Immersion Gold Processes

Epithas® TWX-40 RAIG. Uyemura has introduced a reduction-assisted immersion bath for board shops whose customers require an immersion gold deposit above the standard 1-2 μin on ENEPIG. Epithas TWX-40, is a mixed reaction bath – an elite hybrid – that delivers both immersion and autocatalytic (electroless) modes of deposition. The RAIG process is a proven alternative to earlier attempts to achieve heavier gold deposits on ENEPIG, i.e. extending the dwell time in the immersion bath. That practice forces the immersion bath to do what it was never designed to do, and has been fraught with problems, the most serious of which is virtually inevitable damage to the nickel underlayer.

Platers racking and plating flex panels using Uyemura immersion gold

TWX-40 is a single immersion gold bath with autocatalytic capabilities. Added to a line, manufacturers plating ENEPIG can now deposit 4-8 μin gold in a single step. The standard alternative way to accomplish this is to deposit an autocatalytic gold over immersion gold – an additional step requiring costly additional make-up. For ENEPIG users serving a diverse group of customers, TWX-40 is a proven solution with excellent science behind it. Read more in an article titled “TWX-40 Reduction-assisted Gold Bath Meets Demand for Thicker Gold on ENEPIG.”

Gobright® TWX-40 reduction assisted immersion gold bath is suitable for ENIG, ENEPIG and EPIG surface finish applications. Bath can deposit a higher gold thickness than standard immersion gold, without increasing the probability of nickel corrosion. For maximum compatibility, use Uyemura electroless nickel and/or palladium as the underlying deposit for both PCB & IC packaging.

Epithas TAM-55 mildly acidic immersion gold bath designed to protect and maintain the solderability, and minimize corrosion of electroless nickel in an ENIG deposit. The gold deposit’s grain structure is very tight, not requiring more than 2 microinches to produce a very high, reliable solder joint. TAM-55 is recommended for SMT applications. For maximum compatibility, NPR or ANP Series electroless nickel is recommended as the underlying deposit for IC packages and wafers.

Gobright TAM-55 advanced immersion gold bath minimizes nickel corrosion, optimizes gold distribution. A special additive minimizes nickel dissolution, leaving a robust nickel surface following the immersion gold reaction. TAM-55 protects and maintains the solderability of the electroless nickel in an ENIG deposit. It is an ideal solderable finish for small SMT and BGA pads. For maximum compatibility, Nimuden® NPR Series electroless nickel is the recommended underlying deposit for PCB and IC packaging. TAM-55 may be used for both ENIG and ENEPIG, allowing a single source immersion gold for plating lines that apply both processes.

Inspection of surface finish board which was plated in immersion gold

Gobright TAW-66 is a neutral pH immersion bath formulated to minimize electroless nickel corrosion in an ENIG deposit. The gold deposit is very light, requiring no more than 2 μm to produce a very high reliability solder joint under various environmental conditions, including high humidity and high temperature. TAW-66 immersion gold provides superior performance, with low porosity and low nickel dissolution. It is an ideal solderable finish for small SMT and BGA pads. For maximum compatibility, Nimuden NPR Series electroless nickels are recommended as the underlying deposit for both PCB and IC packaging.

Gobright TAM-LC is a mildly acidic immersion gold bath that protects and maintains the solderability of electroless nickel in an ENIG deposit. Bath is specifically formulated to minimize corrosion of underlying electroless nickel. For maximum compatibility, Nimuden NPR series electroless nickel is recommended as the underlying deposit for PCB and IC package applications.

Gobright TCU-41 immersion gold process deposits gold directly on copper (DIG). The deposit is a very thin layer (2.0 μins or 0.05 μm) of gold with minimum porosity, which prevents the migration of copper to the surface. TCU-41 is primarily used as a solderability preservative; it’s highly stable and is easily controlled using standard analytical methods.

Gobright TCU-38 immersion gold process for plating gold directly on copper (DIG) in soldering applications.

Gobright TFR-33 is a slightly acidic low gold concentration bath formulated to minimize corrosion of the underlying electroless nickel. Deposit protects and maintains the solderability of the electroless nickel in an ENIG deposit, and is ideal as a solderable finish for small SMT and BGA pads. For maximum compatibility, Nimuden NPR electroless nickel is recommended as the underlying deposit for both PCB & IC packaging.

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