Integrated Load Port Buffer for Semiconductor Tool Starvation
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Solution Overview
Problem
Conventional semiconductor manufacturing facilities face inefficiencies due to the need for stockers to buffer FOUPs, which occupy valuable space and can lead to tool starvation, especially in high-throughput environments, as the time to process smaller wafer lots exceeds the transport speed of material transport systems.
Innovation Solution
A load port system that includes two wafer access locations and storage locations, with a transfer module for container buffering and storage near processing tools, allowing direct container transfer between tools and enabling efficient handling of both conventional and small-capacity containers, reducing cycle time and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FOUPs are buffered in local stockers near processing tools, then tool starvation is minimized, but facility floor space is consumed
Solution Approach 1:
The patent combines the load port and stocker functions into a single integrated unit. The load port includes both wafer access locations and storage locations for buffering FOUPs, eliminating the need for separate stockers and reducing facility floor space while preventing tool starvation
Solution Approach 2:
The load port is designed to perform multiple functions: it serves as both a wafer access point and a buffer storage location for FOUPs. This multi-functional design allows the same structure to handle both material transfer and inventory buffering, optimizing space utilization
2Productivity
If lot size of FOUPs is reduced from 25 to 6 wafers, then factory cycle time is improved, but tool starvation increases
Solution Approach 1:
The load port buffers FOUPs in advance before they are needed by the processing tool. By having FOUPs pre-positioned in storage locations within the load port, the system ensures immediate availability of new FOUPs when current ones are completed, preventing tool starvation during reduced lot size operations
Solution Approach 2:
The load port acts as an intermediary buffer between the material transport system and the processing tool. It decouples the tool's processing speed from the transport system's delivery speed, allowing the tool to maintain continuous operation with smaller lot sizes without waiting for FOUP replenishment
3Productivity
If FOUPs are moved directly from tool to tool, then transport moves are reduced and throughput increases, but tools must have buffering capability
Solution Approach 1:
The patent merges the load port and stocker into a single integrated structure that provides buffering capability. This allows FOUPs to be transferred directly between tools through the load port without requiring separate stocker systems, reducing transport moves while maintaining the necessary buffering function
Data Source
AI summary
A system comprising a load port and a transfer module. In one embodiment, the load port includes a plate having a first opening and a second opening, a first workpiece access port, a second workpiece access port and at least one storage location. The storage location(s) may be located either beneath the second workpiece access port or above the first workpiece access port. The transfer mosule, which is located adjacent the load port, includes a load arm for moving the workpiece containers between the first workpiece access port, the second workpiece access port, any of the storage shelves and a material transport system.