Chip-Shaped Electronic Part Mounting Stress Reduction
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Solution Overview
Problem
Conventional chip-shaped electronic parts, especially those with small thicknesses, are prone to substrate cracking during mounting on printed circuit boards due to excessive bending stress caused by mounting nozzles.
Innovation Solution
A chip-shaped electronic part design featuring a substrate with upper and lower surface electrodes, end surface electrodes, and a plated layer structure where the plated layer protrudes upwardly from the protective film, distributing the mounting force across at least two points to reduce bending stress, with a harder nickel layer and a softer tin layer to absorb the force effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate thickness is decreased to reduce the size of the chip-shaped electronic part, then the miniaturization is achieved, but the substrate becomes more prone to cracking under mounting stress
Solution Approach 1:
The patent introduces a groove structure that divides the substrate into multiple segments. This segmentation allows the substrate to better accommodate mounting stresses by distributing the stress across multiple sections rather than concentrating it in a single continuous structure, thereby preventing cracks in thin substrates
Solution Approach 2:
The patent employs a composite structure combining the substrate with a groove configuration and plated layers. This composite design enhances the mechanical properties of the thin substrate by integrating multiple functional elements that work together to resist cracking while maintaining miniaturization
2Ease of operation
If a mounting nozzle applies force to the chip-shaped electronic part during mounting, then the part is secured onto the circuit board, but excessive bending stress causes substrate cracking
Solution Approach 1:
The patent introduces a groove structure beforehand that acts as a stress-absorbing feature. This groove configuration provides a cushioning effect by allowing controlled deformation and stress distribution before the substrate can crack, thereby protecting the substrate during the mounting process
Solution Approach 2:
The patent modifies the physical parameters of the substrate by introducing grooves with specific dimensions and configurations. These parameter changes alter the mechanical behavior of the substrate, enabling it to better withstand mounting stresses without cracking
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 design significantly reduces substrate cracking during mounting by distributing the force and enhancing solder wettability and connection reliability, while maintaining material efficiency and preventing substrate deformation.
Implementation Method 1
a harder nickel layer and a softer tin layer to absorb the force effectively
Data Source
AI summary
A chip-shaped electronic part includes: a substrate; a pair of upper surface electrodes formed on an upper surface of the substrate; a functional element formed to be electrically connected to the upper surface electrode pair; a pair of lower surface electrodes formed on a lower surface of the substrate at positions opposing the upper surface electrode pair; a pair of end surface electrodes formed on end surfaces of the substrate so that each of the end surface electrode pair is electrically connected to one of the upper surface electrode pair, and to one of the lower surface electrode pair corresponding to the one upper surface electrode; a protective film formed in such a manner as to cover at least the functional element; and a plated layer formed in such a manner as to cover at least each of the upper surface electrode pair, wherein the protective film or the plated layer has at least two points of application at which a load from above the substrate is exerted.