PCB plating hole, chemical copper and direct electroplating process

- Nov 17, 2018-

1. Acceleration Acceleration response

The term refers broadly to all chemical reactions in which the reaction is accelerated by the addition of some accelerator.In the narrow sense, it refers to the process of PTH plating, after the activation reaction, the shell of palladium colloid (such as sulfuric acid or acid containing fluorine, etc.) is stripped out in the accelerating tank, so that the palladium metal exposed to the copper ions can contact directly, and the reaction before the chemical copper layer is obtained.

2. Accelerator, Accelerator

Board language can sometimes be used in conjunction with Promotor in terms of additives that promote chemical reaction acceleration.The resin to be impregnated is also involved in the a-stage with some accelerator.In the PTH process, when the tin palladium colloid lands on the hole wall of the bottom material, the outer tin shell should be dissolved with acids to make the palladium react directly with chemical copper. This kind of acid stripping is also called "accelerating agent".

3. Activation

Generally refers to the initial state of excitement required for a chemical reaction.In the narrow sense, the process of palladium colloid landing on the wall of the non-conductor hole during the PTH process is referred to as the Activator.Another similar word of Activity is Activity.

4. Activator Activator

In the PCB industry, active ingredients, such as inorganic zinc chloride or ammonium chloride, and organic hydrohalogenated amines or organic acids, are commonly used to assist in cleaning the surface of the weld metal at high temperatures.These additives are called activators.

5. Back Light(Back Lighting) backlighting

It is an enlarged visual method to check whether the copper wall of the through hole is intact.The method is to grind the substrate outside the hole wall carefully close to the hole wall in a certain direction, and then use the principle of translucent resin to shoot the light from the thin substrate behind.If the wall of the chemical copper hole is intact without any holes or pinholes, the copper layer must be able to block light and appear dark in the microscopy.Once there are holes in the copper wall, there must be some points of Light to be observed, and the photographic evidence can be amplified. It is called "backlight inspection Method" or Through Light Method, but only half of the hole wall can be seen.

6. Barrel the hole wall, and roll

In the circuit board, it is often used to indicate the hole wall of PTH, such as the fracture of the copper hole wall.However, in electroplating process, it is used to mean "roll plating". Many small parts to be plated are stacked in rotatable barrel to connect with the flexible cathode conductive rod hidden in it by touching and lapping each other.During operation, each small piece can be plated by vertical rolling up and down. The voltage used for this type of rolling is about three times higher than that of normal plating.

7, Catalyzing

Catalysis is the additional "introducer" added to each reactant before a general chemical reaction, so that the required reaction can be carried out smoothly.In the circuit board industry, it refers to the "activation catalysis" of the "palladium chloride" tank to the non-conductor plate, and the growing seeds are first buried in the chemical copper plating layer.However, this academic term is now more commonly referred to as "Activation" or "Nucleating", or Seeding.Catalyst Catalyst Catalyst Catalyst

Chelate Chelate Chelate

In some organic compounds, some adjacent atoms have redundant "electron pairs" with foreign divalent metal ions (such as Ni2+, Co2+, Cu2+, etc.), which can form a Ring together. Similar to the crab's two big pincers, the Ring can be used to hold the external object together.Compounds with this function are known as Chelating agents.For example, EDTA(ethylenediamine tetraacetic acid) and ETA are common chelating agents.

9. Circumferential Separation ring break

The copper wall of the plating hole of the circuit board is provided with the function of plug welding and Interconnection between layers.The reason for the annular hole may be the absence of PTH, and the poor tin-lead plating may lead to insufficient cover in the hole, resulting in erosion and breakage, etc. The disconnection of the whole-ring hole wall is called annular hole, which is a serious defect in quality.

10. Colloid

A fluid in the classification of substances, such as milk, mud, etc., is a colloidal solution.It is a collection of large or small molecules that are suspended in the liquid, unlike true solutions such as sugar water and salt water.PTH process the "palladium" in the activated tank solution is the true solution at the initial stage of the preparation by the supplier, but when it reaches the site after aging, the colloidal solution state appears, and only in the gel tank solution can the plate finish the activation reaction.