Abstract: Techniques for designing integrated circuit (IC) package substrates are provided. One of the provided techniques include routing a first set of interconnects in a first region of an IC package substrate based on a first routing template and routing a second set of interconnects in a second region of the IC package substrate based on a second routing template. The first routing template is associated with output pins on the IC package substrate while the second routing template is associated with interconnects on at least one IC die of the multiple IC dies. In one scenario, the first routing template is a common routing template. As such, when a different IC die is used with an identical, or otherwise similar, IC package substrate, interconnects associated with output pins on that IC package substrate does not need to be rerouted as they may be routed based on the common routing template.