE in problem areas.
2Reliability
If dummy areas are added to standard cells to reduce local layout effects, then the performance is improved, but the area of the standard cell increases
Solution Approach 1:
Instead of adding dummy areas to all standard cells uniformly, the patent applies dummy areas only to specific standard cells where local layout effects are most significant. This partial application approach ensures sufficient performance improvement in critical areas while minimizing the overall area increase across the entire integrated circuit.
Solution Approach 2:
The standard cell structure is segmented into distinct functional regions: the active cell area containing the circuit and the dummy areas serving as protective buffers. This segmentation allows for optimized placement of dummy areas only where needed, rather than uniformly increasing the area of all cells.
3Object-affected harmful factors
If more dummy areas are provided in standard cells, then the mitigation of local layout effects is enhanced, but the device complexity increases
Solution Approach 1:
The dummy areas are designed with uniform characteristics matching the active cell area, using the same material composition and structural properties. This homogeneity simplifies the manufacturing process and reduces device complexity by eliminating the need for specialized processing steps for dummy areas, while still providing effective mitigation of local layout effects.
Data Source
AI summary
A standard cell of an IC includes a cell area including a transistor configured to determine a function of the standard cell; a first dummy area and a second dummy area respectively adjacent to two sides of the cell area in a first direction; and an active area extending in the first direction across the cell area, the first dummy area, and the second dummy area. The active area includes a first active area and a second active area spaced apart from each other in a second direction perpendicular to the first direction and extend parallel to each other in the first direction. At least one of the first active area and the second active area provided in the first dummy area is biased, and at least one of the first active area and the second active area provided in the second dummy area is biased.