PCB Backdrill

Backdrill is the process of creating vias by removing the stub in multilayered printed wiring boards, to allow signals to flow from one layer of the board to another. It is special craftsmanship of control depth drilling.

Advantages:

• Reduced deterministic jitter

• Lower bit error rate (BER)

• Less signal attenuation with improved impedance matching

• Minimal design and layout impact

• Increased channel bandwidth

• Increased data rates

• Reduced EMI/EMC radiation from the stub end

• Reduced excitation of resonance modes

• Reduced via-to-via crosstalk

• Lower costs than sequential laminations

General Characteristics

• Mostly are rigid boards on the back

• Normally used on 8 layers or above

• Board thickness is over 2.5mm

• Minimum hold size is 0.3mm

• Backdrill is 0.2mm larger than the vias

• Tolerance of backdrill depth+/-0.05MM