PCB Substrate Adhesion via Conductive Ink Oxidation
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Solution Overview
Problem
Conventional printed circuit board substrates require expensive vacuum equipment for forming conductive layers, limiting substrate size and increasing production costs due to the need for vacuum processes like sputtering to achieve high-density circuits.
Innovation Solution
A substrate with a base film and conductive layers formed using a conductive ink containing metal particles, where the region near the interface between the base film and the first conductive layer contains a metal oxide species and a metal hydroxide species, allowing for strong adhesion without vacuum equipment, using a process involving heating in a controlled atmosphere to form the first conductive layer and subsequent plating for the second conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sputtering is used to form conductive layers, then adhesion strength between base film and conductive layer is improved, but equipment cost and process complexity increase
Solution Approach 1:
The patent replaces the mechanical vacuum-based sputtering system with a chemical solution-based process. Conductive ink containing metal particles is applied to the base film and dried to form the conductive layer, eliminating the need for vacuum equipment while maintaining adhesion through chemical bonding mechanisms.
Solution Approach 2:
The patent uses a disposable conductive ink formulation that can be applied directly to the base film. The ink contains metal particles suspended in a binder that adheres to the base film, providing a low-cost alternative to expensive vacuum deposition equipment and processes.
2Manufacturing precision
If sputtering is used to form conductive layers, then conductive layer thickness is reduced, but production cost increases
Solution Approach 1:
The patent replaces the expensive vacuum sputtering process with a simple drying process where conductive ink is applied and allowed to evaporate the solvent, leaving behind a thin conductive layer of metal particles. This dramatically reduces production cost while achieving the required thin layer thickness.
Solution Approach 2:
The patent changes the formulation parameters of the conductive ink, including metal particle size, concentration, and binder composition, to optimize the thickness and conductivity of the resulting layer. By controlling these parameters, the patent achieves thin conductive layers without requiring expensive precision deposition equipment.
3Strength
If vacuum equipment is used for forming conductive layers, then adhesion strength is improved, but substrate size is limited
Solution Approach 1:
The patent replaces the vacuum-based process with a atmospheric drying process that is not constrained by vacuum chamber size. This allows substrates of any size to be processed, as the conductive ink can be applied and dried directly on the substrate surface without requiring evacuation of a large vacuum space.
4Productivity
If sputtering is used to form conductive layers, then high-density circuits are achieved, but process time and equipment operation cost increase
Solution Approach 1:
The patent replaces the time-consuming vacuum sputtering process with a rapid drying process. The conductive ink is applied and the solvent evaporates quickly, forming the conductive layer in minutes rather than hours. This dramatically reduces process time while achieving the same high-density circuit patterns.
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
Enables a significant reduction in conductive layer thickness at lower costs without the need for vacuum equipment, maintaining high adhesion strength between the base film and conductive layers, thus facilitating the production of high-density printed circuit boards.
Implementation Method 1
a region near an interface between the base film and the first conductive layer contains a metal oxide species based on a metal of the metal particles and a metal hydroxide species based on the metal of the metal particles
Implementation Method 2
performing heating in an atmosphere having an oxygen concentration of 1 ppm or more and 10,000 ppm or less at 150° C. or more and 500° C. or less to form a first conductive layer
Implementation Method 3
a first conductive layer formed on at least one of surfaces of the base film by application of a conductive ink containing metal particles
Implementation Method 4
a second conductive layer formed, by plating, on a surface of the first conductive layer
Data Source
AI summary
A substrate for a printed circuit board includes a base film having an insulating property; a first conductive layer formed on at least one of surfaces of the base film by application of a conductive ink containing metal particles; and a second conductive layer formed, by plating, on a surface of the first conductive layer, the surface being on a side opposite to the base film, wherein a region near an interface between the base film and the first conductive layer contains a metal oxide species based on a metal of the metal particles and a metal hydroxide species based on the metal of the metal particles, the metal oxide species in the region near the interface between the base film and the first conductive layer has a mass per unit area of 0.1 μg/cm2 or more and 10 μg/cm2 or less, and a mass ratio of the metal oxide species to the metal hydroxide species is 0.1 or more.