Stretchable Mounting Board Non-Uniform Conductive Filler
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Solution Overview
Problem
Existing stretchable mounting boards face challenges in securing mounting strength while maintaining bendability and simplicity in manufacturing, as solder leaching occurs with conductive members, and complex processes are required to prevent short circuits and ensure substrate protection.
Innovation Solution
A stretchable mounting board with a substrate, mounting electrode portions containing conductive fillers and resin, and solder portions, where the conductive filler's sectional area varies across different regions to enhance bonding strength and prevent solder leaching, manufactured using a method involving multiple heat treatments and specific resin types to control solder wettability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal foil or metal powder is used as the conductive member to improve solder wettability, then solder bonding is enhanced, but solder leaching occurs causing the conductive member to break and reducing mounting strength
Solution Approach 1:
The patent applies local quality by creating a mounting electrode portion with non-uniform conductive filler distribution. The second region (solder contact side) has a larger sectional area of conductive filler than the first region (substrate contact side), concentrating the anti-leaching function where solder contact occurs while maintaining overall electrical conductivity and mechanical strength.
Solution Approach 2:
The patent uses composite materials by combining conductive filler with resin to form the mounting electrode portion. This composite structure provides both electrical conductivity from the filler and mechanical strength from the resin matrix, preventing the conductive member from breaking even when solder leaching occurs.
2Adaptability or versatility
If metal plating is used as the conductive member to secure bendability, then flexibility is improved, but substrate protection is required to prevent short circuits between wiring patterns
Solution Approach 1:
The mounting electrode portion is formed with locally concentrated conductive filler in the second region, creating a non-uniform distribution that provides both electrical functionality and mechanical strength without requiring substrate protection layers, simplifying the overall process.
3Adaptability or versatility
If the conductive member is reduced in region to secure bendability, then flexibility is improved, but a special device is required increasing manufacturing complexity
Solution Approach 1:
The patent achieves bendability without special devices by creating local quality variation in conductive filler distribution. The mounting electrode portion has optimized filler concentration in different regions, providing both flexibility and electrical functionality using standard manufacturing processes.
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
The solution allows for a simple manufacturing process while securing the mounting strength of electronic components, preventing solder leaching and ensuring reliable bonding without compromising bendability or increasing process complexity.
Implementation Method 1
a phenomenon called solder leaching occurs in which the conductive member and the solder react with each other to generate a brittle metal compound
Implementation Method 2
performing a first heat treatment on the first electrode layer; performing a second heat treatment on the second electrode layer
Implementation Method 3
performing a third heat treatment to melt and solidify the solder paste to form a solder portion that bonds the electronic component and the first electrode layer
Data Source
AI summary
A stretchable mounting board that includes: a stretchable substrate; a mounting electrode portion on a main surface side of the stretchable substrate and containing a conductive filler and a resin; a solder portion connected to the mounting electrode portion; and an electronic component electrically connected to the mounting electrode portion with the solder portion interposed therebetween. The mounting electrode portion has a first main surface on a stretchable substrate side thereof, a second main surface on a solder portion side thereof, a first region including the first main surface, and a second region including the second main surface, and wherein, in a cross-section along a thickness direction of the mounting electrode portion passing through the first region and the second region, a sectional area of the conductive filler in the second region is larger than a sectional area of the conductive filler in the first region.