PCB gold dipping and gilding board
The role of these two processes
Gold dipping board and gold plating board are commonly used in circuit board production today With the improvement of IC integration, IC pins become denser The vertical tin spraying process is difficult to flatten thin pads, which makes it difficult to place SMT; In addition, the shelf life of sprayed tinplate is very short Gold plated plate just solves these problems It is used for surface mount process, especially for 06.03 and 0402. Ultra small surface mount. Because PCB pad is directly related to the quality of solder paste printing process, it has a decisive impact on the quality of subsequent reflow soldering. Therefore, the entire circuit board is gold plated, which is very common in high-density and ultra small surface mount processes
In the trial production stage, due to the purchase of components and other factors, the circuit board is not usually welded as soon as it arrives, but it usually takes several weeks or even weeks to use it The shelf life of gold plate is many times that of tin plate So everyone is happy to accept it In addition, the sample stage of cost gold plated PCB is almost the same as that of lead tin alloy plate
What is gilding: the whole plate is gilded
Generally, it refers to [electroplated gold] [electroplated nickel gold plate], [electrolytic gold], [electroplated gold], [electroplated nickel gold plate]. Soft gold is different from hard gold (usually used as gold finger). The principle is to dissolve nickel and gold (usually referred to as gold salt) in chemical water, immerse the circuit board in the electroplating cylinder and energize it to form a nickel gold coating on the copper foil surface of the circuit board. The characteristics of high hardness, wear resistance and oxidation resistance are widely used in the names of electronic products.
What is the heavy money
A coating is formed by chemical oxidation and reduction reaction, which is usually thick. This is a chemical nickel gold coating deposition method, which can reach a thicker gold layer, usually called immersion gold.
Difference between Immersed Gold Plate and Gold Plate
1. The crystal structure formed by gold immersion and gold plating is different. Immersion is much thicker than gilding. Immersed gold will be golden yellow, more yellow than gold plating. The customer was more satisfied.
2. The crystal structures formed by gold immersion and gold plating are different. Gold dipping is easier to weld than gold plating, and will not cause poor welding and customer complaints. The stress of immersion gold-plated plate is easier to control, which is more conducive to bonding processing for products with bonding. At the same time, it is precisely because the gilding is softer than the gilding, so the gilding plate is not as wear-resistant as the gold finger.
3. There is only nickel and gold on the bonding pad of the gold impregnated plate. In the skin effect, the signal is transmitted on the copper layer and will not affect the signal.
4. Gold immersion has a denser crystal structure than gold plating and is not easy to produce oxidation.
5. As cabling becomes more intensive, the line width and spacing reach 3-4 MIL. Gold plating is easy to short-circuit the gold wire. There is only nickel on the bonding pad of the immersion gold plate, which will not cause gold wire short circuit.
6. Immersion gold-plated plate only has gasket There is nickel gold on the board, so the mask on PCB solder circuit and copper layer are more firmly combined During compensation, the project will not affect the spacing
7. It is generally used for boards with relatively high demand. Better flatness. Usually gold leaching is used. After assembly, the dipped gold usually does not show as a black pad. The flatness and standby life of the gilded plate are as good as those of the gilded plate.
The above is the explanation given by the editor of pcb circuit board company.
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