The surface of the circuit board has several treatment processes: bare board (surface without any treatment), rosin board, OSP (organic solder protective agent, slightly better than rosin), tin spray (lead tin, HASL), gold plated plate, ENIG board, etc., these are more perceptual.
Let's briefly introduce the difference between gold plating and gold sinking process. Gold finger boards all need to be gold-plated or gold-sunk.The difference between gold sinking process and gold plating process Gold sedimentation is the method of chemical deposition, through the method of chemical redox reaction to generate a layer of coating, generally thick thickness, is a kind of chemical nickel and gold layer deposit method, but To reach a thick gold layer. Gold plating is the principle of electrolysis, also known as plating method.Other metal surface treatments are also mostly used by electroplating method. In the actual product application, 90% of the gold plate is gold plate, because the poor welding of gold plating plate is his fatal disadvantage, is also the direct reason for many companies to abandon the gold plating process! The gold sinking process deposits a stable color, good brightness, flat coating and good soldability on the surface of the printing line.It can be divided into four stages: pretreatment (deremoval, Micro-corrosion, activation, rear immersion), nickel sinking, gold sinking, post-treatment (waste gold washing, DI washing, drying).The countersunk gold thickness is between 0.025-0.1um. Gold is applied in the circuit board surface processing, because of the gold electrical conductivity, good oxidation resistance, long life, generally used such as button board, gold finger board, etc., and gold plated plate and gold sunk board is the most fundamental The difference is that gold plating is hard gold (wear resistant), and sunk gold is soft gold (not wear resistant).
1. The crystal structure formed by gold sinking and gold plating is different. The thickness of gold sinking is much thicker than gold plating, and gold sinking will be golden and more yellow than gold plating (this is to distinguish gold plating And one of the ways to sink gold), the gold-plated will be slightly white (nickel color). 2. The crystal structure formed by gold settling and gold plating is not the same. The gold settling is easier to weld than gold plating, and will not cause poor welding.The stress of the sunk gold board is easier to control, for the state Products, more conducive to the state of the processing.At the same time, because gold is soft than gold plating, so gold board do gold fingers are not wear-resistant (the disadvantages of gold board). 3. There is only nickel gold on the gold plate on the welding plate. In the skin convergence effect, the signal is transmitted in the copper layer. 4. The submerged gold is more dense than the gold-plated crystal structure, and it is not easy to produce into oxidation. 5. With the increasing requirement of the processing precision of the circuit board, the line width and spacing have been below 0.1mm.Gold ding is easy to produce gold wire short circuit.The gold sinking plate only has nickel and gold on the welding plate, So it's not easy to produce a gold wire short circuit. 6. Only the gold sinking plate has nickel and gold on the welding plate, so the combination of the welding resistance and copper layer on the line is stronger.The works will not affect the spacing during the compensation.7. For boards with higher requirements, flatness is better. Gold is generally used, and gold generally does not appear black pads after assembly.The flatness and service life of the sunk gold sinking plate It's better than a gilt board So at present, most factories use the gold sinking process to produce gold panels.But the gold sinking process is more expensive (more gold content) than the gold plating process, so there is still a lot of low-price production Use gold plating process (such as remote control board, toy board).