ENIG and Gold plated

ENIG and Gold plated

Pcb circuit board difference between immersion gold(enig) and gold plating

    Today, I will talk about the difference between the immersion gold and gold plating of the PCB board. The gold plate and the gold plate are the processes that are often used in PCB circuit boards. Many customers cannot correctly distinguish the difference between the two. Some customers even think that the two are not There are differences, this is a very wrong view and must be corrected in time. So what impact do these two "golden plates" have on the board? Below I will explain specifically to you, and thoroughly help everyone to help clear the concept. (Professional pcb circuit board manufacturer, has more than 20 years of pcb circuit board production and operation, welcome new and old customers to come to consult and purchase)

    In today's increasingly superior technical capabilities, IC pins are becoming more and more dense, and the tin-spraying process is difficult to flatten the fine pads, which makes it difficult to solder SMT patches. The standby life of the board is also shorter, and the PCB is made of gold-plated board to solve these problems. For some ultra-small surface-mounting boards such as 0603 and 0402, the quality is decisive, so the whole board is plated with high precision. And in the ultra-small patch process is more common. In the sample stage, due to the influence of the component procurement cycle, it is generally necessary to wait for a period of time after the PCB board is completed, and the cost of the sample is not much different from that of the spray tin. (Professional pcb circuit board manufacturer, has more than 20 Year of pcb circuit board production and operation, welcome new and old customers to come to consult and purchase)

So everyone chooses gold plating, then what is gold plating, we say the whole plate gold plating, generally refers to "electroplating gold", "electroplated nickel gold plate", "electrolytic gold", "electric gold", "electric nickel plate", with soft gold The distinction between hard gold and gold (usually hard gold is used for gold fingers). The principle is to dissolve nickel and gold (commonly known as gold salt) in chemical potion, immersing the board in the plating tank and turning on the current on the board. Nickel-gold plating is formed on the surface of the copper foil, and the nickel-nickel gold is widely used in electronic products because of its high hardness, wear resistance and oxidation resistance

    The difference between the gold plate and the gold plate of the circuit board:

    1. Generally, the thickness of gold is much thicker than that of gold plating. Shenjin will be goldener than gold plating, and customers will be more satisfied with Shenjin. The crystal structure formed by the two is different.

    2. Because the crystal structure formed by immersion gold and gold plating is different, immersion gold is easier to weld than gold plating, which will not cause poor welding and cause customer complaints. At the same time, because Shenjin is softer than gold plating, gold fingerboards are generally plated with gold and hard gold.

    3. The immersion gold plate only has nickel gold on the pad. The signal transmission in the skin effect is not affected by the signal in the copper layer.

    4. Compared with gold plating, Shenjin has a denser crystal structure and is less prone to oxidation.

    5. As the wiring becomes more and more dense, the line width and spacing have reached 3-4 MIL. Gold plating is prone to shorts in gold wire. The gold plate has only nickel gold on the pad, so it will not produce a gold wire short circuit.

    6. The immersion gold plate only has nickel gold on the pad, so the soldering on the line is more firmly combined with the copper layer. The project does not affect the spacing when making compensation.

    7, generally used for relatively high requirements of the board, the flatness is better, generally use Shen Jin, Shen Jin generally does not appear after the black pad phenomenon. The flatness and standby life of the Shenjin plate are as good as the gold plate.

The above is the difference between the gold plate and the gold plate. Now the price of gold is expensive on the market. In order to save costs, many manufacturers have been reluctant to produce gold plate, but only the gold plate with nickel gold on the pad. A lot cheaper. I hope this introduction will provide you with reference and help. (Professional pcb circuit board manufacturers, our company is a good production of Jiangsu circuit board manufacturers, with more than 20 years of pcb circuit board production and operation, welcome new and old customers to come to consult and purchase)

Electroless nickel immersion gold (ENIG) is a type of surface plating used for printed circuit boards. It consists of an electroless nickel plating covered with a thin layer of immersion gold, which protects the nickel from oxidation.

ENIG has several advantages over more conventional (and cheaper) surface platings such as HASL (solder), including excellent surface planarity (particularly helpful for PCBs with large BGA packages), good oxidation resistance, and usability for untreated contact surfaces such as membrane switches and contact points.

Early ENIG processes suffered from reliability issues which caused the ENIG finish to separate from the copper pads, taking the parts with them. ENIG also does not wet as evenly or easily as HASL. In addition, a "black-pad" of nickel (Ni) phosphorus (P) could form during the electroless nickel plating step, more specifically due to the solder mask sulfur substances leaching into the plating bath, greatly reducing solder joint reliability. To remedy this, a layer of electroless palladium can be plated onto the nickel to create ENEPIG surface finish.

ENEPIG is a costlier finish, but offers the best characteristics for printed circuit boards. The process requires more steps, compared to other common finishing types.

The electroless nickel step is an auto-catalytic process that involves depositing nickel on the palladium-catalyzed copper surface. The reducing agent containing nickel ions must be replenished in order to provide proper concentration, temperature and pH levels necessary to create a consistent coating. During the immersion gold step, the gold adheres to the nickel-plated areas through molecular exchange, which will protect the nickel until the soldering process. The gold thickness needs to meet certain tolerances to ensure that the nickel maintains its solderability.

IPC Standard IPC-4552 covers the quality and other aspects of ENIG finish on printed circuit boards. IPC-7095 covers some "black pad" related features such as so called mud crack appearance and nickel protrusion spike.