What causes black pad?

In short, “Black Pad” is caused by too much phosphorus, and or contamination in the nickel plating bath. It is not visually detected prior to assembly because gold is plated over the nickel.

What is ENIG plating?

Known for its corrosion resistance and uniform plating deposit, electroless nickel immersion gold (ENIG) is a type of plating commonly used for printed circuit boards. Electroless nickel immersion gold plating consists of a layer of gold over a layer of nickel.

Is ENIG the same as immersion gold?

Electroless nickel immersion gold (ENIG or ENi/IAu), also known as immersion gold (Au), chemical Ni/Au or soft gold, is a metal plating process used in the manufacture of printed circuit boards (PCBs), to avoid oxidation and improve the solderability of copper contacts and plated through-holes.

What is difference between HASL and ENIG finish?

This strong joint also makes HASL a good finish for high-reliability applications. However, HASL leaves an uneven surface despite the leveling process. ENIG, on the other hand, provides for a very flat surface making ENIG preferable for fine pitch and high pin count components especially ball-grid array (BGA) devices.

What is Black Pad in Enig?

Black pad is a term that usually refers to nickel corrosion on electroless nickel and gold immersion (ENIG) surface finishes on PCBs. The defect is not seen as part of normal QC procedures as the immersion gold masks the appearance of the nickel under the gold.

What does ENIG look like?

ENIG is a two-layer metallic coating – Nickle is the barrier to the copper pad and is also the material to which components are soldered. Gold on the other hand protects the Nickle during storage and also provides low contact resistance.

How thick is ENIG plating?

between 0.05 to 0.23 µm
ENIG plating thickness of each layer should be between 0.05 to 0.23 µm for the immersion gold layer and 2.5 to 5.0 µm for the electroless nickel. The thicker the immersion gold layer, the more likely it is to result with a black pad due to process complications.

Is ENIG conductive?

excellent electrical conductivity, anti-oxidation & anti-rust, good heat dissipation, higher surface thickness.

How thick is ENIG?

Is ENIG RoHS compliant?

An ENIG finish has excellent corrosion resistance; it’s suitable for aluminum wire bonding, is perfect for fine-pitch technology, has excellent solder-ability, and has excellent shelf-life; an ENIG finish is RoHS compliant.

Is ENIG hard gold?

ENIG plating is much softer than hard gold plating. Grain sizes are about 60 times larger with ENIG plating, and hardness runs between 20 and 100 HK25. ENIG plating holds up well at only 35 grams of contact force or less, and ENIG plating typically lasts for fewer cycles than hard plating.

Is ENIG lead-free?

Electroless Nickel Immersion (ENIG) ENIG is an answer to major industry trends such as lead-free requirements and rise of complex surface components (especially BGAs and flip chips), which require flat surfaces.

What is ENIG surface finish?

ENIG is short for Electroless Nickel Immersion Gold, also known as immersion gold (Au), chemical Ni/Au, or soft gold. An ENIG finish is formed by the deposition of Ni-P alloy on a catalyzed Pd surface generated through displacement reaction on a copper surface, followed by a thin layer of gold finish.

Is ENIG soft gold?

Because of the principle of replacement, the ENIG plating layer is “pure gold”, so it is often classified as “soft gold”, so some people use it for aluminum wire bonding.

Can you wire bond to ENIG?

ENIG is an ideal surface for aluminum wire bonding. However, with only 2- 4 micro-inches of gold it is not suitable for gold wire bonding. Soft gold at 10 – 25 micro-inches is needed for successful gold wire bonding.

What is the difference between Enig and Enepig?

ENEPIG is similar to ENIG in both utilize electro-less nickel on top of copper plating; the difference is while ENIG has gold deposited directly on top of nickel, ENEPIG has an additional layer of palladium between the nickel and final gold layer (see below Fig.

What is Enepig plating?

ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) is a type of surface plating applied on a Printed Circuit Board to protect it from environmental factors during storage and operation.

What is the difference between ENIG and Enepig?

What is black pad ENIG?

What is Enig plating?

What is ENIG Plating? Can you answer this question? ENIG (Electroless Nickel Immersion Gold) is a surface plating that is applied over the copper pads on a Printed Circuit Board to protect them from corrosion and other abnormalities. Initially, the copper pad is covered by a Nickel (Ni) layer followed by a thin immersion Gold (Au) layer.

What are the problems associated with ENIG use?

This blog explains why there are problems associated with ENIG use and how a new product on the market – ENIG-PremiumTM – solves these problems. Electroless Nickel Immersion Gold (ENIG) is now arguably the most used finish in the PCB industry, however it can have reliability problems such as black pad related failures and brittle solder joints.

Is black pad a problem with ENIG finishing?

As long as nickel and gold are used in the ENIG finishing process, black pad can still be a potential issue. However, it simply illustrates why working with our team at MCL can be one of the most prudent business decisions you make.

Is Enig a reliable finish for PCBs?

Electroless Nickel Immersion Gold (ENIG) is now arguably the most used finish in the PCB industry, however it can have reliability problems such as black pad related failures and brittle solder joints. Here’s why: