Desmear Processes


Desmear Processes

Okuno-Auromex has been an innovator providing leading edge, and environmentally acceptable technology to the PCB industry.

Desmear Processes

As stated in the introduction, PCBs are three dimensional platforms that allow integration and interconnection of electronic devices. In that regard, the Z axis, or vertical dimension is interconnected by Plated Through Holes (PTHs). This is accomplished by “drilling” holes through the various layers of multilayer boards which are then metalized to provide a conductive interconnection. However, the drilling process is not always perfect and may results in defects such as residues of resin/laminate materials in the PTH which would interfere with subsequent processing.

The Desmear processes are intended to remove these “residues” and thus facilitate further processing of the PCB without defects.

Okuno Chemical Industries, Okuno-Auromex partner, has a long history of developments for desmearing dating back to the 1960s. Their efforts resulted in the OPC line of proprietary products utilized in the first generation of electroless copper plating technology.

Since then, the OPC Processes have evolved with new developments intended to address the needs of current laminate and PCB technology. They include a full package of swelling, micro etching and neutralizing agents intended not only remove smears in through

holes, but also “roughen” the surface of insulating resin and thus improve the adhesion between resin and electroless plating deposits.

Additional information on the OPC products is found in the table below:





OPC-1080 Conditioner

Inflating agent to low natural wastage. Excellent cleaning effect inside of holes and removal efficiency of smear.

Micro etching

OPC-1200 EPO Etch

Give micro etching on epoxy resin surface and inside hole without attacking copper laminate, and provide hydrophilicity on surface.

OPC-1540 MN

Give micro etching inside hole without attacking copper laminate. Can be applied with OPC-1200 Epo Etch.


OPC-1300 Neutralizer

Excellent cleaning power to epoxy resin surface which was roughened by OPC-1200 Epo Etch. Can remove manganese compound residues and has
strong penetration effects to small holes or complicated parts.