What is a flex coverlayer? What’s its purpose? Are they new or have they been around a while? Why do they matter to my design? Coverlayers are polymer materials used to cover and protect the copper traces of the flex circuit product. As implied, there are a number of different options available for protecting the circuits, and they serve different design requirements in terms of cost, performance, and flexural endurance optimization. When specifying the choice, it is critical to call out not just the type of coverlayer material but also the thickness requirement. This can be very important in certain types of constructions, especially when a flex circuit will experience dynamic flexing during use. It is also important to know and understand that there are different types of materials available for use as coverlayer materials and that there is no single, ideal solution. The appropriate material choice will be based on a number of factors, such as application, cost, projected life, etc. Coverlayer selection requires a thorough analysis that balances both cost and performance to ensure the proper choice. Key considerations include how much will the flex circuits be bent in the fiel...