Multilayer Ceramic Capacitor Terminals for Warped Substrate Welding
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with stress due to thermal expansion coefficient differences between the capacitor and the mounting substrate, leading to potential damage or detachment, especially in high-temperature environments, and existing welding techniques face challenges with warpage and coplanarity issues.
Innovation Solution
The design incorporates metal terminals with extending portions and protrusion bending portions that create gaps between the capacitor and the substrate, allowing for reliable welding even with warped substrates and non-coplanar surfaces, using laser welding to join the components efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is used to mount the metal terminal to the mounting substrate, then the electrical connection is established, but the solder may melt or weaken in high-temperature environments causing detachment or increased ESR
Solution Approach 1:
The patent replaces the soldering process with laser welding to join the metal terminal to the mounting substrate. Laser welding creates a metallurgical bond that is resistant to high temperatures, eliminating the solder melting and weakening problems that occur in high-temperature environments. The laser beam directly melts and fuses the metal terminal material with the substrate, creating a heat-resistant joint.
Solution Approach 2:
The patent changes the joining method from soldering (which has a limited temperature range) to laser welding (which can withstand high temperatures). This parameter change in the joining process enables the assembly to operate reliably in high-temperature environments up to the melting point of the metal terminal material, significantly expanding the service temperature range.
2Strength
If general welding techniques are used, then strong joining is achieved, but warpage and coplanarity issues prevent reliable surface contact
Solution Approach 1:
The patent applies preliminary action by pre-bending the metal terminal into a specific three-dimensional shape with protrusion bending portions before the welding process. This pre-shaping ensures that when the metal terminal is placed on the mounting substrate, the protrusion portions make contact first, compensating for warpage and coplanarity issues. This preliminary configuration enables reliable laser welding even when the surfaces are not perfectly flat.
Solution Approach 2:
The patent transitions from a two-dimensional planar contact assumption to a three-dimensional contact model by creating protrusion bending portions that extend in the vertical dimension. This dimensional change allows the metal terminal to contact the substrate at multiple points along its length, accommodating substrate warpage and achieving reliable welding without requiring perfect coplanarity.
3Reliability
If the metal terminal is kept floating and spaced away from the mounting substrate, then stress from thermal expansion is reduced, but welding requires secure surface contact which is difficult to achieve
Solution Approach 1:
The patent applies dynamics by creating a flexible, bent metal terminal structure with extending portions that can adapt to the mounting substrate surface. The three-dimensional shape with protrusion bending portions allows the terminal to dynamically contact the substrate at multiple points, maintaining both the stress-resistant floating configuration and the welding-required surface contact.
Solution Approach 2:
The patent applies local quality by differentiating the metal terminal structure into different functional regions: the extending portions that maintain spacing for stress resistance, and the protrusion bending portions that provide localized contact points for welding. This local differentiation allows the terminal to simultaneously achieve both stress resistance and welding compatibility.
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 configuration enables reliable mounting and welding of multilayer ceramic capacitors on warped or non-coplanar substrates, reducing stress and detachment risks while improving welding speed and efficiency.
Implementation Method 1
laser welding to join the components efficiently
Implementation Method 2
since the metallic terminal member having metallic luster reflects laser energy, efficient welding cannot be performed
Data Source
AI summary
A multilayer ceramic electronic component includes a first metal terminal including a first terminal joining portion connected to a first end surface, first and second extending portions extending from both ends of the first terminal joining portion toward a mounting surface, and first and second mounting portions connected respectively to the first and second extending portions in a length direction connecting the end surfaces to each other. A second metal terminal includes a second terminal joining portion connected to the second end surface, a third extending portion extending from the second terminal joining portion toward the mounting surface, and a third mounting portion connected to the third extending portion and extending in a length direction connecting the end surfaces to each other. The first and second mounting portions include first, second, and third protrusion bending portions protruding toward the mounting surface.