PCB Blogger-China PCB Factory,HOYOGO

As an environmentally friendly surface treatment process, Immersion silver is to deposit a layer of silver with a thickness of 6-18u” on the surface of copper to ensure the reliable soldering of electronic devices on the circuit board. Immersion silver is a process carried out after electrical and visual inspection. The specific process is as follows: Immersion Silver Process: The Advantage of Immersion Silver: The thickness of the sinking silver has a protective function on the copper surface. Immersion silver can provide superior and reliable welding points for lead-free soldering; it has good corrosion resistance and low ion pollution; It cost less than the ENIG process and it’s flatter than the tin-plated surface. Its flat surface is suitable for the production of high-density circuit boards, SMT (Surface Mount) with dense pitch, BGA (Ball Grid Array) and direct wafer mounting. And immersion silver’s process is simple. Its contrasting color makes it easy to check,

　　 OSP  is the abbreviation of “Organic Solderability Preservative”, also known as a Preflux. It refers to an organic thin film layer chemically formed on a clean bare copper surface. 　　 OSP  has three board categories of materials: Rosin, Active Resin and Azole. Nowadays, the most widely used by manufacturer is the Azole OSP. The Azole OSP has undergone 5 generations of improvement, namely BTA, IA, BIA, SBA and the latest APA. 　　 OSP  has many advantages. Its process is simple and reusable. OSP is low-toxic, environmentally friendly, and has good thermal shock resistance. If the PCB surface is treated with OSP, the surface will be smooth. When we print solder paste or paste SMD components, OSP can reduce the component offset and reduce the probability of SMD solder joints, making it convenient for downstream manufacturers to assemble. It allows solder and copper to be soldered directly and has good wettability. OSP processing has low energy consumption, low processi

　　PCBs surface treated with  immersion gold and gold plating  have strong oxidation resistance and conductivity. They’re slightly better than the surface treatment of immersion tin we mentioned earlier. In order to plate a gold layer on the PCB, we can adopt two processes, immersion gold and gold plating. Many people think these two processes are the same, but they are not. There are big differences between them. 　　 Immersion gol d : Immersion gold is also known as ENIG. It adopts the method of chemical deposition, which is to generate a plating by chemical redox reaction. And it is also a way to reach a thicker layer of chemical nickel gold. 　　 Gold plating : Gold plating is flash gold, the principle of electrolysis, generally refers to the "electroplating gold", "electrolytic gold", "electric gold" and so on. There are soft gold and hard gold, and generally hard gold is used for gold fingers. The principle is to dissolve nickel and gol

　　The base purpose of PCB surface treatment is to ensure good solderability or electrical properties. Since copper is oxidized in the air, the composition of copper will becomes impure, PCB surface treatment is required for copper. There are many kinds of PCB surface treatment processes, and different processes will affect the cost of the final PCB processing. Now, let’s talk about the difference between  HASL and  Immersion tin . 　　 HASL : It is to soak the PCB into the molten tin-lead. After PCB surface is covered with enough tin-lead, the excess tin-lead is scraped off with hot air to enhance the continuity and solderability of the PCB pads. It is thicker, typically between 50 and 150 microns. The main purpose of  HASL  is to prevent oxidation, effectively separating the copper surface from the air. 　　 Immersion Tin : As the name suggests, it is chemically plated with a layer of tin on the PCB pad. It is thinner, typically between 10 and 30 microns. It is a