Multilayer Wiring Board Structure for Warpage Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thin multilayer wiring boards face issues with warpage, leading to low mounting yields and reliability, which are exacerbated by the increasing complexity and miniaturization of radio frequency front-end modules in advanced mobile devices.
Innovation Solution
The proposed wiring board design includes a glass core with through holes, first and second adhesion layers, and first and second wiring layers, where the remaining copper ratio in the first wiring layer is set to 70-100%, and the adhesion layer's Young's modulus is 0.1 to 0.85 times that of the wiring layer's, to suppress warpage and enhance connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of laminated resins is reduced to provide thin RFFMs, then the thickness of packages is reduced, but warpage increases leading to low mounting yields and low reliability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the copper remaining ratio in the wiring layer (70-100%) and the Young's modulus ratio between adhesion layer and wiring layer (0.1-0.85 times). These parameter optimizations suppress warpage in thin wiring boards while maintaining package thickness reduction, thereby improving mounting yields and connection reliability
Solution Approach 2:
The patent uses composite materials by combining the adhesion layer made of at least one specific material with the wiring layer made of different materials having different Young's moduli. This composite structure allows the adhesion layer to compensate for warpage in the thin wiring board while maintaining electrical connectivity and mechanical strength
2Length of stationary object
If the thickness of laminated resins is reduced to provide thin RFFMs, then the thickness of packages is reduced, but warpage increases
Solution Approach 1:
The patent controls warpage by optimizing specific parameters: the copper remaining ratio in the wiring layer is set to 70-100% and the Young's modulus of the adhesion layer is set to 0.1-0.85 times that of the wiring layer. These parameter adjustments enable thin package design while suppressing warpage deformation
Solution Approach 2:
The adhesion layer serves as an intermediary between the wiring layer and the substrate. By positioning the adhesion layer at the interface and controlling its mechanical properties (Young's modulus), it acts as a mediator that compensates for warpage forces and maintains planarity in thin wiring boards
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 design achieves suppressed warpage and high connection reliability, enabling thinner wiring boards suitable for advanced mobile devices.
Implementation Method 1
a first adhesion layer in close contact with the first major surface and respective inner walls of the through holes, the first adhesion layer having portions each closing the bottom portion of a respective one of the through holes
Implementation Method 2
a second adhesion layer in close contact with the second major surface and the portions of the first adhesion layer
Implementation Method 3
the first adhesion layer is comprised of at least one material having a first predetermined Young's modulus, and the first wiring layer is comprised of at least one material having a second predetermined Young's modulus, the first predetermined Young's modulus being 0.1 to 0.85 times the second predetermined Young's modulus
Data Source
AI summary
A wiring board includes a first wiring layer disposed on the first adhesion layer; and a second wiring layer disposed on the second adhesion layer, wherein a proportion of copper remaining in the first wiring layer is represented by C=B/A (%), where A is a total area of the first wiring layer, B is an area of copper in the first wiring layer, and C is a remaining copper ratio C defined as the proportion of copper remaining in the first wiring layer, and wherein when the remaining copper ratio C is set to 70 to 100%, the first adhesion layer is comprised of at least one material having a first predetermined Young's modulus, and the first wiring layer is comprised of at least one material having a second predetermined Young's modulus, the first predetermined Young's modulus being 0.1 to 0.85 times the second predetermined Young's modulus.