Flexible Circuit Materials for High-Temperature Applications


Reading time ( words)

Abstract

Many opportunities exist for flexible circuits in high-temperature applications (automotive, military, aerospace, oil and gas). Flex circuits in these applications have been hindered by a lack of materials that can survive higher temperatures. Some materials, especially some thermoset adhesives, break down over time at higher temperature, becoming brittle or losing adhesion to copper. Polyimides tend to perform much better under high temperature.

The other issue is the lack of good test methods to verify that flex materials can survive higher temperatures. Several methods for testing copper clad laminates exist, but there are very few for coverlays and bondplies. We will discuss different test methods for measuring high-temperature capability including the new IPC service temperature test. We will also report on test results for various flexible materials and our recommendations for the best flexible materials for high temperature applications. This will include development work on new flex materials for high-temperature applications.

Introduction

More applications require flexible circuits that must survive high-temperature environments. These include automotive applications near the engine, oil and gas down-hole pumps, and aerospace applications near jet engines. There have been limited test methods to determine what temperatures flexible materials can survive.

The damage caused by high-temperature environments will mainly fall in three categories: loss of adhesion between copper and dielectric, loss of adhesion between dielectric layers, and embrittlement  of the dielectric layers. At the highest temperatures the copper would also become brittle, but in most cases the flexible circuit dielectrics fail first. Thermoset adhesives seem to be most sensitive to embrittlement especially compared to polyimide films which are much more resistant to high temperatures.

Read the full article here.


Editor's Note: This article originally appeared in the June 2015 issue of The PCB Magazine.

Share

Print


Suggested Items

PCB Technologies Expands Capabilities

04/16/2021 | Nolan Johnson, I-Connect007
Nolan Johnson speaks with Arik Einhorn and Yaad Eliya of Israel-based PCB Technologies about how they’ve increased their capabilities down to 1 mil line and space to better support their customers from the military, aerospace, and medical markets.

I-Connect007 Editor’s Choice: Five Must-Reads for the Week

03/26/2021 | Andy Shaughnessy, Design007 Magazine
This week, we have a round-up of stories from around the industry, including a Real Time with… IPC APEX EXPO interview with Ventec, an article by Tamara Jovanovic about eliminating “garbage in, garbage out,” a review of an EIPC webinar by Pete Starkey, and news about another trade show going virtual this summer. And last but certainly not least, we bring you our one-minute video salute to all the fantastic people in this industry who we’ve worked with for decades. Enjoy!

Bonding Hybrid Multilayer Constructions at Rogers Corporation

03/10/2021 | Real Time with...IPC
John Ekis, Rogers Corporation's market segment director for aerospace and defense, discusses the SpeedWave family of low-dielectric constant, ultra-low-loss prepreg materials with excellent filling and bonding characteristics for hybrid multilayer constructions. SpeedWave prepreg is also compatible with FR-4 fabrication processes and lead-free PCB assembly processing. SpeedWave is available in multiple spread and open weave glass style and resin content combinations, and is also compatible with FR-4 fabrication processes and lead-free PCB assembly processing.



Copyright © 2021 I-Connect007. All rights reserved.