The surface treatment methods used in PCB board proofing are different, and each surface treatment method has its unique characteristics. Taking chemical silver as an example, its manufacturing process is extremely simple, and it is recommended to be used in lead-free soldering and SMT; especially for fine circuit effects Even better, the most important thing is to use chemical silver for surface treatment, which will greatly reduce the overall cost and lower cost. Below, the editor of Intellectual Innovation will introduce you to several common surface treatment methods for PCB board proofing.
1. HASL hot air leveling (also known as tin spraying)
Tin spraying is a commonly used treatment method in the early stage of PCB board proofing. Now it is divided into lead HASL and lead-free HASL. Advantages of HASL: After the PCB is completed, the copper surface is completely wetted (the tin is completely covered before soldering), suitable for lead-free soldering, the process is mature and the cost is low, suitable for visual inspection and electrical testing, and it is also a high-quality and reliable PCB board One of the proofing processing methods.
2. Electroless Nickel Gold (ENIG)
Nickel gold is a surface treatment process that is widely used for PCB board proofing. Remember: the nickel layer is a nickel-phosphorus alloy layer. According to the phosphorus content, it is divided into high-phosphorus nickel and medium-phosphorus nickel. The application is different, so I won’t introduce it here. the difference. The advantages of nickel-gold: suitable for lead-free soldering; the surface is very flat, suitable for SMT, suitable for electrical testing, suitable for switch contact design, suitable for aluminum wire bonding, suitable for thick plates, strong resistance to environmental attacks.
3. Nickel gold plating
Electroplated nickel gold is divided into "hard gold" and "soft gold". Hard gold (such as: gold-cobalt alloy) is often used on gold fingers (contact connection design), and soft gold is pure gold. Nickel-gold electroplating is widely used on IC substrates (such as PBGA). It is mainly suitable for bonding gold wires and copper wires, but it is suitable for electroplating on IC substrates. The bonding gold finger area needs additional conductive wires to be electroplated. Advantages of electroplated nickel gold pcb board proofing: suitable for contact switch design and gold wire bonding; suitable for electrical testing
4. Nickel gold (ENEPIG)
Nickel-palladiu-gold is now gradually beginning to be used in the field of pcb board proofing, and it was used more in semiconductors before. Suitable for gold; aluminu wire binding. Advantages of using nickel-palladiu-gold pcb board for proofing: it is applied on the IC carrier board, suitable for gold wire bonding and aluminu wire bonding. Suitable for lead-free soldering; compared with ENIG, there is no nickel corrosion (black plate) problem; the cost is cheaper than ENIG and electro-nickel-gold, and it is suitable for a variety of surface treatment processes and exists on the board.
In addition to the above several pcb board proofing treatment methods, it also includes chemical tin. This kind of chemical tin surface treatment is suitable for horizontal line production and is also used. In fine line processing projects, when you choose the pcb board proofing surface treatment method, you need to be based on actual conditions Depending on the situation, contacting the characteristics of the surface treatment method and the budgeted cost, you can also choose spot wholesale products from pcb board proofing manufacturers as appropriate.
