Another option is to use a combination of blind and buried vias. Blind vias connect either the top or bottom side of the board to inner layers. Buried vias usually connect only the inner layers. Figure 2-7 illustrates this method using 4-mil laser-drilled microvias in the center of the pads and burying the dog bone on layer 2.

Figure 2-7 Buried Vias

Since the buried via does not extend through the underside of the board, the designer can use another set of laser-drilled blind microvias, if needed, to connect the bypass capacitors and other discrete components to the bottom side.

More information on these advanced techniques is available by contacting your local TI field sales office.