Difference between Various Materials for Teflon PCBs

Teflon pcb materials used in PCB manufacturing may affect the circuit performance of end users. This means that there must be interaction between the manufacturer and the designer, and the end user should be aware of the PCB manufacturer’s concerns about these materials. This is very important for good yield and highly reliable and high quality finished products, as each type of high frequency material has its own unique manufacturing considerations.

The most common high frequency materials are PTFE (polytetrafluoroethylene), PTFE with ceramic filler and non PTFE thermosetting resin system with ceramic load. Less commonly used are LCP or liquid crystalline polymer materials.

Characteristics of teflon pcb materials
PTFE materials have been used in high frequency circuits for a long time in PCB manufacturing industry. In addition to pure PTFE, some substrates may contain a small amount of microfibre glass immersed in it. Others can be PTFE with braided glass reinforcement. Some may be PTFE with ceramic fillers. However, compared with all other types of materials used in high frequency circuits, near pure PTFE is the most challenging type of circuit material faced by PCB manufacturers. The reasons are as follows:

PTFE CTE high
PTFE does not allow other materials to adhere easily
PTFE is a soft material, easy to deform
However, from the point of view of electrical properties, it is better to use PTFE materials. PCB manufacturers find the most easy to handle ceramic filled PTFE substrates.

Use teflon pcb material
When using PTFE materials, PCB manufacturers must be careful not to stain during drilling, not to change substrates by scrubbing or other mechanical processes, fine tune dimensional stability issues, and use best practices to minimize manual damage to soft substrates. PTFE substrate requires a special through-hole preparation process to make the copper coating adhere to the hole wall, while another special process is to laminate PTFE materials with other bonding materials.

Since there is no known method or process for PTFE stain removal, it is important to minimize heat during drilling, as heat can cause fouling. For pure PTFE, the cleanest possible drilling requires the use of new drilling tools to ensure that no stains are generated, but the ceramic filled PTFE substrate can withstand re sharpening tools.

The pure PTFE substrate needs wet chemical treatment before copper plating to ensure good adhesion. Generally, sodium naphthalene or derivatives can remove fluorine atoms to make PTFE substrate accept copper plating. Ceramic filled PTFE must undergo an additional baking process to remove moisture absorbed by the substrate during the wet chemical phase. Another option is to use a special plasma cycle using helium to avoid the baking process.

Laminating on PTFE requires bonding media, and most of the bonding materials commonly used in PCB industry are also suitable for PTFE. However, the manufacturer must be careful not to change the bare substrate surface after the copper etching process, as any scrubbing will polish the soft PTFE surface and hinder further bonding.

Teflon pcb Conclusion
Due to its widespread use in high frequency applications, PTFE applications are unique. If you want to improve PCB efficiency by using Teflon.

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