Interposer RC Coupling Model for 2.5D IC Signal Integrity
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Solution Overview
Problem
Existing modeling and simulation tools for integrated circuits (ICs) do not effectively account for frequency-dependent capacitive couplings in semiconductor interposers, leading to performance degradation in 2.5D IC designs due to unmodeled electrical coupling between conductors.
Innovation Solution
A tool and method are provided for modeling and simulating frequency-dependent capacitive couplings in semiconductor interposers by generating a substrate mesh model with impedance elements, connecting RC nodes to substrate mesh nodes, and using existing EDA tools to analyze and simulate these effects, thereby improving design accuracy and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing modeling and simulation tools are used for ICs, then the design process is simple and familiar, but frequency-dependent capacitive couplings in semiconductor interposers are not effectively accounted for, leading to performance degradation
Solution Approach 1:
The patent introduces an interposer substrate as an intermediary component between IC dies and the PCB. This substrate, formed from semiconductor material like silicon, provides a platform for mounting multiple IC chips and routing connections among them. The substrate's RC characteristics are modeled to account for electrical coupling effects, thereby improving reliability of the 2.5D IC package while managing the complexity through a standardized intermediary structure.
Solution Approach 2:
The patent applies parameter changes by modeling the interposer substrate's resistance and capacitance characteristics, particularly the frequency-dependent capacitive couplings. By extracting and analyzing RC parameters of the substrate, the tool transforms the physical substrate into an electrical model with specific parameters (resistance values, capacitance values, coupling coefficients) that can be used for accurate simulation of signal integrity and timing in 2.5D IC designs.
2Measurement precision
If RC effects of the interposer are considered, then the electrical coupling between conductors is accurately modeled, but the complexity of the simulation increases
Solution Approach 1:
The patent segments the interposer substrate into a grid of discrete nodes, creating a mesh model where each node represents a specific location on the substrate. This segmentation allows the continuous RC distribution of the substrate to be represented as a finite network of resistors and capacitors connected between nodes. The conductive patterns are also segmented into segments that align with the substrate nodes, enabling precise modeling of electrical coupling at discrete locations while keeping the simulation computationally manageable.
Solution Approach 2:
The patent uses an intermediary modeling layer that extracts RC parameters from the physical interposer substrate and transforms them into an electrical circuit model. This intermediary representation includes substrate resistance values, substrate capacitance values, and coupling coefficients that mediate between the physical substrate geometry and the electrical simulation requirements. This intermediary model achieves high measurement precision for electrical coupling while avoiding the need for full-wave electromagnetic simulations.
3Manufacturing precision
If a detailed substrate mesh model is created, then the RC nodes are accurately connected to substrate locations, but the computational resources and time required increase
Solution Approach 1:
The patent applies partial action by creating substrate mesh nodes only at locations where they are needed for accurate RC modeling. Rather than creating a uniformly dense mesh across the entire substrate, the tool places nodes strategically at locations corresponding to conductor segments, via locations, and regions of interest. This partial meshing approach achieves the necessary manufacturing precision for RC node placement while significantly reducing the total number of nodes and edges in the model, thereby decreasing computational resources and design cycle time.
Data Source
AI summary
A method comprises analyzing front side conductive patterns and back side conductive patterns on a semiconductor interposer using a machine implemented RC extraction tool, and outputting data representing a plurality of respective RC nodes from the RC extraction tool to a tangible persistent machine readable storage medium. A substrate mesh model of the semiconductor interposer is generated, having a plurality of substrate mesh nodes. Each substrate mesh node is connected to adjacent ones of the plurality of substrate mesh nodes by respective substrate impedance elements. A set of inputs to a timing analysis tool is formed. The plurality of RC nodes are connected to ones of the plurality of substrate mesh nodes of the substrate mesh model. The set of inputs is stored in a tangible machine readable storage medium.