MLCC Terminal Electrode Coating to Reduce Sintering Stress
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Solution Overview
Problem
Traditional methods for fabricating multilayer ceramic capacitors (MLCCs) result in high internal stress and device cracks due to high-temperature sintering, leading to defects and reduced yield, particularly when achieving high capacitance with uneven electrode density distribution.
Innovation Solution
The method employs ultra-low-temperature electrochemical deposition to fabricate terminal electrodes and insulating protective layers, using electrochemical deposition and chemical plating at temperatures below 80°C to form continuous metal coatings on inner electrodes, eliminating the need for high-temperature sintering and ensuring uniform electrode density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-temperature sintering is used to fabricate terminal electrodes, then the electrode formation is achieved, but high internal stress is generated causing device cracks and defects
Solution Approach 1:
The patent changes the temperature parameter from high-temperature sintering (800-900°C) to low-temperature electrochemical deposition (room temperature or slightly elevated), fundamentally altering the process conditions to avoid thermal stress while achieving electrode formation
Solution Approach 2:
The patent replaces the thermal-mechanical sintering process with an electrochemical deposition process, substituting thermal energy with electrical energy to achieve electrode formation without generating thermal stress
2Ease of manufacture
If high-temperature sintering is used to form terminal electrodes, then the electrode is formed, but internal stress is released causing serious device cracks and defects
Solution Approach 1:
The patent changes the temperature parameter from high-temperature sintering (800-900°C) to low-temperature electrochemical deposition (room temperature or slightly elevated), fundamentally altering the process conditions to avoid thermal stress while achieving electrode formation
Solution Approach 2:
The patent converts the harmful effect of thermal stress generated during sintering into a beneficial low-stress process by using electrochemical deposition, where the electrochemical reaction naturally occurs without generating significant thermal stress
3Manufacturing precision
If additional high-temperature insulating ceramic protective layers are added to reduce density difference, then the breading effect is reduced, but high-temperature heat treatment causes internal stress and device cracks
Solution Approach 1:
The patent changes the temperature parameter from high-temperature processing to low-temperature electrochemical deposition, achieving electrode formation and protective layer application without generating thermal stress that causes cracks
Solution Approach 2:
The patent combines the terminal electrode formation and protective layer application into a single low-temperature electrochemical deposition process, eliminating the need for separate high-temperature sintering steps
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 reduces internal stress, improves yield, and enhances the reliability of MLCCs by maintaining uniform electrode density and preventing cracks, while reducing fabrication costs.
Implementation Method 1
processing plating of wet chemical immersion by immersing the MLCC in a metal solution at a temperature below 80°C, to, through electrochemical deposition, start slowly growing a metal coating on surfaces of the inner electrodes
Data Source
Figure 1
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AI summary
A method is provided for fabricating a terminal electrode. The terminal electrode is applied on a multilayer ceramic capacitor (MLCC). The method prints inner electrodes on full area together with protective layers. The MLCC uses the thickness of thinned dielectric ceramic layers and the stacking of nickel inner-electrode layers. High capacitance is achieved at ends and sides with high electrode-to-ceramic ratios. Thus, the present invention uses a coating technology of ultra-low-temperature electrochemical deposition to fabricate low internal-stress MLCC terminal electrodes together with insulating protective layers for improving MLCC yield while cost reduced.