Ceramic Copper Cladding With Oxygen Diffusion for Fine Grain Control

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Solution Overview

Problem

The existing active metal brazing (AMB) process for manufacturing ceramic copper clad laminates results in excessively large copper grains, which hinder the recognition of circuit patterns by CCDs and affect automated packaging processes such as chip welding and wire bonding.

Innovation Solution

A method involving chemical oxidation and thermal treatment of copper materials to form a copper oxide layer, diffuse oxygen atoms into the copper, and then remove the oxide layer before soldering to a ceramic substrate, thereby controlling copper grain size and improving CCD recognition rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If active metal brazing (AMB) process is used to bond copper to nitride ceramic substrate, then bonding strength is improved, but copper grain size becomes excessively large

Engineering Contradiction:
Improvebonding strengthVSAvoidcopper grain size
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by introducing oxygen atoms into the copper material before the brazing process through chemical oxidation and thermal diffusion. This pre-treatment modifies the copper's internal structure to inhibit grain growth during subsequent high-temperature brazing, thereby maintaining fine grain size while achieving strong bonding

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the chemical composition parameter of copper by introducing oxygen atoms (0.01-0.05 wt%) through controlled oxidation and thermal diffusion. This parameter change fundamentally alters the copper's grain growth behavior during brazing, enabling strong bonding without excessive grain growth

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If copper grain size is reduced for better CCD recognition, then measurement precision is improved, but bonding strength may be compromised

Engineering Contradiction:
ImproveCCD recognition rateVSAvoidbonding strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent changes the chemical composition by introducing controlled oxygen content (0.01-0.05 wt%) into the copper material. This parameter modification enables the copper to maintain fine grain structure (improving CCD recognition) while simultaneously achieving strong bonding strength through the modified microstructure

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If chemical oxidation and thermal treatment are applied to control grain size, then manufacturing precision is improved, but process complexity increases

Engineering Contradiction:
Improvecopper grain size controlVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the oxidation and diffusion processes into a single integrated thermal treatment step. The copper material undergoes chemical oxidation followed by thermal diffusion in one continuous process sequence, simplifying the overall manufacturing process while achieving precise grain size control

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses controlled parameter changes (temperature, time, oxygen concentration) during thermal treatment to achieve grain size control. By optimizing these parameters, the process becomes more predictable and controllable, reducing overall process complexity

Inventive Principle:
Principle #35Parameter changes

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 method effectively controls copper grain size, enhancing the CCD recognition rate and improving the bonding strength between the copper and ceramic substrates, thus facilitating more efficient automated packaging processes.

Implementation Method 1

chemically oxidizing the copper material to form a copper oxide layer on a surface of the copper material

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

thermally treating the chemically oxidized copper material to diffuse oxygen atoms into the copper material

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12284766B2Ceramic-cladded copper plate and method for manufacturing ceramic-cladded copper plate
Publication Date: 2025.04.22 BYD CO LTD

AI summary

A method for preparing a ceramic copper clad laminate is provided, including following steps: providing a copper material; forming a copper oxide layer on a surface of the copper material; thermally treating the copper material on which the copper oxide layer is formed, to diffuse oxygen atoms in the copper material; removing the copper oxide layer on the thermally treated copper material; and soldering the copper-oxide-layer-removed copper material to a ceramic substrate to obtain a ceramic copper clad laminate.