Semiconductor Heat Conductive Member for Accurate Overheat Protection

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Solution Overview

Problem

Conventional semiconductor devices face challenges in achieving high sensitivity and accuracy of overheat protection circuits due to temperature gradients and switching noise, which can lead to incorrect heat detection and reduced safety.

Innovation Solution

The integration of a heat conductive member with higher thermal conductivity than the semiconductor substrate, formed using wiring patterns that are electrically connected to the heat source, improves heat conduction to the heat detection element, enhancing the sensitivity and accuracy of the overheat protection circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the distance between the power transistor and the overheat protection circuit is reduced to improve sensitivity and accuracy, then heat detection accuracy is improved, but temperature gradient within the power transistor causes incorrect heat detection

Engineering Contradiction:

Improveheat detection accuracyVSAvoidheat detection correctness

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A heat conductive member is introduced as an intermediary between the power transistor (heat source) and the temperature sensor (heat detection part). This member has higher thermal conductivity than the semiconductor substrate, enabling accurate heat detection while electrically isolating the sensor from switching noise. The heat conductive member acts as a thermal bridge that resolves the contradiction by providing a dedicated heat transfer path without requiring direct physical contact between the power transistor and sensor.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a buffer zone is provided between the power transistors and the overheat protection circuit to prevent malfunction from switching noise, then noise immunity is improved, but sensitivity and accuracy of the overheat protection circuit are reduced

Engineering Contradiction:

Improvenoise immunityVSAvoidheat detection sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The heat conductive member serves as an intermediary that provides thermal coupling while maintaining electrical isolation. This allows the temperature sensor to be positioned close to the power transistor for high sensitivity, while the heat conductive member itself acts as the buffer that prevents switching noise from affecting the sensor, thus resolving the contradiction between noise immunity and detection sensitivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the conventional electrical connection method with a thermal conduction mechanism. Instead of relying on electrical proximity for heat detection, the system uses thermal conduction through the heat conductive member, which has high thermal conductivity but provides electrical isolation. This substitution allows the sensor to be electrically isolated from noise while maintaining thermal coupling for accurate detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If discrete components are used for heat source and temperature sensor, then design flexibility is improved, but delay in temperature transfer and offset in temperature detection value occur

Engineering Contradiction:

Improvedesign flexibilityVSAvoidtemperature transfer delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The invention merges the heat source (power transistor) and temperature sensor into a single integrated semiconductor device structure, with both components formed on the same semiconductor substrate. The heat conductive member is also integrated within the device, creating a compact unified structure. This integration eliminates the physical separation and connection delays inherent in discrete component designs, while maintaining design flexibility through the ability to configure the heat conductive member's geometry and material properties.

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 configuration allows for faster and more accurate heat detection, improving the sensitivity and accuracy of the overheat protection circuit and reducing malfunctions caused by noise, thereby enhancing the safety and reliability of semiconductor devices.

Implementation Method 1

a heat conductive member formed across both of the heat source and the heat detection element, a thermal conductivity of the heat conductive member being higher than a thermal conductivity of the semiconductor substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9875950B2Semiconductor device

Publication Date: 2018.01.23 ROHM CO LTD

AI summary

A semiconductor device includes a heat source and a heat detection element which are formed on a semiconductor substrate; and a heat conductive member formed across both of the heat source and the heat detection element, a thermal conductivity of the heat conductive member being higher than a thermal conductivity of the semiconductor substrate, and wherein the heat source, the heat detection element and the heat conductive member are integrated on the semiconductor substrate.