Metal Foil Laminated Polyimide Substrate Adhesion
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Solution Overview
Problem
Existing metal foil laminated polyimide resin substrates face challenges in achieving excellent adhesiveness to anisotropic conductive films and adhesive materials, particularly in forming fine-pitch wiring with reliable adhesion and filling characteristics between the metal foil and the polyimide resin substrate.
Innovation Solution
A metal foil laminated polyimide resin substrate is developed with a surface roughness of 3.0 μm or less, a specific surface area ratio of 1.25 to 2.50, and a chromium content of 2.0 mg/m², which is bonded to the polyimide resin substrate using a hot-press forming machine, enhancing adhesiveness and filling characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface roughness of metal foil is increased to improve adhesion to polyimide resin substrate, then adhesion strength is improved, but the filling characteristics between metal foil and substrate deteriorate
Solution Approach 1:
The invention optimizes the surface roughness parameter of the metal foil to a specific range (Ra 0.5-3.0 μm) to simultaneously achieve adequate adhesion strength and good filling characteristics. This parameter optimization resolves the contradiction by finding the optimal balance point where both requirements are satisfied.
2Strength
If chromium content on metal foil surface is increased to improve adhesion to adhesive organic materials, then adhesion strength is improved, but manufacturing complexity increases
Solution Approach 1:
The invention specifies a quantitative range for chromium content (0.1-10.0 mg/m²) that achieves adequate adhesion without requiring complex surface treatment processes. This parameter specification resolves the contradiction by providing a simple, controllable range that delivers the desired adhesion performance.
3Strength
If metal foil surface area is increased to improve adhesion contact, then adhesion strength is improved, but the surface roughness control becomes more difficult
Solution Approach 1:
The invention establishes a specific surface roughness range (Ra 0.5-3.0 μm) that provides adequate adhesion contact area while remaining controllable through standard manufacturing processes. This parameter specification resolves the contradiction by defining a range that balances adhesion performance with manufacturing feasibility.
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 results in improved adhesion and reliability between the polyimide resin substrate and adhesive organic materials, enabling the formation of fine wiring with reduced rejection rates and enhanced peel strength, suitable for high-density flexible wiring substrates and build-up circuit boards.
Implementation Method 1
a metal foil laminated polyimide resin substrate which comprises: a metal foil which is directly laminated on one side or both sides of a polyimide resin substrate; wherein the surface of the metal foil to be bonded to the polyimide resin substrate has a surface roughness (Rzjis) of 3.0 μm or less, a surface area ratio (B) of 1.25 to 2.50...
Data Source
AI summary
The present invention relates to a metal foil laminated polyimide resin substrate whereina metal foil is directly laminated on one side or both sides of a polyimide resin substrate; andthe surface of the metal foil to be bonded to the polyimide resin substrate has a surface roughness (Rzjis) of 3.0 μm or less; a surface area ratio (B) of 1.25 to 2.50, in which the surface area ratio (B) is calculated as a ratio [A/6550] of a surface area of a two-dimensional region with a surface area of 6550 μm2 which is determined by a laser method (three-dimensional area: A μm2) to the area of the two-dimensional region; and a chromium content per unit area of the two-dimensional region of 2.0 mg/m2 or more.