There is a very common process used in the surface treatment of circuit boards, which is called the immersion gold PCB process. The immersion gold process is to deposit a nickel-gold plating layer with stable color, good brightness, flat plating, and good solderability on the surface of the printed circuit. During production, the cost of the immersion gold board is relatively high.
1. Heat Dissipation
The thermal conductivity of gold is good, and the pad made of it has the best heat dissipation due to its good thermal conductivity. Good heat dissipation. The lower the temperature of the PCB board, the more stable the chip work. The immersion gold board has good heat dissipation. Comprehensive heat dissipation holes can be used on the CPU bearing area of the notebook board and the BGA component soldering base, while the OSP and silver board heat dissipation sex is average.
2. Welding Strength
The solder joints of the immersion gold board are full after three times high temperature. The solder joints of the bright OSP board are gray and dark after three times high temperature, which is similar to oxidation. After three times of high-temperature soldering, it can be seen that the solder joints of the immersion gold board are full and the bright soldering is good. The activity of solder paste and flux will not be affected, while the board solder joints of the OSP process are dull and lustrous, which affects the activity of solder paste and flux, which is easy to cause empty soldering and increased rework.
3. Electrical Testability
Immersion gold boards can be directly measured before and after production and shipment. The operation technology is simple and is not affected by other conditions; OSP boards are organic solderable film on the surface, and the organic solderable film is non-conductive, so it cannot be directly measured. It must be measured before OSP, but after OSP, excessive micro-etching is prone to cause poor soldering; the surface of the silver plate has general film stability, which requires harsh external environments.
4. Process Difficulty and Cost
Immersion gold craft boards are difficult to process, have high requirements for equipment, and have strict environmental protection requirements. Because of the large use of gold elements, the cost is the highest among lead-free craft boards; the process of silver fusion boards is slightly less difficult and has equivalent water quality and environmental requirements. Strictly, the cost is slightly lower than that of the immersion gold board; the OSP board has the simplest process and the lowest cost.