Multilayer Insulating Structure for High-Voltage Signal Isolation

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Solution Overview

Problem

Existing semiconductor devices for motor drive systems face challenges in efficiently managing high voltage differences between control and drive elements, requiring dedicated high withstand voltage processes that increase production costs and development time.

Innovation Solution

A semiconductor module with a coupled-inductor type insulating element that uses a multilayer insulating structure and a transformer chip to transmit signals between control and drive elements, allowing for independent production of control and drive elements through general low withstand voltage processes, eliminating the need for dedicated high voltage processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated high withstand voltage processes are used to manage high voltage differences, then reliability is improved, but manufacturing cost and development time increase

Engineering Contradiction:

Improvehigh voltage withstand capabilityVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the electrical parameter approach by using voltage division through multiple insulating layers with different dielectric constants, transforming the high voltage withstand problem into a series of lower voltage stress distributions across layers, allowing standard processes to achieve high voltage reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite insulating structures with multiple layers of different dielectric materials (different dielectric constants) to achieve high voltage withstand capability. This composite approach distributes electric stress across materials with complementary properties, enabling reliable high voltage operation using standard manufacturing processes

Inventive Principle:

Principle #40Composite materials

2Reliability

If dedicated high withstand voltage processes are used, then reliability is improved, but development time increases

Engineering Contradiction:

Improvehigh voltage withstand capabilityVSAvoiddevelopment time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent makes standard low voltage semiconductor manufacturing processes universal by designing insulating elements that can be fabricated using existing process tools and techniques, eliminating the need for separate high voltage process development streams and reducing development time while maintaining reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If multilayer insulating structure with different dielectric constants is used, then high voltage management efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvehigh voltage difference managementVSAvoidinsulating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the insulating element into multiple layers with different dielectric constants, where each layer is positioned between specific conductive layers. This segmentation distributes electric stress across multiple interfaces and materials, achieving superior high voltage management while keeping each individual layer simple and manufacturable using standard processes

Inventive Principle:

Principle #1Segmentation

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 reduces production costs and development time by enabling the use of existing low voltage processes for both control and drive elements, while ensuring efficient signal transmission and protection functions across high voltage differences.

Implementation Method 1

a first insulating portion that is formed on the principal surface of the semiconductor layer so as to cover the first conductive layer and that includes a first insulating layer of at least three or more layers, a second insulating portion that is formed on the first insulating portion, that has a dielectric constant differing from a dielectric constant of the first insulating layer

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS20230411281A1Semiconductor device, semiconductor module, motor drive device, and vehicle

Publication Date: 2023.12.21 ROHM CO LTD

AI summary

A semiconductor device includes a semiconductor layer that has a principal surface, a first conductive layer that is formed on the principal surface of the semiconductor layer, a first insulating portion that is formed on the principal surface of the semiconductor layer so as to cover the first conductive layer and that includes a first insulating layer of at least three or more layers, a second insulating portion that is formed on the first insulating portion, that has a dielectric constant differing from a dielectric constant of the first insulating layer, and that includes a second insulating layer not included in the first insulating portion, and a second conductive layer that is formed on the second insulating portion, that faces the first conductive layer through the first insulating portion and the second insulating portion, and that is connected to a potential differing from a potential of the first conductive layer.