PCB process PK: tin spraying vs gold plating vs gold deposition

　　Gold plate and gilded plate are commonly used processes in the production of circuit boards nowadays, and many people are unable to correctly distinguish the differences between the two. Some even believe that there is no difference between the two, but in fact, they are not. Usually, when people choose gold plating, what is gold plating? When we refer to whole plate gold plating, we generally refer to "electroplated gold", "electroplated nickel gold plate", "electrolytic gold", "electroplated gold", "electroplated nickel gold plate". There is a distinction between soft gold and hard gold (usually hard gold is used for gold fingers), and the principle is to dissolve nickel and gold (commonly known as gold salt) in chemical solution, Immerse the circuit board in an electroplating cylinder and apply current to generate a nickel gold coating on the copper foil surface of the circuit board. Electroplated nickel gold is widely used in electronic products due to its high hardness, wear resistance, and resistance to oxidation. So what is sinking gold? Gold deposition is to generate a layer of coating through chemical Redox, which is generally thicker. It is one of the Electroless nickel immersion gold gold deposit methods, and can achieve a thicker gold layer.

　　In fact, there are two types of gold plating processes: one is electroplating gold, and the other is sinking gold. For the gold plating process, the effect of tin coating is greatly reduced, while the effect of tin coating on sinking gold is relatively better; Unless the manufacturer requires binding, most manufacturers now choose the sinking gold process! In general, PCB surface treatment can be divided into the following types: gold plating (electroplated, deposited gold), silver plating, OSP, and tin spraying (with or without lead). These are mainly used for FR-4 or CEM-3 boards, and paper based materials also have surface treatment methods coated with rosin; If the production and material process of solder paste and other SMD manufacturers are excluded, the issue of poor soldering (poor soldering) is considered.

　　Here, we only focus on PCB issues, and there are several reasons:

　　During PCB printing, is there an oil film on the PAN position that can block the effect of tin coating; This can be verified by conducting a tin float test.

　　Whether the lubrication position of the PAN position meets the design requirements, that is, whether the pad design can ensure sufficient support for the parts.

　　Is the solder pad contaminated? This can be obtained through ion contamination testing; The above three points are basically the key aspects considered by PCB manufacturers.