Double-sided copper foil substrate for pi-type high-frequency and high-speed transmission and preparation method thereof

Abstract

The invention discloses a double-sided copper foil base plate for PI type high-frequency and high-speed transmission. The double-sided copper foil base plate sequentially comprises a first low-profilecopper foil layer, an upper pole low dielectric adhesive layer, a core layer, a lower pole low dielectric adhesive layer and a second low-profile copper foil layer from top to bottom, wherein the core layer is a polyimide film, the Rz values of the first low-profile copper foil layer and the second low-profile copper foil layer are 0.4-1.0 [mu]m, the components of the formulas of the upper pole low dielectric adhesive layer and the lower pole low dielectric adhesive layer contain a polyimide-based resin, sintered silica, teflon, a fluorine-based resin and a phosphorus flame retardant so as toachieve the Dk value of 2.0-3.0 (10 GHz) and the Df value of 0.002-0.010 (10 GHz), the adhesion strength of the stacked structure formed from the first low-profile copper foil layer, the upper pole low dielectric adhesive layer, the core layer, the lower pole low dielectric adhesive layer and the second low-profile copper foil layer is more than 0.7 kgf / cm, and the water absorption is 0.01-1.5%.According to the present invention, the obtained double-sided copper foil base plate has advantages of good electrical property, high-speed transmission, low thermal expansion coefficient, stable dk / df performance in high temperature and humidity environments, ultra-low water absorption, good UV laser drilling ability, low rebound force suitable for high density assembly and excellent mechanical property.

Description

technical field [0001] The invention relates to a double-sided copper foil substrate for FPC (flexible circuit board) and the technical field of its preparation, in particular to a double-sided copper foil substrate for PI (polyimide) type high-frequency and high-speed transmission. Background technique [0002] With the rapid development of information technology, in order to meet the requirements of high-frequency and high-speed signal transmission, rapid heat dissipation and heat conduction, and minimized production cost, the design and application of various forms of mixed-pressure multilayer boards have emerged as the times require. Printed circuit boards are an indispensable material in electronic products, and as the demand for consumer electronics grows, so does the demand for printed circuit boards. As flexible printed circuit boards (FPC, Flexible Printed Circuits) have the characteristics of flexibility and three-dimensional space wiring, under the development of ...

AI Technical Summary

Problems solved by technology

In addition, the high-frequency substrates currently used in the industry are mainly LCP (liquid crystal) boards and PTFE (polytetrafluoroethylene) fiber boards. However, they are also limited by the process technology, which requires high manufacturing equipment and requires high temperature environments (> 280°C), it can only be operated at a temperature of 280°C, which also causes uneven film thickness, and uneven film thickness will make it difficult to control the impedance of the circuit board; in addition, it is faced with problems such as the inability to use fast press equipment, resulting in difficult processing, etc.

Although other resin films do not have the above problems, they face problems such as poor electrical properties, weak adhesion or poor mechanical strength.

[0004] General epoxy resin products do not perform well under the small aperture (<100μm) UV (ultraviolet ray) laser processing in the downstream industry, and it is easy to cause shrinkage of the through hole (PTH, Plating Through Hole). Large-diameter mechanical drilling method has poor process adaptability

[0005] In addition, in the preparation of multi-layer boards and soft-rigid boards, due to the high water absorption of general PI and TPI copper foil substrates, reaching 1-2%, it will cause board explosion problems and seriously affect the yield.

[0006] In terms of cost, efficiency and workability, high-frequency substrates are prepared by LCP and TPI (thermoplastic polyimide) methods, which require high-temperature lamination, and the lamination temperature is between 280-330°C, especially in production and transmission performance For products with a thickness above 38um, the efficiency is low and the cost is high

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