PCB Substrate Fine Particle Interlayer Peel Strength
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Solution Overview
Problem
The existing substrates for printed circuit boards face issues with poor peel strength between the base film and the metal layer, leading to difficulties in etching and conductive pattern formation, which results in tapered circuit shapes and increased signal loss due to surface irregularities.
Innovation Solution
A substrate with a base film and a metal layer where fine particles, made of the same metal or its compound, are disposed between the base film and the metal layer, improving peel strength and etching properties without deteriorating the conductive pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface of the copper foil is made irregular to increase peel strength, then the bonding strength between base film and metal layer is improved, but the etching property deteriorates and conductive pattern formation becomes poor
Solution Approach 1:
The invention applies local quality by creating a dual-surface copper foil structure where the bonding surface (contacting base film) has irregularities for high peel strength, while the etching surface (contacting resist) remains flat for good etching property. This local differentiation of surface properties resolves the contradiction between adhesion and etchability.
Solution Approach 2:
The copper foil is segmented into functionally distinct surfaces: one surface optimized for bonding to the base film with irregularities and higher Rz value (0.7-2.2 μm), and another surface optimized for etching with flatness and lower Rz value (0.03-0.5 μm). This segmentation allows each surface to independently fulfill its specific function without compromising the other.
2Strength
If the copper foil surface is made irregular to improve peel strength, then the bonding between base film and metal layer is enhanced, but side etching increases causing circuit shape tapering
Solution Approach 1:
The invention applies local quality by creating a dual-surface copper foil structure where the bonding surface (contacting base film) has irregularities for high peel strength, while the etching surface (contacting resist) remains flat for good etching property. This local differentiation of surface properties resolves the contradiction between adhesion and etchability.
Solution Approach 2:
The copper foil is segmented into functionally distinct surfaces: one surface optimized for bonding to the base film with irregularities and higher Rz value (0.7-2.2 μm), and another surface optimized for etching with flatness and lower Rz value (0.03-0.5 μm). This segmentation allows each surface to independently fulfill its specific function without compromising the other.
3Strength
If the copper foil surface is made irregular to increase peel strength, then the bonding between base film and metal layer is improved, but signal loss increases due to skin effect
Solution Approach 1:
The invention applies local quality by creating a dual-surface copper foil structure where the bonding surface (contacting base film) has irregularities for high peel strength, while the etching surface (contacting resist) remains flat for good etching property. This local differentiation of surface properties resolves the contradiction between adhesion and etchability.
Solution Approach 2:
The copper foil is segmented into functionally distinct surfaces: one surface optimized for bonding to the base film with irregularities and higher Rz value (0.7-2.2 μm), and another surface optimized for etching with flatness and lower Rz value (0.03-0.5 μm). This segmentation allows each surface to independently fulfill its specific function without compromising the other.
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 substrate achieves high peel strength and good etching properties, ensuring reliable conductive pattern formation and reduced signal loss, while maintaining the integrity of the metal layer.
Implementation Method 1
a plurality of fine particles are disposed between the base film and the metal layer
Implementation Method 2
the fine particles are formed of a metal the same as a main metal of the metal layer or formed of a metal compound of the main metal
Implementation Method 3
by etching the metal layer to form a conductive pattern
Implementation Method 4
when high frequencies are propagated in a conductive pattern formed by etching the metal layer, a current that is concentrated near the surface by the skin effect flows along the irregularities on the bonding surface
Data Source
AI summary
A substrate for a printed circuit board according to an embodiment of the present invention includes a base film having an insulating property, and a metal layer formed on at least one surface side of the base film. In the substrate for a printed circuit board, a plurality of fine particles are disposed between the base film and the metal layer, and the fine particles are formed of a metal the same as a main metal of the metal layer or formed of a metal compound of the main metal. The fine particles preferably have an average particle size of 0.1 nm or more and 20 nm or less. The fine particles are preferably formed of a metal oxide or a metal hydroxide. The fine particles are preferably present between the base film and the metal layer so as to form a layer. The metal layer preferably includes a metal grain layer formed by firing metal nanoparticles.