A Routing Method based on Nearest Via Assignment for 2-Layer Ball Grid Array Packages

In this paper, we propose a routing method for 2-layer ball grid array packages that generates a routing pattern satisfying the constraint of wire congestions. In the proposed method, the via of a net is restricted to be placed near the ball of the net, and a routing pattern that satisfies the constraints is formulated as a mixed integer programming. In experiments with several data, we obtain a routing pattern that satisfies the constraints of wire congestion within a practical time by using a mixed integer programming solver.

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