Microfluidic Chip Carrier Socket for 3D EPIC Thermal Management

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Solution Overview

Problem

3D Electronic Photonic Integrated Circuit (EPIC) stacks face challenges in thermal management due to increased power density and thermal resistance from vertically stacked layers, and lack of suitable designs for liquid cooling and interconnectivity.

Innovation Solution

The solution involves a chip carrier socket and printed circuit board assembly with conductive vias for electrical connectivity, fluid inlet and outlet ports for microfluidic cooling, and optical vias for photonic interconnects, enabling efficient thermal management and integration of electronic and photonic layers with reduced copper connectivity and enhanced cooling through micro/nano-fluidic channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vertically stacked 3D EPIC layers are used to increase computing density, then processing power and integration density are improved, but thermal management becomes more difficult due to increased power density and thermal resistance

Engineering Contradiction:
Improvecomputing densityVSAvoidthermal management
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent implements microfluidic cooling channels integrated within the 3D EPIC stack, using liquid coolant flow to actively remove heat from hot spots. Fluid inlet and outlet ports are provided in the carrier, with channels extending between stacked IC dies to enable efficient thermal extraction without compromising computing density.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If traditional heatsinks are used for cooling, then heat removal from top or bottom layers is improved, but heat from intermediate layers is blocked by electronic isolation layers causing very high temperatures

Engineering Contradiction:
Improveheat removalVSAvoidcooling effectiveness
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is segmented into multiple independent channels that access different layers of the 3D stack. Rather than a single heatsink, the patent provides separate fluid channels that can cool intermediate layers directly, bypassing the blocking effect of isolation layers and enabling targeted thermal management for each layer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional 2D heatsink cooling to 3D integrated microfluidic channels that penetrate through multiple layers. The cooling architecture moves from surface-level heat removal to volumetric cooling throughout the stack, allowing heat extraction from intermediate layers that were previously inaccessible.

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

3Reliability

If more conductive vias are added for electrical connectivity, then electrical interconnect performance is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveelectrical connectivityVSAvoidvia structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The carrier structure is designed with multi-functionality, where the same via structures serve both electrical connectivity and fluidic cooling purposes. Conductive vias are integrated with microfluidic channels, allowing a single structural element to fulfill multiple functions and reducing overall device complexity despite the need for extensive interconnects.

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

4Speed

If optical vias are implemented for photonic interconnects, then communication bandwidth is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecommunication bandwidthVSAvoidvia alignment
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent merges electrical and optical via structures into a unified carrier architecture. Optical vias are aligned with conductive vias and microfluidic channels, allowing simultaneous fabrication and assembly. This integration reduces the number of separate alignment operations and simplifies manufacturing despite the high precision requirements for photonic interconnects.

Inventive Principle:
Principle #5Merging (Combining)

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 design facilitates high-density computing with low power consumption, flexible integration, and efficient thermal extraction, supporting millions of processor cores while allowing for scalable and modular EPIC systems with improved thermal uniformity and reduced interconnect delays.

Implementation Method 1

The carrier bottom comprises one or more conductive vias passing from a first surface of the carrier bottom to an opposite second surface of the carrier bottom, each of the conductive vias being configured to provide electrical connectivity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

One or both of the carrier bottom and the carrier top comprises a fluid inlet port and a fluid outlet port, the fluid inlet port and fluid outlet port each being configured to allow passage of cooling fluid

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

efficient thermal extraction, supporting millions of processor cores while allowing for scalable and modular EPIC systems with improved thermal uniformity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

either or both of the carrier bottom and the bottom top comprises an optical via passing from one surface to another of the carrier bottom or carrier top

Methodology Applied
Scientific EffectOptical transmission: Optical Fibre

Data Source

PatentEP3602621B1Chip-carrier socket for microfluidic-cooled three-dimensional electronic/photonic integrated circuits
Publication Date: 2024.05.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3602621B1 patent drawingFigure 1~2
  • EP3602621B1 patent drawingFigure 3~4
  • EP3602621B1 patent drawingFigure 5~6

AI summary

A chip carrier socket for an electronic-photonic integrated-circuit (EPIC) assembly comprises a carrier bottom and a carrier top configured to mate to the carrier bottom while enclosing the EPIC assembly within an enclosed cavity. The carrier bottom comprises one or more conductive vias passing from a first surface of the carrier bottom to an opposite second surface of the carrier bottom, each conductive via providing electrical connectivity between an electrically conductive pad on the first surface of the carrier bottom and a respective electrically conductive pad, solder ball, or electrically conductive spring on the second surface of the carrier bottom. One or both of the carrier bottom and the carrier top comprises a fluid inlet port and a fluid outlet port. Further, either or both of the carrier bottom and the bottom top comprises an optical via passing from one surface to another of the carrier bottom or carrier top.