Multilayer Resin Substrate Via Structure for Peeling Resistance
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Solution Overview
Problem
Conventional multilayer resin substrates experience peeling issues at the bonding portion between planar conductors and interlayer connection conductors due to stress concentration, especially when external forces are applied, particularly at boundaries between materials with low mechanical strength.
Innovation Solution
Incorporating a constricted portion with a smaller planar cross-sectional area in the second interlayer connection conductor, made of a different material, reduces stress concentration and prevents peeling by distributing stress more effectively across the bonding interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional interlayer connection conductor structure is used, then the substrate can be manufactured with standard processes, but stress concentration occurs at the bonding portion between planar conductor and interlayer connection conductor causing peeling when external force is applied
Solution Approach 1:
The patent applies local quality by creating a constricted portion with different cross-sectional area within the interlayer connection conductor. This localized structural variation allows the conductor to have different mechanical properties at different locations - the constricted portion acts as a stress relief zone while the bonding portions maintain adequate strength, thereby preventing peeling at the conductor-resin interface when external forces are applied.
Solution Approach 2:
The patent changes the geometric parameter of the interlayer connection conductor by introducing a constricted portion with a smaller cross-sectional area than the bonding portions. This parameter change (cross-sectional area variation) modifies the stress distribution along the conductor length, concentrating stress in the constricted portion rather than at the vulnerable bonding interfaces, thus improving reliability.
2Reliability
If the bonding portion is made of different materials to achieve electrical connection, then electrical conductivity is improved, but mechanical strength decreases making peeling more likely
Solution Approach 1:
The patent uses different materials at different locations of the interlayer connection conductor - the bonding portions use materials optimized for strong adhesion to conductors and resin, while the constricted portion uses materials optimized for electrical conductivity. This local differentiation allows each section to perform its primary function optimally without compromising the other.
Solution Approach 2:
The patent employs composite material structure in the interlayer connection conductor, combining different materials with complementary properties. The bonding portions use materials with high adhesion strength, while the constricted portion uses materials with high electrical conductivity, creating a composite structure that satisfies both electrical and mechanical requirements.
3Ease of manufacture
If a uniform cross-sectional area is used throughout the interlayer connection conductor, then manufacturing is simplified, but stress concentrates at the bonding portion causing peeling under external force
Solution Approach 1:
The patent introduces a localized structural feature (constricted portion) into the otherwise uniform interlayer connection conductor. This local variation is designed to specifically address the stress concentration problem at bonding portions while maintaining relative manufacturing simplicity through established fabrication techniques that can create controlled cross-sectional variations.
Data Source
AI summary
A multilayer resin substrate includes a stacked body including resin layers stacked on each other, a first planar conductor on a resin layer, and an interlayer connection conductor on a resin layer. The interlayer connection conductor includes a first interlayer connection conductor connected to an external conductor, and a second interlayer connection conductor bonded to the first interlayer connection conductor and a planar conductor. The first and second interlayer connection conductors are made of different materials. The second interlayer connection conductor includes a constricted portion including a smaller planar cross-sectional area than a different portion, between a bonding portion to which the first interlayer connection conductor is bonded and a bonding portion to which the planar conductor is bonded.