DBM Semiconductor Package Assembly for Thermal Stress Relief

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Solution Overview

Problem

Semiconductor device packages face challenges with thermal cycling stresses due to mismatched coefficients of thermal expansion between ceramic insulating layers and metal layers, leading to cracking of conductive adhesives, and exposed metal surfaces are prone to corrosion, affecting thermal dissipation and reliability.

Innovation Solution

A semiconductor device package design featuring a direct-bonded metal substrate with a patterned metal layer that reduces contact surface area with the die attach paddle, combined with a pre-applied thermally conductive adhesive on the exposed metal surface to enhance thermal dissipation and prevent corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a large contact surface area between metal layer and die attach paddle is used to improve thermal dissipation, then thermal dissipation performance is improved, but thermal cycling stresses increase due to mismatched coefficients of thermal expansion

Engineering Contradiction:

Improvethermal dissipation performanceVSAvoidthermal cycling stresses

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The metal layer is configured with a patterned design featuring reduced contact surface area at peripheral regions while maintaining adequate thermal dissipation pathways. This local variation in contact area distributes thermal cycling stresses more uniformly, preventing concentration at edges while preserving overall thermal performance through the central region.

Inventive Principle:

Principle #3Local quality

2Temperature

If exposed metal surfaces are used to improve thermal dissipation, then thermal dissipation is improved, but corrosion resistance deteriorates

Engineering Contradiction:

Improvethermal dissipationVSAvoidcorrosion resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The metal layer is formed as a composite structure with a corrosion-resistant material layer (such as nickel or palladium) deposited over a thermally conductive base metal layer (such as copper). This composite configuration provides both excellent thermal dissipation properties from the copper base and superior corrosion resistance from the protective outer layer, eliminating the trade-off between these two requirements.

Inventive Principle:

Principle #40Composite materials

3Temperature

If conductive adhesive is applied to improve thermal dissipation, then thermal dissipation is improved, but cracking occurs due to thermal cycling stresses

Engineering Contradiction:

Improvethermal dissipationVSAvoidadhesive layer integrity

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patterned metal layer design anticipates and cushions against thermal cycling stresses before they can damage the conductive adhesive. By reducing peripheral contact area and optimizing stress distribution pathways in advance, the structure prevents stress concentration that would otherwise cause adhesive cracking during thermal cycling, thereby protecting the adhesive layer integrity while maintaining thermal performance.

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 solution reduces thermal cycling stresses and corrosion, improving the reliability and quality of semiconductor device packages by simplifying integration and reducing defects such as voids and contamination during assembly and usage.

Implementation Method 1

a thermally conductive adhesive disposed on the second metal layer. At least a surface of the thermally conductive adhesive is exposed external to the semiconductor device package, and the thermally conductive adhesive is configured for coupling the semiconductor device package with a thermal dissipation appliance

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The base layer can electrically isolate the first metal layer from the second metal layer

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

a first metal layer disposed on a first surface of the base layer, and a second metal layer disposed on a second surface of the base layer... one of the metal layers can be coupled to a die attach paddle

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20240162110A1Semiconductor device package assemblies and methods of manufacture

Publication Date: 2024.05.16 SEMICON COMPONENTS IND LLC

AI summary

In a general aspect, a semiconductor device package can include a die attach paddle having a first surface and a second surface that is opposite the first surface; a semiconductor die coupled with the first surface of the die attach paddle, and a direct-bonded-metal (DBM) substrate The DBM substrate can include a ceramic layer having a first surface and a second surface that is opposite the first surface, a first metal layer disposed on the first surface of the ceramic layer and coupled with the second surface of the die attach paddle, a second metal layer disposed on the second surface of the ceramic layer, and a thermally conductive adhesive disposed on the second metal layer, At least a surface of the thermally conductive adhesive can be exposed external to the device package. The thermally conductive adhesive can be configured for coupling the device package with a thermal dissipation appliance.