Material Choices for High-Speed Flexible Circuits


Reading time ( words)

Abstract

High-speed rigid boards have existed for many years, with fluoropolymers being the most common dielectric used. More recently, flexible circuit materials have been developed, and these new products use a variety of polymer (including fluoropolymers) and composite film approaches to allow high-speed flex circuits. This article will provide guidelines on how to compare the different options. The electrical benefits of the different polymers and constructions will be reviewed as well as the physical and flexible properties of different constructions. As with any new materials, the ease of processing is an important consideration, especially since some of these new products use thermoplastic adhesives or require high-temperature lamination of bondplies and coverlays.

Introduction

High-speed rigid boards have existed for many years and continue to improve. Initially, most high-speed rigid boards used fluoropolymer dielectrics (fluorine-containing polymers like Teflon®). Now many new dielectrics have been developed for high-speed rigid boards, which has broadened both the material supplier base and the number of fabricators that can make high-speed rigid boards.

Materials for high-speed flexible circuits are a much more recent development. This article will review the key material choices for making high-speed flexible circuits while also explaining why older flex materials were not a good choice for today’s high-speed circuits.

When talking about high-speed circuits, we are really talking about controlled impedance applications. This could be either microstrip or stripline designs. This paper will discuss flexible clads, as well as bondplies and coverlays. For controlled impedance circuits, the electrical properties of the clad and bondplies are critical for striplines. The electrical properties of the clad and coverlay are critical for microstrips. 

To read the full version of this article which appeared in the April 2017 issue of The PCB Magazine, click here.

Share




Suggested Items

Material Application for Mini Backlight Unit

04/12/2022 | Aaron Chen, Wazam New Material Co. Ltd.
In 1980, about 90% of the materials used to make PCBs was FR-4. As time went by, technology developed, and electronic devices relentlessly integrated into every area of our lives. The constant acceleration of upgrading meant endless challenges and opportunities for CCL suppliers. Wazam New Material Co. Ltd. is a CCL supplier that strives to be attentive to the needs of its end customers and provide comprehensive solutions. One example is the mini backlight unity (MBLU) application material.

Engineering RF Dielectric Material to Enable 5G/6G Antenna Devices

04/11/2022 | Chudy Roosevelt Nwachukwu, ITEQ Corporation
Accurate characterization of frequency-dependent inhomogeneous dielectric material properties is key to the optimal design of high performance and cost-effective PCB antennas. These antennas will be required to enable the plethora of devices forecasted for 5G/6G communication. Therefore IT-88GMW, an advanced resin system reinforced with tightly woven thin glass fibers has been formulated to improve the Q-factor of interconnects and passive components fabricated on PCB laminates.

Improved Thermal Interface Materials For Cooling High-Power Electronics

03/31/2022 | Jeff Brandman, Aismalibar North America
Heat has been a significant concern in electronics since the beginning of the electronics age when hot glowing vacuum tubes were first used to receive and transmit data bits. The transistor and integrated circuit effectively solved that basic problem, but increases in integration resulted in increased concentration of heat, exacerbated by relentless increases in operating frequency. While improvements in electronics technology have been able to mitigate many thermal issues at chip level thanks to improved semiconductor designs devised to operate at lower voltages (thus requiring less energy) the thermal management challenge continues to vex electronic product developers.



Copyright © 2022 I-Connect007. All rights reserved.