Optimal allocation of testers to products with a queue time restriction in sort testing

The test of each wafer product in Sort (final IC testing) is done by allocating a tester and an appropriate Sort Interface Unit (SIU) to the product, to perform the test programs over the wafer. This allocation problem is a more complex allocation problem in the presence of a queue time restriction. In this paper, this problem is formulated and solved to determine the optimal allocation of testers and SIU´s to wafer products over a planning horizon, such that overall WIP throughout the planning horizon is minimized. The optimal solution also comprehends restrictions on the amount of wafers that may be shipped to other testing sites and replenishment policies regarding new SIU´s.