Teflon, commonly known as PTFE or polytetrafluoroethylene, has an inert molecular structure, making it an excellent material for non stick coatings. It can make teflon pcb. Compared with traditional FR4 materials, PCB manufacturers are increasingly using PTFE laminates because of their unique characteristics in high frequency applications.
Although the manufacture of PCB made of PTFE is very similar to that of traditional PCB, manufacturers need to be careful when dealing with softer materials, and pay special attention to those areas which are different from PTFE because of their uniqueness, so as to fine tune their process. Nature and chemistry.
For example, PTFE laminates are softer and their surfaces are more likely to bend, wrinkle or sag than FR4 laminates. Although these surface defects are acceptable in consumer electronic circuits, they can seriously affect the functional performance at high frequencies. Therefore, PTFE laminates require flat supports during storage to prevent sagging or sagging, which can solidify over time.
For metallization, marking and multi-layer surface treatment
Mechanical preparation of copper surfaces of PTFE laminates is not recommended. Equipment suitable for conventional rigid materials (e.g. bristles, pumice scrubbers and composite brushes) should not be used because soft PTFE substrates may stretch to absorb stress, resulting in unpredictable dimensional results.
To prepare PTFE surfaces, the standard process used in the PCB industry is sodium etchant or plasma gas cycle. These processes can strip or remove fluorine from PTFE surface, making it suitable for metallization, labeling and multilayering.
To avoid registration problems due to dimensional stretching, manufacturers use soap or degreasing baths to remove potential organic matter. They also use chemical cleaners to remove the antirust coating from the copper foil. This usually removes about a fortieth of an inch from the foil surface to promote photoresist adhesion.
The following is teflon pcb fabrication.
PTFE and copper films can be bonded without the use of adhesive films and / or prepreg. Typically, manufacturers use 700 ° F and 450-500 psi pressure as the starting point for the lamination process. The temperature and pressure vary with the ceramic filler and other components of the PTFE laminate.
Manufacturers also use adhesive films with lower melting points to reduce the processing temperature to about 250-425 ° F. Others may use a ceramic filled binder as a glass fiber reinforced prepreg, requiring a process temperature of 550 ° F.
Although there are no hard and fast rules for drilling copper laminated PTFE substrates, new tools must always be used. In general, slow feed and high chip load are preferred to eliminate spurious laminate fiber or PTFE tailing.
Due to the improved dielectric constant and low CTE of this material, manufacturers can also benefit from other benefits, such as easier drilling and cleaning of holes with ceramic filled laminates. However, ceramic filling can increase the wear of drill bit by 25-50%.
Metallization and copper plating
Because the z-axis CTE of pure PTFE laminates is very high, it is necessary to use copper plating with high tensile strength on the through hole wall. High ductility copper reduces the possibility of pad lift, barrel rupture and blistering because PTFE has an inherent low modulus.
Manufacturers use a standard PTFE plasma cycle process to enhance the adhesion of smobc to copper before using solder resist. For the best results, it is best to finish the solder resist coating within 12 hours after the circuit is etched.
At PCB global, we are currently manufacturing teflon pcbs for microwave applications and the defense industry, and have the knowledge, experience and ability to advise customers on the use of Teflon based PCBs and how to apply them to custom PCB designs for their intended purposes.