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The difference between Immersion Gold Plate and Gold Plated Plate
2021-09-24
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Author:Aure

The difference between Immersion Gold Plate and Gold Plated Plate



One, Immersion Gold Board

A layer of plating is generated by the method of chemical oxidation-reduction reaction, which is generally thicker.

Second, the gold plate

As the integration of IC becomes higher and higher, IC pins become more and more dense. The vertical tin spraying process is difficult to flatten the thin pads, which brings difficulty to the placement of SMT; in addition, the tin spraying board The shelf life is very short. The gold-plated board just solves these problems: 1 For the surface mount process, especially for 0603 and 0402 ultra-small surface mounts, because the flatness of the pad is directly related to the solder paste printing process Quality has a decisive influence on the quality of subsequent reflow soldering. Therefore, the whole board gold plating is common in the high-density and ultra-small surface mount process. 2 In the trial production stage, the influence of factors such as component procurement is often not the board. Soldering immediately, but often has to wait a few weeks or even months before using it. The shelf life of the gold-plated board is many times longer than that of the lead-tin alloy, so everyone is willing to use it. Besides, the gold-plated PCB is in the sample stage. The cost is almost the same as that of the lead-tin alloy plate.



The difference between Immersion Gold Plate and Gold Plated Plate


However, as the wiring becomes denser, the line width and spacing have reached 3,4MIL. Therefore, the problem of gold wire short circuit has been brought about:

As the frequency of the signal gets higher and higher, the signal transmission in the multi-plated layer caused by the skin effect has more obvious influence on the signal quality:

The skin effect refers to: high frequency alternating current, the current will tend to concentrate on the surface of the wire to flow.

According to calculations, skin depth is related to frequency:

Other shortcomings of gold-plated board have been listed in the difference table between immersion gold board and gold-plated board.

Three, Immersion Gold Board

In order to solve the above problems of gold-plated boards, PCBs using gold-plated boards mainly have the following characteristics:

1.Because the crystal structure formed by immersion gold and gold plating is different, immersion gold will be golden yellower than gold plating, and customers will be more satisfied.

2.Because the crystal structure formed by immersion gold and gold plating is different, immersion gold is easier to weld than gold plating, and will not cause poor welding and cause customer complaints.

3.Because the immersion gold board only has nickel and gold on the pad, the signal transmission in the skin effect is on the copper layer and will not affect the signal.

4.Because immersion gold has a denser crystal structure than gold plating, it is not easy to produce oxidation.

5.Because the immersion gold board only has nickel gold on the pad, it will not produce gold wire and cause a slight short.

6.Because the immersion gold board only has nickel and gold on the pad, the combination of the solder mask and the copper layer on the circuit is stronger.

7, The project will not affect the spacing when making compensation.

8. Because the crystal structure formed by immersion gold and gold plating is different, the stress of the immersion gold plate is easier to control, and for products with bonding, it is more conducive to the processing of bonding. At the same time, it is also because immersion gold is softer than gold plating. , So the gold finger is not wear-resistant.

9.The flatness and standby life of the immersion gold circuit board are as good as the gold-plated board.

Three, the whole board is gold-plated

Generally refers to "electroplating gold", electroplating nickel gold plate, "electrolytic gold", "electric gold", "electric nickel gold plate", there is a distinction between soft gold and hard gold (usually used as gold fingers). The principle is Dissolve nickel and gold (commonly known as gold salt) in chemical water, immerse the circuit board in the electroplating cylinder and pass current to form a nickel-gold plating layer on the copper foil surface of the circuit board. The characteristics of wear resistance and oxidation resistance are widely used in electronic product names.