Issue link: https://resources.pcb.cadence.com/i/1180282
High Density Interconnect Working with HDI October 2019 24 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. Router Interface Full pad definitions pass to the Allegro PCB Router, which cause DRCs within the router application. Drill to Metal DRC Drill hole to metal-based checking covers both holes associated with circuitry (pins and vias) and holes associated with mechanical pins, where the antipad can be used as an implicit route keepout area. Drill holes are commonly referred by their plating category; plated or non-plated. The suite of drill hole checks are based on Allegro PCB Editor pin types (connect and mechanical pins). Typically connect-pin-based holes are plated; mechanical-pin-based holes, non-plated. It is possible, however, to define each type as plated or non-plated. Logic can only be assigned to a connect pin. The term hole is used in the DRC system and Constraint Manager as the drill hole associated with circuit-based pins and vias. Unlike computer-aided-manufacturing checks, where generic PTH to metal checking occurs against minimum constraint values, an integrated CAD system must provide the flexibility to check holes against the diverse set of net-based rules. For example, if the rules for a 60V net to GND via or pin require a 1-mm clearance, this same clearance would be required to the edge of the padless holes associated with these elements. A hole-to-metal check occurs only when the respective hole is void of pads on conducting layers. This can be a result of Null pad entries in the padstack definition or instance or using the dynamic pad suppression. When pads exist on pins and vias, the hole check yields to the conventional pin and via checks. The following example illustrates the potential benefits of drill-based checks. The channel width with pads present restricts the number of lines routed between the pin pads to just one. The removal of used pads, coupled with a hole-to-line space that permits the line to be routed closer to the hole edge but tangent to the annular ring, opens the channel to permit two lines between.