The surface treatment methods used by PCB factories in PCB prototyping are numerous, each with its own unique characteristics. For example, chemical silver has a simple process and is recommended for lead-free soldering and SMT, especially for achieving a fine line effect. Using chemical silver for surface treatment can greatly reduce overall costs. Today, we will introduce several common surface treatment methods for PCB board proofing.
Tin HSAL is a common early PCB proofing processing method, now divided into HASL and lead-free HASL. The advantages of HASL include complete wetting of the copper surface, suitability for lead-free soldering, a mature and low-cost process, and suitability for visual inspection and electrical testing.
Nickel gold is a relatively large-scale PCB proofing surface treatment process. The nickel layer is a nickel-phosphorus alloy layer, with high-phosphorus nickel and medium-phosphorus nickel variations. The advantages of nickel gold include suitability for lead-free soldering, a very flat surface suitable for SMT, electrical testing, switch contact design, aluminum wire binding, thick plates, and resistance to environmental attacks.
Nickel gold plating is divided into “hard gold” and “soft gold”. Hard gold, such as gold-cobalt alloy, is commonly used on gold fingers, while soft gold is pure gold. Electroplating of nickel and gold is widely used on IC substrates, mainly for bonding gold and copper wires. The advantage of electroplated nickel-gold PCB board proofing is its suitability for contact switch design, gold wire binding, and electrical testing.
Nickel-Palladium-Gold is gradually being applied in the field of PCB proofing and has been used more on semiconductors before. It is suitable for bonding gold and aluminum wires, and has the advantage of being suitable for lead-free soldering. Compared with ENIG, it does not have the nickel corrosion (black disk) problem and is cheaper, making it suitable for a variety of surface treatment processes and on-board use.
Tin HSAL is a common early PCB proofing processing method, now divided into HASL and lead-free HASL. The advantages of HASL include complete wetting of the copper surface, suitability for lead-free soldering, a mature and low-cost process, and suitability for visual inspection and electrical testing.
Nickel gold is a relatively large-scale PCB proofing surface treatment process. The nickel layer is a nickel-phosphorus alloy layer, with high-phosphorus nickel and medium-phosphorus nickel variations. The advantages of nickel gold include suitability for lead-free soldering, a very flat surface suitable for SMT, electrical testing, switch contact design, aluminum wire binding, thick plates, and resistance to environmental attacks.
Nickel gold plating is divided into “hard gold” and “soft gold”. Hard gold, such as gold-cobalt alloy, is commonly used on gold fingers, while soft gold is pure gold. Electroplating of nickel and gold is widely used on IC substrates, mainly for bonding gold and copper wires. The advantage of electroplated nickel-gold PCB board proofing is its suitability for contact switch design, gold wire binding, and electrical testing.
Nickel-Palladium-Gold is gradually being applied in the field of PCB proofing and has been used more on semiconductors before. It is suitable for bonding gold and aluminum wires, and has the advantage of being suitable for lead-free soldering. Compared with ENIG, it does not have the nickel corrosion (black disk) problem and is cheaper, making it suitable for a variety of surface treatment processes and on-board use.
