Release Material for Circuit Board Thermal Bonding
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Solution Overview
Problem
Existing circuit boards face issues with ion migration due to moisture, leading to potential destruction and requiring complex manufacturing processes, while existing solutions for water resistance and noise suppression are either ineffective or costly.
Innovation Solution
A circuit board design using a thermoplastic liquid crystal polymer cover film, thermally bonded with a specific release material configuration that ensures uniform thickness coverage over conductor circuits, combining ultrahigh-molecular-weight polyethylene and high-density polyethylene films with aluminum foils to maintain electrical properties and suppress noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermoplastic liquid crystal polymer cover film is used to provide water-vapor barrier property, then water resistance is improved, but the manufacturing process becomes complicated and dielectric property deteriorates
Solution Approach 1:
The patent removes the adhesive layer from the conventional laminated structure, using direct thermal bonding between the liquid crystal polymer cover film and the circuit board. This extraction of the adhesive component simplifies the manufacturing process and eliminates the complexity associated with adhesive application and curing steps.
Solution Approach 2:
The patent employs a thermoplastic liquid crystal polymer as the cover film material, which combines water-vapor barrier properties with good adhesion and electrical insulation characteristics. This composite material approach allows direct thermal bonding without adhesive while maintaining dielectric properties and water resistance.
2Ease of manufacture
If ultraviolet ray is irradiated on the cover film surface to soften it for thermocompression bonding, then bonding is achieved, but the cover film deforms and uniform thickness coverage becomes difficult
Solution Approach 1:
The patent changes the softening method from ultraviolet irradiation to thermal heating. By controlling the temperature parameter during thermal compression bonding, the cover film softens uniformly without the localized deformation caused by UV irradiation, enabling uniform thickness coverage while maintaining bonding capability.
3Strength
If an adhesive layer is used to laminate the cover film, then bonding is achieved, but dielectric property deteriorates and manufacturing steps become complicated
Solution Approach 1:
The patent extracts and eliminates the adhesive layer from the laminated structure, relying on direct thermal bonding between the liquid crystal polymer cover film and the circuit board. This removal of the adhesive component preserves dielectric properties while maintaining sufficient bonding strength through the thermal fusion of the thermoplastic material.
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 provides superior heat resistance, water-vapor barrier properties, and electrical performance while maintaining low signal loss and noise, even at high signal frequencies, and is cost-effective to manufacture.
Implementation Method 1
a cover film on at least a conductor circuit side of outermost layers of the board structural body, wherein the board structural body is covered with the cover film at an approximately uniform thickness
Implementation Method 2
a specific release material configuration that ensures uniform thickness coverage over conductor circuits, combining ultrahigh-molecular-weight polyethylene and high-density polyethylene films with aluminum foils
Data Source
AI summary
Provided is a method of manufacturing a circuit board including preparing a board structural body (11) and covering a conductor circuit element (13) on an outermost layer of the board structural body (11) with a cover film (14), wherein a heat treatment is performed while having a release material (15) interposed between the cover film (14) and a heat-processing device. The release material (15) is a laminate at least including, sequentially from the cover film toward the heat-processing device, a low friction film (16) selected from an ultrahigh-molecular-weight polyethylene film and a polytetrafluoroethylene film, a first aluminum foil (17), a first high-density polyethylene film (18a), a second high-density polyethylene film (18b), and a second aluminum foil (19). The first high-density polyethylene film (18a) and the second high-density polyethylene film (18b) are positioned such that respective MD directions are perpendicular to each other.