JPS6238855B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for transporting a wafer, and more particularly to a method for transporting a wafer using a transport belt.

(Prior art) Various processes performed on semiconductor wafers, such as resist coating and exposure in the photolithography process, require different processing apparatuses, so the wafers that have been coated with resist are placed on a conveyor belt and transferred to the exposure apparatus. be transported. Transferring wafers using this conveyor belt method is extremely useful because the movement of wafers can be automated. However, if there is a large difference in the processing capacity of the processing device installed at the front stage of the conveyor belt compared to the processing capacity of the processing device installed at the rear stage (both processing capacities per unit time), for example, there is a 2:1 relationship. However, there is a problem in that wafers that are loaded at a later stage are overloaded.

Conventional techniques for avoiding such inconveniences include, for example, Japanese Utility Model Application Publication No. 51-76372 and Japanese Patent Application Publication No. 55-22832. In all of these, the above-mentioned problems are solved by sorting the objects to be conveyed, which are conveyed in one line, into two lines by a branching or sorting device.

(Problems to be Solved by the Invention) However, these prior art techniques require a special sorting mechanism in addition to the conveyance path, and also require a drive device to drive these sorting mechanisms. Exposure in the manufacturing process of semiconductor devices, especially photolithography process,
When transporting wafers to the developing device, dust is extremely difficult to handle, and smooth transport must be maintained to minimize changes in the resist over time, so a simpler transport method is required that causes fewer transport problems. However, it is still not satisfactory.

(Means for Solving the Problem) The present invention configures a substantially Y-shaped branch transport path with three transport belts for transporting wafers, and controls the rotation direction of the drive device for the transport belts. This is a method of changing the transfer direction of wafers on a branch conveyance path. Specifically, the wafer transferred to the branch conveyance path by rotation of the first conveyance belt is transferred onto a second or third conveyance belt. In this method, one of the second and third conveyor belts is rotated in the same direction as the first conveyor belt, and the other is rotated in the opposite direction.

(Function) The transfer belt on the transfer side rotates in the same direction as the transfer direction on the almost Y-shaped branch transfer path, and the transfer belt on the non-transfer side rotates in the opposite direction, so the non-transfer side pushes the wafer toward the transfer side. This acts to prevent wafers from stagnation on the branch transport path.

(Embodiment) FIG. 1 is a schematic plan view of an embodiment apparatus employing the method of the present invention, in which 1 is a wafer, 2 to 6 are conveyor belts (hereinafter sometimes simply referred to as belts),
Reference numeral 7 represents an inner guide, 8 to 12 represent sensors for detecting the arrival of a wafer, and 13 and 14 represent outer guides. Further, the arrow indicates the direction in which the wafer is transferred to the branch transport path section A. Each of the belts 2 to 6 rotates in the forward or reverse direction independently or in conjunction with a certain portion of the belt, thereby rotating the wafer 1.
is loaded on this rubber belt and transported. Preferably, they are all installed at approximately the same height. Furthermore, since the inner guide 7 and outer guides 13 and 14 are guides for the transfer path of the wafer 1, they form walls that are higher than the height of the conveyor belts 2 to 6 plus the thickness of the wafer 1.
Further, the forward rotation described in the present invention is assumed to be right rotation throughout the specification.

Now, the wafer transport method of the present invention will be explained in detail with reference to FIG.
When the wafer 1 is transported from the processing device A by the normal rotation of the transport belt 2, the sensor 8 detects the arrival of the wafer 1, and the belt rotation (not shown) determines whether the wafer 1 is to be supplied to either the subsequent device B or C at the branching point. A control device determines the direction of rotation of the belt. For example, when loading the wafer 1 into the subsequent processing device B, the belt rotation control device operated by the detection signal of the sensor 8
Belts 3 and 5 are rotated in the forward direction, and belt 4 is rotated in the reverse direction. Then wafer 1 is transferred from belt 2 to wafer 3.
Then, it moves on the belt 5 and is input (carried in) to the device B. When the wafers 1 are continuously conveyed on the belt 2 at certain intervals, the sensor 8 detects the wafers 1 that arrive one after another, and the sensor 9 detects the wafers 1.
The arrival signal is sent to the belt rotation control device, and in order to load the next wafer 1 into the apparatus C, the belts 4 and 6 are rotated in the forward direction and the belt 3 is rotated in the reverse direction. If the interval between the wafers 1 conveyed on the belt 2 is long enough for the wafers 1 to pass through the sensor 8 and be input into the subsequent processing device B or C, then the sensor 9 or 1
0 is not necessarily required. In other words, the belts 3 and 4 may be rotated alternately from forward to reverse and from reverse to forward based on the passing signal from sensor 8. However, it must be noted that the conveyor belts 3 and 4 must always be rotated in an opposite relationship. That is, when transferring the wafer 1 from the belt 2 to the belt 3 or 4, the wafer 1 often stagnates at the branching point and is not transferred to the belt 3 or 4. Either one of the belts 3 or 4 rotates in the opposite direction to the conveyance direction in either the subsequent device B or C. For example, when conveying to device B, it is the device C that rotates in the opposite direction to the conveying direction.
This is to prevent the wafer from entering by reverse rotation and to send the wafer 1 to the conveyor belt 3 for conveying it in the direction of the apparatus B.

In addition, in this embodiment device, the conveyor belt 2,
By rotating 3, 4, 5 and 6 in the opposite direction, device B
The present invention can also be used in such cases, since it is possible to ensure a stable supply of the wafers 1 carried out from the devices B and C to the device A, which has a processing capacity equal to the total processing capacity of the two devices B and C. be able to. In this case as well, belts 3 and 4 must of course be rotated in opposite directions. Then, the conveyance of the wafer 1 is controlled by the rotation of the belts 5 and 6 based on the signals detected by the sensors 11 and 12 so that the wafers 10 carried out from the apparatuses B and C do not collide with each other at the confluence part (the branch part in the above example). It can be controlled by

Since the rotations of the conveyor belts 3 and 4 are always reversed and synchronous, it is also possible to install two drive sources, for example, two motors, and rotate them synchronously. As shown, a combination of one motor 13, a pulley 14, and a chain 15 may be used. Note that the arrow in FIG. 2 indicates the direction of rotation.

(Effects of the Invention) As described above, the present invention provides a method for transferring wafers when the wafer transfer path is branched into two during wafer transfer using a transfer belt system that connects processing equipment that performs various processes on semiconductor wafers. In addition to the first major effect of being able to convey smoothly without stagnation at the branching section, there is also an imbalance in processing capacity per unit time between the processing equipment installed at the front stage of this transport path and the processing equipment installed at the latter stage. , it is possible to correct unevenness in conveyance amount due to batch processing (collective processing) and individual processing, etc., and when adopted in this type of system, it exhibits outstanding effects. In addition, the method of the present invention allows wafers to be transferred in a branched manner only by controlling the rotational direction of the transfer belt, and therefore can be implemented with a simple device that does not require a particular sorting mechanism.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of an embodiment of an apparatus employing the method of the invention, and FIG. 2 is an explanatory diagram of the conveyor belt drive method of the invention. 1...Wafer, 2-6...Transport belt, 7...
Inner guide, 8 to 12... Sensor, 13, 14...
...Outer guide, A, B, C... Processing device, I...
Branch conveyance path section.

Claims (1)

[Claims] 1 A first, second, and third conveyor belt form a substantially Y-shaped branch conveyor path, and a semiconductor wafer is placed on the first conveyor belt and is transferred by the movement of the conveyor belt. in the wafer transport method, in which the wafer is transferred to one of the second and third transport belts on the branch transport path,
The wafers on the first conveyor belt are rotated in the same direction by rotating one of the conveyor belts in the same direction as the first conveyor belt and the other in the opposite direction. A method of transporting a wafer, the method comprising transporting a wafer to either one of a rotating second or third transport belt.