Automated material handling system

Abstract

An automated material handling system includes a plurality of bays, a continuous conveyer and at least one vehicle. Each bay has a plurality of tools and a stocker. The stocker is a rectangular solid having a first long side and a second long side. The first long side equips with a plurality of transferring ports connecting to the tools and the second long side equips with at least one transferring port connecting to the continuous conveyer. The vehicle is guided along the continuous conveyer for handling materials between the stockers.

Description

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to an automated material handling system, and particularly to an automated material handling system that transports materials through a conveyer.

(2) Description of the Prior Art

With continuous advances of manufacturing technologies, the size of materials (such as wafers and glass substrates) produced in the semiconductor or photoelectric industry also increases constantly. Those materials generally are grouped in lots, and each of the lots contains 25 pieces that are loaded in a cassette for transporting. Its weight is too heavy for human to carry. Hence nowadays most plants adopt automated material handling system (AMHS) as the main facility to transport the cassettes.

Refer to FIG. 1 for a conventional single loop AMHS 10. It includes an overhead single loop track 11. Bays 12 of various functions are setup around the tracks 11 according to manufacturing process requirement planning. The track 11 carries a plurality of overhead shutters (OHS) 13, and each holds a cassette. The overhead shutters 13 move in and out of each bay 12 to transport materials. As the materials are transported between the bays 12, it is generally called an Interbay transport system.

Each bay 12 has a stocker 14 and a plurality of tools 15. The tools 15 in the same bay 12 are usually interrelated in the manufacturing process. Hence in the manufacturing process planning, one bay 12 may be seen as a manufacturing unit.

The stocker 14 mainly functions as a transfer station and a buffer zone of material handling between the overhead shutters 13 and the tool 15. The conventional stocker 14 is a rectangular solid having two opposing long sides, and each equips with a plurality of transferring ports 141. It has one short side connecting to the track 11, and a crane in the center to transport materials among the transferring ports 141. The stocker 14 has one or two transferring ports 141a and 141b close to the track 11 to serve as the material transport input and output ports to the overhead shutters 13. The rest transferring ports 141 are connected to the tools 15 and serve as the material transport input and output ports between the tools 15 and the stocker 14.

The conventional single loop automated material handling system provides only one way transport track. Control of vehicles and transport planning are simpler. Thus it is widely used in the industry. However, in practice, there are still many drawbacks, notably:

• • a. Poor transport efficiency: Due to the conventional technique transports only one way, in the event of rework is required in the manufacturing process, the materials have to be moved back to the original bay for processing. But the vehicle cannot be moved backwards directly. It has to continuously travel forwards and finish the entire journey of the track before returning to the original bay to process rework. Hence transport efficiency is undesirable.
  • b. When the conventional technique is adopted for one way interbay transportation of a long distance, the problem of empty vehicles occurs. This problem happens in the plant configuration that requires to set up the bays at a long distance one way. Hence vehicle dispatching has to take into account of the time required to transport the empty vehicles.
  • c. When the conventional technique is adopted for sectional interbay transportation, the system cost is higher. Referring to FIG. 2, for the sectional interbay transportation, the entire transport system is divided into several independent bay areas. Between the independent bay areas, there is no need for material transport. But to facilitate identification, different bays 12 have their numbers suffixed by different English characters. As the conventional single loop handling system 10 has to be a complete system, waste of system investment happens between the independent bay areas (as the areas shown by the broken line).
  • d. The conventional techniques is constrained by the number of the vehicles and cannot provide buffer zones for the working in process (WIP).
  • e. The transport direction of the conventional techniques is fixed, and cannot be altered or provide two-way transport function.

Therefore, it is desirable to provide a smoother and more efficient material handling system that can overcome the disadvantages associated with the conventional automated material handling system.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an automated material handling system to improve material handling efficiency.

It is another object of the present invention to provide an automated material handling system to prevent transport of empty vehicles.

It is yet another object of the present invention to provide an automated material handling system to reduce waste of system investment between independent bay areas when sectional interbay transport is adopted.

It is still another object of the present invention to provide an automated material handling system that provides more buffer zones to hold the materials for WIP.

It is a further object of the present invention to provide an automated material handling system that provides a two-way transport function to make material handling more flexible.

To achieve the foregoing objects, the automated material handling system according to the invention includes a plurality of bays, a continuous conveyer and a plurality of vehicles.

In one aspect, the bays may be arranged in a linear fashion or an annular loop according to manufacturing process planning. Each bay may be a manufacturing unit consisting of a plurality of tools and a stocker. The tools in the same bay generally are interrelated in the manufacturing process of the same manufacturing unit.

In another aspect, the stocker is a rectangular solid having a first long side and a second long side opposing each other that have respectively a plurality of transferring ports. A crane is located between the two sides. The transferring ports on the first long side are connected to the tools to transport materials therebetween. The second long side has at least one transferring port connecting to the conveyer to transport the materials between the vehicles and the transferring port. The crane transports the materials among the transferring ports in the stocker. Hence the stocker may serve as a material transfer station of each bay or a buffer zone.

In yet another aspect of the present invention, the continuous conveyer may be configured in a linear layout or a single loop layout, and adopt an overhead structure to be braced by a ceiling and the second side of the stocker. When the cassettes are carried by the vehicles, each cassette may hold one lot of materials. The vehicles are traveled on the route provided by the continuous conveyer, and the materials are transferred in the stocker of each bay.

The automated material handling system according to the invention includes a first bay and a second bay. The first bay has a first two-way transferring port on a second side of a stocker thereof, and the second bay also has a second two-way transferring port on a second side of a stocker thereof. A continuous conveyer is provided to perform two-way transport between the first and the second two-way transferring ports.

When the manufacturing process of the two bays are identical, the two bays can backup each other during the manufacturing process, and provide buffer zones. In the event that the first bay provides a upstream process and the second bay provides a downstream process, if the materials in the second bay require rework, they may be transported back through the conveyer to the first bay for rework. In addition, to prevent the conveyer from creating errors during the two-way transport, the handling system of the invention further includes a programmable logic controller and an interlock circuit equipment to link the signals of the first bay and the second bay and control the transport direction between the first bay and the second bay.

Another embodiment of the present invention is adopted on sectional interbay material transport. It includes a plurality of independent bay areas, a plurality of sectional conveyers and a plurality of vehicles.

The bay areas in the embodiment set forth above are independent from one another. Each bay area includes at least one bay and one sectional conveyer. Each bay includes a plurality of tools and a stocker. The sectional conveyer is connected to at least one transferring port located on a second side of the stocker to transport materials between the stocker and the vehicles along the travel route of the conveyer.

During material transport in the sectional interbay process, fabrication of the materials is finished in the bat area without the need of transporting to other bay area for processing. Hence the sectional conveyers are independent without connecting to one another. There is no need to set up transport system between the bay areas, thus waste of investment may be avoided. Moreover, since the sectional conveyers are independent, transport direction may be designed individually, either one way or two-way, without the concern of interfering with one another. Hence this embodiment is more flexible in material transport planning.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:

FIG. 1 is a schematic view of a single loop automated material handling system according to the prior art;

FIG. 2 is a schematic view of a sectional Interbay transport according to the prior art;

FIG. 3 is a schematic view of an automated material handling system according to the first embodiment of the present invention;

FIG. 4 is a side view of a stocker according to the first embodiment of the present invention;

FIG. 5 is a schematic view of a conveyer supported by the ceiling and stocker according to the first embodiment of the present invention;

FIG. 6 is a schematic view of the second embodiment of the present invention; and

FIG. 7 is a schematic view of the third embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Refer to FIG. 3 for a first embodiment of the automated material handling system 30 of the present invention. It includes a plurality of bays 31, a continuous conveyer 32 and a plurality of vehicles 33.

In an automated manufacturing process plant, the bays 31 are arranged according to the manufacturing process planning. To facilitate material transport, the bays 31 are generally configured linearly or in an annular loop. Each bay 31 may be seen as a manufacturing unit consisting of a plurality of a plurality of tools 34 and a stocker 35. The tools 34 generally are interrelated in the manufacturing process of the manufacturing unit.

The stocker 35 is a rectangular solid which has a first long side 351 and a second long side 352 that have respectively a plurality of transferring ports 353. The transferring ports 353 may be one way or two-way transferring ports. A crane 36 is located between the two sides. The transferring ports 353 on the first side 351 are connected to the tools 34 for transferring material therebetween. At least one of the transferring ports 353 on the second side 352 is connected to the continuous conveyer 32 to transfer materials between the transferring port 353 and the vehicles 33. The crane 36 transfers the materials among the transferring ports 353. Hence the stocker 35 may serve as a material transfer station in the bay 31. In addition, each transferring port 353 has a plurality of buffer zones 37 laid vertically (referring to FIG. 4) for transferring materials between the transferring ports 353 and the buffer zones 37. Thus the stocker 35 may serve as the material buffer zone of the bay 31 during manufacturing process.

The continuous conveyer 32 may be configured in a linear layout or a single loop layout and connect to the second side 352 of the stocker 35. As the second side 352 is the longer side of the stocker 35, when the continuous conveyer 32 adopts an overhead structure to be braced by a ceiling 4, it can receive more support from the second side 352 (referring to FIG. 5) and has a higher stability. By contrast, if the conveyer 32 is connected to the stocker 35 on the shorter side that provides less bracing area, it receives less bracing support, and the stability of the conveyer 32 also decreases.

When the vehicles 33 are used to carry cassettes, each cassette may hold one lot of materials. The vehicles 33 are traveled on the route provided by the continuous conveyer 32, and the materials are transferred in each bay 31.

Refer to FIG. 6 for a second embodiment of the invention. The automated material handling system 60 includes a first bay 61 and a second bay 62. The first bay 61 has a plurality of first tools 611 and a first stocker 63. The first stocker 63 has a first side 631 and a second side 632 equipping with a first two-way transferring port 64. The second bay 62 also has a plurality of second tools 621 and a second stocker 68. The second stocker 68 has a third side 681 and a fourth side 682 equipping with a second two-way transferring port 69. A continuous conveyer 65 is provided to do two-way transport between the first two-way transferring port 64 and the second two-way transferring ports 69. When the manufacturing process of the two bays 61 and 62 are identical, they can backup each other and provide a buffer zone.

Detailed implementation of the second embodiment is depicted as follow: when production of the first bay 61 reaches its full capacity but the second bay 62 still is idle, the buffered materials in the first bay 61 may be transported through the conveyer 65 between the two bays 61 and 62 to the second bay 62 for processing so that both bays 61 and 62 can achieve optimum production to increase the production efficiency of the whole system. On the contrary, if the second bay 62 reaches full production capacity but the first bay 61 is idle, materials may be transported through the conveyer 65 to the first bay 61 for processing.

The embodiment mentioned above may also be adopted to bays of different manufacturing processes as depicted below. If the first bay 61 provides a upstream process and the second bay 62 provides a downstream process, when the material in the second bay 62 requires rework, the material may be transported by the conveyer 65 to the first bay 61 to do rework. To prevent the conveyer 65 from creating errors during the two-way transport, the handling system of the invention further includes a programmable logic controller (PLC) 66 and an interlock circuit equipment 67 to link the signals of the first bay 61 and the second bay 62 and control the transport direction of the conveyer 65 between the first bay 61 and the second bay 62.

Refer to FIG. 7 for a third embodiment of the invention. It is adopted to a sectional interbay material handling system 70. It includes a plurality of independent bay areas 71a and 71b, a plurality of sectional conveyers 72a and 72b and a plurality of vehicles 73a and 73b.

In the third embodiment, the bay areas 71a and 71b are independent from one another. Each bay area includes at least one bay 71 and a sectional conveyer 72. Each bay 71 includes a plurality of tools 74 and a stocker 75. The sectional conveyer 72 is connected to at least one transferring port 753 located on a second side 752 of the stocker 75. Vehicles 73 are located on the sectional conveyer 72 which provides a travel route to transport materials between the stocker 75 and the vehicles 73.

During material transport of the sectional interbay process, fabrication of the materials is finished in the bat area 71 without the need of transporting to other bay area for processing. The sectional conveyers 72 are independent without connecting to one another. Thus there is no waste of transport system between the bay areas 71. Moreover, since the sectional conveyers 72 are independent, transport direction may be designed individually, either one way or two-way. Hence this embodiment is more flexible in material transport planning than the conventional techniques do.

While the preferred embodiments of the present invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the present invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the present invention.

Claims

1. An automated material handling system, comprising:

a first bay having a first tool and a first stocker, the first stocker having a first side and a second side that have respectively a plurality of first transferring ports, the first tool being connected to the first transferring ports on the first side;

a second bay having a second tool and a second stocker, the second stocker having a third side and a fourth side that have respectively a plurality of second transferring ports, the second tool being connected to the second transferring ports on the third side;

a continuous conveyer connecting at least one of the first transferring ports of the first bay to at least one of the second transferring ports of the second bay; and

at least one vehicle moving along the continuous conveyer for transporting materials between the stockers by the continuous conveyer.

2. The automated material handling system of claim 1, further comprising a crane between the first side and the second side of the first stocker.

3. The automated material handling system of claim 1, wherein the continuous conveyer is an overhead type bracing by a ceiling and the stockers.

4. The automated material handling system of claim 1, wherein the stockers have a plurality of buffer zones located in the vertical direction of the transferring ports.

5. The automated material handling system of claim 1, wherein the first transferring ports of the first bay and the second transferring ports of the second bay are two-way transferring ports.

6. The automated material handling system of claim 1, wherein the the continuous conveyer is a two-way conveyer.

7. The automated material handling system of claim 6, further comprising a control logic, the control logic linking signals of the first bay and the second bay, the interlock circuit equipment controlling transport direction of the conveyer between the first bay and the second bay.

8. The automated material handling system of claim 6, further comprising an interlock circuit equipment, the control logic linking signals of the first bay and the second bay, the interlock circuit equipment controlling transport direction of the conveyer between the first bay and the second bay.

9. A method of transporting materials in an automated material handling system, comprising the steps of:

providing a first bay having a first tool and a first stocker, the first stocker having a first side and a second side that have respectively a plurality of first transporting ports, the first tool being connected to the first transferring port on the first side;

providing a second bay having a second tool and a second stocker, the second stocker having a third side and a fourth side that have respectively a plurality of second transporting ports, the second tool being connected to the second transferring port on the third side;

connecting at least one of the first transferring ports of the first bay to at least one of the second transferring ports of the second bay by a continuous conveyer; and

transporting materials between the stockers by at least one vehicle moving along the continuous conveyer.

10. The method of claim 9, further comprising a step of loading the materials in a cassette before transporting.

11. The method of claim 9, wherein the first transferring ports of the first bay and the second transferring ports of the second bay are two-way transferring ports.

12. The method of claim 11, wherein the first bay provides a upstream manufacturing process, and the second bay provides a downstream manufacturing process, the continuous conveyer transporting the materials in a reverse direction from the second bay to the first bay.