Routing a single trace on multiple layers may leave you with unused sections of plated through holes. In high-speed designs, these stubs will cause signal integrity issues. Your manufacturer can remove the stubs to help limit reflection and impedance differences in your designs by back drilling.
Setting up and analyzing back drilling in your designs is easy with the powerful features in Allegro.
Just set up your back drill parameters and clearance in the padstack editor.
You can configure your layers pairs exactly how you want them, or, Allegro can automatically analyze your design and create just the layer pairs you need. Once defined, you can enable and disable layer pairs as needed. Allegro will set a cut to layer that is one layer before the must not cut layer – where your route is – creating a buffer, so your route isn't drilled out.
