This paper considers the workforce assignment problem to minimize both the deviations of workloads assigned to workers and to maximize the total preference between each worker and each machine. Because of the high expense of technology education and the difficulties of firing employees, there is no part time workers in semiconductor industry. Therefore, multi-skilled workers are trained for performing various operations in several machines. The bicriteria workforce assignment problem in this paper is not easy to obtain the optimal solution considering the aisle structure and it is belong to NP-class. The proposed heuristic algorithms are developed based on the combination of spacefilling curve technique, simulated annealing technique and graph theory focusing on the multiple-row machine layout. Examples are presented for the proposed algorithms how to find a good solution.