A method for preparing a low-loss and high-uniform adhesive sheet and a multi-layer microwave board

Abstract

The invention relates to a low loss and high uniformity adhesive sheet and a method for preparing a multilayer microwave board. The adhesive sheet is composed of an upper thermosetting resin film and a lower thermosetting resin film of a fluorine-based composite film; the upper thermosetting resin film and The components of the lower thermosetting resin film are thermosetting resin, initiator and filler. In order to achieve specific functions, thermoplastic elastomers, flame retardants, antioxidants and plasticizers can be added to it; among them, thermosetting resin and thermoplastic elastic The body is the matrix, the cross-linking agent, flame retardant, antioxidant and plasticizer are the additives, and the filler is the reinforcing material; the additives and reinforcing materials are randomly distributed in the matrix; the thermosetting resin film is semi-cured or uncured. In the cured state, it has certain fluidity and is prepared on the upper and lower surfaces of the fluorine-based composite film through a coating process. The components of the invention exhibit high uniformity and do not contain fiberglass cloth, thus avoiding the impact of the "glass fiber effect" on high-frequency signal transmission.

Description

Technical field [0001] The invention relates to the technical field of microwave copper-clad laminates, in particular to a low-loss and high-uniformity adhesive sheet and a method for preparing a multi-layer microwave board. Background technique [0002] With the rapid development of electronic information technology, microwave circuit components are moving towards integration and miniaturization. Ordinary single-layer microwave composite dielectric substrates can no longer meet actual requirements. Multi-layer microwave composite substrates composed of single-layer substrates and adhesive sheets Composite dielectric substrates have gradually become a hot spot in research and application. At the same time, the increase in transmission signal frequency has also put forward higher requirements for the loss factor of dielectric materials. The traditional epoxy resin system has been gradually eliminated by high-end applications due to its high loss factor. Fluorine-based resin ...

AI Technical Summary

Problems solved by technology

However, its large thermal expansion coefficient, non-hydrophilic and non-oleophilic surface, and high melting point (327°C) limit its application in adhesive sheets.

[0003] The new bonding sheet involved in Chinese patent CN212451274U includes a fluorine-containing resin layer and has a first surface and a second surface oppositely arranged, and the dielectric loss of the thermosetting resin arranged on the first surface and the second surface is less than or equal to 0.005, higher than Material requirements for microwave circuits, and the patent does not mention the thermal expansion coefficient performance of the bonding sheet

In high-frequency applications, the weaving structure of glass fiber cloth will cause differences in dielectric constant in small areas, which will cause "glass fiber effect", affect the stability and reliability of signal transmission, and cannot achieve high uniformity of dielectric constant ; and the thickness of the substrate formed by impregnation of glass fibers also fluctuates due to the weaving of glass fibers, resulting in low uniformity of dielectric constant

Multi-layer microwave boards made of adhesive sheets with low uniformity will cause wave distortion and other problems in high-frequency signal transmission.

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