After entering the 1980s, European and American countries imposed stricter environmental protection requirements, particularly regarding the discharge of toxic formaldehyde and difficult-to-treat chelating agents. This forced most solution suppliers to seek new methods to replace traditional electroless copper plating for achieving through-hole metallization. Direct electroplating technology and its products, after an extended period of trial use, gained recognition from PCB manufacturers in the mid-1990s.

As a replacement for electroless copper plating, direct electroplating technology must meet the following requirements:

(1) On non-conductive hole wall substrates including epoxy glass cloth, polyimide, and PTFE, a conductive layer must be formed through special treatment to enable metal electroplating. At the same time, good adhesion between the plating layer and the substrate must be ensured.

(2) The chemical solutions used to form the conductive layer must cause minimal environmental pollution, be easy to treat for the "three wastes" (waste gas, wastewater, and solid waste), and no longer cause severe pollution.

(3) The process flow for forming the conductive layer should be as short as possible, and the operating range should be sufficiently wide to facilitate operation and maintenance.

(4) It must be adaptable to the fabrication of various types of printed circuit boards, such as high-aspect-ratio PCBs, blind-hole PCBs, and PCBs with special substrates.

Currently, direct electroplating technologies worldwide can be classified into three major categories by material: the first is the technology that uses a colloidal palladium process to produce a thin Pd conductive metal layer on non-conductive surfaces; the second is the so-called MnO₂ grafting technology, which uses conductive polymer materials as the conductive layer; and the third is direct electroplating technology based on coated films of carbon or graphite suspensions.