Issue link: https://iconnect007.uberflip.com/i/1524164
JULY 2024 I PCB007 MAGAZINE 89 BGA breakout microvias together, many additional routing channels are opened up. is allows many more traces for the breakout that could not be achieved with the conventional N-S-E-W dog-bone breakout structure and with only two laminations. is is coupled with the ground plane moved to the surface for improved return paths. Complex and high-density BGA can be connected with very few build-up layers, increasing reliability and ease of construction (Figure 6). Vertical Conductive Structures (VeCS) VeCS was developed by NextGIn Technologies from the Nether- lands in 2017. e innovative, true 3D structure provides for vertical layer connections to layers with- out sequential lamination by using routed trenches. e trenches are made during drilling with new, special drill/router bits produced at various controlled depths. e trenches allow metallization and plating, as seen in Figures 1 and 7a. Figure 4: Trying various stackups for the HDI construction allows the use of UHDI geometries, especially if controlled impedance transmission lines are important, as the dielectrics will be thin. Using horizontal/verti- cal routing pairs with microvia connections will provide the best signal-integrity performance. Figure 5: Top and side view of swing microvias showing the increased routing and break-out density available by creating routing boulevards. Figure 6: Examples of swing microvias used for a fine-pitch, com- plex BGA breakout where the GND return path is merged with the SMT land patterns to provide for higher density and improved signal integrity.