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AUGUST 2026 I I-CONNECT007 MAGAZINE 77 Process Steps for R-VeCS The R-VeCS uses a router bit to form the various elements of the slot. The flow in Figure 4 shows the process without the side wings, but they are added in the first routing step. After plating and filling, the second rout step is removing part of the plat- ing, creating a shield, and individual contacts. All examples use differential pairs, but a single-ended single-differential is also possible. Having multiple differential pairs in a single slot is also possible, but in high-bandwidth applications, this can create ex- cessive crosstalk, as the electromagnetic wave will travel through the shielded slot to the next pair. The formation of stubless slots, or contacts, will be made using laser ablation, acting as a self-limiting process that stops at a copper surface. The correct layer to stop the mechanical forma- tion can be identified through active feedback from the internal contact method. This saves time in setup and achieves much greater consistency in processing. Optimisation of the TDR Response of the R-VeCS Using Side Wings In Figures 5 and 6, the green line is without the opti- misation, showing a high inductance response due to the half-vias. The blue line is an optimisation after adding extra capacitance across the length of the half-vias. The TDR behaviour is directly improved. The capacitive spike after the half-via is the bounce pad at the bottom of the half-via. There are different ways to eliminate this effect. One option is to make an opening below the bounce pad in the GND plane. Depending on the stripline routing shown below, this can affect crosstalk and imped- Figure 4: Forming the R-VeCS. Figure 3: An R-VeCS using side wing shielding and additional pads for compensation of the inductance effect of the dif- ferential connections.