Resin Smearing Evaluation Method
Resin Smear is the effect of resin adhering to the inner copper layer in the hole wall.
-
After cross section, the layer is measured (as shown in the figure below) where resin smear is
detected.
The smear value is the ratio (%) based on the width of resin smear to inner layer copper, that
has
adhered to the hole
wall as shown in the figure below.
- If the evaluation using stack drilling has been done, all the panels are measured.
- The maximum smearing points are measured around final hit counts.
Resin smear ratio[%] = B/A x 100 A: Inner copper layer thickness [µm] B: Resin smear width [µm]
