The agreement of due dates is the need for customer satisfaction, which is a critical factor to survive in today's highly competitive market for Semiconductor industry. However, undesirable and inevitable production variations make it difficult to maintain and improve factory's performance on due dates, especially for those back-end factories closer to customers. We, therefore, propose a WIP management model to help production managers effectively manage work-in-process (WIP) levels to compensate the impact of unexpected production variations and to achieve better due-date performance. This model includes the exception identification, detection, correction and root cause finding. A software package, Vigilance, is employed to construct real-time WIP exception management system. It is constructed to detect WIP exceptions, notify pertinent recipients and track exception resolution. Simulation experiments are conducted to evaluate the proposed exception management system. WIP correction action curtails the back-to-normal duration and prolongs the duration between two successive WIP exceptions. Therefore it provides better on time delivery and reduces the occurrences of WIP exceptions under proper Acceptable WIP deviation levels (AWDL) settings.