MLCC Metal Frame Roughness for Vibration-Resistant Board Bonding
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Solution Overview
Problem
Multilayer capacitors used in power driving systems for vehicles face challenges in thermal, electrical, and mechanical reliability due to direct contact with circuit boards, which leads to easy deterioration of metal frames and reduced durability against vibrations and deformation.
Innovation Solution
The electronic component features a metal frame with a roughened bottom surface and a circuit board with matching roughened electrode pads, enhancing the bonding force and durability by increasing the contact area and preventing direct stress transfer, thereby improving thermal, electrical, and mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal frame is used to mount the multilayer capacitor spaced apart from the circuit board, then durability against vibrations and deformation is improved, but the metal frame deteriorates easily at the contact portion with the electrode pad due to its smooth surface
Solution Approach 1:
The metal frame is designed with differential surface properties: the mounting portion that contacts the circuit board has a rough surface to enhance bonding strength, while the portion contacting the capacitor body maintains smoothness. This local differentiation resolves the contradiction by providing enhanced adhesion only where needed for mounting stability.
Solution Approach 2:
The surface roughness of the metal frame's mounting portion is controlled within a specific range (Ra 0.4 μm to 2.0 μm) to optimize both bonding strength and durability. By precisely controlling this physical parameter, the invention achieves sufficient adhesion to the circuit board while preventing excessive stress concentration that would cause deterioration.
2Strength
If the metal frame surface is made rough to improve bonding force, then bonding strength increases, but the frame may become more susceptible to stress concentration and deterioration
Solution Approach 1:
The surface roughness parameter (Ra) is precisely controlled within the range of 0.4 μm to 2.0 μm. This optimized parameter range provides sufficient surface area for bonding while avoiding excessive roughness that would create stress concentration points, thereby simultaneously achieving strong bonding and high durability.
Solution Approach 2:
The rough surface treatment is applied locally only to the mounting portion of the metal frame that contacts the circuit board, while other portions remain smooth. This localized approach ensures enhanced bonding strength at the critical interface without compromising the overall structural integrity and stress distribution of the frame.
Data Source
AI summary
There are provided an electronic component and a board including the same. The electronic component includes: a capacitor body; a pair of external electrodes respectively disposed on both ends of the capacitor body; and a pair of metal frames including a pair of connection portions connected to the pair of external electrodes, respectively, and a pair of mounting portions connected to the pair of connection portions, respectively. A bottom surface of one of the pair of mounting portions has roughness.