Research and Discussion on New Acid Copper Brightener Intermediates

Full bright acid copper plating due to good toughness of the coating, the bath has good brightness leveling and faster deposition rate, and thus in the plastic plating metal copper-nickel-chromium decorative plating and printing plate hole metallization plating and electroforming Occupies an important position. To achieve good results, the key to its full strength lies in brighteners. For the study of brighteners, various countries in the world have carried out extensive work in this area and have made great efforts to study thiourea derivatives, and began to study other dyes and brighteners and leveling compounds including hydroxyl-containing heterocyclic compounds and polyether compounds. Agent. In the past two decades, many domestic units have also conducted research on acidic copper brighteners and achieved significant results. Take the national road, the international brand of trees, domestic brightener has replaced the imported brightener, and in some respects it also wins the import brightener.

2 Acid Bright Copper Additives

Acidic copper plating requires the addition of brighteners, levelers, and surfactants, and other three types of additives to obtain fine-grained, high-gloss, and high-level mirror effects.

2.1 Brighteners, S-type brighteners are mainly used for grain refinement of Na and H main crucibles, and enhance the brightness of high current density areas in conjunction with leveling agents. The main components are organic sulfur-containing sulfonates and other luminescent groups. The high-grade brightener intermediates include sodium alkoxythiopropane sulfonate (HP), sodium dimethylformamide sulfonate (TPS), and thiimidyl dithiopropane sulfonic acid (SH110). HP is a grain refiner that replaces traditional SP (polydisulfane propane sulfonate) in acid copper plating solution. Compared with SP, it has a clear and bright color, a wide range of dosage, no fog, and a low level effect. advantage. The performance of TPS is similar to that of SP. Its excellent performance in high-area walk. The performance of the brightener component is easier to control. It is a new generation of high-performance acid copper intermediate that replaces SP. The effect of SH110 is basically the same as that of SP. The difference is that it is grain refinement. The combination of agent and leveling agent This process is particularly suitable for circuit board plating and electroforming copper.

2.2 Leveling agents, mostly heterocyclic compounds and dyes.

The main role of the low light brightness and leveling has a good effect. High-grade leveling agent intermediates include tetrahydrothiazolethione (H1) polyethylenimine alkyl compound (GISS), fatty amine ethoxy sulfonate (AESS), mercaptoimidazole propane sulfonate (MESS), The nitrogen level dyes (MDD), H1 has a very good leveling is a good leveling agent to replace N (ethylene thiourea), GISS is a high-performance walking agent made of polyethylenimine condensation under specific conditions , Low current density area walk performance is excellent. AESS is a strong acid copper positioning agent. Adding AESS to the bath can significantly improve the leveling of the light in the low current density area, and it also has a certain wetting effect. MESS is an excellent medium-low brightener that can replace M (2-mercaptobenzimidazole). Compared with M, it has very good water solubility and leveling. The proper increase of the bath will not cause turbidity and the coating will not produce sand. MDD dye is a strong leveling and low-positioning agent, which can make the coating particularly full and bright.

2.3 Surfactants

In the acidic copper plating electrolyte, if a brightener is added alone, the brightening effect on the plating layer is not significant, and a surfactant must be added in order to obtain a bright and leveled coating. Surfactant used in acid bright copper plating baths. Grain refinement with non-ionic surfactants for better effect and stability. Sometimes a small amount of anionic surfactant can also be added as a dispersant, which has a certain effect on improving the coating quality. Common non-ionic surfactant polyethylene glycol (P) molecular weight of 6000,8000,10000; wetting agent MT-100,P must be combined with brightener, leveling agent to obtain full bright coating, MT-100 Sodium succinate, a low-foam wetting agent can increase the plating capacity of the bath and make the deposit deposited in the high and low current density regions uniform.

3 PN in Acidic Copper Plating Brightener

Polyethylenimine alkyl (PN) is a quaternized aminated polyethylenimine derivative. It is a polymeric cationic polymer that acts as a leveling agent and low brightener in acidic copper baths. In the entire acid copper plating additives play a comprehensive role in coordination and harmony, commonly known as mahjong in the "white".

3.1 Work with brighteners

PN needs to be used in conjunction with SP, HP, TPS and the high-level agent should be increased appropriately so that the crystallized layer of the coating can be made finer and smoother without burning the high-potential region, and the brightness of the high-current density region can be enhanced to make the coating color reddish to be bright red.

3.2 Cooperation with leveling agent

The use of PN in combination with H1, GISS, and AESS has a strong cathodic polarization. It is a powerful low-positioning agent that can significantly enhance the brightness of the low-current density region, while also having a good leveling capability. The best deep-plating agent makes the leveling property the best.

3.3 Coordination with surfactants

PN combined with polyethylene glycol can no longer add AEO, deep-drawing ability exceeds AEO and does not need to be removed after the plating process and is combined with MT-100 wetting agent; the plating capacity will be further improved, making the low current density area and The interface of the high current density region achieves a smooth, bright uniform coating.

3.4 PN is the best high temperature carrier in acid bright copper plating brightener

Suitable for complex workpiece plating, can be used in the 15-45 °C range, without inhibiting brighteners, leveling agents due to the high temperature of the bath and play the maximum effect.

4 Summary

According to the practical application of intermediates such as TPS, PN, AESS, GISS, and MESS, the role of the above mentioned intermediates can be brought into full play if they are used accurately, ie, they have a fast bright and smooth filling level, and are obtained at a low current density area. The filling degree and brightness, the current density is wide, the working temperature is wide, and the binding force to the nickel layer is strong, and it is not necessary to remove the film. The stability of the bath is extremely high, the surface of the plating is clear and shining, and the problem of fogging is eliminated, and the pinhole and the sand are greatly reduced.