JPH0425151A - Thin plate carrying device - Google Patents

Abstract

PURPOSE:To enable a thin plate to be accurately detected even if the thin plate is tilted in a carrier by a method wherein a detection beam is tilted to the thin plate. CONSTITUTION:A beam source is previously arranged so as to enable a beam to impinge on the surface of a thin plate 1 forming a certain incident angle with the thin plate 1. For instance, when a beam L is tilted by an angle larger than the angle of inclination + or -alpha of a wafer, the P side edge (hand takeout- intake side) is detected without fail, and moreover the beam L is prevented from being reflected from the underside of the wafer, and even if the beam L is reflected by the upside of the wafer 1, it is shut off by a pinhole 6b as it travels in a direction tilted by an angle of theta+ or -2alpha, Therefore, either the upside or the underside of the thin plate 1 can be detected, so that the accurate height of the thin plate 1 can be detected eliminating the light reflected from the surface of the thin plate 1. By this setup, the mis-detection of the presence and the height of the thin plate can be prevented when the thin plate 1 is tilted inside a carrier.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for loading and unloading thin sheets into and out of a carrier for storing thin sheets, and in particular to a device for semiconductor manufacturing such as a semiconductor printing device and a surface inspection device. The present invention relates to a thin plate loading/unloading device suitable for use in a device to take out a thin plate such as a mask, a resicle, or a semiconductor wafer from a carrier and to store it in the carrier.

[Prior Art] FIGS. 2(a) to 2(C) show an example of a conventional wafer loading/unloading device. In the apparatus shown in the figure, when a predetermined wafer 1 is carried in and out of a carrier 2 containing a plurality of wafers 1 by means of the hunt 3, the procedure is as follows.

A light beam L is incident from the light emitting element 4 parallel to the plane of the wafer 1, and is detected by the light receiving element 5. By driving the carrier 2 up and down by an elevator mechanism (driving unit not shown) 7, the wafer 1 or the beam is intercepted, and a signal as shown in FIG. 2(C) is detected by the light receiving element 5 and stored in a semiconductor memory or the like. be done.

By setting a constant slice level for the signal shown in FIG. 2(C), the position of an arbitrary wafer 1 (height from a predetermined reference position) can be determined. From this position (height) data, the relative position (a, b..., e) of any wafer 1 with respect to the height of the hand 3 is calculated, and by driving the elevator 7, the hand 3 and any wafer 1 are The height was adjusted.

[Invention or problem to be solved] However, the conventional examples have the following drawbacks.

This will be explained using FIGS. 2(b) and 2(C). That is, since the wafer 1 and the beam are arranged in parallel,
When the wafer 1 is tilted by a slight angle α as shown in FIG.
Then, the light is detected by the light receiving element 5. Therefore, only the beam that would normally be blocked by the wafer 1 is detected by the light receiving element 5, resulting in an erroneous detection as if the wafer 1 were not present at that position.

This can be seen in Figure 2 (C). The ideal output signal of the light receiving element 5 when the wafer 1 is only tilted is shown by the solid line.

If the wafer is tilted, the signal will shift as shown by the dotted line. This deviation ic' -C will result in a detection error, and if Hunt 3 is inserted into Carrier 2 according to this detection signal, there is a risk that Hunt 3 or the wafer loaded on Hunt 3 will come into contact with the wafer there. It will come to life.

In addition, if the wafer is tilted, the ``detection conditions'' will vary depending on the position of the edge to be detected. In other words, Fig. 2 (
In b), detection is performed at different positions with respect to the light receiving element 5 depending on whether the beam is blocked by the hunt 3, the edge on the P side being carried in or out, or the edge on the Q side opposite to the edge. If the position of scattering due to the edge is different, there will be a difference in the detected signal, resulting in a detection difference between the P side and the Q side. P
Since it is difficult to determine whether to detect the side or the Q side because it depends on the inclination of the wafer, it cannot be corrected and is a cause of detection errors.

The invention was made in view of the problems in the conventional example described above, and involves storing a plurality of thin plates in a carrier that can hold the plates with their planes facing each other and leaving a predetermined gap between them. In thin plate conveying equipment for loading and unloading,
The purpose is to prevent erroneous detection of the presence or absence and position of a thin plate when the thin plate in the carrier is tilted.

[Means and Operations for Solving the Problems] In order to achieve the above object, the present invention includes means for detecting the position of the thin plate in the carrier, and means for storing and/or storing the thin plate with respect to the carrier number two.
A thin plate loading/unloading device having a loading/unloading stage and an L stage for taking out the thin plate, characterized in that the carrier is arranged so that the incident beam is directed in advance to the surface of the normally stored thin plate. In one embodiment, one of the peeling means for carrying in and out of the thin plate and the edge on the opposite side thereof is detected.

[Function] According to the above configuration, by tilting the incident beam with respect to the surface of the thin plate, it is possible to detect either the upper surface or the lower surface of the thin plate, and the reflected light from the surface of the thin plate is removed to accurately detect the thin plate. It is possible to perform accurate height detection. Furthermore, if one of the edges on the opposite side of the carrying-in/out means is detected, the distance between the beam detection position and the beam interruption position becomes constant, and the detection error of the thin plate position can be reduced.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

First Embodiment FIG. 1(a) lj shows the configuration of a wafer general loading/unloading device according to a first embodiment of the present invention.

In the figure, 1 (A, B, . . . , E) is a wafer to be detected. 2 is a carrier for storing wafers, and is mounted on the elevator 7.

3 is a handle for loading and unloading the wafer 1, 4 is a light emitting element such as a semiconductor laser, and 5 is a light receiving element such as a photo I-sensor. The beam from the light-emitting element 4 is detected by the light-receiving element if the beam is not blocked by the wafer 1. 6a is the beam
It is a bin pole to make the desired diameter. The smaller the beam diameter, the more the detected signal waveform (Figure 1 (C)
)) becomes sharper and the detection accuracy improves. however,
If it is made too small, the amount of light may be insufficient or the beam divergence angle may become large due to diffraction from the pinhole, resulting in a decrease in detection accuracy or inability to detect. Therefore, it is necessary to determine the size of the bin pole 6a by matching it with the size and brightness of the light emitting part of the light emitting element 4, which is the light source. Also, 6
b is a pinhole for blocking scattered light from the wafer edge and the like.

Here, the light emitting element 4, the light receiving element 5 and the bottle hole 6a
As shown in FIG. If α1 is about 20', the slope θ should be 20' and θ<]° (hourly rotation is positive).The Hunt 3 is designed to avoid mechanical interference with the detection system when loading and unloading wafers. , as shown in FIG. 1(a), is located at a position aligned with and shifted from the detection position H.

Now, the height from elevator 7 to each wafer A-E is ax
e (to the bottom surface of the wafer), the driving amount of the elevator from the reference position is X, the height of the detection position H is b, and the distance between the detection position H and the top surface of the hand 3 is expressed as x.

When the elevator 7 is driven from above to below, the lower surface of the wafer A blocks the beam L, and the amount of light received by the sensor 5 becomes smaller. Furthermore, as the electric heater is driven, when the upper surface of the wafer A passes through the beam, the amount of received light increases and returns to the original level. Thereafter, the amount of received light is increased or decreased in the same manner for wafers B to F. FIG. 1(C) shows the output signal with the horizontal axis representing the relative height (h-x) of the detection position H with respect to the drive amount X of the electric motor.

In the apparatus shown in FIG. 1, as mentioned above, by tilting the beam L more than the tilt of the wafer 1 ±α,
The edge on the P side (hunt loading/unloading side) is always detected,
In addition, the beam L is not reflected to the sea urchin from the lower surface, and even if it is reflected from the upper surface of the wafer, it proceeds in a direction inclined by θ±2α and is blocked by the bin pole 61. However, as shown in Figure 1 (
By setting a constant slice level to the output signal of C), the positions a, b, . . . , e to the sea urchin can be determined. Here, a to e represent the heights from the second surface of the elevator to the bottom surface of the elevator. These height data are stored in a memory or the like, and when loading or unloading an arbitrary wafer, for example wafer A, from the reference position b = a-
fl (h-a=x, fl is a V large 1Il (+) between the detection position and the top of the hand, or drives an elevator to align the heights of the top of the hand and the bottom of the hand to the sea urchin.

By aligning the detection beam L with the wafer 1 and tilting the detection beam L as described above, the following effects were obtained.

(1) Even if the wafer is tilted in the carrier 2, it is not affected by reflection from the wafer surface.

(2) The wafer edge on the hunt side and the wafer edge on the opposite side are detected separately.

(3) As a result, detection accuracy has been improved compared to the conventional method.

[Other Embodiments] FIG. 3(a) shows another embodiment of the present invention. The same figure (b
) is a view of the same figure (a) seen from the left side. This device uses detection systems 9A and 9 similar to those in the first embodiment.
There are two lines, B and B, arranged as shown in the figure.

The detection system 9A detects wafers A-E as described in the first embodiment.
The lower surface of the hunt is detected on the hunt loading/unloading side (P side), and the detection system 9B
The upper surfaces of wafers A to E are detected on the P side in a similar manner. With this arrangement, the wafer or carrier 2
wafer holding grooves 8 (8a to 8e) at different levels (for example, across the holding groove 8a on the right side and the holding groove 8b on the left side in the figure).
Even if it is stored, it will be detected, and the space for hand 3 or 1 to enter and exit will be reliably detected. In this way, an operation in which the wafer detection position and the hand 3 loading/unloading position are different can be achieved if the stopping accuracy of the elevator vertical mechanism is sufficiently matched.

[Effects of the Invention] As explained above, according to the present invention, since the detection beam is tilted with respect to the thin plate, even if the thin plate is tilted in the carrier, it will not be affected by the tilt, and the thin plate will not be affected by the tilting in the carrier. Edges and opposite edges can be detected separately. This has resulted in improved detection accuracy.

[Brief explanation of drawings]

FIG. 1(a) is a schematic configuration diagram of a wafer loading/unloading device according to the first embodiment of the present invention, FIG. 1(b) is an enlarged explanatory diagram of the main parts of the device of FIG. 1(a), Figure 1 (C) shows the relationship between the position of the sea urchin in the device shown in Figure 1 (a) and the light beam detection output. Figure 1 (a) of each of the conventional examples
) to (C), and FIGS. 3(a) and 3(b) are a side view and a front view showing a schematic configuration of a wafer loading/unloading device according to a second embodiment of the present invention. AB 2, carrier 3 Hand 4, light emitting element 5 Light receiving element 6a 6b 7・Elevator a8b 9A Bin halter...8 e 9B Detection system wafer 1 wafer holding groove

Claims (2)

[Claims] (1) A thin plate loading/unloading means for storing and/or taking out a plurality of thin plates from a carrier capable of holding a plurality of thin plates with their planes facing each other with a predetermined gap between them; The light emitting means irradiates a light beam in a direction that allows the light beam to pass through the gap, and the light receiving means detects the light that has passed through the gap from the light emitting means. 1. A thin plate loading/unloading device comprising: detection means for non-contact detecting the presence or absence of another thin plate at a position within a carrier to be stored. (2) The thin plate loading/unloading device according to claim 1, wherein the detection means detects an edge of the thin plate on the side of the loading/unloading means or an edge on the opposite side.