Multi-layer PCB Core Insulation for Dimensional Stability
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Solution Overview
Problem
Multi-layer printed circuit boards face challenges with positional shifts of plated holes due to material deformation during the lamination process, leading to poor alignment and increased production costs, while also requiring excellent signal transmission properties.
Innovation Solution
A multi-layer printed circuit board design featuring a core insulation layer with superior dimensional stability, made from a resin material different from the external insulation layers, which reduces deformation and enhances signal transmission properties by using materials with specific thermal expansion coefficients, storage modulus, stiffness, and glass transition temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional lamination materials are used to reduce board size and thickness, then miniaturization is achieved, but material deformation occurs during lamination causing positional shifts of plated holes
Solution Approach 1:
The patent divides the PCB into two distinct segments: a core insulation layer with high dimensional stability and external insulation layers with low dielectric constant. This segmentation allows each layer to fulfill its specific function without compromising the other, resolving the contradiction between miniaturization and positioning accuracy.
Solution Approach 2:
Different regions of the PCB are assigned different material properties: the core layer uses materials with high glass transition temperature and appropriate thermal expansion coefficient to maintain dimensional stability, while external layers use low dielectric constant materials for signal transmission. This local differentiation resolves the contradiction by optimizing each region for its specific purpose.
2Productivity
If high density interconnection techniques are employed to increase trace density, then connections per unit area improve, but material deformation during lamination causes alignment problems
Solution Approach 1:
The patent segments the PCB structure into core and external insulation layers with distinct material properties, allowing the core to provide dimensional stability during high-density interconnection manufacturing while external layers maintain signal transmission quality.
Solution Approach 2:
The patent changes the material parameters of the core insulation layer, specifically selecting materials with high glass transition temperature (above lamination temperature) and controlled thermal expansion coefficient, to prevent deformation during the manufacturing of high-density interconnections.
3Reliability
If external insulation layers with low dielectric constant are used to improve signal transmission, then signal transmission property improves, but the core layer needs high dimensional stability to prevent deformation
Solution Approach 1:
The patent divides the insulation requirements into two segments: the core layer handles dimensional stability requirements while external layers handle signal transmission requirements. This segmentation allows both contradictory requirements to be satisfied simultaneously in different parts of the structure.
Solution Approach 2:
Different insulation layers are assigned different material qualities: the core layer uses materials optimized for dimensional stability (high glass transition temperature, controlled thermal expansion), while external layers use materials optimized for signal transmission (low dielectric constant). This local quality differentiation resolves the contradiction.
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 effectively inhibits positional shifts and improves signal transmission speed, reducing defective rates and production costs by utilizing a high-dimensional stability core and low dielectric constant external layers, ensuring reliable and efficient electronic signal transmission.
Implementation Method 1
the core insulation layer contains a resin material different from that of the insulation layers, such that the core insulation layer has a dimensional stability superior to that of the insulation layers
Implementation Method 2
the core insulation layer has a dimensional stability superior to that of the insulation layers
Implementation Method 3
other (or external) insulation layers have a better electronic signal transmission property than that of the core insulation layer, such as lower dielectric constant or dielectric loss (dissipation factor)
Data Source
AI summary
A multi-layer printed circuit board comprises: a core comprising a core insulation layer and traces formed on two sides of the core insulation layer; a plurality of insulation layers sequentially formed at two sides of the core; and a plurality of trace layers respectively formed between two insulation layers and on the outmost insulation layers; wherein the core insulation layer contains a resin material different from that of the insulation layers, such that the core insulation layer has a dimensional stability superior to that of the insulation layers.