- Problem Description：For HDI blind vias interconnected by any layer of high multi-layer, the blind vias are generally the shape of the via end is relatively small and the via caliber is relatively deep, and because of the electromagnetic effect during electroplating, the general current will be grabbed by the area of the via end, and the internal current cannot enter. Secondly, because there will be residual liquid inside, such as after washing, most of the water occupies the space, and the electroplating solution does not match at all, electroplating has no solution, the lack of solution can not form the battery principle of electroplating, it is simply impossible to plate. At the same time, the structure of the blind hole belongs to a unilateral opening, whether it is rubber residue removal, chemical copper or conduction chemical treatment, electroplating process, because they are all treated with chemical liquid, so the difficulty of electroplating treatment is more difficult in the case of chemical exchange and liquid wetting (wetting).

- Solution：Any layer interconnection HDI board Z-axis vertically interconnection technology, which is to first make the core board of each layer (double-sided core board), and then press it with a prepreg, and the hole disk that needs to be connected up and down in the Z axis is printed with conductive paste, and the hole that does not need to be connected is isolated by a prepreg. The advantage of this process is that only one pressing is required, which reduces the number of times the substrate is hot pressed; The conductive paste connection reduces the plating treatment and avoids the problem of the thickness to diameter ratio of the plating of the small hole connection; The upper and lower holes are self-isolated when laminated, and do not require back drilling. Change the traditional practice of plating HDI blind vias by electroplating, and use the low-temperature pressurized nano-sintered interconnected conductive copper paste produced by our company to fill the blind vias, so as to achieve the purpose of metallization and filling in the blanks. Moreover, the density of conductive copper paste is greater than that of the hole copper formed by electroplating, which is superior in reliability and air tightness.

- Improve Performance：The low-temperature sintered nanocomposite conductive plug hole copper paste replaces the three-in-one process of via metallization, electroplating and plug hole, reduces the difference between hole resistivity and expansion coefficient, and forms a high-reliability connection between homogeneous materials.