High-Frequency Circuit Board TFP Coating for Signal Loss Reduction
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Solution Overview
Problem
Conventional high-frequency circuit boards with polyimide substrates face challenges in adapting to the increasing signal frequencies and speeds due to high dielectric constants, moisture absorption, and structural limitations, leading to significant transmission losses and complex manufacturing processes.
Innovation Solution
A method involving coating synthetic TFP film on cured PI film, followed by sequential heating and roasting in a tunnel oven, and hot pressing with copper foil to create a novel material layer structure for high-frequency circuit boards, which simplifies manufacturing and enhances signal transmission capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional polyimide substrates are used for high-frequency circuit boards, then the manufacturing process is simple and cost-effective, but the transmission loss increases and signal quality deteriorates at high frequencies
Solution Approach 1:
The patent uses a composite material structure consisting of a polyimide substrate combined with a low-dielectric-constant coating layer. This composite approach allows the base polyimide to provide mechanical strength and flexibility while the coating layer reduces dielectric constant and signal transmission loss, resolving the contradiction between simple manufacturing and high-frequency performance.
2Adaptability or versatility
If polyimide substrates are used for circuit boards, then the structural flexibility is good, but the dielectric constant is high causing severe high-frequency transmission loss
Solution Approach 1:
The patent applies a specialized low-dielectric-constant coating layer only on the surface where signal transmission occurs, while the bulk polyimide substrate maintains its flexible structural properties. This local quality modification allows the circuit board to be flexible structurally while having low transmission loss at the signal interface.
3Reliability
If polyimide substrates are used for high-frequency applications, then the material is readily available and easy to process, but the moisture absorption is high reducing reliability
Solution Approach 1:
The low-dielectric-constant coating layer acts as an intermediary barrier between the hygroscopic polyimide substrate and the external environment. This coating layer protects the substrate from moisture absorption while not interfering with the ease of manufacturing the base material, thus improving reliability without compromising manufacturability.
4Adaptability or versatility
If traditional multi-layer flexible circuit board structures are used, then the design flexibility is good, but the manufacturing process becomes complex with more process flows
Solution Approach 1:
The patent pre-coats the polyimide substrate with a low-d dielectric constant material before circuit board assembly. This preliminary action integrates the dielectric optimization step into the substrate preparation phase, avoiding the need for additional complex manufacturing processes later while maintaining design flexibility for multi-layer structures.
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 results in a high-speed, low-power consumption, and low-loss signal transmission, enabling the circuit boards to meet the demands of 5G technology products by improving stability and dimensional stability, while reducing production costs and simplifying the manufacturing process.
Implementation Method 1
delivering the whole of the cured PI film coated with the synthetic liquid TFP film into a tunnel oven, and successively passing the same through a plurality of sections of heating and roasting zones in the tunnel oven at a speed of 0.5-20 m/s for roasting in sections
Implementation Method 2
hot pressing a copper foil on the semi-cured TFP film to obtain a novel single-sided material layer structure of a high-frequency circuit board
Data Source
AI summary
The present invention discloses a method for preparing a novel material layer structure of a high-frequency circuit board, comprising the steps of: (1) coating a synthetic liquid TFP film on a cured PI film; (2) delivering the same to a tunnel oven for roasting in sections to form a semi-cured TFP film on a front surface of the cured PI film; and (3) hot pressing a copper foil on the semi-cured TFP film to obtain a novel single-sided material layer structure of a high-frequency circuit board. The present invention also discloses a novel material layer structure of a high-frequency circuit board prepared by performing the above-mentioned method. The prepared novel material layer structure of the high-frequency circuit board has the performance of high-speed transmission of high-frequency signals, and can adapt to the current high-frequency and high-speed trend from wireless network to terminal applications, especially for new 5G technology products. It can be used as a circuit board preparation material to manufacture a circuit board structure, such as a single-layer circuit board, a multi-layer flexible circuit board and a multi-layer soft-hard combined board, which brings great convenience to subsequent preparation for the circuit board and simplifies the process.