Quality Verification
IPC-6012 performance standards require dimensional and structural compliance verification for laser-drilled blind interconnects in high-density printed circuit boards. Fabrication quality assurance relies on micro-via inspection to evaluate laser ablation depth and plating target landing accuracy. The inspection process verifies structural connectivity across micro-via structures before outer layer lamination and assembly soldering steps.
Analysis stops at physical structural dimensions, excluding high-frequency signal integrity performance evaluations.
Defect Identification
Optical cross-sectioning and automated line-scan cameras detect target pad off-registration caused by material shrinkage during lamination cycles. Laser ablation debris remaining at the base of blind vias prevents electrodeposited copper from bonding to inner layer capture pads. Micro-voids embedded inside electrolytic copper plating reduce current-carrying capability, accelerating thermal fatigue failure during thermal cycling tests.
Unplated target pad regions create latent electrical opens that escape bare board electrical continuity testing at room temperature.
Acceptance Criterion
Microsections prepared from coupon structures on the panel edge undergo microscopic measurement under high magnification. IPC Class 3 standards require micro-via plating thickness to exceed fifteen micrometers while maintaining target pad contact area across the entire circumference. Dimensional checks verify target pad offset and void area ratios.
Failure to meet minimum plating thickness triggers lot rejection prior to component loading. Systematic micro-via inspection prevents latent interconnect separation in harsh thermal operating environments.
