Multilayer Ceramic Component Copper Electrode Firing
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Solution Overview
Problem
Existing methods for producing multilayer ceramic components with copper-containing internal electrodes face challenges in preventing oxidation of metallic copper and reduction of the ceramic material, particularly when using Ag/Pd external electrodes, as they require specific low oxygen partial pressures that are not compatible with copper-containing internal electrodes.
Innovation Solution
A method involving a copper-containing metal paste with an organic binder, such as acrylic resin, is used to create external contacts with a controlled oxygen partial pressure between the equilibrium points for Cu/Cu2O and Pb/PbO, allowing debinding and firing under nitrogen with water vapor to prevent oxidation and reduction, while using a glass frit to enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Ag/Pd external electrodes are used with copper-containing internal electrodes, then the component can be produced with lower cost, but the copper internal electrodes will oxidize and the ceramic will reduce under the required low oxygen partial pressure conditions
Solution Approach 1:
The invention changes the oxygen partial pressure parameter during the firing process to a specific range (10^-10 to 10^-15 atm) that prevents both copper oxidation and ceramic reduction. This parameter optimization allows the use of copper-containing internal electrodes with Ag/Pd external electrodes while maintaining component reliability and preventing harmful chemical reactions.
2Reliability
If low oxygen partial pressure is used to prevent copper oxidation, then electrode stability is improved, but ceramic reduction occurs
Solution Approach 1:
The invention precisely optimizes the oxygen partial pressure parameter within a specific range (10^-10 to 10^-15 atm) during firing. This controlled parameter change creates a balanced chemical environment that simultaneously prevents copper oxidation and ceramic reduction, maintaining stability of both electrode and ceramic composition.
3Device complexity
If conventional firing methods are used with copper-containing internal electrodes, then the production process is simple, but oxidation of copper and reduction of ceramic occur
Solution Approach 1:
The invention introduces a specific oxygen partial pressure control parameter (10^-10 to 10^-15 atm) into the conventional firing process. This single parameter optimization enables the use of copper-containing internal electrodes while preventing oxidation and ceramic reduction, maintaining process simplicity while significantly improving component reliability.
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
This approach enables the production of multilayer ceramic components with copper-containing internal electrodes and external contacts that maintain sufficient bonding strength, preventing oxidation of copper and reduction of the ceramic, while ensuring the ceramic and metal components remain thermodynamically stable.
Implementation Method 1
The water vapor partial pressure is set such that the corresponding oxygen partial pressure at the given temperature is between the equilibrium points for Cu/Cu2O and PbTiO3/Pb
Implementation Method 2
The equilibrium point corresponds to an oxygen partial pressure at which both a reduced metal and a metal compound that corresponds to this metal are thermodynamically stable and can coexist without diffusing into one another
Implementation Method 3
ceramic green films that contain a thermohydrolytically degradable binding agent
Implementation Method 4
The external contacts contain glass frit and metallic copper. The bonding strength of the external contacts to the stack is at least 50 N
Data Source
AI summary
A multilayer ceramic component includes a stack containing ceramic layers and electrode layers interspersed among the ceramic layers. The electrode layers contain copper and define first and second internal electrodes. First and second external contacts are on different sides of the stack. The first and second external contacts contain copper and are substantially perpendicular to the ceramic layers and electrode layers. The first internal electrode is connected to the first external contact and the second internal electrode is connected to the second external contact. The first and second internal electrodes overlap each other at a plane intersecting the stack. In areas adjacent to boundaries between the first and second external contacts and the ceramic layers, the first and second external contacts are not oxidized and material making-up the ceramic layers is not diminished. A bonding strength of the external contacts to the stack exceeds 50 N.