Semiconductor Device Wiring Stub for Optical Transceiver Data Rate

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Solution Overview

Problem

Current semiconductor devices face challenges in achieving high data rates for optical transceivers due to limitations in the frequency characteristics of optical outputs, particularly in DMT systems, where the 'GB product' needs to be improved to enhance data transmission efficiency.

Innovation Solution

The introduction of a shunt capacitance in the vicinity of the semiconductor laser to alleviate impedance mismatches between the transmission line and the semiconductor laser, causing 'peaking' in the optical output at specific frequencies, thereby increasing the 'GB product and data rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a stub is provided in the wiring near the semiconductor chip mounting area, then the frequency characteristic of the optical output is improved and data rate increases, but the device structure becomes more complex

Engineering Contradiction:
Improvedata rateVSAvoidwiring structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

A stub (intermediary structure) is introduced in the wiring near the semiconductor chip mounting area to act as a mediator that improves frequency characteristics. The stub serves as an intermediate element that modifies the electrical characteristics of the wiring, enabling better signal transmission at higher frequencies without requiring complete redesign of the entire wiring system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stub modifies the electrical parameters (impedance, capacitance) of the wiring system locally, changing the frequency response characteristics. By adjusting the stub's dimensions and position, the wiring's electrical parameters are optimized to achieve peaking in the frequency response, thereby improving data rate without changing the fundamental wiring architecture.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the GB product is improved to enhance data transmission efficiency, then the data rate increases, but the impedance mismatch between transmission line and semiconductor laser causes reflection losses

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidreflection losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The stub converts the harmful effect of impedance mismatch into a beneficial frequency peaking effect. Instead of simply trying to match impedances perfectly, the stub exploits the impedance discontinuity to create constructive interference at desired frequencies, transforming what would normally be a source of reflection losses into a mechanism for enhancing signal strength and data transmission efficiency.

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

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 approach effectively enhances the data rate of optical transceivers by reducing reflection losses and increasing optical output at specific frequencies, improving the overall performance of DMT systems.

Implementation Method 1

The introduction of a shunt capacitance in the vicinity of the semiconductor laser to alleviate impedance mismatches between the transmission line and the semiconductor laser

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10886695B2Semiconductor device
Publication Date: 2021.01.05 RENESAS ELECTRONICS CORP
  • US10886695B2 patent drawing
  • US10886695B2 patent drawing
  • US10886695B2 patent drawing

AI summary

Improve semiconductor device performance. The wiring WL1A on which the semiconductor chip CHP1 in which the semiconductor lasers LD is formed is mounted has a stub STB2 in the vicinity of the mounting area of the semiconductor chip CHP1.