Abstract:

Cluster tools are widely used as semiconductor manufacturing equipment. In particular, they are suitable for wafer fabrication processes with revisiting process, such as the atomic layer deposition (ALD) process in which the wafers need to visit some processing modules for many times. How to ?nd an ef?cient way for scheduling a multi-cluster tool is critical for productivity improvement and cost reduction.

In this study, we analyze the steady-state throughput and the scheduling of the two-cluster tool with four blades including revisiting process. We consider the case where all wafers follow the same processing ?ow within two cluster tools. The two-cluster tool with four blades including revisiting process problem is decomposed into the two-cluster tool with four blades without revisiting process problem and the single cluster tool with two blades including revisiting process problem.

First, we apply the analyzing method to the single cluster tool with two blades including revisiting process problem. We determine the robot actions in the cluster tool including revisiting process. Based on the result, we build a transformation model of the two-cluster tool with four blades including revisiting process by regarding the consecutive revisiting processing modules as one processing module. Then, we use mixed integer programming method to find the solutions of the robot actions for the transformation model.

Finally, we use simulation system to validate its effectiveness. The result of transformation model of the two-cluster tool with four blades including revisiting process shows that it is the same as the result of the original model of two-cluster tool with four blades including revisiting process by the simulation system in the 1-unit or 2-unit cycle.