Linear Tool Vacuum Process Device Wafer Transport Control
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Solution Overview
Problem
Existing semiconductor process devices face productivity decreases due to unstable process times, where a wafer planned for one process chamber cannot be transported as scheduled, blocking the transport path for another chamber, even with rescheduling and temporary evacuation methods.
Innovation Solution
Implementing a linear tool type semiconductor process device with units that restrict the number of unprocessed wafers per process chamber, using wafer holding mechanisms in load locks and buffer rooms, and dynamically managing reservations to prevent path blocking, allowing flexible operation conditions based on process steps and chamber availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wafer is transported to a process chamber based on a predetermined schedule, then productivity is improved under stable process conditions, but productivity decreases when process time becomes unstable and blocks transport paths
Solution Approach 1:
The transport schedule is changed from a static predetermined plan to a dynamic rescheduling system that adapts to actual process completion times. The control unit continuously monitors process chamber status and adjusts transport timing in real-time, allowing the system to handle variable process durations without blocking transport paths or reducing productivity
Solution Approach 2:
The system implements a feedback mechanism where the control unit receives status information from process chambers about actual process completion times, compares this with the scheduled transport plan, and automatically reschedules transport operations when deviations are detected. This closed-loop control ensures productivity is maintained despite process time variability
2Productivity
If the number of unprocessed wafers in each process chamber is restricted, then transport path blocking is prevented and throughput is improved, but device complexity increases due to reservation management systems
Solution Approach 1:
The control unit performs multiple functions: it manages transport scheduling, monitors process chamber status, tracks wafer positions, handles rescheduling decisions, and maintains reservation records. By consolidating these diverse functions into a single control system, the patent avoids the need for separate complex management mechanisms for each function, thereby limiting the increase in overall device complexity while achieving improved throughput
Data Source
AI summary
An efficient method of controlling transportation in a linear tool type vacuum process device in a state that a length of time required for a process is not stable. For each process chamber, the number of unprocessed wafers that are in process or are being transported to the process chamber is counted, and in deciding a transport destination of a wafer, when the number of unprocessed wafers is equal to or larger than a charge limit amount, a transport destination of a wafer is decided excluding the process chamber. Also, a wafer holding mechanism on a transport path to a process chamber is reserved, and a transport destination of a processed member to be transported next is decided according to a status of reservation.