Copper Processes
for Under Bump Metallization


Epithas® MCL-10 - acid soak cleaner removes surface oils and contamination and wets the surface to enhance solution transfer. (Also available: MCL-067 CMOS-compatible, low-foaming acid soak cleaner.)

Micro-etch – removes copper surface oxide and roughens the copper, enhancing nickel adhesion.

Acid rinse – ensures that the copper surface is oxide-free and residual copper has been removed.

Pre-dip – minimizes acid dilution of the subsequent activator bath.


Epithas PD-3 Electroless Palladium
The Epithas PD-3 process deposits palladium as a surface finish on wafers and electronic components. The palladium surface is solderable and wire bondable. High palladium concentration allows analysis at longer intervals; low operating temperatures minimize utility expense. The highly stable bath is also tolerant of impurities, including nitrate, copper and nickel.

ENPR-18 electroless nickel is a mildly acidic plating bath for fine line circuitry in silicon wafer plating. Bath formulation allows deposition of electroless nickel without bridging. Highly stable, easy to use; 6-8% phosphorus content as-plated.

Epithas NPR-24, is a mildly acidic electroless nickel formulated for fine line circuitry in silicon wafer plating. This bath allows the deposition of EN without bridging; easy to use and optimized for automatic solution control using the Uyemura STARLiNE DASH controller.

TDS-20 – cyanide-free immersion gold bath was engineered for surface mount applications and wafer plating. Neutral pH; will not corrode the underlying nickel. Provides excellent solder joint reliability, including small solder balls. The thin gold coating maintains long-term solderability and prevents nickel oxidization and passivation.

Epithas TMX-16 – electroless gold for silicon wafers is cyanide-free, with a neutral pH. Ideal for surface mount and wafer plating. Will not corrode the underlying nickel, thus it provides excellent solder joint reliability.

CMOS-Compatible Process for Copper Metallization

Epithas CACL-067 – acid soak pretreatment for silicon wafer plating, including SOI wafers.

Epithas LEC-19 – micro-etch removes naturally-occurring oxidation from aluminum and aluminum alloy surfaces. Pretreatment for electroless nickel on aluminum for silicon wafers, including SOI wafers.

Epithas NPR-18CM – electroless nickel for wafer plating, including SOI wafers, involving fine line circuitry.

Read about our UBM process for aluminum

Read Under Bump Metallization: Some Economical Alternatives published in US Tech.

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For more details, or to arrange test processing, contact your Uyemura representative.