Modeling Slip Velocity and Pressure Gradients across Smooth Copper Foils
Modelling slip velocity and pressure gradients across smooth copper foils prevents resin starvation and locks dielectric thickness tolerances during lamination.
Ten-Point Height Rz
Peak Parameter
The average distance between the five highest peaks and the five deepest valleys within a sampling length characterizes the extreme features of a surface profile. Using the ten-point height Rz provides a more sensitive measurement of surface spikes and pits than an arithmetic average. This metric is essential in PCB manufacturing for assessing the risk of dielectric breakdown between layers.
A single large copper peak could penetrate a thin prepreg layer even if the average roughness remains low.
Mechanical Interlock
Bonding processes rely on these peak features to create a mechanical connection between the resin and the foil. The ten-point height Rz helps to quantify the effectiveness of the micro-etching chemicals used in multilayer production. If the peaks are too high, they can cause impedance variations or trap air bubbles.
Defect Detection
Inspection of the hole walls after drilling often utilizes this metric to identify gouges or smearing. A high value for the ten-point height Rz indicates that the drill bit is dull or the feed rate is too aggressive. This roughness can prevent the electroless copper from forming a continuous layer, leading to intermittent connections.
Advanced laser scanners provide the data needed to calculate this value without damaging the surface. This measurement ensures that the surface topography is suitable for the subsequent plating and assembly steps.