Anisotropic Semiconductor Substrate Thermal Balance

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Solution Overview

Problem

Semiconductor substrates tend to experience temperature rises, particularly at their central portions due to anisotropic thermal conductivity, which existing designs fail to efficiently manage, leading to potential overheating and operational limitations.

Innovation Solution

A semiconductor device with a rectangular substrate shape, where one side has higher thermal conductivity than the other, satisfying the mathematical relation L1/L2 = (K1/K2)^0.5 within a ±5% tolerance, ensuring balanced heat dissipation in both directions, combined with a heat sink and metal block for isotropic thermal conduction, and optionally incorporating a temperature sensing element to manage temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional semiconductor substrate design is used, then the device structure is simple, but the central portion experiences temperature rise due to anisotropic thermal conductivity

Engineering Contradiction:

Improvetemperature rise at central portionVSAvoidsubstrate shape configuration

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The semiconductor substrate is designed with an asymmetric rectangular shape where the length in the first direction (L1) and length in the second direction (L2) are specifically configured to satisfy L1/L2 = (K1/K2)^0.5. This asymmetric geometry compensates for the anisotropic thermal conductivity (K1 ≠ K2) by creating unequal heat dissipation paths in different directions, thereby balancing the thermal resistance and preventing temperature rise at the central portion.

Inventive Principle:

Principle #4Asymmetry

2Temperature

If the substrate dimensions are adjusted to balance thermal resistance, then temperature distribution is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvetemperature distribution uniformityVSAvoiddimensional tolerance of substrate

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The invention specifies a mathematical relationship L1/L2 = (K1/K2)^0.5 that connects the geometric parameters (L1, L2) with the material properties (K1, K2). By changing the substrate dimensions to satisfy this relationship, the thermal resistance in both directions is balanced, achieving uniform temperature distribution. The ±5% tolerance range provides practical manufacturing guidance while maintaining the thermal balance effect.

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

This configuration effectively suppresses temperature rises at the central portion of the semiconductor substrate, ensuring efficient heat dissipation and maintaining operational stability even under extreme conditions by balancing thermal resistance paths and utilizing anisotropic thermal conductivity properties of gallium oxide substrates.

Implementation Method 1

A thermal conductivity in a first direction of the semiconductor substrate is different from a thermal conductivity in a second direction of the semiconductor substrate

Methodology Applied

Scientific EffectAnisotropic thermal conductivity: Anisotropy

Implementation Method 2

The semiconductor substrate is configured to satisfy a mathematical relation of L1/L2=(K1/K2)0.5... ensuring balanced heat dissipation in both directions

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

combined with a heat sink and metal block for isotropic thermal conduction

Methodology Applied

Scientific EffectIsotropic thermal conduction: Conduction (thermal)

Data Source

PatentUS20230207635A1Semiconductor device

Publication Date: 2023.06.29 DENSO CORP

AI summary

A semiconductor device includes a semiconductor substrate having a rectangular shape with a side extending in a first direction and another side extending in a second direction. A thermal conductivity in the first direction of the semiconductor substrate is different from a thermal conductivity in the second direction of the semiconductor substrate. The semiconductor substrate is configured to satisfy a mathematical relation of L1/L2=(K1/K2)0.5 with an inclusive tolerance range of −5% to +5%, where L1 denotes a length of the semiconductor substrate in the first direction, L2 denotes a length of the semiconductor substrate in the second direction, K1 denotes the thermal conductivity in the first direction of the semiconductor substrate, and K2 denotes the thermal conductivity in the second direction of the semiconductor substrate.