Technology discussion – RA vs ED Copper

Wondering about the differences between Rolled Annealed (RA) copper and Electro Deposited (ED) Copper in flex circuit design?
Read More

The most common question PFC receives during the DFM process (Design for Manufacturing) with our customers, has to do with the bend radius of the circuit we are designing. As we have mentioned many times IPC calls out the bend radius to be ten times the thickness of the circuit. The industry response is seven times the thickness and depending on the materials used in the design, we can go to five times the thickness.

Flexibility in the copper comes from multiple factors. Of course the thinner the copper, the more flexible. In addition to the thickness (or thinness), copper grain also affects flexibility. There are two common types of copper that are used in the PCB and flex circuit markets. Electro Deposited (ED) and Rolled Annealed (RA).

With ED copper, there is a huge diversity of foils regarding surface roughness, treatments, grain structure, etc. As a general statement, ED copper has a vertical grain structure. The standard ED copper typically has a relatively high profile or rough surface as compared to rolled annealed copper. ED copper tends to lack flexibility and does not promote good signal integrity.

RA copper has been used extensively in the flex industry for decades. The grain structure and smooth surface is ideal for dynamic, flexible circuitry applications. Another area of interest with rolled copper types exists in the high-frequency signals and applications. It has been proven that copper surface roughness can impact high-frequency insertion loss and a smoother copper surface is advantageous.

More news

HDI Technology Discussion
Driven by market demand for new applications requiring smaller interconnects with dense components, HDI technology increases density by miniaturization of holes, pads, and conductors to create a smaller interconnect solution. Read more about PFC’s …
Find out more
The Medical Market
The medical market for flex circuits continues to be strong. Read more about the trends driving this growth and the solutions PFC provides to support it.
Find out more
High speed flex challenges
Challenges exist in the industry with the lack of readily available industry information on high speed flex. Read more about why that information gap exists and how PFC is bridging it.
Find out more
DesignCon White Paper Now Available for Download
The white paper jointly presented by DuPont, Taconic and PFC Flexible Circuits Limited in the technical sessions at DesignCon 2016 is now available for download.
Find out more
Special Web Feature: HDI Technology – Flex Circuits and Assembly
HDI flex requires the flex circuit vendor to design, manufacture and assemble. This is what PFC provides. Read more about HDI and PFC’s capabilities here.
Find out more
Special Web Feature: High Speed Flex Solutions
Why are flex circuits superior for high frequencies? What you need to know about high speed flex solutions and how PFC can help.
Find out more
Older posts...