Fluorine-based polymer high-frequency substrate, covering film, bonding sheet, and preparation method thereof

Abstract

The invention discloses a fluorine-based polymer high-frequency substrate, a covering film, a bonding sheet and a preparation method thereof. The fluorine-based polymer high-frequency substrate is a single-sided copper-clad substrate, an FRCC and a double-sided copper-clad substrate, and the single-sided copper-clad substrate comprises a copper foil layer, a low dielectric adhesive layer, a fluorine-based polymer layer and a polyimide layer. The FRCC comprises a copper foil layer, a low dielectric adhesive layer, a fluorine-based polymer layer, a polyimide layer and a release layer, the double-sided copper-clad substrate comprises a copper foil layer, a low dielectric adhesive layer, a fluorine-based polymer layer and a polyimide layer, and the covering film and the bonding sheet both comprise a low dielectric adhesive layer, a fluorine-based polymer layer, a polyimide layer and a release layer. The low Dk / Df characteristic of the fluorine-based polymer is utilized, and the low dielectric adhesive layer with lowDk / Df and the copper foil with low roughness are matched, so that the finished product has low dielectric loss and is beneficial to high-frequency and high-speed transmission. In addition, the copper foil and the fluorine-based polymer layer are bonded by the low dielectric adhesive layer, and the PI film is used as a support, so that the substrate has good bonding strength, low thermal expansion coefficient and high dimensional stability.

Description

technical field [0001] The present invention relates to the field of FPC (flexible circuit board) and its preparation technology, in particular to low Dk / Df high-frequency single-sided copper foil substrate, FRCC (flexible glue-coated copper foil), double-sided copper foil substrate, cover film and Bondply (adhesive sheet), providing 5G and millimeter wave application solutions. Background technique [0002] Printed circuit boards are an indispensable material in electronic products. As the demand for consumer electronics grows, the demand for printed circuit boards is also increasing. Due to the characteristics of flexibility and three-dimensional space wiring, flexible printed circuit boards are currently widely used in computers and their peripheral equipment, communications products and consumer electronics, among others. [0003] Furthermore, due to the development of electronic products towards high-frequency and high-speed applications, current electronic products n...

AI Technical Summary

Problems solved by technology

[0004] However, the surface properties of fluorine-based resins have extremely low surface energy, so it is not easy to adhere to metals, and it is easy to cause delamination, which makes the yield of fluorine-based substrates low, requires surface treatment, and has fewer options for copper foil Use low-roughness copper foil with low transmission loss, or have to be adhered by other adhesive layers

In addition, its high coefficient of thermal expansion (about 200ppm / °C) is likely to cause poor dimensional stability, and dimensional changes will directly affect the production of conductor lines and problems such as alignment deviation, especially for high-density requirements, and lines are becoming more and more In subtle cases, the degree of influence is more obvious

In addition, fluorine-based resins are limited by the process technology, which requires high manufacturing equipment and can only be operated in a relatively high temperature environment (>280°C), which also causes uneven film thickness, which will cause The impedance value of the circuit board is not easy to control, and the high-temperature lamination process will cause PTFE extrusion to affect the conductivity of the copper plating and form an open circuit, resulting in poor reliability and reduced reliability; in addition, PTFE is mostly flake The roll-to-roll lamination process cannot be used, resulting in difficult processing, low mass production, and more consumables

In addition, in the SMT (surface mount) high-temperature process or other FPC processes, such as bending, strong acid and strong alkali liquid process, the subsequent strength is insufficient, resulting in a decrease in yield

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