Ultra-thin Polyimide Circuit Fabrication via Peelable Release Carrier
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Solution Overview
Problem
Current methods face difficulties in fabricating ultra-thin polyimide films less than 6 μm thick, as they are prone to breaking during stretching and pose challenges in adhesive application, making it hard to produce flexible circuit boards with such thin films.
Innovation Solution
A method involving a base layer with low surface energy fillers, such as fluoropolymers, is used to form a peelable adhesion with a polyimide layer, allowing for the formation of a metal layer on the polyimide layer without breaking it, and enabling easy peeling of the base layer, even at thicknesses below 6 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the polyimide film thickness is reduced to less than 6 μm to achieve ultra-thin flexible circuit boards, then the flexibility and weight are improved, but the film becomes prone to breaking during stretching and processing
Solution Approach 1:
A release film is introduced as an intermediary carrier between the ultra-thin polyimide film and the processing environment. The release film provides mechanical support during stretching and processing, preventing the ultra-thin polyimide film from breaking. After processing, the release film is peeled off, leaving the intact ultra-thin polyimide film with metal circuits.
Solution Approach 2:
The polyimide film is formed on the release film before any stretching or processing operations. This preliminary formation ensures that the ultra-thin film is supported by the release film during subsequent processing steps, preventing breakage before the film can be used in the final application.
2Adaptability or versatility
If the polyimide film thickness is reduced to less than 5 μm to achieve greater thinness, then the flexibility is improved, but biaxial orientation stretching cannot be applied without breaking the film
Solution Approach 1:
The release film serves as a mediator that enables biaxial stretching of ultra-thin polyimide films. By providing a supportive substrate, the release film allows the stretching process to be applied to films thinner than 5 μm without causing breakage, which would otherwise be impossible.
Solution Approach 2:
The polyimide film is formed on the release film before biaxial stretching. This preliminary formation on a supportive carrier enables the stretching process to be successfully applied to ultra-thin films, achieving biaxial orientation that would be impossible with free-standing ultra-thin films.
3Reliability
If adhesive coating is applied on ultra-thin polyimide films with thickness less than 6 μm to enable circuit formation, then the circuit bonding is improved, but the processing difficulty increases significantly
Solution Approach 1:
The release film acts as an intermediary processing carrier that simplifies adhesive coating operations. By providing a stable, handleable substrate, the release film enables adhesive coating to be applied uniformly and reliably to ultra-thin polyimide films without the processing difficulties that would arise from handling free-standing ultra-thin films.
Solution Approach 2:
The adhesive coating is applied to the release film rather than directly to the ultra-thin polyimide film. This preliminary action on a thicker, more manageable substrate enables reliable adhesive application, which can then be transferred to the polyimide film without the handling difficulties of working directly with ultra-thin materials.
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
This approach allows for the successful fabrication of ultra-thin flexible circuit boards with polyimide layers as thin as 0.1 to 5 μm, enabling biaxial stretching without damage and facilitating adhesive application, thus overcoming the limitations of conventional methods.
Implementation Method 1
A method may comprise, for example, forming a base layer containing polyimide, forming a polyimide layer on the base layer, the polyimide layer having a first surface and a second surface opposite to each other, the first surface of the polyimide layer being peelably adhered in contact with the polyimide layer
Data Source
AI summary
The present disclosure relates, according to some embodiments, to the fabrication of a flexible circuit board, which includes forming a base layer comprising polyimide, forming a polyimide layer on the base layer, the polyimide layer having a first surface and a second surface opposite to each other, the first surface being peelably adhered in contact with the base layer, forming a metal layer on the second surface of the polyimide layer, and peeling the base layer from the polyimide layer with the metal layer remaining on the second surface of the polyimide layer.