JPS6210999Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the transportation of a thin plate-shaped workpiece (hereinafter referred to as a wafer) such as a silicon wafer, and more specifically, the invention relates to a wafer transportation path of a wafer cassette containing a large number of wafers. The present invention relates to a positioning detection device for.

Normally, wafers are stored and handled in wafer cassettes, and for example, wafers are taken out one by one from the wafer cassette and transferred to various wafer processing devices (hereinafter referred to as processing devices) such as resist coaters and developing machines. It is transported to a processing station and subjected to predetermined processing. This method of taking out wafers from a wafer cassette is as shown in the first figure, in which a wafer cassette 1 is placed on an elevator table 2 that can be moved up and down on a wafer transport path, and a wafer is formed in the wafer cassette 1 by a transport belt 4 or the like. By sequentially lowering the elevator table 2 at predetermined pitches while driving the conveyor belt 4 on the wafer conveyance path, the wafers 3 stored in the wafer cassette 1 are sequentially taken out onto the conveyor belt 4, starting from the lowest wafer 3. . The wafers 3 that have undergone predetermined processing are stored in the wafer cassette 1 by raising the elevator table 2 sequentially at predetermined pitches, contrary to the above-mentioned unloading method.

When processing a large number of wafers 3 in succession, for example, as shown in FIG. 2, a large number of wafer cassettes 1 ₁ , 1 ₂ , . . . , 1 _o are moved to separate elevator tables 2 ₁ , 2 ₂ , . ...2 _o , and as described above, when all the wafers 3 stored in the first wafer cassette ₁₁ have been removed, they are then stored in the second wafer cassette ₁₂ . The wafers 3 in the wafer cassette 1 are sequentially taken out and conveyed by passing under the empty first wafer cassette ₁₁ , and subsequent wafers in the wafer cassette _1o are conveyed in the same manner. It's becoming like that.

In this way, the wafer cassette 1 is transferred to the conveyor belt 4.
The wafer cassette 1 is placed on the elevator table 2 in order to take out and store the wafers 3 from the wafer cassette 1 by moving the wafer cassette 1 up and down at a predetermined pitch with respect to the wafer transport path formed by the elevator table 2, etc. When placing it, it is necessary to place it correctly in a predetermined position. Otherwise, the position of not only the wafer cassette 1 but also the wafer 3 with respect to the conveyor belt 4 will shift, and not only will the wafer 3 not be taken out and stored smoothly, but the wafer 3 may be damaged. For this reason, a device (hereinafter referred to as a wafer cassette positioning detection device) for detecting whether or not the wafer cassette 1 is correctly placed on the elevator table 2 at a predetermined position has been added to the above-mentioned wafer transfer device. ing.

However, as shown in FIG. 3, the conventional wafer cassette positioning detection device has a sensor such as a switch 5 embedded in the elevator table 2, and when the wafer cassette 1 is placed, the contact 6 of the switch 5 is pressed. Since the switch 5 is configured to detect whether or not it has been correctly placed at a predetermined position, the lead wire 7 of the switch 5 may become twisted as the elevator table 2 moves up and down, and if used for a long time, the lead wire 7 may become twisted. The problem was that the wire could break inside the sheath. In order to eliminate this drawback, the light emitting element and the light receiving element are installed on the main body frame outside the elevator table so as to face each other with the wafer cassette 1 in between, and when the wafer cassette is placed on the elevator table, the wafer cassette is separated from the light emitting element. A device has been proposed that detects by blocking the light beam reaching the light receiving element, but a wafer cassette positioning detection device with such a configuration does not detect the light emitting element even if the wafer cassette is placed at a position slightly deviated from the predetermined position. If there is a wafer cassette in the optical path from the wafer cassette to the photodetector, it will operate in the same way as if it were placed correctly, making it difficult to accurately detect whether the wafer cassette is placed in the correct position. Also, since it would operate even if something else accidentally blocked the light, there was a risk of malfunction.

The present invention eliminates all of the drawbacks of the conventional wafer cassette positioning detection device described above, is durable for long-term use, and provides a wafer cassette positioning detection device that accurately detects that the wafer cassette is correctly placed at a predetermined position on the elevator table. The purpose is to provide an apparatus, which will be described below with reference to the drawings.

FIG. 4 shows an exploded view of one embodiment of the apparatus according to the present invention, in which figure a shows the exploded view when the wafer cassette 1 is mounted, and figure b shows the state where the wafer cassette 1 is not mounted. A pair of guides 9, 9 for positioning the wafer cassette 1 is fixedly installed on the elevator table 8 at the position where the wafer cassette 1 is placed. Groove-shaped recessed part 1 for fitting
1 is formed. In addition, these guides 9, 9
A deep notch 12 is formed in the elevator table 8 in correspondence with the recess 11 . A detection lever 14 rotatably supported by a shaft 13 fixed to the side surface of the notch 12 is provided inside the notch 12.
is pivotally supported with one end protruding into the recessed part 11 and the other end protruding outside the elevator table 8, and a light shielding plate 15 is fixed to its tip. Further, a light emitting element 16 and a light receiving element 17 are installed on the main body frame 19 outside the elevator table 8 so as to face each other with the light shielding plate 15 interposed therebetween when positioning the wafer cassette 1. Therefore, the wafer cassette 1 is moved to the elevator table 8.
When the wafer cassette 1 is placed correctly in the predetermined position, the support 10 at the bottom of the wafer cassette 1 will fit into the recess 11 of the guides 9, 9.
, one end of the detection lever 14 that had been protruding inside the recessed part 11 is pressed downward by the support 10, and as a result, the detection lever 14 rotates and the other end rises, causing the light shielding plate 15 to emit light. The light flux from the element 16 to the light receiving element 17 is blocked, and it is detected that the wafer cassette 1 is correctly placed at a predetermined position on the elevator table 8. Note that once the wafer cassette 1 is placed on the elevator table 8, its position will not shift until it is removed from the elevator table 8, so it is necessary to check only when the wafer cassette 1 is placed to see if it has been correctly placed in the predetermined position. As long as it can be detected. Therefore, as the elevator table 8 moves up and down after the wafer cassette 1 is placed, the light shielding plate 15 may be removed from the optical path of the light emitting element 16 and the light receiving element 17. Further, the device shown in the fourth figure is only one embodiment of the present invention, and the present invention is not limited thereto. For example, the light beam can be directly detected at the end of the detection lever 14 without using the light shielding plate 15. Alternatively, switching means such as a micro switch may be used as described below.

In FIG. 5, a micro switch 20 installed on the main body frame 19 outside the elevator table 8 is used as a means for detecting the rotation of the detection lever 14.
FIG. 5A is an assembled view showing a state in which the wafer cassette 1 is placed on the elevator table 8, and FIG. 1B shows a state in which the wafer cassette 1 is not placed. In this embodiment, when the wafer cassette 1 is placed at a predetermined position on the elevator table 8, the detection lever 1 is activated as shown in FIG. 5a.
One end of the wafer cassette 4 comes into contact with the contact 21 of the microswitch 20 to detect that the wafer cassette 1 is placed in the correct position.

Further, as an embodiment of the device according to the present invention, as shown in the assembly diagram of FIG. 6a and the same FIG.
may be configured. In other words, the detection lever 2
2, one end of which is loosely fitted into a small hole drilled in a predetermined portion of the elevator table 24, and is urged by a coil spring 23 to protrude into the recessed part 11 formed by the guides 9, 9. The other end protrudes outside the elevator table 24, and when the wafer cassette 1 is correctly placed on the elevator table 24, the support 10 at the bottom of the wafer cassette 1 presses one end of the detection lever 22 against the coil spring 23. By pressing down the end, the detection lever 22
The entire body is lowered, and a light shielding plate 15 fixed to the other end blocks the light flux from the light emitting element 16 to the light receiving element 17.
It is designed to detect that the wafer cassette 1 has been placed correctly.

As described above, the apparatus according to the present invention detects a wafer fitted into the groove-shaped recess 11 formed by the guides 9, 9 using the detection lever having one end protruding from the groove-shaped recess 11. Since the pillar 10 at the bottom of the cassette 1 is detected, the positioning accuracy of the wafer cassette 1 with respect to the elevator table is better than that of conventional wafer cassette positioning detection devices, and the detection results are highly reliable. Moreover, in the device according to the present invention, the detection means consisting of a combination of a light emitting element 16 and a light receiving element 17 or a switching means such as a micro switch 20 is installed on the main body frame 19 outside the elevator table. Despite its simple structure, it has excellent effects such as the lead wires of the detection means are not damaged due to vertical movement and can withstand long-term use.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a general example, FIG. 2 is a side view of a general example in which wafers are continuously transferred from a large number of wafer cassettes, and FIG. 3 is a perspective view of a conventional wafer cassette positioning detection device. 4a is an exploded perspective view of the first embodiment of the wafer cassette positioning detection device according to the present invention, FIG. 4b is a perspective view of the wafer cassette in FIG. 4a with the wafer cassette removed, and FIG. FIG. 5b is an exploded perspective view of the embodiment of FIG. 5a.
FIG. 6a is an exploded perspective view of the third embodiment, and FIG. 6b is a sectional view taken along line A to A in FIG. 6a. 2, 8, 24...Elevator table, 4...
...Conveyor belt, 9...Guide, 10...Strut, 1
1... recessed part, 12... notch part, 13... shaft, 1
4, 22...detection lever, 15...shading plate.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) An elevator table that moves up and down at a predetermined pitch relative to the wafer transport path and that has a recess formed in its upper surface into which the lower part of the wafer cassette fits; a detection lever that has one end protruding into the recess and whose other end that protrudes outside the elevator table is displaced in accordance with the displacement of the protruding end; A wafer cassette positioning detection device comprising means for detecting displacement of a protruding end of a detection lever to the outside of an elevator table. (2) One end is made to protrude into a recess formed on the top surface of the elevator table, and the other end is made to protrude outside the elevator table, and the key point is the side surface of a notch formed in the elevator table corresponding to the recess. The wafer cassette positioning detection device according to claim 1, which is a detection lever rotatably pivoted on the wafer cassette. (3) one end is made to protrude into a recess formed on the top surface of the elevator table through a small hole provided in the elevator table, and attached to the elevator table by applying a biasing means in the direction of the protrusion; The wafer cassette positioning detection device according to claim 1, which is a detection lever whose other end protrudes outside the elevator table. (4) The wafer cassette positioning detection according to claim 1, wherein the means for detecting the displacement of the detection lever is composed of a light emitting element and a light receiving element facing each other with a part of the detection lever interposed therebetween. Device. (5) The first claim for utility model registration is that the means for detecting the displacement of the detection lever is a micro switch.
The wafer cassette positioning detection device described in .