Surface Leveling
Mechanical abrasive processing of multi-layer printed circuit panels levels protruding copper overburden and cured resin flash flush with surrounding dielectric material. High-density interconnect fabrication applies planarization grinding after copper electroplating or conductive paste filling of blind microvias. Flat panel topographies enable precise photolithographic imaging and uniform dielectric spacing during subsequent layer lamination.
Abrasion Control
Rotating abrasive wheels or belt sanders wet-grind panel surfaces under controlled downforce to remove copper bumps without gouging base laminate material. Controlling slurry chemistry and grit size during planarization grinding prevents mechanical smearing of ductile copper into adjacent dielectric resin pores. Non-uniform grinding pressure across large panel formats causes thickness variations in outer copper foils, affecting controlled etching tolerances.
Optical surface profilometers measure peak-to-valley roughness following grinding to verify readiness for subsequent barrier metal deposition. Over-grinding thins surface copper below design minimums, increasing trace resistance and lowering current-carrying capacity.
Substrate Damage
Excessive mechanical shear force introduces micro-scratches and localized delamination along glass fiber interfaces near the board surface. Incomplete removal of surface copper overburden leaves conductive residue that creates electrical shorts between adjacent dense surface traces. Planarization grinding must maintain surface flatness within three microns across the active image area to meet IPC Class 3 registration limits.
