VCSEL Substrate with Conductor-Filled Trench for Heat Dissipation

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Solution Overview

Problem

Conventional substrates for VCSEL chips, such as Cu-core FR4 and HTCC substrates, exhibit high thermal resistance, leading to inadequate heat dissipation and performance degradation of the VCSEL chip due to increased temperature.

Innovation Solution

A substrate with a conductive core and a conductor-filled trench extending through a layer stack to the conductive core, allowing for improved heat dissipation and reduced thermal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional substrates (Cu-core FR4 or HTCC) are used for VCSEL chip mounting, then the substrate structure is simple and easy to manufacture, but thermal resistance is high leading to inadequate heat dissipation

Engineering Contradiction:

Improvesubstrate manufacturing simplicityVSAvoidVCSEL chip temperature

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The substrate is segmented into multiple functional layers including a conductive core, insulating layers, and conductor-filled trenches. This segmentation allows each layer to perform its specific function optimally - the conductive core provides thermal conduction path while insulating layers provide electrical isolation, resolving the contradiction between manufacturing simplicity and heat dissipation effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The substrate employs composite material structure combining conductive materials (copper core, conductor-filled trenches) with insulating materials (FR4 layers, alumina). This composite approach enables simultaneous achievement of electrical isolation and thermal conduction, addressing the heat dissipation problem while maintaining manufacturing feasibility through established composite material processing techniques.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional substrates are used, then manufacturing process is simple, but heat dissipation performance is inadequate causing VCSEL performance degradation

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidVCSEL chip performance stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The conductor-filled trenches act as intermediary thermal conduction paths between the VCSEL chip and the conductive core. These trenches provide dedicated thermal pathways that mediate heat transfer from the chip to the core, improving heat dissipation performance and reliability while using standard fabrication processes to maintain manufacturing simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If the conductor-filled trench size matches the VCSEL chip size, then heat dissipation efficiency is maximized, but manufacturing precision requirements increase

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidtrench size matching precision

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent provides flexibility in trench dimensional parameters, allowing the trench size to match either the VCSEL chip size or the emission region size. This parameter variation approach enables optimization of heat dissipation efficiency while accommodating manufacturing precision capabilities - smaller trenches for high-precision applications, larger trenches for standard manufacturing processes.

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

The substrate with a conductor-filled trench significantly enhances heat dissipation for the VCSEL chip, improving its performance in terms of optical power, wavelength, and efficiency, while also reducing power consumption and response time.

Implementation Method 1

a substrate with a conductive core and a conductor-filled trench extending through a layer stack to the conductive core, allowing for improved heat dissipation and reduced thermal resistance

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20250070532A1Optical device including a substrate with a conductor-filled trench on a conductive core

Publication Date: 2025.02.27 WELLS FARGO BANK NA

AI summary

An optical device may include a substrate including a conductive core, a first layer stack on a first surface of the conductive core, a conductor-filled trench extending through the first layer stack to the conductive core such that the conductor-filled trench is on the first surface of the conductive core, and a second layer stack on a second surface of the conductive core. The optical device may include a vertical-cavity surface-emitting laser (VCSEL) chip above the conductor-filled trench. The VCSEL chip may include an array of VCSELs. A size of the conductor-filled trench may match a size of the VCSEL chip, match a size of an emission region of the array of VCSELs, or be greater than the size of the emission region of the array of VCSELs and less than the size of the VCSEL chip.