Rensselaer Polytechnic Institute, Troy, NY 12180 As Multichip Modules (MCMs) evolve from niche solutions to necessary ingredients of high performance computing systems, this change must be reflected in the associated CAD tools for MCM system design. Given the transmission velocities of modern thin film substrates, conventional design techniques where chips are developed in isolation from the substrate fall short of producing optimal solutions. Critical to the success of these tools is the ability to influence chip pad placement. Our research indicates that an integrated chip/MCM co-design environment should be established. MCM CAD tools must provide advice for and accommodate an interactive pad migration facility, where chip designers are provided recommended signal pad locations that contribute to the optimization of the overall system.