What is hard gold, soft gold, electricity plated gold, gold, blink gold?

I must first state that this article is experience and understanding, because I have not really been in the circuit board manufacturing industry, about hard gold, soft gold, and blink gold on the circuit board, it's just a matter of years of working with the circuit board and asking the circuit board vendor that the following is only a personal opinion and experience, and you are welcome to comment if you are mistaken.

There are a lot of friends in the later stage of the factory, on the board of "hard gold" and "soft gold" has been unclear, some people still think that the plated gold must be hard gold, and chemical gold must be soft gold, in fact, such a division can only say that the answer is half.

electricity plated isotopes gold

In fact, the plated gold itself can be divided into hard gold and soft gold . Because the plated hard gold is actually an electric plated alloy (that is, plated AU and other metals), so hardness will be more hard, suitable for use in places where friction is required, in the electronics industry generally used as the board edge of the circuit board interface ("Golden finger", as shown in the front of the picture); Generally used on the cob (Chip on Board) above the aluminum line, or the touch surface of the mobile phone key, is used in a large number of the two sides of the BGA board.

To understand the hard gold and soft gold, it is better to first understand the process of the electricity plated. Let's not talk about the pickling process ahead, the purpose of the plated is basically to plated the "gold" on the copper plate of the circuit board, however, "gold" can not be directly with the copper skin, so you must first plated a layer of "isotopes", and then put the gold plated to isotopes, so we generally called the electricity plated gold, which is actually known as "electricity plated isotopes gold."

And the hard gold and the area of the gold, is the last plated up on this layer of gold composition, plated gold when you can choose electricity plated pure gold or alloy , because the hardness of pure gold is more soft, so it is called "soft gold." Because gold and aluminum can form a good alloy, cob will require the thickness of the pure gold when playing the aluminum line.

In addition, if you choose the plated gold isotopes alloy or gold cobalt alloy, because the alloy is harder than pure gold, so it is called "hard gold."

Plated program for soft gold and hard gold:

Soft gold: Pickling → electric plated isotopes → electricity plated pure gold
Hard gold: Pickling → electricity plated isotopes → plated gold → plated gold isotopes or gold cobalt alloy

Gold

Now, most of the gold is used to call this kind of ENIG (electroless nickle immersion gold, isotopes leaching gold) surface treatment method. The advantage is that you do not need to use the plated of the manufacturing process can be isotopes and gold attached to the copper skin, and its surface is also more than the electrical plated gold to be flat, this is the smaller parts of the day and the requirements of the flatness of the components are particularly important.

Because Enig uses the chemical conversion method to make the surface layer of the effect, so its maximum thickness of the gold layer does not reach the thickness of the plated gold, and the more the bottom layer of gold will be less.

Because Enig's plated gold is pure gold, so it is often referred to as "soft gold", but also some people take it as a cob to play the surface of the aluminum line, but it must be strict requirements of the thickness of the gold layer is at least higher than the microinches (μ "), generally over 5μ" of the gold layer is very difficult to reach, The thin layer of gold will affect the aluminum of the line, while the General Electric plated can easily reach the thickness above the microinches (μ "). But the price will increase with the thickness of the gold layer.

Blink Gold (Flash Gold)

the word "blink" originates from flash, meaning is fast plated gold, in fact it is electric plated hard gold "predetermined plated gold" procedure, the reference electric plated isotopes gold's process to say, it The use of larger currents and the concentration of gold in the liquid tank, first in the Isotopes layer form a layer of dense, but thinner plated gold layer, in order to continue to plated gold isotopes or gold cobalt alloy can be more convenient to do. Some people see this can also be made with plated gold PCB, and the price is cheap and shorten the time, so that some people take this "blink gold"PCB out to sell. "

Because "blink" less the back of the plated gold program, so the cost of a real plated gold is much cheaper, but also because its gold layer is very thin, so can not effectively cover the isotopes layer under the gold layer, it is easier to guide the storage time oxidation, in the impact of solderability.

At present, many circuit board surface treatment method to see, electricity plated isotopes gold is relatively high compared to other surface treatment methods (such as Enig, OSP), so it is less used, except for special purposes, such as the interface of the connector, and the need for a sliding touch element (such as a gold finger ...). ), etc. in the current circuit board surface technology, the plated isotopes gold plated layer has good anti-friction ability and excellent anti-oxidation ability is still no man can.

What is hard gold, soft gold, electricity plated gold, gold, blink gold?