Final Finishing


Final Finishing


Okuno-Auromex has been an innovator providing leading edge, and environmentally acceptable technology to the PCB industry.

Final Finishing

Final Finishes are applied to copper areas of a PCB that are not covered by solder mask because they are intended for soldering and wirebonding of electronic components during the assembly process.

Prior to the “lead-free” environmental regulations, electronics’ final finishes were produced using hot air solder level (HASL). However, legislation such as ROHAS, and the ever increasing requirements of surface planarity to accommodate smaller surface mount components necessitated the development of alternative final finish as the finishes. Today, traditional HASL accounts for approximately 10% of the final finishes and has been replaced by Electroless Nickel Immersion Gold (ENIG), Electroless Nickel Immersion Palladium & Gold, Immersion Tin, Immersion Silver and Organic Solderability Preservatives, OSPs.

Each of the Alternative Final Finishes provides a cost-benefit profile intended for specific application. ENIG is the most reliable of all final finishes and it’s use predominates in high reliability applications such as Telecom, Military and others.

Okuno-Auromex is proud to introduce a full package of electroless nickel immersion gold technology. For further information about ENIG please follow the link below:

Electroless Nickel Immersion Gold (ENIG)

Electroless nickel immersion gold (ENIG) is one of the final finishes used for printed circuit boards. It consists of electroless nickel plating (4-5 um) followed by a thin layer of immersion gold. This process provides excellent corrosion resistance, solderabilty, pad co-planarity which allows for extended shelf life relative to the other final finishes. It is a good choice for fine-pitch SMT and BGA technologies.

Okuno-Auromex offers ICP, a proprietary technology for electroless nickel immersion gold, applicable to rigid and flex PCBs, and ceramic substrates. The technology includes pre-treatment

cleaners and activators, electroless nickel and immersion gold products. The relatively low acidity process results in a lower likelihood of “black pad” problem and is thus an ideal solution for fine pattern application.

Our ICP Clean S-135K can clean and prepare a copper surface for subsequent processing. The ICP Accera is a palladium catalyst that activates a copper layer for subsequent electroless nickel plating. The ICP Nicoron FPF seriesare a medium phosphorous (7%P) process with a thickness range of 3-7 um.

It is bright, smooth, defect free and relatively corrosion resistant. It is ideally suited for the subsequent immersion gold process.

Our Flash Gold 330 offers uniform fine gold deposits and is compatible with ICP Nicoron FPF later without erosion effect. The ENIG layered deposit structure provides excellent solderabilty, corrosion and oxidation resistance.

The table below provides additional product information:





ICP Clean S-135K

Low foam degreasing agent. Remove oil dirt or organic compound, and increase wettability.


Sodium per sulfate or Sulfuric acid

Acid Activating

Sulfuric acid or Hydrochloric acid


ICP Accera

Contain the optimum Pd to reduce drag-out rate. Improve strong adhesion and stability. Can be applied for long period.

Post Dipping

ICP Post Dip RP

Give good covering power of electroless nickel plating without spoiling the ability of palladium on the conductor.

Electroless Nickel Plating

ICP Nicoron FPF

Excellent bending resistance. Good in solder wettability and solder bonding strength. Gain fine and uniform semi-bright appearance film.

ICP Nicoron FPF-FL

New electroless nickel plating agent. Developed for eliminating nickel bright effect.

Gold Plating

Flash Gold 330

Give uniform and fine plating film. Excellent solder wettability and solder bonding effect. Can be applied at low bath temperature.