Multiple Ground Plane Thermal Sink for Superconducting Circuits

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Solution Overview

Problem

Monolithic Microwave Integrated Circuits (MMICs) face inefficiencies in heat removal at cryogenic temperatures due to superconducting solder bumps, leading to unacceptably high temperature gradients, as existing ground planes maintain all devices at the most stringent operating temperature, resulting in excessive cooling resource usage for components with lower temperature requirements.

Innovation Solution

The implementation of separate dedicated ground planes with varying thermal via sizes and numbers to match different operating temperature requirements, coupled to a thermal sink layer for efficient heat management, allowing each set of circuits to maintain its desired operating temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a single ground plane is used to maintain thermal equilibrium, then temperature uniformity is improved, but cooling resource efficiency deteriorates due to over-cooling devices with lower temperature requirements

Engineering Contradiction:
Improvetemperature uniformityVSAvoidcooling resource efficiency
Core Design Contradiction:
TemperatureVSUse of energy by stationary object

Solution Approach 1:

The ground plane is divided into multiple separate ground planes, each dedicated to specific devices with similar temperature requirements. This segmentation allows independent thermal management for each ground plane, enabling precise temperature control without over-cooling other devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each ground plane is designed with specific thermal via characteristics (size, number, distribution) tailored to the local thermal requirements of the devices it serves. This local optimization ensures that each ground plane achieves its target temperature efficiency without being constrained by the requirements of other devices.

Inventive Principle:
Principle #3Local quality

2Temperature

If thermal vias are increased to improve heat removal, then temperature control is improved, but device complexity increases due to varying via specifications

Engineering Contradiction:
Improvetemperature controlVSAvoidvia specification variation
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The thermal via structure is segmented into multiple ground plane-specific via sets. Each ground plane has its own dedicated thermal vias with optimized characteristics, allowing independent thermal management without requiring complex global via design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces variability in the vertical dimension by placing thermal vias at different depths and positions for different ground planes. This dimensional approach allows complex thermal management requirements to be satisfied through spatial differentiation rather than increasing via count uniformly across all layers.

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

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 solution enables proportional thermal sink capacity based on circuit temperature requirements, reducing temperature gradients and optimizing cooling resources, thereby efficiently maintaining devices at their specific operating temperatures.

Implementation Method 1

separate dedicated ground planes... coupled to a thermal sink layer for efficient heat management... respective thermal vias (contacts)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3682473B1Multiple ground plane thermal sink
Publication Date: 2021.07.21 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3682473B1 patent drawingFigure 1
  • EP3682473B1 patent drawingFigure 2
  • EP3682473B1 patent drawingFigure 3~4

AI summary

A superconducting system is provided that includes a coplanar superconducting circuit. The coplanar superconducting circuit includes a first ground plane region, a second ground plane region electrically isolated from the first ground plane region by portions of the coplanar superconducting circuit, and a tunable coupler having a first port and a second port. The tunable coupler comprises a variable inductance coupling element coupled between the first port and the second port, a first termination inductor having a first end coupled between a first end of the variable inductance element and a second end coupled to the first ground plane region, and a second termination inductor having a first end coupled between a second end of the variable inductance element and a second end coupled to the second ground plane region.