What is Teflon PCB and how to manufacture

Teflon PCB manufacturing

Manufacturing of a Teflon PCB is the combination of a series of works that are correlated to each other. As the processing of Teflon materials isn’t the same as FR4 or CEM, you need to pay attention to each step to get the best outcome.

Let’s have a look at the most noteworthy steps of Teflon circuit board manufacturing.

Preparation of PCB surface
Here, manufacturers have to prepare a substrate surface so that they can perform the metalization and layer formation properly.

As Teflon is a soft material, you can’t use rough equipment that deforms this material during fabrication.

For example, bristles, composite brushes, pumice scrubbers, etc are not good choices for the surface preparation of Teflon circuit boards. But these products are very common in PCB manufacturing containing materials except Teflon. So what’s the solution to this case?

Manufacturers use Sodium etchants and plasma gas most of the time. Do you know why?
Sodium etchants are Halogen-free (especially Fluorine). That’s why these etchants can extend the hold time of these PCB materials after processing. You need to rinse Teflon with water and Alcohol after picking it out from the Sodium solution.

Besides, plasma gases are also dependable. These gases can be recycled through Hydrogen gas which has a positive impact on the manufacturing cost. This process is suitable for metalization, layering, and marking.

Use of solder mask
The application of PCB solder masks is a crucial part of manufacturing. You need to apply this within 12 hours of Sodium etching. Besides, you must make sure that there is no moisture absorption while using a solder mask.

Drilling
This step is necessary to make sure that the drilled holes are precise and that there is no remaining Teflon in the holes. But how?

Here, manufacturers use a sharp drill with a high chip load and slow-pace feeding. As Teflon has improved rigidity with a low CTE, there is no need to apply too much stress during drilling.

Copper plating
It is highly recommended to use plated copper having a high tensile strength so that the possibility of pad lifting and barrel cracking decreases to a certain degree.

Besides, copper cladding with high ductility copper keeps Teflon away from blistering.

Lamination of materials
Teflon PCB lamination is performed under almost 370°C temperature and 450-500 PSI pressure. You don’t need to use bonding films in this way.

You can keep the operating temperature at 120-215°C by using bonding films. But, then you need to apply Oxide pretreatment that is similar to the lamination of FR4 materials.

Storing
As Teflon is a soft-natured PCB material, you must keep it safe from mechanical and thermal pressures. Most noteworthy, store Teflon PCBs in a dry and cold place that is free from oxidation and chemical contamination.

Do you know how to produce the prototype of Teflon PCB? Here are the basic steps for your convenience:

PCB design
The very first step is the designing of the Teflon PCB prototype. You can use design software like Altium Designer, KiCAD, etc, and stencil to create a perfect prototype design.

Material selection
The next step is selecting the rightest base material for the prototype. Recently, plastic materials have become very popular in this case. Remember, Teflon is not the base material of this circuit board.

Design testing
In this step, component placement and connections in the design are checked through a simulation.  

Bug-fixing
Here, manufacturers detect bugs and faulty connections in the prototypes and resolve these issues to deliver a flawless design.

Prototyping
A prototype board is made in this stage.

Functional test
In the end, a functional test is run to check its functionality and find any minute bugs which were ignored earlier.

After completing these steps, the manufacturer sends the prototype Teflon circuit board for final production.