Desmear
Desmear product is specially designed to remove the resin smear of hole walls by using the strong oxidizing of Potassium permanganate after drilling process. It makes effective conductivity in both inner-layer and out-layer, and also forms honeycomb texture in the hole walls simultaneously. This surface structure is benefit for the following Palladium adsorption in PTH process and further enforces the adhesion between electroless copper and base materials, which may prevent hole wall pull away and blow hole defects.
Desmear QHD series product
Jiangnan Fine Chemistry's Desmear QHD process is used for PTH pretreatment which applied for multilayer
Sweller QHD-200,
Oxidizer QHD-220,
Neutralizer QHD-250。
Sweller QHD-200: loosen the smear on the hole walls and make it easily to be removed in process.
Oxidizer QHD-220: etch off the smear from both glass fiber and copper surface, it’s better to form proper electroless copper.
Neutralizer QHD-250: clean up the residues of resin oxide and manganate in the surface of hole wall to ensure excellent reliability of subsequent PTH process
QHD process is low cost ownership, simple operation and suitable for both flexible and rigid PCB.
Process flow
Desmear picture-1 |
Desmear picture-2 |
Process control parameter 
