Semiconductor Dummy Region Layout for Critical Dimension Uniformity
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Solution Overview
Problem
Existing semiconductor fabrication technologies face challenges in achieving across-chip uniformity and electrical performance due to physical variations during the manufacturing of semiconductor structures, particularly in the integration of device and dummy regions.
Innovation Solution
The introduction of dummy regions in semiconductor structures, designed to mitigate loading effects during fabrication processes, where these regions are formed on the substrate alongside device regions, and their layout is optimized to converge the critical dimension distribution and reduce defects, using a method that includes defining dummy N-type and P-type transistors similar to functional transistors but non-functional, and blank cells to enhance uniformity and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If device regions are fabricated without dummy regions, then manufacturing process is simpler, but across-chip uniformity and electrical performance deteriorate due to physical variations
Solution Approach 1:
The patent creates dummy regions that are copies of device regions in terms of geometric layout and material composition, but without functional connectivity. These dummy copies mimic the physical characteristics of functional devices to compensate for manufacturing variations, thereby improving across-chip uniformity without adding functional complexity
Solution Approach 2:
The patent employs dummy regions with identical material composition and geometric dimensions as device regions to create a homogeneous fabrication environment. This homogeneity ensures that manufacturing processes experience consistent physical conditions across the entire chip, reducing variations in critical dimensions and improving electrical performance uniformity
2Manufacturing precision
If dummy regions are added to mitigate loading effects, then across-chip uniformity improves, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the fabrication of dummy regions with device regions into a single integrated process flow. Both region types are patterned, etched, and filled simultaneously using the same manufacturing steps, eliminating the need for separate dummy region fabrication processes and reducing overall process complexity
Solution Approach 2:
The patent incorporates dummy regions into the layout design phase before fabrication begins. By pre-positioning dummy regions in areas where loading effects are anticipated, the manufacturing process proceeds without requiring additional corrective steps or process adjustments, thereby maintaining ease of manufacture
3Reliability
If more dummy regions are introduced, then fabrication defects are reduced, but the number of transistors and area increases
Solution Approach 1:
The patent applies dummy regions selectively in specific locations where manufacturing variations and loading effects are most pronounced, such as edge regions or areas with high device density gradients. This localized application of dummy structures provides defect reduction benefits without unnecessarily increasing the overall chip area
Data Source
AI summary
A semiconductor structure and a method of fabricating thereof including a substrate having a device region and a dummy region. The device region includes a number of N-type device cells having a plurality of operational N-type transistors and a number of P-type device cells having a plurality of operational P-type transistors. The dummy region includes a number of N-type dummy cells having a plurality of non-operational N-type transistors and a number of P-type dummy cells having a plurality of non-operational P-type transistors, and a total number of the N-type device cells and P-type device cells is equal to a total number of the N-type dummy cells and P-type dummy cells.