Semiconductor Bonding Structure for Stable Heat Dissipation

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Solution Overview

Problem

The heat dissipation performance at the bonding interface of semiconductor devices degrades over time, affecting the reliability of power modules used in electrical appliances and hybrid vehicles.

Innovation Solution

A semiconductor device configuration with a solid-phase diffusion bonding layer between metal support layers and semiconductor elements, where the insulation layer is lower in Vickers hardness than the support layers, enhancing the bonding interface's stability and heat dissipation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solder layer is used to bond semiconductor elements to a conductor layer, then the bonding interface provides electrical and thermal connection, but the heat dissipation performance degrades over long-term use

Engineering Contradiction:

Improveheat dissipation performance stabilityVSAvoidlong-term use duration

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the bonding method from soldering to solid-phase diffusion bonding, altering the physical and chemical parameters of the bonding interface. This creates a metallurgical bond with superior thermal stability that maintains heat dissipation performance over long-term operation, resolving the degradation issue inherent in solder-based connections.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite structure involving a diffusion barrier layer and a capping layer in addition to the solid-phase diffusion bonding interface. This multi-layer composite approach enhances the stability and durability of the bonding interface, preventing degradation and maintaining reliable heat dissipation over extended periods.

Inventive Principle:

Principle #40Composite materials

2Reliability

If solid-phase diffusion bonding is used between metal support layers and semiconductor elements, then heat dissipation performance is stabilized over long period, but manufacturing complexity increases

Engineering Contradiction:

Improveheat dissipation performance stabilityVSAvoidbonding structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a diffusion barrier layer as an intermediary between the metal support layer and the semiconductor element. This intermediate layer facilitates controlled solid-phase diffusion bonding while preventing unwanted intermetallic growth, thereby stabilizing heat dissipation performance without requiring overly complex bonding structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding interface is segmented into multiple functional layers: the metal support layer, the diffusion barrier layer, the semiconductor element, and optionally a capping layer. This segmentation allows each layer to perform its specific function optimally, achieving reliable heat dissipation through a structured yet manageable complexity.

Inventive Principle:

Principle #1Segmentation

3Strength

If the insulation layer has lower Vickers hardness than the support layers, then bending stress is reduced and metal bond is enhanced, but the insulation layer becomes more susceptible to mechanical damage

Engineering Contradiction:

Improvemetal bond strengthVSAvoidbending stress

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The patent modifies the hardness parameter of the insulation layer by selecting materials or compositions with lower Vickers hardness than the metal support layers. This parameter change allows the insulation layer to act as a stress-absorbing element that reduces bending stress concentration, thereby enhancing the metal bond strength at the bonding interface.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The softer insulation layer serves as a pre-positioned cushioning element between the rigid metal support layers and the semiconductor element. This beforehand cushioning effect absorbs and distributes bending stresses, protecting the brittle semiconductor element and enhancing the overall bond strength before mechanical failures can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The configuration stabilizes heat dissipation performance over a long period, reducing bending stress and enhancing the metal bond, thereby maintaining consistent current and reducing parasitic inductance.

Implementation Method 1

a solid-phase diffusion bonding layer which is interposed between the support layer and the element metal layer

Methodology Applied

Scientific EffectSolid-phase diffusion: Diffusion

Implementation Method 2

the heat from the plurality of semiconductor elements is transmitted to the conductor layer, via the solder layer

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20240055355A1Semiconductor apparatus

Publication Date: 2024.02.15 ROHM CO LTD

AI summary

A semiconductor device includes an insulation layer, a support layer located on the insulation layer and containing a metal, and a semiconductor element bonded to the support layer. The semiconductor element includes an element metal layer facing the support layer. A solid-phase diffusion bonding layer is interposed between the support layer and the element metal layer. The insulation layer is lower in Vickers hardness than the support layer.