JP5387926B2 - Plate-like body detection device, case port and storage device - Google Patents

Description

  The present invention relates to detection of a plate-like body.

  Patent Document 1 (JP4215079B) discloses a reticle storage device, which is a plate-shaped mask used for exposure of a semiconductor or the like. In Patent Document 2 (JP2001-22053A), in order to detect the presence or absence of a reticle in the case, LED light is projected from the front of the case opening to the side of the reticle, and passes through the opposite side of the reticle. Is disclosed. However, if an LED or the like is placed in front of the case, it will prevent the reticle from being put in and out of the case. Therefore, if the light source is disposed obliquely with respect to the front surface of the case and the light receiving element is disposed on the side opposite to the light source when viewed from the case, it is difficult to align the light source and the light receiving element.

JP4215079B JP2001-22053A

An object of the present invention is to reliably detect a plate-like body by using a light projecting / receiving sensor having a light source and a light-receiving element without blocking the front surface of the plate-like body.
Another object of the present invention is to provide a case port and a storage device provided with such a detection device.

This invention is a plate-like body detection device for detecting whether or not the plate-like body is present at a predetermined position,
A light projecting / receiving sensor comprising a light source for projecting spot-like detection light obliquely toward one side surface of the plate-like body, and a light receiving element for receiving reflected light;
A diffusive reflection part located on the optical path of the detection light when there is no plate-like body and far from the plate-like body when viewed from the light emitting / receiving sensor,
When the side surface of the plate-like body is transparent, the detection light incident on the side surface of the plate-like body is reflected several times inside the plate-like body and emitted in a direction different from the light emitting / receiving sensor, and the side surface of the plate-like body is mirror-like In the case of the reflecting surface, the light projecting / receiving sensor is arranged so that the detection light is obliquely incident on the side surface of the plate-like body and is regularly reflected in a direction different from that of the light projecting / receiving sensor.

  In the detection apparatus according to the present invention, if there is no plate-like body, the detection light is incident on the diffuse reflection portion, and a part of the detection light returns to the light projecting / receiving sensor by diffuse reflection. The plate-like body may have a transparent or mirror side surface, and in the case of the mirror surface, the detection light incident obliquely is specularly reflected in the opposite direction to the light projecting / receiving sensor and does not return to the light projecting / receiving sensor. In the case of being transparent, the light is reflected a plurality of times inside the plate-like body and emitted from the surface on which the detection light is incident. The emitted light travels in the opposite direction to the light projecting / receiving sensor and does not return to the light projecting / receiving sensor. And a detection part detects a plate-shaped object from being below the predetermined intensity | strength of the reflected light which injects into a light projection / reception sensor. Therefore, the presence or absence of the plate-like body can be reliably detected without arranging the light projecting / receiving sensor in front of the plate-like body.

Further, the present invention is a case port for storing a case that houses the plate-like body and includes an opening for transferring the plate-like body on the front surface,
A case housing portion and the detection device of the present invention;
The light emitting / receiving sensor of the detection device is arranged so that the detection light is incident obliquely from the opening of the case to the inside of the case,
On the left and right side surfaces inside the case, the diffuse reflector is provided at a position where detection light incident from the opening of the case enters when no plate-like body is present.

  In this invention, since the detection light is incident obliquely on the side surface of the plate-like body, the light projecting / receiving sensor can be disposed at a position where the front of the opening of the case is not blocked. Therefore, the light projecting / receiving sensor does not hinder the transfer of the plate-like body to the case. In this specification, arranging the light projecting / receiving sensor so as to satisfy a predetermined condition means that the position of the light projecting / receiving sensor and the optical axis of the detection light are arranged so as to satisfy a predetermined condition.

  Preferably, the detection device is configured so that the detection light incident on the inside of the transparent plate-like body is incident on the next side surface on the opening side of the plate-like body along the optical path of the detection light at an angle larger than the critical angle. The light emitting / receiving sensor is arranged. When the detection light is incident on this surface at a critical angle, the detection light travels along the side surface of the plate-like body, and a light path is formed that is regularly reflected on the most ridge surface of the case and returns to the light projecting / receiving sensor. When the detection light is incident on the next side surface on the opening side of the plate-like body at an angle larger than the critical angle, the detection light returning to the light projecting / receiving sensor is small and hardly causes erroneous detection.

The present invention is further a storage device comprising the case port of the present invention,
A storage unit for storing the plate-like body in a state of being taken out of the case;
A transfer part for taking in and out the plate-like body from the case of the case port;
And a control unit that controls the transfer unit based on the determination by the detection unit of the detection device.

  This storage device can reliably detect the presence or absence of a plate-like body in the case, for example, trying to store another plate-like body in a case that already contains the plate-like body, or removing a plate-like body from an empty case. There is no attempt to take it out.

Horizontal sectional view of the storage device of the embodiment Vertical sectional view of the case port in the embodiment Side view of the case used in the examples The figure which shows the detection of the plate-shaped object in the case in an Example

  In the following, an optimum embodiment for carrying out the present invention will be shown. The scope of the present invention should be determined according to the understanding of those skilled in the art based on the description of the scope of the claims, taking into account the description of the specification and well-known techniques in this field.

  1 to 4 show an embodiment. FIG. 1 shows a storage 2, 4 is a case port, a port for loading and unloading the case, and 6 a load port for loading and unloading the pod. Both the case and the pod store the reticle, and the shape is a thin rectangular parallelepiped, and the case and the pod have different procedures and standards for loading and unloading the reticle. The ports 4 and 6 are mainly ports that are accessed by an operator, but may be accessible to an automatic guided vehicle, an overhead traveling vehicle, and the like. Moreover, you may provide the port which an overhead traveling vehicle etc. accesses separately in the upper part of the storage apparatus 2. FIG. The stored article is not limited to a reticle, but may be a semiconductor wafer or the like, and is stored in a case in a plate shape and stored in a highly clean environment.

  Reference numeral 8 denotes a rotating shelf that stores reticles taken out from the case and pod and rotates in multiple stages in the height direction and around the vertical axis. Reference numeral 10 denotes a reticle transfer device. A turntable 15 is moved up and down along a lift guide 13, and includes a telescopic arm 17 such as a scalar arm, and a reticle is transferred by a hand 18 at the tip of the arm 17. Reference numeral 12 denotes a pod transfer device. The turntable 16 is moved up and down along the lift guide 14 and includes a telescopic arm 18 such as a scalar arm, and the pod is transferred by the hand 20 at the tip of the arm 18. Reference numeral 22 denotes a pod opener, and an inner case storing a reticle is taken in and out of a pod (not shown). Reference numeral 24 denotes a pod shelf for storing the pod. The reticle transfer device 10 can access any opening of the rotating shelf 8, the pod opener 22 and the case port 4, and the transfer device 12 can access any opening of the pod shelf 24, the pod opener 22 and the load port 6. it can. The structure and type of the transfer devices 10 and 12 are arbitrary.

  Reference numeral 26 denotes a controller that controls each part of the storage device 2 and stores the ID and location of the stored pod, case, and reticle, for example, the frontage address on the rotating shelf 8 and the address in the shelf at the case port 4. Store in inventory file. And remembers the entrance and exit of pods, cases, and reticles. Reference numerals 27 and 28 denote input panels for inputting / removing pods and cases, and the controller 26 controls the transfer devices 10 and 12, the rotating shelf 8, and the ports 4 and 6 according to inputs from the operation panels 27 and 28. When a case and a pod are carried in and out of an automatic guided vehicle, an overhead traveling vehicle, etc., the controller 26 communicates with a host controller (not shown) and controls the storage device 2 according to the instruction.

  FIG. 2 shows the structure of the case port 4. Reference numeral 30 denotes a case loading unit. For example, an operator can open the door 39 to load cases in a plurality of stages. Instead of loading the cases, the cases are simply stored in the shelves. May be. Reference numeral 32 denotes a transfer device, which includes a lift 34 that moves up and down along a lift guide 33, and a hand 35 that expands and contracts such as a scalar arm and a slide fork on the lift. The transfer device 32 transfers stored articles such as reticles between the case in the case loading unit 30 and, for example, the uppermost reticle storage place 38 of the case loading unit 30. The type and structure of the transfer device 32 are arbitrary. For example, the reticle transfer device 10 may directly access the case in the case loading unit 30.

  A detection device 36 is provided for each stage of the case loading unit 30 along the support 37 in the case port 4, and the detection device 36 is oblique to the opening 42 on the front surface of the case shown in FIGS. 3 and 4. Are arranged at positions where detection light is projected. Instead of providing a separate detection device 36 at each stage of the case loading unit 30, one detection device may be moved up and down along the support 37. Reference numeral 36 'denotes a detection device provided in the reticle place 38, which is arranged at a position where it does not interfere with the hand 35 and the like. For example, the reticle is detected by irradiating the end surface of the reticle with laser light or the like to detect reflected light. The detection devices 36 and 36 ′ report the presence or absence of the reticle to the controller 26, and the controller 26 controls the transfer device 32 and the reticle transfer device 10 based on this report. However, the transfer device 32 may be controlled by a local controller in the case port 4.

  FIG. 3 shows a case 40 and a hand 35 handled by the case port 4. In this specification, the right side of FIG. 3 is called the front, and the front side of the case 40 is called the front. In the case port 4 and the like, the right side of FIG. A door 41 that can be opened and closed is provided in front of the case 40, and is opened and closed by a mechanism (not shown) of the case loading unit 30, and 42 is an opening that is opened and closed by the door 41. The case 40 accommodates a plate-shaped article such as a reticle 44 therein. The inner surface of the case 40 is not a mirror-like light reflecting surface, and at least a part of the incident light is reflected in the direction opposite to the direction of the incident light. In this specification, the mirror surface is a surface where diffuse reflection can be ignored and has no relation to whether it is transparent or opaque. When the inner surface of the case is mirror-like, a member such as a film or a coating film that diffuses or reflects the detection light at a position where the detection light first enters is provided.

  The reticle 44 has a rectangular shape in plan view, and is made of a transparent material such as quartz, glass, or synthetic resin. Its four side surfaces are mirror-like, but the four side surfaces of the reticle 44 may be transparent or opaque. The refractive index of the reticle is higher than 1, for example, a critical angle near 40 degrees. The stored article is not limited to a reticle, and may be a plate-like body, particularly a plate-like body having a mirror-like side surface.

  FIG. 4 shows the positional relationship between the detection device 36 and the case 40 in the case loading unit 30. The detection device 36 includes a laser 50 such as a semiconductor laser or a gas laser and a light receiving element 52, and the laser 50 and the light receiving element 52 calibrate the light projecting / receiving sensor. The detection unit 54 assumes that the reticle 44 exists when the intensity of the reflected light received by the light receiving element 52 is equal to or less than a predetermined value, and does not exist when the intensity of the reflected light exceeds the predetermined value. Instead of the laser 50, the light from the LED or the like may be changed by a lens to a parallel beam whose spot size is equal to or smaller than the thickness of the reticle 44. The light receiving element 52 is a photodiode or the like, and detects reflected light in a direction almost opposite to the light from the laser 50.

  When a reticle having a transparent side surface is present, light from the detection device 36 enters the point P1 at an incident angle γ obliquely from the opening 42 on the front surface of the case 40 along the optical path L1, and the reticle 44 at an output angle β. Refracts in. A part of the detection light is regularly reflected at the exit angle γ at the point P1 and travels along the optical path L2. If the refractive index of the reticle 44 is n, then nsin β = sin γ. If the incident angle at the point P2 is α, α can be made larger than the critical angle by selecting the incident angle γ with α = π / 2−β. The detection light exits from the reticle 44 at a point P3, is reflected by the farthest surface of the case 40 at a point P4, returns to the inside of the reticle 44 at a point P5, and the incident angle is α and larger than the critical angle at point P6. Exit the reticle 44 and proceed along the optical path L3. The optical path L3 is opposite to the detection device 36. Here, the significance of making the incident angle α at the point P2 larger than the critical angle will be described. When the incident angle α is equal to the critical angle, light traveling along the side surface of the reticle 44 is generated, and this light travels along the optical path L4. It becomes. On the other hand, when the angle α is larger than the critical angle, a part of the detection light is diffusely reflected at the point P4 and returns to the point P3, and may follow the optical path L1 in the opposite direction. Proceed to point P5 and do not return to detector 36. In the reticle 44, the detection light is incident on the side surface S 1 adjacent to the opening 42 at an incident angle α larger than the critical angle and reflected, and then reflected on the side surface S 2 opposite to the opening 42. Next, the detection light is incident and reflected on the side surface S3 opposite to the side surface S1 at an incident angle α larger than the critical angle, and is emitted from the opening 42 side at an emission angle γ in the direction opposite to the detector 36.

  When a reticle having an opaque side surface and a specular surface is present, the detection light is regularly reflected at the reflection angle γ at the point P 1, follows the optical path L 2, and does not return to the detection device 36. If the reticle 44 does not exist, the detection light is diffusely reflected by the diffuse reflector 43 and part of the light returns to the detection device 36.

As described above, the detection light strongly returns to the detection device 36 only when the reticle 44 does not exist. When the intensity of the reflected light is determined by the detection unit 54, the presence or absence of the reticle 44 can be known. Moreover, the detection device 36 does not block the front of the opening 42 of the case 40 and does not interfere with the transfer device 32 or the like. Further, when the detection light is incident on the transparent reticle on the next side surface of the opening 42 at an incident angle larger than the critical angle, the detection light returning to the detection device 36 can be particularly reduced. Further, when the detection light is sequentially reflected on the three side surfaces of the reticle and returned to the surface on the opening 44 side, the detection light can be easily emitted to the side opposite to the detection device 36.

2 Storage device 4 Case port 6 Load port 8 Rotating shelf 10 Reticle transfer device 12 Pod transfer device 13, 14 Lift guides 15, 16 Turntables 17, 18 Arm 19, 20 Hand 22 Pod opener 24 Pod shelf 26 Controller 27, 28 Operation Panel 30 Case Loading Unit 32 Transfer Device 33 Elevating Guide 34 Elevating Table 35 Hand 36 Detection Device 37 Support 38 Reticle Place 39 Door 40 Case 41 Lid 42 Opening 43 Diffuse Reflecting Unit 44 Reticle 50 Laser 52 Light Receiving Element 54 Detection Part

L1-L3 light path
P1 to P7 points
S1-S3 side

Claims (4)

A detection device for detecting whether or not a plate-like body is present at a predetermined position,
A light projecting / receiving sensor comprising a light source for projecting spot-like detection light obliquely toward one side surface of the plate-like body, and a light receiving element for receiving reflected light;
A diffuse reflection part that diffuses and reflects detection light when the light emitting and receiving sensor is far from the plate and there is no plate,
Since it is below a predetermined intensity of the reflected light incident on the light emitting / receiving sensor, it comprises a detection unit that detects a plate-like body,
When the side surface of the plate-shaped body is transparent, the detection light incident on the side surface of the plate-shaped body is reflected multiple times inside the plate-shaped body and emitted in a direction different from the light emitting and receiving sensor, and the side surface of the plate-shaped body is mirror-like In the case of the reflecting surface, the light emitting / receiving sensor is arranged so that the detection light is incident on the side surface of the plate-like body obliquely and is regularly reflected in a different direction from the light emitting / receiving sensor. Body detection device. A case port for storing a case that houses the plate-like body and has an opening for transferring the plate-like body on the front surface,
A case housing part and the detection device according to claim 1;
The light emitting / receiving sensor of the detection device is arranged so that the detection light is incident obliquely from the opening of the case to the inside of the case,
A case port, wherein the diffuse reflection part is provided at a position on the left and right side surfaces inside the case where detection light incident from an opening of the case is incident when no plate-like body is present.   The detection device emits and receives light so that the detection light incident on the inside of the transparent plate enters the next side surface on the opening side of the plate along the optical path of the detection light at an angle larger than the critical angle. The case port of claim 2, wherein a sensor is disposed. A storage device comprising the case port of claim 2 or 3,
A storage unit for storing the plate-like body in a state of being taken out of the case;
A transfer part for taking in and out the plate-like body from the case of the case port;
A storage device, further comprising: a control unit that controls the transfer unit based on determination by the detection unit of the detection device.

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