PCB Technical - PCB circuit board terminology and circuit board dictionary

1, PCB circuit board term Acceleration rapid reaction (through-hole plating, chemical copper, direct plating)

broadly refers to various chemical reactions, if certain accelerators are added, the reaction can be accelerated. In a narrow sense, it refers to the process of plated through hole (PTH), after the activation reaction, in the rapid bath, the outer shell of the adsorbed palladium colloid is stripped with acid (such as sulfuric acid or fluorine-containing acid, etc.) to expose the active The palladium metal is in direct contact with the copper ions, and the chemical copper layer is obtained before the treatment reaction.

2. Accelerator, accelerator (through-hole plating, chemical copper, direct plating)

refers to additives that can accelerate chemical reactions. Circuit board terms can sometimes be used interchangeably with Promotor. For the resin to be impregnated, a certain accelerator is also involved in its A-stage. In the PTH process, when the tin-palladium colloid falls on the pore wall of the substrate, it is necessary to dissolve the tin shell on the outside with an acid, so that the palladium can directly react with the chemical copper. Chemical agent".

3, Activation (through-hole plating, electroless copper, direct plating)

generally refers to the state of excitement required at the beginning of a chemical reaction. In a narrow sense, it refers to the process in which palladium colloids land on the walls of non-conducting holes in the PTH process, and this bath solution is called Activator. There is also a similar word for Activity, which refers to "activity".

4, Activator activator (through hole plating, chemical copper, direct plating)

In the PCB industry, it often refers to the activating ingredients in the flux, such as inorganic zinc chloride or ammonium chloride, and organic hydrohalogenated amines or organic acids, etc., which can help "pinoleic acid" treat the surface of welded metal at high temperatures. Carry out cleaning work. These additives are called Activator.

5, BackLight (BackLighting) backlight method (through-hole plating, chemical copper, direct plating)

is a magnified visual inspection method to check the integrity of plated through-hole copper walls. The method is to carefully thin the substrate outside the hole wall from a certain direction to approach the hole wall, and then use the principle of resin translucency to inject light from the thin substrate on the back. If the quality of the chemical copper hole wall is intact and there are no holes or pinholes, the copper layer must be able to block light and appear dark in the microscope. Once there is a hole in the copper wall, there must be a light spot to be observed, and can be enlarged and photographed for evidence, called "backlight inspection method", also known as ThroughLightMethod, but only half of the hole wall can be seen .

6, Barrel hole wall, barrel plating (through-hole plating, chemical copper, direct plating)

is often used on circuit boards to indicate the hole wall of PTH, such as BarrelCrack, which means that the copper hole wall is broken. However, in the electroplating process, it is used to mean "barrel plating". It is to stack many small parts to be plated in a rotatable barrel plating barrel and touch each other to overlap with the soft parts hidden in it. The sex cathode conductive rod is connected. During operation, the small parts can be electroplated in vertical rolling up and down. The voltage used in this barrel plating is about three times higher than that of normal electroplating.

7, Catalyst (Plating through holes, chemical copper, direct plating)

"Catalysis" is an additional "introducer" added to each reactant before the general chemical reaction, so that the required reaction can be carried out smoothly. In the circuit board industry, it refers specifically to the PTH process in which the "palladium chloride" bath "activates and catalyzes" the non-conductor plates, and bury the growing seeds for the electroless copper coating. However, this academic term is now more colloquially referred to as "Activation" (Activation) or "Nucleating" (Nucleating), or "Seeding". In addition, Catalyst, its correct translation is "catalyst".

8, Chelate chelate (through-hole plating, electroless copper, direct plating)

In some organic compounds, there are redundant "electron pairs" on some adjacent atoms, which can form a ring with foreign divalent metal ions (such as Ni2+, Co2+, Cu2+, etc.), similar to a crab The two big claws of the cleavage are like holding a foreign object together, which is called stinging effect. The compound with this function is called ChelatingAgent. Such as EDTA (ethylenediaminotetraacetic acid), ETA, etc. are common chelating agents.

9, CircumferentialSeparation ring-shaped hole (plated through hole, chemical copper, direct plating)

The plated through-hole copper wall of the circuit board has the function of providing plug-in soldering and inter-layer interconnection (Interconnection). The importance of the integrity of the hole wall is self-evident. The cause of the ring-shaped hole may be the lack of PTH, the poor tin and lead plating caused the hole to be insufficiently covered, and it was also corroded. Serious shortcomings in quality.

10, Colloid colloid (through-hole plating, chemical copper, direct plating)

is a fluid in the classification of substances, such as milk, muddy water, etc., which are colloidal solutions. It is composed of many giant or small molecules gathered together and present in a suspended state in a liquid, which is different from true solutions such as sugar water and brine. The "palladium" in the activation bath of the PTH process is a true solution at the initial stage of preparation by the supplier, but when it reaches the on-site operation after aging, it also shows the state of colloidal solution, and only in the colloidal bath. Only the board can complete the activation reaction.

11, DirectPlating direct plating, direct plating (through-hole plating, chemical copper, direct plating)

This is a new process that has emerged in recent years. It is intended to eliminate the traditional chemical copper containing formaldehyde, which is harmful to the human body, from PTH, and the hole wall is prepared for metalization (such as black hole method, conductive polymer method, electroplating chemical copper Method, etc.), and then directly electroplating copper to complete the hole wall, there are now a variety of commercial processes are being promoted.

12, EDTA ethylamine tetraacetic acid (through-hole plating, electroless copper, direct plating)

is the abbreviation of Ethylene-Diamine-Tetra-Acetic Acid. It is an important organic chelating agent. The colorless crystal is slightly soluble in water. The four dissociable hydrogen atoms in the molecular formula can be replaced by sodium atoms to form disodium, trisodium or tetrasodium salts, which greatly improves the solubility in water. Two negative ends are freed after hydrolysis, which can capture the divalent metal ions in the water. For example, the two chelating clips of crabs are generally called "chelating". EDTA has a wide range of uses, such as various cleaning agents, shampoos, chemical copper and electroplating, antioxidants, heavy metal detoxifiers, and other drugs. It is an extremely important additive.

13, Electroless-deposition electroless plating (through-hole plating, chemical copper, direct plating)

In a bath of metal ions (such as copper or nickel) capable of autocatalytic reduction, the metal or non-metal surface with strong negative charge is set in it, and metal can be continuously deposited without external current. The process is called "electroless plating". The circuit board industry is dominated by "non-electric copper", and the synonymous word "chemical copper" is also called "sink copper" in the mainland industry.