JPH01125842A - Device for indexing reference point of transfer boat - Google Patents

Abstract

PURPOSE:To make it possible to index a reference point of a transfer boat with a high accuracy by a method wherein the title device is provided with a detecting mechanism for detecting the position of a specified groove on the side bars of the transfer boat held on a boat receiving stand and a boat receiving stand feed mechanism which is operated according to the undetection of the specified groove. CONSTITUTION:A detecting mechanism 30 mounted to a holder driving unit is placed in the vicinity of a specified groove 6 of a transfer boat 2 lowered on a boat receiving stand 11. In case the mechanism 30 does not detect the specified groove 6, a feed mechanism 19 feeds the stand 11 in the right direction, for example, according to the undetection and the feed operation is continued until the specified groove 6 is detected. Information on the position of the mechanism 30 and the position of the stand 11 at a time when the groove 6 is detected by the mechanism 30 is set as the reference point of the transfer boat and information on this reference point is written in a computer of a transferring machine, for example, and is used as a reference for a wafer transferring operation subsequent to that. In such a way, the reference point of the transfer boat 2 can be calculated by measuring automatically the position of the specified groove.

Description

DETAILED DESCRIPTION OF THE INVENTION Shin-1 The present invention relates to a reference point indexing device for a transfer boat, and more particularly to a reference point indexing device for a transfer boat in a transfer machine that transfers wafers to a transfer boat.

Referring to FIGS. 3 and 4, a transfer boat 2 is used to transfer semiconductor wafers 1 between various stations for processing and the like. The transfer boat 2 has a transverse member 4 that connects two side rods 3 on which the way/~l is placed, and a handle 5 that is gripped by a conveyor (not shown) or the like. Grooves 6 are cut into the side rod 3 at an appropriate pitch P, and the wafer 1 is cut into the grooves 6.
By inserting the wafer into the wafer, it is possible to prevent mutual pressure contact between adjacent wafers 1 during transfer. In order to automate the attachment and detachment of wafers 1 to and from the transfer boat 2, the reference plane 7 and the first
The distance F between the groove 6 and the groove 6 is precisely machined.

At each station, a transfer boat 2 is provided with a transfer machine 10 as shown in FIGS.
(not shown) onto the boat pedestal 11, the transfer machine IO moves the boat pedestal 11 to the transfer position 2t12, the holder 13 is sent to the transfer position 12 by the holder drive device 14, and the holder 13 is The clamping part 15 and IB are the transfer boat 2
The wafers 1 are lowered to the sides of the wafers 1 and then brought close to each other, whereby the wafers 1 are held between the holders 13. After raising the clamping parts 15 and 16, insert the holder 13 into the cassette) 1
? When the wafer 1 is sent to the position shown in FIG.

In this way, the wafer 1 is transferred from the transfer boat 2 to the cassette 17.

In order to transfer the wafers l held in the cassette 17 and subjected to various treatments to the transfer boat 2, the above procedure may be reversed. However, the transfer from the cassette 17 to the holder 13 is performed by a push-up means (not shown).

The wafer 1 has a thickness T (FIG. 3) of about 600 μm, and is very thin and easily damaged, so it must be handled carefully. Since the groove width W (Fig. 3) of yI6 of the transfer boat 2 is approximately 770 μm, the holder 13 is approximately 0.1 mm (g100
If the positioning is not performed with a higher precision than the wafer (μm), the edge of the wafer 1 may hit a portion of the transfer boat 2 other than the groove 6 and be damaged. Furthermore, if the wafers 1 do not fit in the groove 6, there is a strong possibility that adjacent wafers 1 will come into contact with each other and cause scratches on their surfaces, resulting in a fatal problem.

The transfer boat 2 is usually made of quartz due to the need for a dust-free environment and stability against high-temperature processing. It is difficult to precisely process quartz, and there are variations in the reference surface/first groove distance F.
Moreover, when subjected to high temperature processing together with the wafer 1, it is exposed to thermal deformation. Therefore, in order to ensure accuracy higher than the above-mentioned approximately 0.1 mm, conventionally, the reference surface/first groove distance F was measured each time the wafer 1 was transferred and written into a computer, or the distance was manually measured. I was indexing 1 groove and 6.

This has the drawback that not only is the efficiency of the transfer operation low, but there is also a risk of dust generation due to human operations.

Accordingly, the problem to be solved by the present invention is the above-mentioned drawback of the prior art due to variations and fluctuations in the one-groove interval F of the reference surface. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for determining the reference point of a transfer boat by measuring the position of its particular groove.

! 10. Referring to FIGS. 1 and 2, the reference point indexing device of the transfer boat 2 is a specific groove 6 (FIG. 3) in the side rod 3 of the transfer boat 2 held on the boat cradle 11. A configuration is used which includes a detection mechanism 30 that detects the position of the boat cradle feeding mechanism 18 that operates in response to non-detection of the specific groove by the detection mechanism 30.

Referring to FIGS. 5A and 6A, preferably the detection mechanism 30 is provided with a light source 31 and a sensor 32, and the light source 31
The optical path of the luminous flux B from
The reflected light R from the side rod 3 is detected. More preferably, the light source 31 is a laser light source and the luminous flux B is a laser luminous flux.

"Blood" The action will be explained using illustrated examples. As shown in FIG. 2, the transfer boat 2 lowered onto the boat cradle 11J: consists of a stop plate 23 driven by a pneumatic cylinder 21 and a starting plate 25 driven by a pneumatic cylinder 22. It is held by a holding mechanism 18. As shown in FIG. 8, in this case a detection mechanism 30 attached to the holder drive device 14 is placed in the vicinity of the specific groove 6 of the transfer boat 2 lowered onto the boat pedestal 11. Preferably, the groove 6 at the right end of the transfer boat 2 in FIG. 3 is the specific groove, and the initial position of the detection mechanism 30 is slightly to the right of the specific groove 6.

If the detection mechanism 30 does not detect the specific groove 6, the feeding mechanism 18 feeds the boat cradle 11, for example, to the right in FIG. Continue operation. The position of the detection mechanism 30 and the boat cradle 11 when the specific groove 6 is detected by the detection mechanism 30
The information regarding the location of the transfer boat is used as a reference point for the transfer boat. This reference point information is written into a computer (not shown) of the transfer machine 10, for example, and is used as a reference for subsequent wafer transfer operations.

The detection mechanism 30 is composed of a light source 31 and a sensor 32 as shown in FIGS. 5A and 6A.
When the initial position of 0 is slightly to the right of the specific groove 6 in FIG. 3 and the feeding mechanism 19 sends the boat holder 11 to the right in FIG. 3 in response to non-detection of the specific groove 6, the light source 31
The specific groove 6 can be detected when the sensor 32 detects the absence of the reflected light H based on the luminous flux B from the sensor 32 . When there is no wafer 1 in the specific groove 6, the light beam B passes through the groove 6 and there is no reflected light R, and even when there is a wafer 1 in the specific groove 6, there is no reflection from the surface of the quartz transfer boat side rod 3. This is because the reflection from the side surface of the wafer 1 is very small compared to the light R. When the light beam B is a laser beam, the reliability of detection of the specific groove 6 is improved.

Thus, the object of the present invention is achieved by providing a device for determining the reference point of the transfer boat 2 by visual measurement of its particular groove position. At the same time, the above-mentioned drawbacks of the prior art due to variations and fluctuations in the reference surface/first groove distance F are solved.

In the embodiment shown in FIGS. 1 and 2, of the two pneumatic cylinders, the pneumatic cylinder 2 on the side of the reference surface 7 of the transfer boat 2
1 is made larger than the diameter of the opposite pneumatic cylinder 22, and the force acting on the stop plate 23 attached to the pneumatic cylinder 21 is made larger than that of the stop plate 25 of the other pneumatic cylinder 22. Therefore, the stopper 24 fixed to the stop plate 23 always comes into contact with the boat cradle 11, and the stop plate 25
The reference surface 7 is pushed up to the stop plate 23 by the pressure of
The position of the reference surface 7 when the transfer boat 2 is held is constant even if the dimensions of the transfer boat 2 are different.

Further, in this embodiment, the legs 8 of the transfer boat 2 are placed on the movable plate portion 20 with a pole bearing of the boat pedestal 11, so that the transfer boat 2 can be easily moved according to the pressure of the stop plates 23 and 25. When the transfer boat 2 is removed from the boat pedestal 11, the movable pan 20 may be automatically returned to its initial position by suitable restoring means (not shown).

The feed mechanism 19 in the illustrated example includes a feed screw 27 driven by a feed motor 26, preferably a pulse motor, and a feed nut 28 that meshes with the feed screw 27 and is fixed to the boat pedestal 11.

As explained in detail above, the transfer boat reference point indexing device according to the present invention detects the position of a specific groove in the side beam of the transfer boat held on the boat cradle, and uses this to index the reference point. This is used as a reference point.

It has the following effects.

(a) It is possible to determine the transfer boat reference point with high accuracy exceeding 0.1 mm.

(b) Even if there is a manufacturing dimensional error in the first groove interval F of the reference surface of the transfer boat, an accurate reference point can always be determined.

(c) Even if the transfer boat in use is thermally deformed, the reference point indexing accuracy is not affected.

(d) Since the reference point of the transfer boat can be determined unattended, it is suitable for fully automated wafer transfer operations, and dust generation in the clean room can be suppressed.

(E) By using the movable plate portion 20 with a pole bearing, it is possible to prevent errors caused by friction between the legs of the transfer boat and the boat pedestal.

(f) If a laser beam is used as the detection mechanism, the accuracy of the transfer boat base point indexing can be further improved.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a reference point indexing device for a transfer boat according to the present invention, FIGS. 3 and 4 are explanatory diagrams of a transfer boat, and FIGS. 5A, 5B, 6A, and FIG. 6B is an explanatory diagram of the operation of the detection mechanism, and FIGS. 7, 8, and 9 are explanatory diagrams of the transfer machine. 1... Wafer, 2... Transfer boat, 3.
...Side rod, 4...Horizontal member, 5...Handle,
6...Groove. 7...Reference plane, 8...Foot, 10...Movement aa,
11... Boat cradle, 12... Transfer position,
13... Holder, 14... Holder drive device,
15.18... Holding part, 17... Cassette, 1
8... Holding mechanism, 19... Feeding mechanism, 20...
・Movable plate part, 21.22...Pneumatic cylinder, 2
3.25... Stopping plate, 24... Stopper, 26.
...Feed motor, 27...Feed screw, 28...
Feed nut, 30...Detection mechanism, 31...Light source, 32...Sensor, B...Light flux, R...Reflected light. Patent Applicant Okura Electric Co., Ltd. Patent Application Agent Patent Attorney Tsugube Ichi Tore

Claims (3)

[Claims] (1) A detection mechanism that detects the position of a specific groove in a side beam of a transfer boat held on a boat cradle, and a boat cradle feeding mechanism that operates in response to non-detection of the specific groove by the detection mechanism. Reference point indexing device for transfer boat. (2) In the reference point indexing device according to claim 1, there is provided a light source that sends out a light beam to an optical path passing through the specific groove at a position facing the detection mechanism, and a light source that sends out a light beam to an optical path passing through the specific groove, and A reference point indexing device for a transfer boat, wherein the detection mechanism is provided with a sensor for detecting reflected light. (3) The reference point indexing device for a transfer boat according to claim 2, wherein the light source is a laser light source and the light beam is a laser beam.