1、 Nature

It is suitable for acidic copper chloride etching solution to replace hydrogen peroxide to regenerate the etching solution. The chemical reaction is mild and the risk is low.

The etching rate is easy to control, so that high etching quality can be achieved in a stable state.

It can etch all printed circuit boards suitable for acidic copper chloride etching solution - including multilayer board inner layer, double-sided board and single panel of full board electroplating process.

It is applicable to manual control and automatic addition (the equipment needs an automatic addition system).

2、 Main function

In the etching process of acidic copper chloride, Cu2 + in copper chloride is oxidizing, which can oxidize copper on the plate surface to Cu +, and its reaction is as follows:

Etching reaction: cu2cl2 formed by Cu + CuCl2 → cu2cl2 is insoluble in water. In the presence of excess Cl -, it can form soluble complex ions. Its reaction is as follows:

Complexation reaction: cu2cl2 + 4CL - → 2 [cucl3] 2 - with the etching of copper, there are more and more Cu1 + in the solution, and the etching ability will soon decline, and finally lose its efficiency. In order to maintain the etching ability, the etching solution can be regenerated in various ways to convert Cu1 + into Cu2 + and continue normal etching.

The regeneration principle of 102# acid etching additive is mainly to oxidize Cu + in the solution with oxidant and supplement Cl - in the etching solution at the same time.

3、 Technical indicators

Appearance: colorless to light yellow clear liquid

0 degree: 1.20 ± 0.05

4、 Use and control methods

1. Manual control: add the calculated amount of hydrochloric acid into the etching solution to be regenerated, mix it evenly, then add 102# etching additive and stir it to mix it.

2. Automatic control add:

Addition amount of hydrochloric acid: the concentration of 31% hydrochloric acid in acidic copper chloride etching solution is 80-100ml / L, and hydrochloric acid is also required to participate in chemical reaction in the regeneration process. Generally, the addition of hydrochloric acid is completed by the controller controlling the ratio of hydrochloric acid to 102# etching additive, which is usually 2-3:1.

Supplement of 102# etching additives: determine an appropriate redox potential and the ratio of 102# etching additives to hydrochloric acid according to the requirements of etching speed. As long as the etching speed is determined, 102# etching additives can be added to achieve this speed without special control.

3. 102# the regeneration rate of etching additive is much milder than that of hydrogen peroxide (only one tenth or slower). The regeneration speed is directly proportional to the concentration of hydrochloric acid and usually takes several seconds to tens of seconds to complete.

4. 102# excessive addition of etching additives will oxidize chloride ions into chlorine, causing chlorine to escape, pollute the air and cause harm to human body.

5、 Common problems in etching process

1. Slow etching rate

This is usually caused by low temperature, low spray pressure or improper control of the chemical composition of the etching solution. When the above conditions are well controlled, the reason for the slow etching rate may be that the amount of copper dissolved is too high. At this time, it is necessary to adjust and regenerate the etching solution.

2. The solution precipitates

This is due to the low acidity in the solution or the lack of complexing agent Cl -. The precipitate is Cu2 Cl2 which is insoluble in water. Add hydrochloric acid.

3. Photoresist damage

This happens when excess acid is present. Especially at higher temperatures. It can be adjusted by neutralizing with NaOH or replacing part of the solution with water. If the acid concentration and photoresist conditions are appropriate, the failure may be caused by the plate surface cleaning to the photoresist coating stage or improper exposure or baking.

4. There are yellowish brown patches on the surface of copper

This residue is generally cuprous hydroxide, which is insoluble in water. It is produced when the local acidity of the plate surface is insufficient when it is etched, and the concentration of hydrochloric acid is too low to dissolve it, resulting in yellowish brown irregular patches remaining on the plate surface. After cleaning with dilute hydrochloric acid solution, it can be seen that there is still unetched residual copper under it. In addition, when the Cl - concentration and acidity in the etching solution are too low, there will be white deposition on the plate surface after etching, which may be the muddy deposition of cuprous chloride insoluble in water. In order to remove the sediment on the plate surface, it can be cleaned with 5% hydrochloric acid solution, and then sprayed and rinsed with water.

6： Packaging, storage and safety

It belongs to dangerous goods (secondary oxidant). 25kg, 200kg plastic barrel or according to customer requirements.

It is an unstable chemical and needs to be stored separately in a cool and ventilated place. Avoid dust falling in and sun exposure. It is strictly prohibited to contact with acids, otherwise toxic chlorine will be produced.

Valid for three months.

These are the most conservative estimates.