Incoming Work-In-Progress Prediction in Semiconductor Fabrication Foundry Using Long Short-Term Memory

Table 1

Existing statistical WIP forecasting steps.

Step	Description
1	Given the process flow name of product is , retrieve all process steps for
2	For each process step in , get the turn-around-time of , ; this value is predefined in the manufacturing execution system (MES) of the fab.
3	Let denotes the total photolithography layers in , denotes the number of photolithography layers in completed per day, the day-per-mask-layer (DPML) committed for , is denoted as; denotes the total turn-around-time (TAT) for , denoted as; The run rate for , is
4	Cycle time (CT) for a process step , is
5	For each lot, sum the next steps of until the CT reaches 24 hours. The last would be the forecasted destination step of the lot after 24 hours
6	To forecast the destination step of the lot for the next day, sum the next steps of until the CT reaches hours. The last would be the forecasted destination step of the lot for the next day