Fluororesin PCB Substrate With Nitrogen Surface for Etching Adhesion
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Solution Overview
Problem
The adhesion between wires and the base film in printed circuit boards is compromised due to corrosion of the metal layer during wet etching, which forms water-soluble fluoride at the interface between the metal layer and resin film in conventional composite films.
Innovation Solution
A substrate for printed circuit boards is developed with a base film made of fluororesin and an electrically conductive layer comprising bonded conductive particles, where the surface contains at least 0.2 atomic percent nitrogen, enhancing adhesion through the formation of fluorine compounds that are easily discharged and minimizing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is used as the electrically conductive layer in conventional composite films, then good electrical conductivity is achieved, but water-soluble fluoride forms at the interface during wet etching causing corrosion and adhesion loss
Solution Approach 1:
The patent changes the composition parameters of the electrically conductive layer by incorporating nitrogen-containing organic compounds in addition to metal particles. This compositional modification prevents the formation of water-soluble fluoride during wet etching while maintaining electrical conductivity, thereby eliminating corrosion and improving adhesion stability.
Solution Approach 2:
The patent creates a composite electrically conductive layer combining metal particles with nitrogen-containing organic compounds. This composite structure provides both electrical conductivity from the metal particles and corrosion resistance from the nitrogen-containing compounds that form protective fluorine compounds during wet etching, resolving the contradiction between conductivity and adhesion stability.
2Ease of manufacture
If wet etching is used to remove non-conductive metal layers, then wire patterning is achieved, but the fluoride formed during etching corrodes the metal layer and reduces adhesion
Solution Approach 1:
The patent converts the harmful effect of fluoride formation during wet etching into a beneficial protective mechanism. The nitrogen-containing organic compounds in the electrically conductive layer react with fluoride to form protective fluorine compounds that prevent corrosion of the metal particles, thus transforming the etching process from harmful to beneficial for adhesion maintenance.
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 improves the adhesion of wires by preventing corrosion of the electrically conductive layer during wet etching, ensuring stable bonding between the wire and base film.
Implementation Method 1
the electrically conductive layer includes a nitrogen-containing organic compound... formation of fluorine compounds that are easily discharged and minimizing corrosion
Data Source
AI summary
A substrate for a printed circuit board includes a base film having a main surface and an electrically conductive layer disposed on the main surface. The base film is made of a fluororesin. The electrically conductive layer is a layer including a plurality of electrically conductive particles bonded together. An amount of nitrogen present in the main surface is 0.2 atomic percent or more.