Ground Bond Wire Crossover Layout for VCSEL Crosstalk Reduction

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Solution Overview

Problem

Crosstalk levels in driverless optical modules using VCSEL arrays are increased due to electromagnetic interference between signal bonding wires, leading to system performance degradation.

Innovation Solution

A semiconductor package design featuring ground bonding wires that cross over signal bonding wires to provide additional return paths and EMI shielding, reducing crosstalk levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wire bonding process is used to connect VCSEL pads to PCB traces, then electrical connection is established, but electromagnetic interference between signal bonding wires increases crosstalk levels

Engineering Contradiction:

Improveelectrical connectionVSAvoidcrosstalk level

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ground bonding wire acts as an intermediary element positioned between signal bonding wires to shield them from electromagnetic interference. The ground wire serves as a mediator that absorbs or redirects EMI away from signal paths, reducing crosstalk while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful electromagnetic interference into a beneficial shielding effect by strategically placing ground bonding wires that cross over signal bonding wires. The ground wires, which would normally just provide reference potential, are repurposed to actively shield signal paths from EMI, turning a passive element into an active protection mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If ground bonding wire crosses over signal bonding wire, then EMI shielding is provided, but wire bonding process complexity increases

Engineering Contradiction:

ImproveEMI shieldingVSAvoidwire bonding process

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The wire bonding process is made dynamic and adaptive by allowing ground bonding wires to cross over signal bonding wires at specific points rather than following fixed parallel paths. This dynamic routing approach enables the ground wires to optimally position themselves for EMI shielding while maintaining compatibility with standard wire bonding equipment and processes.

Inventive Principle:

Principle #15Dynamics

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 design effectively reduces crosstalk levels by creating additional paths for electromagnetic interference shielding, thereby enhancing the performance of driverless optical modules.

Implementation Method 1

A semiconductor package design featuring ground bonding wires that cross over signal bonding wires to provide additional return paths and EMI shielding, reducing crosstalk levels

Methodology Applied

Scientific EffectElectromagnetic interference shielding: Faraday Cage

Data Source

PatentUS20230402818A1Semiconductor package having ground bonding wire that crosses over signal bonding wire for crosstalk reduction and associated method

Publication Date: 2023.12.14 AIROHA TECHNOLOGY CORPORATION

AI summary

A semiconductor package includes a printed circuit board (PCB), a semiconductor device, a first signal bonding wire, and a first ground bonding wire. The PCB includes a first PCB ground pad and a first PCB signal trace. The semiconductor device includes a first device ground pad and a first device signal pad. The first signal bonding wire is coupled between the first device signal pad and the first PCB signal trace. The first ground bonding wire is coupled between the first device ground pad and the first PCB ground pad, wherein the first ground bonding wire crosses over the first signal bonding wire.