Copper Metallization for Semiconductor Thermal Stress

Solution Overview

Problem

Semiconductor components used in power applications face heat evolution due to current loading, leading to thermal stress and potential damage, and high electrical resistance contributes to increased heat generation, which is exacerbated by thermal expansion in conductor structures with high cross sections.

Innovation Solution

A semiconductor component with a metallization layer composed of copper or copper alloy, connected to bonding electrodes, is used to reduce electrical resistance and enhance mechanical strength, employing a dual or single damascene process for metallization layer formation, with a barrier layer to prevent material degradation, and an auxiliary layer for increased mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conductor structures with high cross section are used to achieve low electrical resistance, then electrical losses are reduced, but thermal expansion problems worsen under thermal loading

Engineering Contradiction:

Improveelectrical lossesVSAvoidthermal expansion stability

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent employs a composite metallization structure consisting of a copper base layer providing low electrical resistance and an overlaying metal layer (such as tungsten, molybdenum, or nickel) with low thermal expansion coefficient. This composite structure combines the high conductivity of copper with the thermal stability of the overlaying metal, thereby reducing electrical losses while maintaining dimensional stability under thermal loading.

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If copper metallization is used to reduce electrical resistance, then electrical losses are reduced, but reliability under thermal loading worsens due to thermal stress

Engineering Contradiction:

Improveelectrical lossesVSAvoidthermal loading reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent employs a composite metallization structure consisting of a copper base layer providing low electrical resistance and an overlaying metal layer (such as tungsten, molybdenum, or nickel) with low thermal expansion coefficient. This composite structure combines the high conductivity of copper with the thermal stability of the overlaying metal, thereby reducing electrical losses while maintaining dimensional stability under thermal loading.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the metallization structure by adding an overlaying metal layer with specific thermal properties. This parameter change in the metallization composition transforms the thermal expansion characteristics of the overall structure, enabling it to withstand thermal loading while maintaining low electrical resistance.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If multiple metallization layers are used to improve electrical conductivity, then electrical losses are reduced, but device complexity increases

Engineering Contradiction:

Improveelectrical lossesVSAvoidmetallization structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent employs a composite metallization structure consisting of a copper base layer providing low electrical resistance and an overlaying metal layer (such as tungsten, molybdenum, or nickel) with low thermal expansion coefficient. This composite structure combines the high conductivity of copper with the thermal stability of the overlaying metal, thereby reducing electrical losses while maintaining dimensional stability under thermal loading.

Inventive Principle:

Principle #40Composite materials

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 achieves reduced electrical losses and increased reliability under thermal loading by utilizing copper's high conductivity and mechanical strength, effectively managing thermal stress and maintaining component endurance.

Implementation Method 1

at least one metallization layer which is composed of copper or a copper alloy and is arranged above the semiconductor substrate and connected to at least one bonding electrode and electrically coupled to at least one main electrode zone

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

employing a dual or single damascene process for metallization layer formation, with a barrier layer to prevent material degradation

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS10347580B2Semiconductor component comprising copper metallizations

Publication Date: 2019.07.09 INFINEON TECH AUSTRIA AG

AI summary

A semiconductor component having improved thermomechanical durability has in a semiconductor substrate at least one cell comprising a first main electrode zone, a second main electrode zone and a control electrode zone lying in between. For making contact with the main electrode zone, at least one metallization layer composed of copper or a copper alloy is provided which is connected to at least one bonding electrode which likewise comprises copper or a copper alloy.