Incremental placement or ECO placement is a new field in VLSI layout to meet the demand of high performance design.It detects illegal cell positions and moves cells locally to find a feasible placement solution.This paper proposes an incremental placement algorithm for standard-cell design mode.It adopts row partitioning to cope with various placement constraints

and then inserts trouble cells one by one.An integer programming (IP) problem is constructed and solved to get the best solution of cell insertion.A dual diagonal searching (DDS) method is proposed to solve this special IP problem.We prove that DDS can always be the best solution and its time complexity is

O(n

).Experiments on a group of industrial test cases show that our algorithm is efficient and robust.It runs 10 times faster than a simple heuristic method and reduces more than 20 percent placement modification in ave

rage.