Dual-Sided Laser Chip Cooling With an Overhanging Interposer

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Solution Overview

Problem

Current laser chip cooling solutions are limited to single-sided cooling due to wire bonds on the top surface, necessitating expensive and complex high-performance cooling methods like thermoelectric or liquid cooling to manage thermal control effectively.

Innovation Solution

Implementing a dual-sided cooling architecture by replacing wire bonds with a thermally conductive interposer that overhangs the laser chip, allowing for thermal coupling to both the top and bottom surfaces, enabling the use of less complex and cost-effective air-cooled heatsinks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If single-sided cooling architecture is used with wire bonds on top surface, then electrical connection is achieved, but thermal management capability deteriorates requiring expensive cooling solutions

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the electrical connection function from the top surface wire bonds and relocates it to the bottom surface through conductive pillars. This extraction clears the top surface for cooling substrate placement, resolving the contradiction by separating electrical connection (moved to bottom) from thermal management (applied to top surface).

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from single-sided (one-dimensional) cooling to dual-sided (two-dimensional) cooling by adding cooling capability to both top and bottom surfaces. This dimensional expansion allows simultaneous electrical connection and effective thermal management without requiring complex single-sided cooling systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If thermoelectric or liquid cooling solutions are used for single-sided cooling, then thermal control is improved, but manufacturing cost increases

Engineering Contradiction:
Improvelaser chip temperature controlVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies cooling to both top and bottom surfaces (excessive action beyond single-sided cooling), which distributes thermal management across two surfaces. This partial application of cooling to each surface reduces the thermal load on individual cooling systems, enabling the use of simpler, less expensive cooling solutions while maintaining effective temperature control.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If wire bonds are placed on top surface for electrical connection, then electrical functionality is achieved, but cooling substrate placement area is reduced

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidcooling substrate placement area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the electrical connection function from the top surface wire bonds and relocates it to the bottom surface through conductive pillars. This extraction completely clears the top surface for cooling substrate placement, resolving the contradiction by separating electrical connection (moved to bottom) from thermal management (applied to top surface).

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bottom surface is given dual functionality: it serves both for electrical connection (through conductive pillars) and as a mounting surface for the cooling substrate. This multi-functionality resolves the contradiction by making the bottom surface serve both purposes simultaneously, eliminating the need for wire bonds on the top surface.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces thermal resistance and lowers costs by allowing dual-sided cooling with air-cooled solutions, achieving effective thermal management with less complex cooling systems.

Implementation Method 1

a thermally conductive interposer that overhangs the laser chip, allowing for thermal coupling to both the top and bottom surfaces

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

allowing for the use of less complex and cost-effective air-cooled heatsinks

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

air-cooled heatsinks

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3989375B1Novel package designs to enable dual-sided cooling on a laser chip
Publication Date: 2024.05.29 INTEL CORP
  • EP3989375B1 patent drawingFigure 1~2A
  • EP3989375B1 patent drawingFigure 2B~3B
  • EP3989375B1 patent drawingFigure 3C~3D

AI summary

Embodiments disclosed herein include dual sided cooling architectures for laser packages. In an embodiment, an electronic package comprises a package substrate, and a laser chip attached to the package substrate. In an embodiment, the laser chip has a first surface and a second surface opposite from the first surface. In an embodiment, an interposer is disposed over the laser chip, where the interposer overhangs an edge of the laser chip. In an embodiment, the electronic package further comprises an interconnect between the interposer and the package substrate.