Trace Optimization
Route planning techniques that decrease the density of copper lines escaping from fine-pitch ball grid arrays reduce the count of routing layers in a printed circuit board. Implementing escape rate reduction techniques helps board designers route signals from high-pin-count chips using fewer microvias and signal layers. This approach utilizes strategies such as pad-in-via-in-pad, necking down traces, or utilizing zigzag routing paths between solder balls.
It prevents the need for excessive sequential lamination steps and reduces overall board thickness and cost.
Yield Optimization
Manufacturing yield enhancement achieved by maximizing the spacing between traces exiting dense ball grid array footprints prevents short circuits during lamination. Through escape rate reduction, designers widen the gap between adjacent copper traces, which decreases the likelihood of solder bridging or chemical over-etching. This method decreases the density of copper traces in tight areas, resulting in a more uniform distribution of resin and reducing the risk of resin starvation or delamination.
In high-volume manufacturing, it leads to a lower scrap rate and more reliable board assembly.
Layout Density
Interconnection density in modern packages demands structured routing paths that bypass the congestion of inner ball grid array rows. Applying this technique balances the routing channels across different board layers to avoid bottle-necks. It ensures that the copper layout remains within the capabilities of standard trace width and spacing limits.