Vertical Dimensional Measurement
Laser triangulation profiling characterizes the topography of holes left by laser ablation or mechanical drilling during circuit board fabrication. This crater depth metrology assesses the distance from the top surface of a copper laminate to the lowest point of an excavated feature. Data gathered through this process confirms the vertical alignment and material removal rate across high density interconnect substrates.
Spatial Verification
High resolution sensors scan across the feature to record a cross sectional profile. Multiple points generate a point cloud that maps the morphology of the floor relative to the surrounding land. Automated analysis software calculates the vertical distance by subtracting the elevation of the base from the reference plane defined by the top copper foil.
This subtraction eliminates errors from board warpage or substrate tilt. Systematic calibration against optical flats ensures that variations in temperature or ambient lighting do not skew the reported values.
Acceptance Parameter
Performance specifications dictate a required depth to maintain proper plating thickness within the base of the feature. Manufacturers target specific tolerances to prevent barrel cracking or bottom copper pull out during thermal cycling. Excessive depth increases the risk of damaging underlying dielectric layers while insufficient depth fails to expose the landing pad for interconnection.
Control of this metric directly stabilizes the reliability of microvia structures under accelerated stress testing.
