1. Hot air leveling (tin spraying)

　　Hot air leveling, also known as hot air solder leveling (commonly known as tin spraying), is a process of coating the surface of a PCB with molten tin (lead) solder and flattening it with heated compressed air, forming a coating layer that is not only resistant to copper oxidation but also provides good solderability. Hot air leveling forms copper tin intermetallic compounds at the junction of solder and copper. PCB should sink into the melted solder during hot air leveling; The wind knife blows out the liquid solder before it solidifies; The wind knife can minimize the crescent shape of the solder on the copper surface and prevent solder bridging.

　　2. Organic Solderability Protector (OSP)

　　OSP is a process for surface treatment of copper foil on printed circuit boards (PCBs) that complies with RoHS instructions. OSP is the abbreviation for Organic Solderability Preservatives, which is translated as organic solder mask, also known as copper protector, and also known as Preflux in English. Simply put, OSP is the process of chemically growing an organic film on a clean bare copper surface. This layer of film has anti oxidation, heat shock resistance, and moisture resistance to protect the copper surface from further rusting (oxidation or vulcanization, etc.) in a normal environment; But in the subsequent welding high temperature, this protective film must be easily removed by the flux quickly, so that the exposed clean copper surface can immediately combine with the molten solder to form a solid solder joint in a very short time.

　　3. Full plate nickel gold plating

　　Nickel gold plating on a PCB surface involves first plating a layer of nickel on the conductor, followed by a layer of gold. Nickel plating is mainly used to prevent diffusion between gold and copper. There are two types of nickel gold electroplating nowadays: soft gold plating (pure gold, the gold surface does not look bright) and hard gold plating (smooth and hard surface, wear-resistant, containing cobalt and other elements, the gold surface looks brighter). Soft gold is mainly used for making gold wires during chip packaging; Hard gold is mainly used for electrical interconnections in non welded areas.

　　Analysis of the Development Advantages of Horizontal Electroplating

　　The development of horizontal electroplating technology is not accidental, but a necessary result for the special functions of high-density, high-precision, multifunctional, and high aspect ratio multi-layer printed circuit board products. Its advantage is that it is more advanced than the vertical hanging plating process currently used, with more reliable product quality and the ability to achieve large-scale production.