Multilayer Ceramic Capacitor Sputtered Electrodes
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Solution Overview
Problem
Multilayer ceramic capacitors (MLCCs) face challenges in achieving a high effective volume ratio due to non-uniform external electrode thickness, with dipping methods resulting in excessive thinness at corners and thickness variations, which affects reliability and moisture tolerance.
Innovation Solution
The formation of external electrodes using a sputtering method, specifically the barrel-type sputtering method, to achieve a thickness ratio of 0.7 to 1.2 for connection and band parts, ensuring uniformity and density, with a thickness range of 50 nm to 2 μm, and the use of protective layers to prevent plating solution penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the dipping method is used to form external electrodes, then the formation process is simple, but the electrode thickness becomes non-uniform with excessive thinness at corners and excessive thickness in other portions
Solution Approach 1:
The patent replaces the mechanical dipping method with a sputtering process to form external electrodes. The sputtering method uses physical vapor deposition to deposit conductive material uniformly across the capacitor body surfaces, eliminating the thickness non-uniformity caused by dipping while maintaining ease of manufacture through a controlled deposition process
Solution Approach 2:
The patent changes the formation parameters by controlling the sputtering process to achieve a specific thickness ratio (0.7 to 1.2) between connection parts and band parts. This parameter control ensures uniform electrode thickness across different surfaces (third, fourth, fifth, and sixth surfaces) while optimizing the effective volume ratio
2Ease of manufacture
If the dipping method is used to form external electrodes, then the process is straightforward, but the effective volume ratio cannot be secured due to thickness variations
Solution Approach 1:
The sputtering process replaces the dipping method to precisely control the amount of conductive material deposited. This ensures that the external electrodes have optimal thickness (50 nm to 2 μm) that maximizes the effective volume ratio while maintaining ease of manufacture through a controlled deposition process
Solution Approach 2:
The patent optimizes the electrode thickness parameters by controlling the sputtering deposition to achieve a thickness ratio of 0.7 to 1.2 between different electrode portions. This precise parameter control increases the effective volume ratio by eliminating excessive material in non-critical areas while maintaining adequate coverage
3Ease of manufacture
If external electrodes are formed with non-uniform thickness, then the formation process is simpler, but the moisture tolerance reliability deteriorates
Solution Approach 1:
The sputtering process replaces the dipping method to form uniform external electrodes. The controlled deposition ensures consistent thickness across all exposed surfaces, providing reliable moisture protection while maintaining ease of manufacture through a standardized deposition process
Solution Approach 2:
The patent controls the electrode thickness parameter within a specific range (50 nm to 2 μm) with a thickness ratio of 0.7 to 1.2 between different portions. This parameter optimization ensures uniform coverage that prevents moisture penetration while maintaining ease of manufacture
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 results in improved moisture resistance reliability and effective volume ratio by ensuring uniform and dense external electrodes, reducing thickness variations and enhancing connectivity and mountability.
Implementation Method 1
The formation of external electrodes using a sputtering method, specifically the barrel-type sputtering method
Data Source
AI summary
A multilayer ceramic capacitor includes a body having a dielectric layer and internal electrodes disposed to be alternately exposed to the third and fourth surfaces with the dielectric layer interposed therebetween. External electrodes include connection parts respectively formed on opposing surfaces of the body, band parts formed to extend from the connection parts to portions of side surfaces of the body, and corner parts in which the connection parts and the band parts are contiguous. A thickness of each of the external electrodes may be 50 nm to 2 μm. The external electrodes may be formed using a barrel-type sputtering method. A ratio t2/t1 may satisfy 0.7 to 1.2, where t1 is a thickness of each connection part and t2 is a thickness of each band part. A ratio t3/t1 may satisfy 0.7 to 1.0, where t3 is a thickness of each corner part.