Issue link: https://iconnect007.uberflip.com/i/1526114
SEPTEMBER 2024 I SMT007 MAGAZINE 59 ple fabricators. In general, for the same design strategy and similar delta copper profiles under the component, the larger the package foot- print, the higher the average coplanarity and the higher variation that was measured. is highlights the need to optimize copper balanc- ing for coplanarity as package size increases. With optimized copper balancing, the copla- narity increased, but the difference between high-flow, mid-flow, and low-flow materials was much lower. is demonstrates that suffi- cient copper balancing can enable the usage of lower flow materials—even with large package footprints. Figure 12 shows the full data set of mea- sured coplanarity across copper balance strat- Figure 10: Coplanarity for 28 x 28 mm package by copper balance strategy, material, and fabricator. Figure 11: Coplanarity difference between higher and lower flow laminates across package size. Figure 12: Measured coplanarity by copper balance strategy and package footprint size.