The technological difference between immersion gold and gold fingers

- Sep 22, 2018-

Let's first introduce what is sinochem?Circuit board copper is mainly copper, copper solder easily oxidized in the air, it will cause solder bad or poor contact, electrical conductivity, that is, reducing the performance of the circuit board, then need to surface treatment of copper solder, heavy gold is gold plated, gold can effectively cut off copper metal air and prevent oxidation, so heavy gold is a way of dealing with surface anti-oxidation, is through the chemical reaction on the surface of copper covered with a layer of gold, also known as gold.

So what is golden finger?Let's say it's a brass contact, or a conductor.In detail, the memory chip is connected to the memory slot. All the signals are transmitted through the gold finger, which is composed of a large number of yellow conductive contacts.

The advantage of the gold precipitation process is that the surface of the printed circuit has a stable color, good brightness, smooth coating and good weldability.Generally, the gold thickness is 1-3 Uinch, which can be divided into four stages to complete: pre-treatment (oil removal, micro-erosion, activation and post-immersion), nickel precipitation, gold precipitation, post-treatment (waste water washing, DI washing, drying).

However, compared with other tin spraying processes, the cost of gold precipitation process is relatively high. If the thickness of gold exceeds the conventional process in the plate making plant, the cost is even higher.Such as: your circuit board with the fingers need to sink gold, or the line width of the board/pad spacing is not enough, so it is best to do heavy + gold plating process for the finger, this circuit board welding is very good, circuit performance is also stable, bonding pad will not fall off, not bad contact, there will be no short circuit etc. Phenomenon, at the same time also is very shock drop, of course, we won't fall off the board.

There are also cases where the circuit board has gold fingers, but the board surface other than gold fingers can choose the process of tin spraying according to the situation, that is, the process of tin spraying + gold-plated fingers. Under the condition of sufficient wire width of the circuit board and distance between the solder pan and the welding requirements are not high, the production cost can be effectively reduced without affecting the use of the board.However, if the wire width of the plate is insufficient and the distance between the pads is insufficient, then the adoption of the tin spraying process in this case will increase the production difficulty, which will lead to a lot of short circuit conditions such as tin bridging, and will also lead to the frequent insertion and peeling of cash fingers, resulting in poor contact.

Therefore, according to the actual situation of the circuit board, we can choose the plate making process suitable for ourselves, which controls the cost but cannot affect the use of the board.