Bondwire Faraday Cage for Crosstalk Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In high-frequency SERDES link implementations using low-cost bondwire packages, bondwire-to-bondwire crosstalk degrades signal quality due to limited die space, where previous methods of spacing bondwires are not effective.

Innovation Solution

The implementation of shielding bondwires connected to a reference voltage and each other on both the package and die sides forms a two-dimensional Faraday cage around victim bondwires, reducing crosstalk noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spacing between bondwires is increased to reduce crosstalk, then signal quality improves, but die space utilization deteriorates

Engineering Contradiction:

Improvesignal qualityVSAvoiddie space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent introduces shielding bondwires as intermediary elements positioned between noisy aggressor bondwires and sensitive victim bondwires. These shielding bondwires act as mediators that block electromagnetic coupling between the two groups, reducing crosstalk without requiring increased spacing between functional bondwires. The shielding bondwires are connected to reference voltage on the package side and to each other on the die side, forming a two-dimensional Faraday cage structure that effectively isolates the victim bondwires from electromagnetic interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If shielding bondwires are added to reduce crosstalk, then signal-to-noise ratio improves, but device complexity increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidbondwire configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the electrical connection parameters of the shielding bondwires to achieve effective shielding with minimal complexity. Specifically, the shielding bondwires are connected to reference voltage on the package side and to each other on the die side, creating a two-dimensional Faraday cage configuration. This parameter change optimizes the shielding effectiveness while maintaining compatibility with standard bonding processes and existing package structures, avoiding the need for complex three-dimensional shielding structures or additional connection layers.

Inventive Principle:

Principle #35Parameter changes

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

This configuration reduces crosstalk by up to 10 dB, particularly effective at lower frequencies, thereby enhancing signal-to-noise ratios and protecting sensitive analog signals.

Implementation Method 1

Methodology Applied

Scientific EffectFaraday cage: Faraday Cage

Data Source

PatentUS8664774B1Bondwire configuration for reduced crosstalk

Publication Date: 2014.03.04 LATTICE SEMICON CORP

AI summary

To protect victim bondwires in a packaged electronic component from crosstalk induced by noisy aggressor bondwires, shielding bondwires are configured between the victim bondwires and the aggressor bondwires. The shielding bondwires, on either side of the victim bondwires, are connected to the same reference voltage on the package side of the component and to each other on the die side of the component, e.g., via a metal connection mounted on the die. As configured in one embodiment, the shielding bondwires and metal connection form a two-dimensional Faraday cage that shields the victim bondwires from crosstalk induced by the aggressor bondwires.