Semiconductor Lot Scheduling via Dynamic Tool Rescheduling
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Solution Overview
Problem
In semiconductor fabrication, the limited number of specialized fabrication tools can lead to bottlenecks and increased production costs due to idle tools or waiting lots, as the predetermined route for wafer processing is based on the capabilities of specific tools, resulting in reduced throughput and inefficient use of resources.
Innovation Solution
A system that dynamically reschedules the processing route of wafers based on inspection data and release rules, allowing wafers to be transferred to alternative tools with different performance ratings, thereby optimizing tool utilization and throughput by configuring physical or software constraints to enable dispatch to less busy or differently rated tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined route is assigned to wafers based on specific tool capabilities, then product quality is ensured, but tool utilization efficiency deteriorates and production throughput is reduced
Solution Approach 1:
The patent implements dynamic route assignment that adjusts wafer routing in real-time based on tool status, workload, and capability matching. Instead of static predetermined routes, the system continuously evaluates available tools and dynamically assigns wafers to optimize both quality constraints and utilization efficiency, resolving the contradiction between reliable quality assurance and productive throughput.
Solution Approach 2:
The system changes the parameter of route assignment from fixed to variable, allowing multiple possible routes for the same wafer based on real-time conditions. By parameterizing tool selection based on capability matrices, workload metrics, and quality requirements, the system can adapt routing decisions to simultaneously satisfy quality constraints and maximize overall production efficiency.
2Manufacturing precision
If specialized fabrication tools are selected for specific products, then manufacturing precision is maintained, but device complexity increases and flexibility is reduced
Solution Approach 1:
The patent establishes a universal tool capability matrix that maps multiple tools to multiple product types based on their respective capabilities. Instead of dedicating specific tools to specific products, the system identifies which tools can perform which processes for which products, enabling any suitable tool to handle any suitable product. This multi-functionality approach maintains manufacturing precision through capability matching while dramatically increasing production flexibility and reducing device specialization complexity.
3Ease of operation
If the number of selected fabrication tools is limited, then ease of operation is maintained, but productivity is reduced due to idle tools and waiting lots
Solution Approach 1:
The system implements self-service automated routing that eliminates the need for manual intervention in wafer assignment decisions. The automated route assignment algorithm independently evaluates tool capabilities, current workload, and quality requirements to make optimal routing decisions without operator involvement. This maintains operational simplicity by removing complex manual scheduling while simultaneously increasing productivity through efficient utilization of all available tools, preventing both idle tools and waiting lots.
Data Source
AI summary
In the disclosure, a scheduled route of a lot may be rescheduled to another fabrication tool performing the same fabrication processes as to expand the production line and throughput. The controlling method includes at least the following steps. The lot is scheduled with a predetermined route having a plurality of fabrication tools configured to process the lot with a plurality of fabrication processes in a sequence. The lot is monitored as the lot is being processed by the fabrication tools in each of the fabrication processes, and inspection data is generated for each fabrication process. The lot is rescheduled to another fabrication tool outside of the predetermined route for one of the fabrication processes according to a release rule and the inspection data.