Acceleration reaction—In a broad sense, it refers to various chemical reactions. If certain accelerators are added, they can be reacted and accelerated. In the narrow sense, in the PTH process, after the activation reaction, the outer shell of the adsorbed palladium colloid is stripped off in the speeding bath solution and acid (sulfuric acid or fluorine-containing acids, etc.) is exposed to expose the active palladium. The metal is then in direct contact with the copper ions, and the reaction is processed before the chemical copper layer is obtained.