Pure Additive™ Processes

Subtractive and Pure Additive™ methods

Subtractive method, one of the most common methods, manufactures electronic circuits by applying a thin metallic sheet to the board surface and melting away unrequired sections. Pure Additive™ method prints metallic particles only onto the required ares and apply electroless plating technology.

Pure Additive™ method requires fewer manufacturing steps, providing lower manufacturing cost and shorter lead time.

Fewer processes for copper patterning

Comparison of subtractive and Pure Additive methods

*Processes after copper petterning are done by necessity. There is not much difference between subtractive and Pure Additive™ processes.

Our technologies

Operating our mass-production factory in Tokyo

Highly accurate inkjet-printing of silver nanoparticle ink

Conventional electroless Cu plating is slow because of its speed-stability trade-off

Original bath control and surface technology enables 10x faster electroless Cu plating

Strong metal-substrate adhesion mechanism

Fully on-demand solder masking and cutting

From Manufacturing to Shipment

Film

This is the 50-μm PET (Polyester) film we use for the substrate of P-Flex™. While 125-μm PET film is also available, 50-μm PET film has higher flexibility.

The surface of this heat-resistant film is specially finished to achieve good adhesion to our silver ink.

As the film is thicker than popular substrates of flex PCBs, it is generally easier to handle and to cut into complicated shapes.

Flex PCB manufacturing process film

Printing

This is the process in which the seed layer is formed by applying silver nano ink using an inkjet printer.

We use production-level inkjet printers which enables roll-to-roll printing to eject silver ink with a high precision. The minimum conductor width and space are 200 μm.

Finer conductor width and space than 200 μm are in development.

Flex PCB manufacturing process printing

Sintering

This is the process in which the seed layer made up of nano particles is exposed to heat.

Silver nano particles are loosely connected when they are printed, and inappropriate as a seed layer of plating.

Sintering with customized parameters tightens the connection of silver particles to form the solid seed layer.

Flex PCB manufacturing process sintering

Plating

This is the process in which the copper layer is formed on top of the seed layer.

Having the copper layer on the seed layer loweres the resistance to 1% or less, and enables soldering as well.

Currently the copper thickness is only 3 μm. 6 and 9 μm are in development.

*Note that you need low-temperature solder and perform soldering at around 200 °C. Contact us for our recommended solder.

Flex PCB manufacturing process plating

Solder resist

This is the process in which the special solder resist layer for flex PCB is formed.

Solder resist is used to prevent unintended electrical connections between conductors.

We also use inkjet printing, which does not require masks, with production-level printers and customized solder resist ink.

Flex PCB manufacturing process solder resist

Cutting

This is the process in which PCBs are cut out into specified shapes from rectangle-shaped film.

We have developed a high-precision alignment technology and a size correction technology, which achieved a high repeatability of cutting.

We adopt laser-cutting, which does not require dies, to achieve lower production cost and shorter lead time.

Flex PCB manufacturing process cutting

Inspection

Checks are performed to identify any cuts or short circuits, scratches, dimensional tolerance problems, discrepancies between the solder resist and circuit patterns, etc.

PCBs are inspected at the end of every manufacturing process as well.

Flex PCB manufacturing process inspection

Shipment

Finished boards are put into bags according to pattern and packed in a way that makes it easy for each customer to identify the content of the delivered package.

Flex PCB manufacturing process shipment