Metal-Based Circuit Board Insulation Layer with Boron Nitride Filler
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Solution Overview
Problem
Metal-based circuit boards face challenges in achieving optimal heat radiation, insulation, and peel strength, particularly when the proportion of inorganic fillers in the insulation layer is increased, leading to reduced performance due to air bubbles and porosity issues in liquid crystal polyester-based compositions.
Innovation Solution
A circuit board laminate with a metal substrate, an insulation layer containing 50% or more of an inorganic filler comprising boron nitride and at least one of aluminum nitride and aluminum oxide, where boron nitride is within a 35-80% volume range, and a metal foil, which reduces porosity and enhances peel strength and withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the proportion of inorganic filler in the insulation layer is increased to improve heat radiation, then thermal resistance is reduced, but air bubbles and porosity increase leading to reduced insulation ability and peel strength
Solution Approach 1:
The patent applies parameter changes by precisely controlling the proportion of boron nitride in the inorganic filler mixture. By maintaining boron nitride within 35-80% by volume, the insulation layer achieves optimal balance between heat radiation and insulation properties, preventing excessive porosity while maintaining thermal performance
Solution Approach 2:
The patent uses composite materials by combining liquid crystal polyester with a specific mixture of inorganic fillers (boron nitride, aluminum nitride, and/or aluminum oxide). This composite structure leverages the high thermal conductivity of boron nitride while the liquid crystal polyester matrix maintains insulation properties and reduces porosity
2Temperature
If the proportion of inorganic filler is increased to improve heat radiation, then thermal resistance is reduced, but peel strength decreases
Solution Approach 1:
The patent applies parameter changes by controlling the boron nitride proportion within 35-80% by volume. This parameter control ensures that the insulation layer maintains sufficient peel strength (7.0 N/cm or more) while achieving the desired heat radiation performance
Solution Approach 2:
The liquid crystal polyester acts as an intermediary material between the inorganic fillers and the metal substrate. It provides a binding matrix that maintains peel strength while allowing the inorganic fillers to contribute their thermal conductivity, preventing direct contact between fillers and substrate that would cause peeling
3Temperature
If the proportion of inorganic filler is increased to improve heat radiation, then thermal resistance is reduced, but withstand voltage decreases
Solution Approach 1:
The patent applies parameter changes by controlling the boron nitride proportion within 35-80% by volume. This controlled composition ensures the insulation layer achieves both heat radiation performance and sufficient withstand voltage (4.0 kV or more), preventing the formation of conductive pathways that would occur with excessive filler content
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 achieves superior heat radiation, insulation, and peel strength, with increased withstand voltage and reduced thermal resistance, enabling effective processing and durability of the circuit board.
Implementation Method 1
the inorganic filler being made of boron nitride and at least, one of aluminum nitride and aluminum oxide... superior in heat radiation... reduced thermal resistance
Data Source
AI summary
A circuit board laminate includes a metal substrate, an insulation layer disposed on the metal substrate, and a metal foil disposed on the insulation layer. A metal-based circuit board includes a metal substrate, an insulation layer disposed on the metal substrate, and a circuit pattern disposed on the insulation layer. The insulation layer contains a liquid crystal polyester and 50% by volume or more of an inorganic filler. The inorganic filler is made of boron nitride and at least one of aluminum nitride and aluminum oxide. A proportion of boron nitride in the inorganic filler is within a range of 35 to 80% by volume.