Composite Solder Layer via Kinetic Spray for Thermal Conductivity

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Solution Overview

Problem

Conventional solder joints in integrated circuits (ICs) face limitations due to the use of lower melting point solders that compromise thermal and electrical conductivity, leading to performance constraints and potential damage during soldering, while also being restricted by manufacturing techniques and material compatibility.

Innovation Solution

A composite solder material is created by blending a solder metal matrix with high thermal and electrical conductivity filler materials, such as copper, gold, and silver, which is then processed into a powder blend for kinetic spraying, allowing for the formation of a thin, low-oxide, high-conductivity solder layer with improved thermal and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high conductivity materials (copper, gold) are used for interface joints, then thermal and electrical conductivity is improved, but melting point becomes too high for IC manufacturing temperatures

Engineering Contradiction:

Improvethermal and electrical conductivityVSAvoidmelting point

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent creates a composite material combining high conductivity filler (copper, gold, or silver) with solder matrix material. The filler provides the desired thermal and electrical conductivity, while the solder matrix enables low-temperature processing compatible with IC manufacturing. This composite structure resolves the contradiction by integrating materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the physical and chemical parameters of the solder joint by incorporating filler materials with specific properties (high conductivity, appropriate melting point). By adjusting filler concentration, size, and distribution, the patent optimizes both conductivity and melting point to meet IC manufacturing requirements.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If lower melting point solders are used to prevent IC damage, then manufacturing temperature is reduced, but thermal and electrical conductivity deteriorates

Engineering Contradiction:

Improvemelting pointVSAvoidthermal and electrical conductivity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent uses composite materials where the solder matrix provides low melting point for safe IC processing, while embedded high conductivity filler particles (copper, gold, silver) compensate for the lower conductivity of pure solder. This resolves the contradiction by combining materials that individually address different requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The composite solder material performs multiple functions simultaneously: the solder matrix provides low melting point and wetting properties, while the filler provides high conductivity. This multi-functional material resolves the contradiction by making a single material system capable of meeting opposing requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If solder layer thickness is reduced to improve conductive performance, then thermal and electrical conductivity is improved, but manufacturing precision and tolerance control become more difficult

Engineering Contradiction:

Improveconductive performanceVSAvoidsolder layer thickness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by concentrating high conductivity filler particles within the solder layer to create regions of enhanced conductivity. This allows the overall layer to remain thin for good performance while the filler distribution provides the necessary conductive pathways, making the system less sensitive to exact thickness variations.

Inventive Principle:

Principle #3Local quality

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 composite solder material achieves enhanced thermal and electrical conductivity, minimal solder thickness, and improved solderability, enabling efficient heat transfer and electron flow while preventing IC damage during soldering, with the added benefits of low oxide content and high manufacturing speed.

Implementation Method 1

a kinetic spray device, accelerated towards a substrate or part

Methodology Applied

Scientific EffectGas pressure acceleration: Pressure Gradient

Implementation Method 2

The gas from the first storage container flows through a main gas line to an input end of the kinetic spray gun

Methodology Applied

Scientific EffectGas flow: Fluid Spray

Implementation Method 3

spraying the powder materials through a convergent-divergent nozzle onto the substrate

Methodology Applied

Scientific EffectPhysical deposition: Deposition (physical)

Data Source

PatentUS7758916B2Material and method of manufacture of a solder joint with high thermal conductivity and high electrical conductivity

Publication Date: 2010.07.20 OERLIKON METCO (US) INC

AI summary

The present invention provides a powder blend or composite powder that is fed into a kinetic spray device, accelerated towards a substrate or part in order to form a composite solder with thermal and electrical properties better than existing solder. The other advantages of building a solder layer in this manner include a low oxide content to improve subsequent solderability, excellent control of the deposition thickness, excellent control of the deposition chemistry and lastly, high speed of manufacture.