Abstract-This work presents a collaborative procedure for multi-objective global routing. Our procedure takes as input multiple global routing solutions, which are generated independently (e.g., by one router that runs in different modes concurrently, or by different routers running in parallel). It then performs multi-objective optimization based on Pareto algebra and quickly generates multiple global routing solutions with a tradeoff between the considered objectives. The user can control the number of generated solutions and the degree of exploring the tradeoff between them by constraining the maximum allowable degradation in each objective. This work then considers the following three multi-objective case studies: minimization of interconnect power and wirelength, minimization of routing congestion and wirelength, and minimization of wirelength with respect to the (finite-capacity) routing resources. The maximum allowable degradation in wirelength is specified in all cases. Our multi-objective procedure runs in only a few minutes for each of the ISPD 2008 benchmarks, even for the unroutable ones, which imposes a tolerable overhead in the design flow. In our simulations, we demonstrate the effectiveness of our procedure using five modern academic global routers.