DATA FORMATS
PCB SIZES
SUBSTRATES
HOLES & PADS
TRACKS & GAPS
SOLDER RESIST AND IDENT
ROUTE
ELECTRICAL TEST
SOLDERABLE FINISHES
BLIND AND BURIED VIAS


HOLES AND PADS

Holes and pads – including aspect ratios and plating thickness.

Maximum aspect ratio 15:1
(hole diameter to board thickness)

Example:
1.6mm thick PCB with 0.12mm finished holes = 13.3:1
8.5mm thick PCB with 0.6 Finished hole = 14.2:1
HOLE SIZE / TOLERANCE
MINIMUM FINISHED HOLE SIZE 0.1 mm / 0.004 thou
MAXIMUM DRILLED HOLE SIZE 6.0 mm
DRILLED HOLE DIAMETER TOLERANCE  
UPTO 1.0MM (0.004 THOU) +/- 0.025 mm / 0.001 thou
1.0MM / 0.0004 THOU TO 2.0MM 0.008 THOU +/- 0.038 mm / 0.0015 thou
OVER 2.0MM / 0.008 THOU +/- 0.050 mm / 0.002 thou
DRILLED HOLES POSITIONAL TOLERANCE  
HOLE POSITIONS LOCATED FROM OUTER LAYER ARTWORKS 0.076 mm / 0.003 thou
HOLE POSITION FROM CAD DATA 0.038 mm / 0.0015 thou
PLATED HOLE DIAMETER TOLERANCE  
UPTO 1.0MM 0.004 THOU +/- 0.050 mm / 0.002 thou
1MM / 0.004 TO 2.00MM / 0.008 THOU +/- 0.076 mm / 0.003 thou
OVER 2MM / 0.008 THOU +/- 0.087 mm / 0.0035 thou

Pads / Hole Registration

REGISTRATION TOLERANCE ( PAD / HOLE RATIO )
DRILL POSITION TOLERANCE +/- 0.038 mm / 0.0015 thou
PAD POSITION TOLERANCE +/- 0.025 mm / 0.001 thou
PHOTO LOCATION TOLERANCE +/- 0.076 mm / 0.003 thou
ETCH FACTOR - 0.013 mm / 0.0005 thou
MIN. ANNULAR RING REQUIREMENTS 0.076 mm / 0.003 thou
TOTAL MANUFACTURE TOLERANCE 0.216 mm / 0.0085 thou

Outer layers: Ratio for a hole dia. of 0.1mm would then be 1:1.46, I.e. 1.46mm Pad minimum would be required to give land requirement of 0.076mm.
Inner Layers: Ratio for a hole dia. of 0.1mm would be 1:1.42 to achieve tangency.

Layer to Layer registration is dependant upon the accumulation of: Photo-location tolerance ( +/- 0.076mm ) Hard tooling tolerance ( +/- 0.025mm ) and the deviation due to pressing and etching. Pressing and etching deviations are dependant upon material thickness and copper weight per square metre. As a guide therefore, +/- 0.2mm registration tolerance per pair of layers is the capability.

PLATING THICKNESS CONTROL
PLATING TYPE THICKNESS PLATING ALLOWANCE
GOLD PLATING 2.5 microns +/- 0.25 +0.10mm (0.004 thou)
TIN / LEAD PLATING 7.5 microns +/- 1.0 +0.15mm (0.006 thou)
NICKEL / GOLD PLATING 2.5 microns +/- 0.5 +0.10mm (0.004 thou)
IMMERSION TIN (UNICRON) 1.0 to 1.2 microns +0.10mm (0.004 thou)