Ceramic Component External Electrode Solder Burst Prevention
Solution Overview
Problem
Ceramic electronic components face issues with solder burst due to moisture absorption by thermosetting conductive pastes, leading to water vapor and decomposition gas generation during reflow steps, which can cause solder to be blown off, especially when there are defects or thin areas in the plating film.
Innovation Solution
A ceramic electronic component design featuring an external electrode with a specific composition and structure, including a mixture of resin and metal components, where the inner external electrode contains a controlled volume of resin to absorb shocks and reduce moisture absorption, and an outer external electrode composed of a higher-melting-point metal to prevent solder burst, with a manufacturing method that involves heating the stack in a controlled atmosphere to form an alloy layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermosetting conductive paste containing resin is used for the external electrode, then the component becomes resistant to shock and heat cycle stress, but moisture absorption by the resin leads to water vapor and decomposition gas generation during reflow heating, causing solder burst
Solution Approach 1:
A plating film is introduced as an intermediary layer between the resin-based external electrode and the solder. This plating film acts as a barrier that prevents water vapor and decomposition gas from reaching and blowing off the solder during reflow heating, thereby resolving the solder burst issue while maintaining the shock resistance provided by the resin
Solution Approach 2:
The thickness of the plating film is controlled within a specific range (0.5-5.0 μm) to optimize its barrier function. By adjusting this parameter, the plating film effectively prevents gas penetration while maintaining electrical conductivity and mechanical integrity, preventing solder burst without compromising the shock-resistant properties of the resin-based electrode
2Ease of manufacture
If the plating film has defective portions or thin areas, then manufacturing cost is reduced, but water vapor and decomposition gas can burst through these defects during reflow heating, causing solder to be blown off
Solution Approach 1:
By optimizing the plating film thickness to 0.5-5.0 μm, the invention ensures sufficient barrier coverage even with manufacturing variations. This parameter control allows for simpler manufacturing processes while maintaining reliable prevention of solder burst, as the plating film remains intact enough to block gas pathways
3Reliability
If a thick plating film is used to prevent solder burst, then solder integrity is maintained, but manufacturing cost and process complexity increase
Solution Approach 1:
The invention identifies an optimal plating film thickness range (0.5-5.0 μm) that provides sufficient barrier function to prevent solder burst while remaining thin enough to simplify manufacturing. This parameter optimization balances reliability and ease of manufacture, avoiding the need for excessively thick plating that would increase process complexity and cost
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
Significantly reduces or prevents solder burst occurrences by controlling the resin volume in the inner external electrode and using a solder barrier layer, maintaining the buffer function while minimizing moisture absorption and decomposition gas generation.
Implementation Method 1
a resin component and a metal component, wherein a volume occupied by the resin component is not lower than 3.79×10−7 ml and not higher than 1.02×10−6 ml
Implementation Method 2
heating the stack onto which the mixture has been applied
Data Source
AI summary
A ceramic electronic component includes a rectangular or substantially rectangular parallelepiped-shaped stack in which a ceramic layer and an internal electrode are alternately stacked and an external electrode provided on a portion of a surface of the stack and electrically connected to the internal electrode. The external electrode includes an inner external electrode covering a portion of the surface of the stack and including a mixture of a resin component and a metal component and an outer external electrode covering the inner external electrode and including a metal component. A volume occupied by the resin component in the inner external electrode is within a prescribed range.