SAFETY SYSTEM FOR OVERHEAD TRANSPORT VEHICLE

• US 20040118980A1
• Filed: 12/19/2002
• Published: 06/24/2004
• Est. Priority Date: 12/19/2002
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Huang, Chien-Jung, Chang, Cheng-Chang, Lin, Li-Ren
• Granted Patent: US 6,779,760 B2
• Time in Patent Office: Days
• US Class Current: 246/1C
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection
• CPC Class Codes: H01L 21/6773 Conveying cassettes, containers or carriers
• CPC Class Codes: H01L 21/67733 Overhead conveying
• CPC Class Codes: H01L 21/67736 Loading to or unloading from a conveyor

Abstract

A safety system for an overhead transport (OHT) vehicle. In one embodiment, the safety system may include a pair of safety panels provided on opposite sides of the load and unload ports on a tool or stocker. An overhead sensor is provided on the OHT and is operably connected to a light curtain on the tool. In the event that the overhead sensor detects an obstruction in the travel path of the OHT during loading of a pod or cassette into the tool or stocker, the light curtain transmits an emergency stop signal to the tool or stocker controller, which terminates further loading operation of the OHT. In another embodiment, the light curtain assumes the look-down sensing function of the overhead sensor in the event that tool components interfere with the look-down function of the overhead sensor.

Claims

1. An overhead transport (OHT) safety system for mounting on a tool and preventing an OHT vehicle from striking an obstruction, comprising:

a light curtain for mounting on the tool;

an OHT overhead transmitter/sensor operably connected to said light curtain for mounting on the OHT vehicle; and

a controller operably connected to said light curtain for connection to the OHT vehicle and receiving an obstruction signal from one of said light curtain and said OHT overhead transmitter/sensor and terminating operation of the OHT vehicle.

2. The OHT safety system of claim 1 wherein said OHT overhead transmitter/sensor is a light-emitting OHT overhead transmitter/sensor.

3. The OHT safety system of claim 1 wherein said OHT overhead transmitter/sensor is a sonic OHT transmitter/sensor.

4. The OHT safety system of claim 1 further comprising an electronic interface operably connected to said controller for receiving said obstruction signal and transmitting an emergency stop signal from said controller to the OHT vehicle.

5. The OHT safety system of claim 4 wherein said OHT overhead transmitter/sensor is a light-emitting OHT overhead transmitter/sensor.

6. The OHT safety system of claim 4 wherein said OHT overhead transmitter/sensor is a sonic OHT transmitter/sensor.

7. The OHT safety system of claim 1 further comprising a pair of safety panels for mounting on the tool in spaced-apart relationship to each other.

8. The OHT safety system of claim 7 wherein said OHT overhead transmitter/sensor is a light-emitting OHT overhead transmitter/sensor.

9. The OHT safety system of claim 7 wherein said OHT overhead transmitter/sensor is a sonic OHT transmitter/sensor.

10. The OHT safety system of claim 7 further comprising an electronic interface operably connected to said controller for receiving said obstruction signal and transmitting an emergency stop signal from said controller to the OHT vehicle.

11. The OHT safety system of claim 10 wherein said OHT overhead transmitter/sensor is a light-emitting OHT overhead transmitter/sensor.

12. The OHT safety system of claim 10 wherein said OHT overhead transmitter/sensor is a sonic OHT transmitter/sensor.

13. An overhead transport (OHT) safety system for mounting on a tool and preventing an OHT vehicle from striking an obstruction, comprising:

a light curtain for mounting on the tool, said light curtain having a light transmitter for transmitting light and a light receiver for receiving the light;

an OHT overhead transmitter/sensor operably connected to said light curtain for mounting on the OHT vehicle; and

a controller operably connected to said light curtain for connection to the OHT vehicle and receiving an obstruction signal from one of said light curtain and said OHT overhead transmitter/sensor and terminating operation of the OHT vehicle.

14. The OHT safety system of claim 13 further comprising a pair of safety panels for mounting on the tool in spaced-apart relationship to each other.

15. The OHT safety system of claim 13 wherein said OHT overhead transmitter/sensor is a light-emitting OHT overhead transmitter/sensor.

16. The OHT safety system of claim 13 wherein said OHT overhead transmitter/sensor is a sonic OHT transmitter/sensor.

17. The OHT safety system of claim 13 further comprising an electronic interface operably connected to said controller for receiving said obstruction signal and transmitting an emergency stop signal from said controller to the OHT vehicle.

18. A method for preventing an overhead transport (OHT) vehicle loading wafers into a tool from striking an obstruction, comprising the steps of:

providing a light curtain on the tool;

providing an OHT overhead transmitter/sensor on the OHT vehicle and operably connecting the OHT overhead transmitter/sensor to said light curtain;

operably connecting a controller to said light curtain and the OHT vehicle; and

transmitting an obstruction signal from one of said light curtain and said OHT overhead transmitter/sensor to said controller and terminating operation of the OHT vehicle by said controller responsive to sensing of the obstruction by said one of said light curtain and said OHT overhead transmitter/sensor.

19. The OHT method of claim 18 further comprising the step of disabling said light curtain and wherein said transmitting an obstruction signal from one of said light curtain and said OHT overhead transmitter/sensor to said controller comprises transmitting said obstruction signal from said OHT overhead transmitter/sensor to said controller.

20. The OHT method of claim 18 further comprising the step of disabling said OHT overhead transmitter/sensor and wherein said transmitting an obstruction signal from one of said light curtain and said OHT overhead transmitter/sensor to said controller comprises transmitting said obstruction signal from said light curtain to said controller.