Shield Ring Wire for Accurate Load Data Extraction in Semiconductor Hierarchical Layouts
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Solution Overview
Problem
In semiconductor device design using hierarchical layout techniques, the accuracy of extracting actual load data, such as wire resistance and capacitance, is compromised at boundary portions between hierarchical blocks due to undetermined layouts and the need for dummy metals, leading to prolonged design times and potential timing constraints.
Innovation Solution
Incorporating a shield ring wire with sections extending in both preferential and non-preferential directions around hierarchical blocks, which eliminates the need for dummy metals at boundaries and allows for accurate extraction of load data by providing a defined space that adheres to layout rules, thereby reducing design time and avoiding timing constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hierarchical layout designing technique is used to divide semiconductor device into multiple hierarchical blocks for parallel design, then design time is reduced and productivity is improved, but measurement precision of actual load data extraction deteriorates at boundary portions between hierarchical blocks
Solution Approach 1:
The shield ring wire is preliminarily configured around hierarchical blocks before actual load data extraction. This preliminary structure defines the extraction region boundaries, ensuring that when hierarchical blocks are designed in parallel, the load data extraction at boundary portions can proceed with high accuracy without waiting for adjacent block layouts to be finalized. The shield ring wire establishes a predetermined extraction region that isolates the measurement process from uncertainties in neighboring block designs.
2Manufacturing precision
If dummy metal is introduced to maintain layout rules at boundary portions, then manufacturing precision is maintained, but device complexity increases and design time increases
Solution Approach 1:
The shield ring wire extracts and isolates the boundary region management function from the main wiring structure. By configuring a dedicated shield ring wire around hierarchical blocks, the patent separates the boundary portion from the internal wiring design, allowing dummy metals to be confined to specific regions within the extraction region rather than requiring them throughout the entire device. This reduces overall device complexity while maintaining layout rule compliance.
Solution Approach 2:
The shield ring wire creates a localized extraction region with distinct properties around each hierarchical block. Within this locally defined region, layout rules can be specifically managed with dummy metals only where necessary at boundaries, rather than applying uniform constraints across the entire device. This local quality approach maintains manufacturing precision at critical boundary portions while minimizing unnecessary complexity in other areas.
3Object-affected harmful factors
If shield wire is provided at boundary sides without external coupling terminals, then crosstalk noise is reduced, but device complexity increases
Solution Approach 1:
The shield ring wire serves multiple functions simultaneously: it defines the extraction region boundary for accurate load data extraction, provides shielding against crosstalk noise at hierarchical block boundaries, and maintains layout rule compliance. By consolidating these functions into a single structural element rather than separate components, the patent reduces device complexity while achieving crosstalk noise reduction, layout compliance, and measurement accuracy.
Data Source
AI summary
A metal wiring layer includes a plurality of hierarchical blocks each divided by a side that serves as a boundary. One of the hierarchical blocks is placed to extend along the outer periphery of the self hierarchical block, and includes: a shield ring wire formed by a single metal wire or by a plurality of metal wires; and a plurality of metal wires that are placed inside the shield ring wire and extend in a preferential direction determined in advance. The shield ring wire has a first section extending in the preferential direction and a second section extending in a non-preferential direction perpendicular to the preferential direction.