Gold plate and gold plate is the process often used in PCB circuit boards, many engineers can not correctly distinguish the difference between the two, and even some engineers think that there is no difference between the two, this is a very wrong view, must be corrected in time. Next, I will talk about the difference between gold and gold plating of pcb circuit boards.
We all choose gold plating, what is gold plating, what we call the whole plate gold plating, generally refers to "electric gold plating" "electroplated nickel gold plate" "electrolytic gold" "electric gold" "electric nickel gold plate", there is a distinction between soft gold and hard gold (general hard gold is used for gold fingers), the principle is to dissolve nickel and gold (commonly known as gold salt) in chemical solutions, Nickel gold coating is formed on the copper foil surface of the circuit board after the circuit board is immersed in the electroplating cylinder and the current is switched on. The electronickel gold coating is widely used in electronic products because of its high hardness, abrasion resistance and non-oxidation.
Then what is the heavy gold? Gold deposition is through the chemical REDOX reaction method to produce a layer of coating, generally thicker, is a kind of chemical nickel gold deposit method, can reach a thicker gold layer. The difference between gold-plated board and gold-plated board:
1. the general gold for the thickness of gold is much thicker than gold, gold will be gold more yellow than gold, look at the surface of the customer is more satisfied with gold. The crystal structure formed by the two is not the same.
2. Due to the different crystal structure formed by sinking gold and gold plating, sinking gold is easier to weld than gold plating, and will not cause poor welding and cause customer complaints. At the same time, because the gold is softer than the gold, the gold finger plate is generally gold-plated, and the hard gold is wear-resistant.
3. only nickel gold on the solder pad, skin effect signal transmission is in the copper layer will not affect the signal.
4. The crystal structure of sunken gold is denser than that of gold plating, and it is not easy to produce oxidation.
5. with the wiring more and more dense, line width, spacing has reached 3-4MIL. Gold plating is easy to produce gold wire short circuit. The gold plating only has nickel gold on the pad, so it will not produce a short circuit of gold wire.
6. Only nickel gold is on the solder pad, so the welding resistance on the line is more firmly combined with the copper layer. The works will not affect the spacing when making compensation.
7. generally used for relatively high requirements of the board, the flatness is better, generally the use of gold, gold generally does not appear after the assembly of the black pad phenomenon. The flatness and service life of the sunken gold plate are as good as those of the gold-plated plate.
The above is the difference between the gold plate and the gold plate, the gold price is expensive on the market now, in order to save costs, many manufacturers have been unwilling to produce gold plate, and only do nickel gold plate on the pad, in the price is indeed a lot cheaper.
1. the gold plate and the gold plate is the same process product, the electric gold plate and the flash gold plate is the same process product, in fact, it is just the different names of different people in the PCB industry, the gold plate and the electric gold plate are more in the mainland counterparts, and the gold plate and the flash gold plate are more in Taiwan counterparts.
2. the gold plate/gold plate is generally more formally called chemical nickel gold plate or nickel metal leaching plate, the growth of nickel/gold layer is plated by chemical deposition; Gold plate/flash gold plate is generally more formally called electroplated nickel gold plate or flash gold plate, the growth of the nickel/gold layer is plated by direct current plating.
As the integration of the IC becomes higher and higher, the IC feet are more and more dense. The vertical tin-spraying process is difficult to blow a thin pad flat, which brings difficulty to SMT mounting; In addition, the shelf life of the tin spray plate is very short. And the gold plate is a good solution to these problems:
1. in the trial production stage, affected by components procurement and other factors are often not the board to weld immediately, but often have to wait for a few weeks or even a few months to use, the shelf life of the gold plate (shelf life) is many times longer than the lead tin alloy, so everyone is willing to use. Moreover, the cost of gold-plated PCB in the sample stage is almost the same as that of lead-tin alloy plate. However, as the wiring becomes more and more dense, the line width and spacing have reached 3-4MIL. This brings the problem of short circuit of gold wire.
2. for the surface mounting process, especially for 0603 and 0402 ultra-small sheet, because the flatness of the pad is directly related to the quality of the solder paste printing process, and has a decisive impact on the quality of the re-flow welding behind, the whole plate gold plating is often seen in the high-density and ultra-small sheet paste process.
As the frequency of the signal gets higher and higher, the impact on signal quality is more obvious because of the skin effect caused by the signal transmission in the multi-coating skin effect refers to: high-frequency AC, the current will tend to concentrate on the surface of the wire flow. According to calculations, skin depth is related to frequency.
In order to solve the above problems of gold-plated plate, the PCB with gold-plated plate mainly has the following characteristics:
1. because the crystal structure formed by gold and gold plating is not the same, gold will be gold more yellow than gold plating, customers are more satisfied.
2. because the crystal structure formed by gold plating and gold plating is not the same, gold plating is easier to weld, will not cause poor welding, cause customer complaints.
3. because the gold plate only has nickel gold on the pad, the signal transmission in the skin effect is in the copper layer will not affect the signal.
4. the project will not affect the spacing when making compensation.
5. because the crystal structure is denser than that of gold plating, it is not easy to produce oxidation.
6. the flatness and service life of the gold plate is as good as that of the gold plate.
7. because the gold plate only has nickel gold on the pad, it will not be produced into gold wire caused by short.
8. because the gold plate only has nickel gold on the pad, the welding resistance on the line is more firmly combined with the copper layer.
9. because the crystal structure formed by gold plating and gold plating is not the same, the stress of the gold plating plate is easier to control, which is more conducive to the processing of Bonding products. At the same time, because the sinking gold is softer than the gilding, the sinking gold plate is not wear-resistant to the goldfinger.
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