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Direct tool loading

Direct tool loading description/claims

This application is a continuation of U.S. patent application Ser. No. 11/177,645, entitled “Direct Tool Loading”, filed on Jul. 8, 2005, and which is a continuation in-part of U.S. application Ser. No. 11/064,880, entitled “Direct Tool Loading,” filed with the U.S. Patent and Trademark Office on Feb. 24, 2005. Both applications are hereby incorporated by reference.

The present invention generally relates to an automated material handling system (AMHS). More specifically, the present invention comprises a load port having a vertically movable container support structure that is able to load and unload containers directly from a container transport system.

It is costly to deliver containers, such as Front Opening Unified Pods (FOUPs) and Standard Mechanical Interface (SMIF) pods, to processing tools and load ports in a semiconductor fabrication facility. One method of delivering FOUPs or bottom opening containers between processing tools is an overhead transport (OHT) system. The OHT system lowers a FOUP onto the kinematic plate of the load port at approximately 900 mm height from the fabrication facility floor. An OHT system uses sophisticated ceiling mounted tracks and cable hoist vehicles to deliver FOUPs to, for example, a load port of a processing tool. The combination of horizontal moves, cable hoist extensions, and unidirectional operation, must be coordinated for transporting FOUPs quickly between processing tools. A transport vehicle must be available at the instant when a processing tool needs to be loaded or unloaded for best efficiency.

OHT systems are often mounted on portions of a facility ceiling, and therefore, are located above the processing tools and load ports. OHT systems utilize free space in the fabrication facility as the processing tools are typically floor mounted equipment. Ceiling mounted OHT systems must raise or lower a container a substantial distance between the OHT track and, by way of example only, a load port. An OHT system preferably has a very high cleanliness performance because any particles created from moving FOUPs along the track may fall onto the tool areas located underneath and potentially damage wafers.

Rail guided vehicles (RGVs) and automatic guided vehicles (AGVs) are often utilized in semiconductor fabrication facilities to move containers along the facility floor between processing tools. RGV's and AGV's are easier to access for maintenance purposes than an OHT system and are typically less costly than ceiling mounted OHT systems. Particle control is also simplified because particles generated by an RGV or AGV remain below the datum plane of a load port. RGVs and AGVs, however, occupy valuable floor space—which is at a premium in a semiconductor fabrication facility—and pose safety issues (e.g., tool operators and RGV's operate in the same space).

Wafer throughput could be improved in a semiconductor facility by delivering wafers to tools by both a floor-based transport system and an OHT system. For example, an OHT system could deliver the FOUP or bottom opening container to a processing tool while the numerous container deliveries between adjacent processing tools are handled by a floor based transport system. This would be the case, for example, when process tools require that the first wafer of every FOUP be tested on a metrology tool in the bay.

Accordingly, there is a need for an improved container delivery system (for either FOUPs and/or bottom opening containers) in semiconductor fabrication facilities. The present invention provides a container delivery system that reduces the cost of container delivery, increases accuracy of container delivery, simplifies installation and maintenance, improves the cleanliness performance and safety features and reduces delays associated with conventional container transport systems.

One aspect of the present invention is to provide a transport system to move containers efficiently between a tool and a conveyor. In one embodiment, the present invention provides a load port having a vertically movable container support plate. The load port lifts a container, whether it is a front opening or bottom opening container, directly off a conveyor reducing the number of times the container is handled during tool loading.

In one embodiment, systems for loading and unloading semiconductor wafers to and from semiconductor processing or storage equipment are disclosed. One system includes a pair of conveyor rails for transporting a container capable of holding semiconductor wafers around a processing facility. The pair of conveyor rails defining a plane on which the container is supported and transported. The system includes a load port positioned adjacent to the conveyor rails. The load port has a support plate for holding a container and an arm coupled to the support plate. The arm is configured to move between a lower position and an upper position, and the lower position is defined between the pair of conveyor rails and below the plane of the conveyor rails. The upper position is in a load/unload position, and the arm has a bend that enables the support plate to be placed over one of the pair of conveyor rails without requiring a notch in the one conveyor rail.

Another aspect of the present invention is to provide a transport system that complements OHT systems and functions as the primary AMHS for a bay (e.g., row of tools) or for the entire fabrication facility. In one embodiment, the present invention loads/unloads containers from a conveyor that transports containers throughout at least a portion of the fabrication facility. In another embodiment, the support plate comprises a carrier advance plate assembly for moving the support plate horizontally. The conveyor may be mounted to the facility floor, flush with the facility floor, beneath the facility floor or raised above the facility floor. Other embodiments of the present invention are compatible with RGVs, AGVs and person guided vehicles (PGVs) to transport containers throughout the fabrication facility.

Still another aspect of the present invention is to provide a transport and delivery system that is easy to service. OHT systems are located high above the facility floor (e.g., 8-20 ft). Thus, OHT systems are not as easy to access as a floor-based transport system. In one embodiment, a conveyor is mounted to the facility floor. Service personnel can easily access the conveyor for maintenance purposes. The load port is also designed to be removed from the tool and lifted over the conveyor.

Yet another aspect of the present invention is to provide a transport system with inherent safety features. In one embodiment, the present invention includes a safety rail that separates the conveyor from the rest of the facility. The rail provides a barrier to prevent a tool operator from coming into contact with a moving container. Another embodiment of the present invention encloses the conveyor within an isolation tube. The tube prevents a tool operator from coming into contact with a moving container. At the same time, the tube isolates the container or article from the rest of the facility by, for example, having an active air flow system for directing particles generated within the tube away from the article. Floor-based transport systems (e.g., conveyor, RGV, AGV) also eliminate the concern that a container will fall from an OHT system and injure an operator.

Another aspect of the present invention is to provide a floor-based transport and delivery system that occupies a similar or smaller foot print than occupied by a conventional load port and floor-based container transport system (e.g., AGV). In one embodiment, the present invention, which comprises a floor mounted conveyor and a load port, occupies the same footprint typically occupied solely by a conventional load port. In another embodiment, the present invention, which comprises a shuttle and load port, also occupies a small footprint on the facility floor.

Another aspect of the present invention is to provide a container transport and delivery system that improves the cleanliness performance without compromising the integrity of the wafers. In one embodiment, containers are transported along a conveyor that passes below the container plate advance assembly of each load port. Particles generated by this transport system fall to the facility floor or are entrained in laminar flow and do not contaminate wafers being processed by the processing tool. In another embodiment, the load port includes a shroud that partially encloses the opening in the port plate. When a container shell is retained by a mechanism in the shroud, the container shell creates a proximity seal with the shroud and forms a mini-environment within the shroud that is isolated from the facility environment.

Another aspect of the present invention is to provide a transport and delivery system that does not require extensive modifications to the existing process tools, fabrication facility layout or fabrication software in order to run efficiently with existing systems. In one embodiment, the load port secures to the front end of a tool through a BOLTS interface (SEMI Standard E63) or the proposed BOLTS-light standard. The controls, which are typically located in a housing underneath the container plate advance assembly, are relocated inside the load port. Thus, a processing tool does not have to be modified at all to accommodate a load port according to the present invention.

Yet another aspect of the present invention is to provide a load port for bottom opening containers. In one embodiment, the present invention comprises a load port that is able to lift a container directly off a conveyor and remove the container shell so that a wafer handling robot may access the wafer. The load port also provides a mini-environment to isolate the exposed wafer from the facility's ambient environment. The mini-environment, in one embodiment, has a higher pressure than the facility's pressure to encourage air flow from the processing tool (clean environment), through the mini-environment and out into the facility.

• Provisional Patent
• Utility Patent

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