SOI Heat Sink Structure for Buried Oxide Thermal Blocking

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Solution Overview

Problem

Integrated circuit devices on silicon on insulator (SOI) substrates face challenges with heat dissipation due to the insulating layer's poor thermal conductivity, which hinders efficient heat removal from the semiconductor layer.

Innovation Solution

The integration of extended active sections in the semiconductor layer and a thermal heat sink that connects to both active sections and the extended sections, providing horizontal and vertical heat conduction paths to effectively dissipate heat from the IC device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a buried oxide layer is used in SOI substrates to reduce losses and distortions in amplifiers, then electrical performance is improved, but heat dissipation deteriorates due to the insulating layer's poor thermal conductivity

Engineering Contradiction:
Improveamplifier performanceVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The heat dissipation path is segmented into two independent directions: horizontal conduction through extended active sections and vertical conduction through thermal heat sinks. This segmentation allows heat to be removed through multiple separate pathways, bypassing the thermal blocking effect of the buried oxide layer while maintaining its electrical insulation function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a horizontal dimension to heat conduction by extending active sections in the plane of the semiconductor layer. This dimensional expansion creates an additional thermal conduction path that is independent of the vertical path blocked by the buried oxide layer, effectively solving the heat dissipation problem without compromising electrical performance.

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

2Reliability

If the insulating layer is maintained to preserve electrical isolation, then electrical performance is improved, but thermal conduction deteriorates

Engineering Contradiction:
Improveelectrical isolationVSAvoidthermal energy removal
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Different regions of the device are assigned different functions: the buried oxide layer maintains electrical isolation in the vertical direction, while extended active sections provide horizontal thermal conduction pathways. This local differentiation allows each component to optimize its primary function without interfering with the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The extended active sections act as thermal intermediaries, conducting heat horizontally from the heat-generating regions to the thermal heat sinks. This intermediary structure enables thermal energy removal while the buried oxide layer continues to provide electrical isolation, effectively decoupling the thermal and electrical functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If extended active sections are added to create thermal conduction paths, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The extended active sections serve multiple functions simultaneously: they act as thermal conduction pathways for heat removal, maintain electrical isolation through their doping structure, and can be integrated with existing transistor layouts. This multi-functionality reduces the need for separate dedicated thermal management structures.

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

Solution Approach 2:

The thermal management function is merged with the existing active semiconductor regions by extending them horizontally. This integration combines the thermal conduction pathway with the electrical structure, eliminating the need for separate thermal management components and reducing overall device complexity.

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 solution enhances heat dissipation by creating additional thermal conductive paths, overcoming the limitations of the insulating layer's low thermal conductivity and ensuring efficient heat removal from the IC device.

Implementation Method 1

a thermal heat sink connected to the second active region and the extended active region and extending above the semiconductor layer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4425541A1Heat sink for soi
Publication Date: 2024.09.04 QORVO US INC
  • EP4425541A1 patent drawingFigure 1
  • EP4425541A1 patent drawingFigure 2~3
  • EP4425541A1 patent drawingFigure 4~5

AI summary

Embodiments of an integrated circuit (IC) device are disclosed. The IC device includes a semiconductor substrate (e.g., a silicon substrate), a buried oxide (BOX) layer formed over the semiconductor substrate and a semiconductor layer formed over the BOX layer. Active semiconductor components are formed using active sections (e.g. drains and sources of field effect transistors (FETs). To help dissipate the heat out of the IC device, extended sections are formed in the semiconductor layer. The extended sections extend from the active sections of the active semiconductor devices. The extended sections thereby provide horizontal thermal conduction out of the active semiconductor devices. Thermal heat sinks are formed over the extended sections to vertically conduct heat out of the IC device.