PCB Drilling

Microvia Formation: When to Drill, When to Blast
Best-practice methods for PCB via fabrication are as varied as the definition of the microvia. All things considered, the best practice is tohan-solo-microvia-drill consult the design rules when determining each via type’s optimal drilling method. 

While there is no set definition for microvia, the industry primarily considers these to be drilled holes with diameters of 0.012” or less.

Moreover, there are three primary subsets of this term in PCB designs:

Through via
Traverses from top layer to bottom layer

Blind via
Starts at outer layer and ends at inner one

Buried via
Begins and ends at inner layers only (not visible from exterior)
Because they use very similar mechanical drilling processes, through and buried vias are simpler to fabricate as they utilize mechanical drilling.

Microvia Circuit Boards