Antenna Cell Placement for Predictable IC Antenna Violation Fixes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As technology nodes decrease in integrated circuits, the reduced channel size and increased metal layers lead to antenna violations, making conventional layer hopping unpredictable and causing design rule checking convergence challenges, while the lack of space for antenna diodes complicates the issue.
Innovation Solution
The introduction of an antenna cell, a predefined interconnect structure, which is positioned on segments of nets with antenna violations to remedy the issue by layer hopping to the top layer, reducing delay variations and improving design rule checking convergence without the need for antenna diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If layer hopping is used to fix antenna violation, then antenna violation is remedied, but timing variations increase and design rule checking convergence becomes unpredictable
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-positioning antenna cells at specific locations on net segments before routing is completed. The antenna cell placement is determined in advance based on net geometry and antenna violation assessment, allowing the routing tool to insert antenna cells at optimal positions without causing timing variations or convergence issues during subsequent routing iterations.
2Reliability
If antenna diodes are added to fix antenna violation, then antenna violation is remedied, but device complexity increases and placement becomes difficult in reduced channels
Solution Approach 1:
The patent extracts the antenna violation remedy function from the traditional antenna diode approach and implements it through a dedicated antenna cell structure. This antenna cell is a self-contained interconnect structure that can be placed independently without requiring additional diodes or complex placement procedures, thereby reducing device complexity while maintaining effectiveness in remedying antenna violations.
Solution Approach 2:
The antenna cell serves as an intermediary structure between the net segment and the antenna violation problem. Instead of directly adding diodes to the net, the antenna cell acts as a mediator that provides the necessary electromagnetic shielding and charge dissipation paths, thereby resolving the antenna violation without increasing device complexity.
3Area of stationary object
If channel size is reduced to reduce die size, then die size decreases, but space for antenna diodes is eliminated
Solution Approach 1:
The patent resolves the space constraint by transitioning from a two-dimensional planar placement approach (antenna diodes in channels) to a three-dimensional solution (antenna cells utilizing vertical interconnect structures). The antenna cell leverages the vertical dimension through multiple metal layers and via connections, providing the necessary electromagnetic shielding and charge dissipation paths without requiring additional horizontal space in the reduced channels.
Data Source
AI summary
A method and system for fixing antenna violation of antenna in an integrated circuit. A pin of a macro circuit is selected, the pin being electrically coupled to a gate of a transistor. A gate area and an antenna ratio for a layer of the integrated circuit is determined and a net area of a net which avoids antenna violation in the integrated circuit is calculated. A length of the net with the net area based on the gate area and the antenna ratio is identified. The antenna cell is positioned across a remainder of a segment of the net in a layer resulting from a portion of the segment being removed, where a distance from the portion to the gate over the net is the length and where the antenna cell routes the net to a top layer of the integrated circuit independent of a position of the antenna cell in the integrated circuit.