Flex printed circuit boards are at the heart of most modern day electronics, it is the circuit board that provides the density to the electronic. The high density electronics have eyes for a much thinner FPC than the conventional ones. The conventional FPCs comprises of three layers formed by copper, polyimide and bonding adhesives. The three layered circuits are being replaced by two-layer circuits that equate to the copper being directly placed on the polyimide without the help of any adhesives. The process of manufacturing a flexible printed circuit is a very complex one within itself. The manufacturing of the circuit can be affected by a shift, as tiny as 0.01mils. The FPCs themselves aren’t very huge in their size, so a small shift could have a major impact on the manufacturing of the circuit board. The manufacturing of a flexible printed circuit is a much more complex than that of a rigid PCB. With regards to this, there have been multiple innovations in the manufacturing process of the flexible printed circuits. Here are some of the inventions in the manufacturing world of FPCs:

1. Flexible printed circuit:
Innovations and New
Technologies

2. Introduction
 Flex printed circuit boards are at the heart of most modern day electronics, it is the circuit
board that provides the density to the electronic. The high density electronics have eyes for a
much thinner FPC than the conventional ones. The conventional FPCs comprises of three
layers formed by copper, polyimide and bonding adhesives. The three layered circuits are
being replaced by two-layer circuits that equate to the copper being directly placed on the
polyimide without the help of any adhesives.
 The process of manufacturing a flexible printed circuit is a very complex one within itself.
The manufacturing of the circuit can be affected by a shift, as tiny as 0.01mils. The FPCs
themselves aren’t very huge in their size, so a small shift could have a major impact on the
manufacturing of the circuit board. The manufacturing of a flexible printed circuit is a
much more complex than that of a rigid PCB. With regards to this, there have been multiple
innovations in the manufacturing process of the flexible printed circuits.
Here are some of the inventions in the manufacturing world of FPCs:

3. Laser drilling of flex panels
 Laser drilling and routing are everyday processes in the manufacturing of a flexible printed
circuit. A high density manufacturing process requires the need of a ultra-violet laser
drilling technology. It is used to drill circuit boards that are under 70 µm. The laser drilling
machines enables a high accuracy in the alignment that ensures the best registration of vias.
This is acquired as the laser drilling machine possesses the capability to acquire the targets
on panels. Laser drilling has lately been adopted for the new roll-to-roll production mode. It
has been used in the sheet-based production for a long time.

4. Automated optical inspections
 FPC products are single or double sided more often than not. These circuits did not go
through the AOI inspection earlier, but in the last five years fine-line flex has become an
important factor in the integration of the Smartphone interconnect. This has led to a
demand for higher quality of the single and double sided FPCs, which has risen up a
compulsion for the AOI-level inspection.
 AOI is a process that involves multiple verification stages and includes manual handling of
the panel sheets. The manual process is a challenging process for the individuals as the FPC
sheets are thin and delicate, this leads to a high accumulation of scrap.

5. Automated optical shaping
 As the core of the fine-line double-sided FPC is lesser than 30 µm, manual repair or
rework is not an option that can be indulged into. It created many defective FPCs,
which have to be scrapped on immediate basis. As the innovations have taken the
front seat, fully automated copper shaping solutions have been innovated over the
past three years to enable seamless shaping and saving fine FPCs. This automated
optical shaping solution uses advanced fluorescent-based imaging and laser
ablation tools working together in a closed-loop shaping system. This negates the
possibility of fine shorts, removes penetration and excludes the damage to the FPC.
With the help of this technology the damaged FPCs can be repaired and restored
easily with a hassle free process, this leads to lesser wastage and a seaming drop in
the production costs.

6. Direct imaging
 The need for direct imaging is increasing in building the FPCs for Smartphone
interconnections. This is becoming necessary to be taken up as the thin flex products do not
have reinforcing glass fiber, this leave them without the ability to move and deform
throughout the production process. The deformations that occur during the process are
accumulated and next to be fixed at the solder mask stage. Direct imaging is becoming a
process of high yield and an increase in the use of this process can be noticed evidently.

7. Roll to roll processing
 The sizes of the sheet to sheet processes incurred many small steps and yielded small
substrate sizes, hence has been replaced by the roll to roll processing. Roll to roll processing
of FPCs is a continuous process and generally does not include break-ups yielding a flexible
printed circuit that is 100m long. With the use of this method, the product efficiency rises as
numerous small FPCs can be produced in a single batch of a long continuous yield of the
roll to roll process.

8. Conclusion
 Innovations in all the fields are running rampant with the growth of economies all over the
world, and the with the use of FPCs in almost every electronic device and high-density
electronic product; innovations in their production process are much appreciated and are
being adopted on a rapid pace by the leading FPC manufacturers.

9. THANK YOU!