The formulation of preventive measures needs to consider the contribution of chemicals and equipment in actual production to various defects so as to avoid or eliminate defects and increase the yield rate.
The prevention of the Jafani effect can be traced back to the copper process of the previous process. For high aspect ratio holes and micro-vias, uniform plating thickness helps to eliminate the hidden danger of the Giovanni effect. Exfoliation, etching, and excessive etching or undercutting in the stripping process promote the formation of cracks, and microetch solutions or other solutions may remain in the cracks. In spite of this, the problem of solder mask is still the most important reason for the occurrence of the Jafani effect. Most of the defect panels with the Jafani effect have side etching or solder mask shedding. This problem is mainly caused by the exposure and development process. . Therefore, if the solder mask develops a "positive leg" and the solder mask is completely cured, the problem of the Giovanni effect can be almost eliminated. To get a good silver layer, the silver must be 100% metallic copper. Each bath solution has good through-hole capability, and the solution in the via can be effectively exchanged. For very delicate structures, such as HDI plates, it is useful to install ultrasonics or ejectors in the pretreatment and sinking baths. For the silver silver process production management, controlling the microetch rate to form a smooth, semi-glossy surface can also improve the Giovanni effect. For original equipment manufacturers (OEMs), the design of large copper planes or high aspect ratio vias and fine lines should be avoided as much as possible to eliminate the hidden dangers of the occurrence of the Giovanni effect. For chemical suppliers, Shen Yinye cannot be very aggressive. To maintain a proper pH, the silver sink has a controlled rate of velocity and can produce the desired crystal structure. It can achieve the best corrosion resistance at the thinnest silver thickness.
Corrosion can be reduced by increasing the plating density and decreasing the porosity. The use of a non-sulfur material package while sealing to isolate the plate from air contact also prevents sulfur entrained in the air from contacting the silver surface. It is best to store the packaged plates in an environment with a temperature of 30°C and a relative humidity of 40%. Although the duration of the storage of the silver plate is very long, it is still necessary to follow the principle of first-in, first-out when it is stored.