RC-Aware Routing Layer Trimming for Consistent IC Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional IC design layer assignment methods do not adequately consider resistance and capacitance (RC) values, leading to inefficiencies due to large differences in RC values among routed layers, which can be exacerbated by slight changes in design parameters.
Innovation Solution
Perform RC-based layer trimming by generating lists of horizontal and vertical layers sorted by RC values and applying an RC constraint to filter layers, creating a subset for layer assignment that ensures consistent RC values within a permitted range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional layer assignment methods are used without RC consideration, then the routing process is simpler and faster, but the RC values of routed layers vary significantly leading to design inefficiency
Solution Approach 1:
The patent applies parameter changes by filtering layers based on RC value parameters. It establishes an RC value range [RCmin, RCmax] and eliminates layers whose RC values fall outside this range, thereby ensuring that only layers with consistent RC characteristics are used for routing. This directly addresses the contradiction by changing the selection criteria from simple geometric parameters to RC-based parameters.
Solution Approach 2:
The patent implements preliminary action by performing RC-based layer filtering before the actual routing assignment process. The system pre-calculates RC values for all candidate layers, determines the RC range based on reference layers, and eliminates unsuitable layers in advance. This preliminary filtering ensures that subsequent routing operations only consider layers with appropriate RC characteristics, resolving the contradiction between simplicity and precision.
2Reliability
If layers with large RC differences are used for routing, then more layer options are available, but slight design changes cause significant performance variations
Solution Approach 1:
The patent changes the selection parameter from unrestricted layer choices to RC-constrained layer choices. By defining an RC value range and filtering layers based on this parameter, the system ensures that selected layers have stable RC characteristics that are less sensitive to design variations. This maintains reliability while still providing sufficient layer options within the RC constraints.
Solution Approach 2:
The patent employs feedback by using RC values as a criterion for layer selection and elimination. The system calculates RC values for candidate layers, compares them against the reference RC range, and provides feedback by eliminating layers that do not meet the RC criteria. This feedback mechanism ensures that only layers with stable RC characteristics are selected, improving design reliability.
3Manufacturing precision
If RC-based layer filtering is applied, then RC value consistency is improved, but additional processing steps are required
Solution Approach 1:
The patent applies preliminary action by performing RC-based filtering before routing assignment. Although this adds processing steps, it eliminates unsuitable layers in advance, preventing unnecessary routing operations on inappropriate layers. This preliminary filtering reduces the overall computational burden and time spent on iterative routing adjustments, offsetting the initial filtering overhead.
Solution Approach 2:
The patent extracts and eliminates layers with inappropriate RC values from the candidate set before routing assignment. By removing unsuitable layers in advance, the system reduces the number of layers that need to be evaluated during routing, thereby reducing the overall processing time despite the added filtering step.
Data Source
AI summary
Aspects of the present disclosure address systems and methods for layer trimming based on resistance and capacitance (RC) values. Data describing an integrated circuit (IC) design is accessed. The IC design comprises a net and a set of routing layers. A first and second list are generated based on the set of layers. The first list comprises horizontal routing layers and the second list comprises vertical routing layers from the set of routing layers. A permitted range of RC values for routing layers in the IC design are determined. The first and second lists are filtered based on the permitted range of RC values. The first and second filtered lists are merged to create a third list of routing layers. The net is assigned to one or more routing layers selected from the third list for routing purposes.