PCB Bridge Chip-to-Chip Interconnection Impedance Matching

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Solution Overview

Problem

Current chip-to-chip interconnection methods, such as wire bonding and silicon bridges, face challenges with impedance matching, limited trace width flexibility, and yield loss issues, particularly in advanced packaging technologies requiring high bandwidth and flexibility.

Innovation Solution

A PCB bridge with adjustable dielectric material and trace width, manufactured using laser cutting techniques, allowing for flexible impedance matching and reworkability, which can be employed in both 2D and 3D configurations to connect semiconductor chips.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wire bonding is used for chip-to-chip interconnection, then flexibility of interconnection is improved, but impedance matching deteriorates

Engineering Contradiction:

Improveflexibility of interconnectionVSAvoidimpedance matching

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a PCB bridge as an intermediary component between two semiconductor chips. This bridge includes a signal trace with adjustable width and dielectric material with adjustable constant, serving as a mediator that enables both flexible interconnection and proper impedance matching. The PCB bridge translates the flexible wire bonding approach into a controlled impedance transmission line structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs parameter changes by making the trace width and dielectric constant adjustable variables. By changing these parameters, the characteristic impedance of the transmission line can be controlled to match source and load impedances, while maintaining the flexibility advantage of wire bonding through the PCB bridge interface.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If silicon bridge is used for chip-to-chip interconnection, then impedance matching is improved, but manufacturing complexity deteriorates

Engineering Contradiction:

Improveimpedance matchingVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a PCB bridge that can be manufactured using standard PCB fabrication processes, which are more accessible and less complex than silicon bridge fabrication. The PCB bridge serves as a disposable or replaceable intermediary component that achieves impedance matching without requiring complex silicon processing or flip-chip bonding infrastructure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical and process-intensive silicon bridge fabrication with a PCB-based transmission line structure. This substitution uses standard PCB manufacturing techniques (copper tracing, dielectric lamination) instead of complex silicon processing, reducing manufacturing complexity while maintaining electrical performance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If trace width is limited by bonding pad pitch, then device miniaturization is improved, but impedance matching flexibility deteriorates

Engineering Contradiction:

Improvetrace widthVSAvoidimpedance matching flexibility

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent resolves the trace width limitation by moving the impedance matching control to another dimension - the dielectric constant. While trace width remains constrained by bonding pad pitch, the adjustable dielectric constant provides an additional degree of freedom to achieve the desired characteristic impedance, effectively compensating for the limited trace width adjustment range.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The PCB bridge provides flexible impedance matching, avoids signal reflections, and supports high bandwidth transmission while being reworkable and cost-effective, with the ability to handle various architectures and reduce packaging requirements.

Implementation Method 1

C=shunt capacitance per unit length, in F/m. represents the capacitance due to close proximity of the conductors.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The chip-to-chip interconnection create the connection between two chips to achieve maximum power transfer and ultra-high bandwidth transmission.

Methodology Applied

Scientific EffectElectromagnetic transmission: Electromagnetic Induction

Data Source

PatentUS11546984B1Architecture for chip-to-chip interconnection in semiconductors

Publication Date: 2023.01.03 WELLS FARGO BANK NA

AI summary

A PCB bridge for interconnection of two or more semiconductor chips for data communication between the semiconductor chips includes a plurality of metal strips; and a dielectric material disposed in between the plurality of metal strips. The PCB bridge is employed in a vertical direction in a semiconductor module for interconnection of two or more semiconductor chips, the vertical direction of the PCB bridge provides a flexible impedance matching by adjusting the dielectric material and a trace width of the PCB bridge, and the vertical direction of the PCB bridge avoids signal reflections by matching the impedance to a source, and a trace length of the PCB bridge is limited by spacing in between two semiconductor chips which further limited inductance of the trace of the PCB bridge.