JPH0652753B2 - Substrate loading / unloading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a substrate loading / unloading apparatus.

Generally, a carrier that stores a large number of wafers is installed in an apparatus that processes or measures wafers. The wafer is supplied from the carrier to the processing or measurement section of the apparatus, and after the processing or measurement is completed there, the wafer is stored again in the carrier and the carrier is passed to the next step.

A belt conveyor type transfer device or a hand type transfer device is used to carry out a wafer from a carrier or carry it into a carrier. The present invention relates to a substrate loading / unloading device in which a hand-type transport device is used.

[Prior Art] In order to take out a wafer at a desired position from a large number of wafers stored in a carrier, a hand-type transfer device must be inserted between adjacent wafers without bringing fingers into contact with the adjacent wafers. Therefore, it is necessary to accurately detect the position of the wafer. For this reason, the wafer handler incorporates a wafer position detection mechanism. FIG. 3 shows a conventional hand-type transfer device in which a wafer position detecting device is incorporated in a wafer handler.

In FIG, 1 is a laser light source, 2 a laser beam, a mirror 4, the finger 5, the carrier 6, 7 wafers, 8 glass rod ₈₁ and the photosensor _82; sensor consisting of _{8 3} which, 10; 12 Is a hand arm, 11 and 13 are axes, 15 is a hand arm extension / contraction drive unit, 16 is a handler rotating mechanism, and 17 is a handler lifting mechanism.

A large number of wafers 7 are stored in the cassette 6. In order to insert the finger 5 between the desired wafer to be carried out and the adjacent wafer, it is necessary to accurately detect the position of the wafer. Therefore, a wafer position detection mechanism is incorporated in the wafer handler for use. The basic structure of the wafer position detection mechanism is a laser source 1, a glass rod 8 ₁ arranged on the back side of the cassette 6, and a mirror 4 for emitting a laser 2 emitted from the laser source 1 toward the glass rod 8 _1. And a photo sensor 8 ₂ ; 8 ₃ for detecting the laser incident on the glass rod.

If the wafer handler in this configuration is tentatively moved from top to bottom in its moving distance, the laser beam 2 if the wafer is present not enter the rod ₈₁ so intercepted by the wafer, the photosensor 8 _2; 8 ₃ Does not detect light. If there is no wafer, photo sensor 8 ₂ ; 8 ₃ is rod 8 ₁
The light incident on is detected. Therefore, the position where the detection light is the least is the center position of the wafer.

As described above, the conventional position detection mechanism checks the presence or absence of the wafer by relatively changing the vertical distance between the wafer and the wafer position detection mechanism. However, the mechanism for accurately performing the relative movement between the wafer and the wafer position detection mechanism must have a complicated configuration.

[Problems to be Solved by the Invention and Solving Means] An object of the present invention is to provide a substrate loading / unloading apparatus that uses a hand-type transporting position to ensure accurate loading / unloading of substrates such as wafers with a simple configuration. It is to be.

In order to achieve this object, the substrate loading / unloading apparatus of the present invention is used for accommodating a substrate in a cassette or for ejecting a substrate from the cassette, and for injecting the finger into or out of the cassette. A hand mechanism, a light source for generating a light beam emitted along the fingers, and an optical sensor for detecting the light beam passing through the cassette without being blocked by the substrate, In a substrate loading / unloading apparatus that adjusts the positional relationship between the fingers and the cassette when the fingers are inserted into the cassette by the hand mechanism using the output of a sensor, the light beam is moved in parallel with the fingers. A beam parallel moving mechanism is provided.

As the beam parallel moving mechanism, it is possible to use one having a glass plate provided so as to rotate in the optical path of the light beam.

[Embodiment] In FIG. 1, reference numeral 1 denotes a laser light source having a narrow beam diameter for providing a laser light having excellent straightness, 2 denotes laser light emitted by 1, and 3 denotes so that the laser light rotates in the optical path of the laser light. The glass plate 4 installed is a reflection mirror for emitting the laser light path translated by the rotating glass plate 3 toward the wafers, and the reference numeral 5 is inserted between the wafers to pull out the wafers from the carrier 6 and to store them. Fingers, 6 is a carrier that accommodates the wafer, 7 is the wafer, and 8 is for detecting the presence or absence of the wafer in the optical path by passing or blocking the laser light emitted from the reflection mirror 4 between the wafers. , An optical sensor for converting the intensity of laser light into an electric signal, 9 carrier bases 10 to 16 for supporting carriers, mechanical parts for moving fingers (details will be described later), and 17 fingers. -5 is a carrier up-and-down mechanism for changing the relative position of the carrier 6 to the wafer 5 and positioning the finger 5 between the wafer at the target position and the wafer adjacent thereto. 10 and 12 are hand arms, 11, 13 and 14 are axes, 15 is a hand arm telescopic drive unit, and 16 is a handler rotating mechanism. In FIG. 2, 18 to 20 indicate three positions of the glass plate 3 in FIG. Reference numerals 21 to 23 are laser optical paths which are refracted by the glass plate at the positions 18 to 20 and translated.

In the configuration shown in FIG. 1, the laser light 2 emitted from the laser light source 1 is refracted by the rotating glass plate 3, and after changing its course, is emitted parallel to the wafer 7 or the finger 5 by the reflection mirror 4. . If there is an obstacle on the laser optical path, the laser light is scattered and the amount of light incident on the optical sensor 8 is reduced, so that the sensor output is reduced and the wafer is on the optical path.

In order to safely insert the fingers between the wafers, it is necessary to know the positional relationship between the fingers and the wafer. In order to know the position of the finger, a wafer may be placed on the finger, the wafer may be detected, and the position may be known. The rotating glass plate can be rotated to any position, and the control device can know the angle. With the fingers contracted, the carrier table 9 is moved upward from the position of the optical sensor 8 and the reflection mirror 4
Between the optical sensor 8 and the optical sensor 8 so that only the wafer 7 placed on the finger 5 exists, the glass plate is rotated to store the rotation angle at which the output of the optical sensor starts to fall, and the wafer thickness direction is measured. The center of is calculated, and the finger position is calculated from that value. Next, the wafer on the finger is removed, the carrier table is lowered, and the carrier is stopped according to the wafer position data roughly set in advance so that the desired wafer is slightly above the finger position. In this state, the position of the desired wafer and the position of the wafer below it are determined by the same method as when the position of the wafer on the fingers is determined by rotating the glass plate.

The position of the finger obtained previously is compared with the positions of the two wafers to determine whether the finger can be inserted. If it is determined that the wafer cannot be inserted, the shift amount to the target position is calculated, the carrier table is moved by the shift amount, and the wafer position is detected again. If this is repeated several times, the fingers and the carrier settle in a positional relationship in which the fingers can be inserted. Therefore, the fingers are inserted into the carrier to carry the wafer.

If the cutoff length of the laser beam is excessively long in the above process, it is determined that the wafer is tilted, and the transfer is stopped.

In the above embodiment, the rotating glass plate is used as the light beam parallel moving means, but instead of this, the reflecting mirror 4 may be moved up and down, or the polygon mirror and f may be placed at the position of the reflecting mirror 4. A combination with a -θ lens may be used.

The wafer handler may be provided with a mechanism for changing the relative distance between the carrier, the finger, and the three members of the laser optical path within the moving range of the laser optical path, so that the adjustment of these three members can be automated. Furthermore, if the wafer is tilted in the carrier, or if the wafer is tilted with respect to the laser light path on the hand (the tilted state of the wafer hinders the safety of wafer transfer), the laser light path is moved in parallel to move the laser It is also possible to calculate the slope by measuring the distance that the light is blocked.

In the embodiment shown in FIG. 1, the carrier 6 is movable, and the fingers 5 and the position detecting device (consisting of members 1, 2, 3, 4, 8).
However, the carrier 6 may be fixed and the fingers and the position detecting device may be movable, or all three may be movable.

EFFECTS OF THE INVENTION As described above, according to the present invention, since the beam parallel moving mechanism as described above is provided, the positions of the substrate and the fingers can be accurately detected, and the substrates can be accurately carried in and out. .

[Brief description of drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention. FIG. 2 is an explanatory view of the light beam parallel moving means of the embodiment shown in FIG. FIG. 3 is a schematic view of a wafer transfer device using a handler incorporating a conventional wafer position detection device. In the figure, 1: laser light source, 2: laser light, 3: rotating glass plate, 4: reflection mirror, 5: finger, 6: carrier, 7: wafer, 8: optical sensor, 9: carrier stand, 10; 12 : Hand arm, 11; 13; 14: Axis, 15: Hand arm telescopic drive unit, 16: Handler rotation mechanism, 17: Carrier up / down mechanism.

Claims (2)

[Claims] 1. A finger for accommodating or removing a substrate in a cassette, a hand mechanism used for intruding the finger into or out of the cassette, and ejecting along the finger. A light source for generating a light beam, and an optical sensor that detects the light beam that has passed through the cassette without being blocked by the substrate, and uses the output of the optical sensor to move the finger. In the substrate loading / unloading device for adjusting the positional relationship between the fingers and the cassette when the fingers are moved into the cassette by the hand mechanism, a beam parallel moving mechanism for moving the light beam in parallel with the fingers is provided. Characteristic board loading / unloading device. 2. The substrate loading / unloading apparatus according to claim 1, wherein the beam parallel moving mechanism has a glass plate provided so as to rotate in the optical path of the light beam.