Ceramic-Clad Copper Plate With Oxygen-Diffused Grain Pinning
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Solution Overview
Problem
Existing ceramic copper clad laminates using nitride ceramic substrates face issues with copper grain growth during active metal brazing, leading to poor CCD recognition and adverse effects on automated packaging processes like chip welding and wire bonding.
Innovation Solution
A method involving the formation of a copper oxide layer on the copper material, followed by thermal diffusion of oxygen atoms into the copper, and subsequent removal of the oxide layer before soldering to a ceramic substrate, controls copper grain size by pinning grain boundaries, enhancing CCD recognition and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If active metal brazing is performed at high temperature to bond copper to nitride ceramic, then bonding strength is improved, but copper grain growth occurs leading to poor CCD recognition
Solution Approach 1:
The patent applies preliminary action by forming a copper oxide layer on the copper material surface before the brazing process, then thermally treating it to diffuse oxygen atoms into the copper bulk. This pre-treatment prepares the copper material to resist grain growth during subsequent high-temperature brazing, enabling both strong bonding and fine grain structure to be achieved simultaneously
Solution Approach 2:
The patent changes the chemical composition parameter of copper by introducing oxygen atoms through thermal diffusion. The oxygen content in copper is controlled within 0.003-0.03 mass%, which modifies the material properties to inhibit grain boundary migration during high-temperature processing, thus controlling grain size while maintaining bonding strength
2Reliability
If high vacuum condition is used during active metal brazing to prevent oxidation, then oxidation resistance is improved, but copper grain growth is accelerated
Solution Approach 1:
The patent performs preliminary oxidation by forming a copper oxide layer before brazing, then uses thermal treatment to diffuse oxygen into the copper. This pre-introduced oxygen acts as a grain growth inhibitor during the high vacuum brazing process, allowing oxidation resistance to be maintained while grain size is controlled
Solution Approach 2:
The patent converts the typically harmful oxidation effect into a beneficial one by intentionally forming copper oxide and diffusing oxygen into copper before brazing. The oxygen, which would normally be avoided during high-temperature processing, is now used as a grain growth inhibitor to control copper grain size while maintaining bonding 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 method results in a ceramic copper clad laminate with controlled copper grain size, improving CCD recognition and automated packaging processes while maintaining strong bonding, thus overcoming the limitations of uncontrolled grain growth.
Implementation Method 1
thermally treating the copper material on which the copper oxide layer is formed, to diffuse oxygen atoms from the copper oxide layer into the copper material
Implementation Method 2
thermally treating the copper material on which the copper oxide layer is formed, to diffuse oxygen atoms from the copper oxide layer into the copper material
Data Source
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.