For the "via filled with copper" option on our Advanced PCB pricing page, it includes two types: electroplated filled vias and copper paste filled vias.

The difference between electroplated filled vias and copper paste filled vias

1. Electroplated filled vias are suitable for board thickness ≤0.6mm and hole diameter ≤0.2mm.

2. Copper paste filled vias are suitable for hole diameters ranging from 0.1mm to 1.0mm and board thickness ranging from 0.2mm to 4.0mm.

     a. For copper paste filled vias, if the board thickness is within 0.2mm, pure copper is used, which is conductive copper paste.

     b. For board thickness above 0.3mm, copper paste is used, which is thermal copper paste, consisting of 70% copper paste and 30% resin.

3. Electroplated filled vias and copper paste filled vias have the same effect, but the processes are different. Electroplated filled vias involve electroplating copper into the holes through deposition, while copper paste filled vias involve directly filling the holes with copper paste.

Advantages of electroplated filled vias

1. Facilitates the design of stacked vias and vias on pad, increasing substrate density and allowing for the application of packages with more I/O pins.

2. Improves electrical performance, aids in high-frequency design, enhances connection reliability, increases operating frequency, and avoids electromagnetic interference.

3. After electroplating, the vias are filled with copper columns, providing better conductivity than conductive resin/glue, aiding in heat dissipation and improving the thermal performance of the board.

4. Via filling and electrical interconnection are completed in one step, avoiding defects caused by filling with resin or conductive glue, and preventing inconsistencies in CTE (Coefficient of Thermal Expansion) that can occur with other filling materials.

5. Blind vias filled with electroplated copper avoid surface depressions, which is beneficial for the design and fabrication of finer circuits.

Before via filling with copper

After via filling with copper