PCB Substrate Metal Diffusion Control for Peel Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrates for printed circuit boards face challenges in maintaining high adhesive force between the resin film and metal layer, especially after weather resistance tests, due to insufficient conditions for increasing peel strength.
Innovation Solution
A substrate with a resin film and a metal layer where the average diffusion depth of the main metal in the resin film is 100 nm or less after a weather resistance test, combined with a modified layer treated with an alkali solution, to enhance adhesiveness and prevent metal layer peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a metal layer is directly stacked on a resin film without adhesive by reducing metal ions in solution, then the thickness of printed circuit board can be decreased, but the adhesive force between metal layer and resin film deteriorates after weather resistance test
Solution Approach 1:
The patent applies preliminary action by forming a metal ion-impregnated layer within the resin film before stacking the metal layer. This pre-prepared layer with controlled metal ion distribution ensures optimal adhesion conditions are established in advance, preventing metal peeling after weather resistance tests while maintaining thin board design
Solution Approach 2:
The patent employs parameter changes by precisely controlling the concentration and distribution of metal ions within the resin film. By adjusting metal ion concentration parameters and creating specific diffusion depth profiles (with 80-95% of metal ions concentrated in the lower 20% thickness region), the adhesive properties are optimized to maintain strong bonding after thermal stress
2Reliability
If metal ion concentration in resin film is increased to improve adhesive force, then peel strength increases, but metal ion diffusion depth increases causing excessive penetration
Solution Approach 1:
The patent applies local quality by creating a non-uniform metal ion distribution within the resin film thickness. Specifically, 80-95% of metal ions are concentrated in the lower 20% thickness region adjacent to the metal layer, while the upper regions maintain lower metal ion concentrations. This localized metal ion enrichment provides strong adhesion at the interface without excessive diffusion into the bulk resin
Solution Approach 2:
The patent controls the diffusion depth parameter of metal ions by adjusting impregnation conditions and resin film properties. The metal ion diffusion depth is precisely regulated so that the average diffusion depth is 0.02-0.5 μm, with the concentration gradient ensuring high peel strength while limiting excessive penetration into the resin bulk
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 effectively maintains a high adhesive force between the resin film and metal layer, ensuring reliable circuit formability and resistance to peeling, even after exposure to high temperatures, while allowing for cost-effective production.
Implementation Method 1
An average diffusion depth of main metal of the metal layer in the resin film is 100 nm or less after a weather resistance test in which the substrate is held at 150° C. for seven days
Data Source
AI summary
A substrate for a printed circuit board according to an embodiment of the present invention includes a resin film and a metal layer stacked on at least one of surfaces of the resin film. An average diffusion depth of a main metal of the metal layer in the resin film is 100 nm or less after a weather resistance test in which the substrate is held at 150° C. for seven days. The average diffusion depth is preferably 80 nm or less before the weather resistance test.