1. A copper anode with a phosphorus content of 0.030?0.075%, the black film is moderately thick, the structure is fine, the combination is strong, and it is not easy to fall; the copper anode with excessive phosphorus content before the danger. Phosphorus is unevenly distributed, so that the anode mud is excessively dissolved, thereby contaminating the bath liquid, and blocking the pores of the anode bag, thereby forming an increase in the cell voltage. An increase in the cell voltage may cause the anode film to fall. Practice the production of the middle side plating and replace the anode with a simple burr.
2. Phosphorus copper with a phosphorus content of 0.3% is unevenly distributed in phosphorus, black phosphorus film is too thick, and copper solubility is poor. Therefore, it is often necessary to entangle the anode, instead of making the anode-anode area ratio 1:1, the practice of copper anode hanging, the copper content in the bath still has a tendency to decline, it is difficult to maintain balance. It is not economical to add copper sulphate frequently. Electroplating is more likely to have multiple phosphorous-copper anodes, and the anode mud is increased, and the cost of practice will increase.
3. In practice, the thickness of the black film formed by the copper anode with high phosphorus content is too thick, and the resistance is added. To maintain the original current, the voltage should be increased. The increase in the cell voltage is beneficial to the discharge of hydrogen ions, and the probability of occurrence of pinholes is increased. This phenomenon is rare for the domestic “MNSP.P.AEO” system, because there are many external active agents, but for some imported light agents, the chance of pinholes will be greatly increased, and other supplements are needed. Add a moisturizer and try to drop the voltage.
4. In practice, the phosphorus content is high, the black film is too thick, the dispersion is uneven, and the low current region is not bright, and the fiber is fine and numb.
Although the thickness of the phosphorus-containing 0.3% copper anode black film can reduce the cuprous ion into the bath liquid, the structure is loose, the dispersion is uneven, and the action is greatly reduced. There is a chemical reversible reaction in other electrolytes:
Cu2++ Cu -→ 2Cu+
At normal temperature, the equilibrium constant of this reaction is K=( Cu+)2/( Cu2+)=0.5X10-4
As the temperature increases, the cuprous ion concentration also increases. Cuprous ions are present in the bath in the form of cuprous sulfate and are oxidized when air is mixed. In the case of a decrease in acidity, cuprous sulfate hydrolyzes cuprous oxide (copper powder), and the same powder is retained in the high current region of the cathode. The accumulation must be quantitative, that is, the burr; in the low current region, the current power decreases, and the hydrogen ion discharge is more. The acidity decreases at this point, and the hydrolysis proceeds in the direction of generating copper powder.
Cu2SO4+H2O=Cu2O+H2SO4
More copper powder stays on the cathode surface, which will constitute a cathode coating that is not bright and fine. In the absence of air mixing, the current density is very small, and this situation occurs in the low current region.
The use of copper anodes with low phosphorus content, because of the fineness of the black phosphorus film, it is difficult to dissolve the cuprous copper into the bath. It only needs to be mixed with air, the concentration of sulfuric acid should not be low, the current density is slightly higher, and the area is not only the amount and hemp. Sand can be defeated.
Why should PCB use phosphorus-containing copper ball _ phosphor bronze ball in PCB application
Application of Phosphorus Copper Balls in PCB
1. Phosphorus copper ball is used in the primary copper and secondary copper process of PCB board, mainly in forming conductive copper layer of through hole.
For PCB products with more than two layers, since the lines between different layers are not directly connected, the structure between the different layers must be connected through the structure of the via holes to facilitate the electrical transmission.
In the process of PCB board, after the inner layer board is fabricated, multi-laminated and mechanically drilled, in order to make the drill hole conductive, the procedure of removing the glue, removing the hair and chemical copper is required. , a thin copper layer is formed. Thereafter, copper plating and secondary copper plating are performed by electrolytic copper plating to increase the thickness of the copper layer to enhance the conductive effect of the via holes. Phosphorus copper balls are the key materials for primary copper and secondary copper.
2, the phosphor bronze ball is the anode material of the PCB copper plating process, and the addition of phosphorus in the copper ball prevents the cuprous copper from affecting the coating quality.
The phosphor bronze ball plays the role of an anode in the plating bath of the PCB, so the phosphor bronze ball is also called the anode copper ball. When the electrolysis reaction begins, the copper atoms in the phosphor bronze ball will lose electrons to form copper ions, and the positively charged copper ions will move to the PCB plate to be plated where the cathode is located, and finally electrons are generated on the surface of the PCB to form copper. membrane.
In theory, in the copper plated copper reaction, phosphorus does not directly participate in the reaction, the purpose of phosphorus addition is mainly to slow the precipitation rate of copper atoms. If the copper atom dissociates too fast, a large amount of cuprous ions will be generated, and the two cuprous ions will react with each other to form copper atoms and copper ions. The copper atoms in the solution are randomly adsorbed on the PCB by electrophoresis, which affects the formation structure of the copper plating layer and deteriorates the quality of the copper plating layer.
Why should PCB use phosphorus-containing copper ball _ phosphor bronze ball in PCB application
Phosphorus copper ball global market forecast
1. The trend of PCB board manufacturers moving to the mainland remains unchanged, and the growth performance of phosphor bronze balls is also the best in the mainland market.
China’s PCB output value has increased rapidly from 8.5% in 2000. It is expected that the output value of this year will reach 25.2% of the world. Due to the continuous fermentation of PCB board products moving to the mainland, the total output value of PCBs in mainland China has reached the first place in the world.
It is estimated that the global phosphor bronze ball market will increase from 146,501 tons in 2003 to 192,988 tons in 2008, and CAGR (03-08) is 5.7%. Among the regions, the growth of the mainland region was the best, with CAGR (03-08) reaching 10.1%.
2. In the past, the phosphor bronze ball was mainly used by European and American manufacturers. After the successful completion of the Taiwanese plant, two large factories appeared.
Phosphorus copper balls affect the quality of PCBs. In the past, large companies that cut into the field included Japanese companies Mitsubishi, Asaba, American companies IMC, UniverTIcal and Finnish Outokumpu.
In recent years, due to the production of PCBs in the Asia-Pacific region, Taiwan and the mainland have also successively invested in the research and development and mass production of phosphor bronze balls by local manufacturers. At present, the more successful manufacturers include Taiwan’s Dongyue and the mainland’s Xijiang Electronics. According to the manufacturer’s declared shipment estimates, the two companies have surpassed other foreign companies, ranking the top two in the world.