JPH0817199B2 - Wafer transfer device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer device used for storing and taking out wafers in a storage box for storing wafers.

[0002]

2. Description of the Related Art Conventionally, in the measurement of wafers, a belt drive device is installed under a storage box in which the wafers to be inspected are stored, and the belts are used to take out the wafers one by one from the lower wafer. . When the wafers are taken out by such a belt drive device, only the wafers that can contact the belt can be taken out, so that it is not possible to selectively take out any wafer in the storage box. In other words, once the measured wafer is returned to the storage box, it is not possible to selectively take out any wafer from the storage box as needed, except when the wafer is at the lowermost stage. Was making it difficult.

[0003]

By the way, in the case of inspecting a wafer, it is required to improve the inspection efficiency and first to automate the transfer. Conventionally, as a device for transferring a wafer, for example, Japanese Patent Laid-Open No. 50-126175, "Wafer Supply Device", Japanese Patent Laid-Open No. 58-123736, "Wafer Transfer Method and Device", Japanese Patent Publication No. 63-322.
No. 49 “Sample Exchanger”, Japanese Patent Laid-Open No. 58-138046 “Wafer Transfer Device”, Japanese Patent Laid-Open No. 58-182846 “Semiconductor Substrate Transfer Device”, Japanese Patent Laid-Open No. 58-155735 “Wafer Transfer Device”. Etc. have been proposed. With these devices, it is difficult to arbitrarily select a wafer in the storage box and take it out or store the wafer in the storage box.

Therefore, an object of the present invention is to provide a wafer transfer device suitable for taking out a wafer from a storage box and storing the wafer in the storage box by realizing highly reliable transfer of the wafer.

[0005]

SUMMARY OF THE INVENTION A wafer detecting apparatus according to the present invention comprises a storage box for opening a front side and a rear side and storing a plurality of wafers at arbitrary intervals, and an apparatus main body for mounting the storage box. An elevating mechanism that is attached to the storage box to change the vertical positional relationship with respect to the storage box, and a light beam is emitted from a light source into the storage box, and the light beam is received by a light receiving element. Wafer detection means for detecting the presence / absence of a wafer, and wafer placement for holding the wafer to be taken in and out of the storage box by vacuum suction, which is installed on the front side of the storage box and moved up and down by the elevating mechanism. An arm provided with a section, and an arm advancing / retreating mechanism for advancing / retreating the arm in and out of the storage box by receiving a driving force from a driving means, thereby moving the wafer in and out of the storage box. Based on the detection output of the wafer detection means, the detection data representing the wafer or the vacant position in the storage box is stored in the storage means, and based on the data, the lifting mechanism is controlled and the movement of the arm is controlled. And a control means for taking out or storing the wafer in the storage box.

[0006]

With this structure, the arm is moved forward and backward with respect to the storage box whose front and rear surfaces are open, and the arm is moved up and down by the lifting mechanism. Then, the presence or absence of the wafer in the storage box is detected by the wafer detection means,
The wafer to be taken out of the storage box and the position of the storage box to be stored are detected. Receiving this wafer detection output, the control means executes the control of advancing / retracting and raising / lowering the arm according to the wafer to be taken out from the storage box or the wafer to be stored in the storage box. That is, the arm is inserted into the storage box, the wafer is placed on the arm, and the wafer is taken out from the storage box.
By mounting the wafer to be stored in the arm and storing the wafer together with the arm in the storage box, the wafer can be efficiently taken out and transferred such as storing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the wafer transfer device of the present invention. The wafer transfer device of this embodiment is configured as a wafer detecting, taking-out and storing device,
A wafer detection device e as a wafer detection means for detecting a wafer in a non-contact manner, and a wafer extraction / accommodation device h for extracting and accommodating a wafer from a storage box are arranged in parallel.

That is, FIG. 3 shows a portion of a wafer detecting device e in the wafer transfer device of the present invention. An elevator 2 as an elevating mechanism is attached to the device body 1, and the upper surface of the device body 1 should be detected. A storage box 5 storing the wafer 4 is installed. The storage box 5 is opened in the front and rear direction, and a plurality of groove portions for holding the wafers 4 at regular intervals are formed on the inner wall portions on both sides thereof. A reflecting mirror 3 is fixed to the back side of the device body 1. A half mirror 6 is installed on the stage of the elevator 2, and
A light emitting element 7 is installed as a light beam irradiating means for irradiating the storage box 5 side with the light beam Li via the half mirror 6, and a reflecting mirror for receiving and reflecting the light beam Li passing through the storage box 5. 3 is installed, and a light receiving element 8 is installed as a light receiving means for receiving the reflected light beam Lr obtained from the reflecting mirror 3. That is, the elevator 2
As shown in FIG. 2, by moving the light emitting element 7 and the light receiving element 8 in the vertical direction (Y: up and -Y: down), the relative positions of the light emitting element 7 and the light receiving element 8 with respect to the storage box 5. The position changing means for sequentially irradiating the wafer 4 in the storage box 5 with the light beam Li is configured.
Therefore, in the wafer detection device e, the light beam Li emitted from the light emitting element 7 passes through the half mirror 6, the reflected light beam Lr is reflected by the reflecting mirror 3 back to the half mirror 6, and returns to the half mirror 6. It is incident on 8. Therefore, when the elevator 2 is scanned from bottom to top with respect to the apparatus main body 1, as shown in FIG. 3, when the wafer 4 is not present, the light beam Li passes through a portion where the wafer 4 is absent and is reflected by the reflecting mirror 3. After that, the light beam enters the light receiving element 8, and as shown in FIG. 4, the reflected light beam Lr hits the wafer 4 and is reflected upward through the half mirror 6. As a result, the reflected light beam Lr is reflected by the presence or absence of the wafer 4 in the storage box 5. The intensity of the beam Lr is increased.
Therefore, the light receiving element 8 receives the reflected light beam Lr representing the presence / absence of the wafer 4, and the change of the minute current is obtained as the detection signal of the wafer 4.

In the wafer unloading / accommodating apparatus h, as shown in FIG. 1, the elevator 2 provided with the light emitting element 7, the light receiving element 8 and the half mirror 6 has a pulse motor 11
It is attached to a ball screw 12 driven by and is slidably supported by two guide shafts 16.

The wafer unloading / housing device h also serves as an elevator 2 as an elevating mechanism for taking out the wafer 4 from the housing box 5 or transferring the wafer 4 in the vertical direction for housing the wafer 4 in the housing box 5. There is. The wafer unloading / accommodating device h is provided with a unloading arm 9 having a flat-plate-shaped wafer mounting portion that is inserted into the storage box 5 to unload and store the wafer 4. This take-out arm 9
A belt 1 is supported by a guide shaft 10 so as to be slidable in the horizontal direction. One end of the belt 1 allows the take-out arm 9 to transfer the wafer 4 together with the elevation of the elevator 2.
5 is fixed. The belt 15 is wound around a pair of pulleys 14 arranged at intervals corresponding to the movement of the takeout arm 9. That is, the belt 15 is
An arm advance / retreat mechanism for moving the take-out arm 9 toward the storage box 5 in the front-back direction and in the X direction in the drawing by rotation is formed.
It rotates by receiving the rotational force applied from the pulse motor 13 via the belt 15.

A vacuum hole is provided in the mounting portion of the take-out arm 9 for mounting the wafer 4, that is, a suction surface for sucking the wafer 4, so that a vacuum for sucking the wafer 4 acts on the wafer 4.

According to this structure, after detecting the presence / absence of the wafer, as shown in FIG. 2, the belt 15 is driven by the pulse motor 13 to move the take-out arm 9 forward to take out the wafer 4 to be taken out. Insert on the bottom side. The pulse motor 13 is stopped, and then the elevator 2 is slightly raised, and then the vacuum is operated to attract the wafer 4 to the wafer mounting surface of the takeout arm 9. When the motor 13 is rotated in the reverse direction in this state, the take-out arm 9 moves backward together with the belt 15, and the take-out arm 9 causes the wafer 4 to move.
Will be taken out from the storage box 5.

Next, FIG. 5 shows a control system of the wafer transfer device shown in FIG. The start switch a is means for instructing the start of detection, taking-out or storage of the wafer 4. Positioning information is stored in the storage means g together with the address. When the start switch a is operated,
A designation start command is given to the address designating means f through the selecting means b, and the position of the wafer 4 in the storage box 5 is determined based on the position information from the wafer detecting device e.

The take-out control means c controls the take-out of the wafer 4 from the storage box 5, and the take-out control means d controls the take-out arm 9.
It is a means for controlling the storage of the wafer 4 in the storage box 5 through. The control output from these control means c and d is added to the elevator drive device i that drives the elevator 2, and is added to the wafer unloading / accommodating device h. That is, the pulse motor 11 and the elevator drive device i of the wafer unloading / accommodating device h are subjected to positioning control based on information from the unloading controller c or the accommodating controller d, and the wafer 4 is ejected from the accommodating box 5. Alternatively, the wafer 4 is stored in the storage box 5.

The detection means j is a means for detecting information on where the wafer 4 is placed at each inspection, and the detection output is supplied to the selection means b, whereby the wafer 4 is detected.
Is selected or the wafer 4 is stored.

FIG. 6 shows a control system of the wafer transfer device according to the present invention. That is, in this wafer transfer device,
A control unit 20 including a one-board microcomputer is installed as control means for controlling the transfer.
0 is a CP that executes the transfer control program for the wafer 4.
An input port 24 is provided together with U21, a ROM 22 as a storage means for storing a transfer control program, a RAM 23 as a storage means for storing data in the middle of calculation of the CPU 21 and a detection signal. Detection signals from the wafer detector e, the vacuum detector 31, and the limit detector 32 are applied to the input port 24. The control output obtained from the CPU 21 is applied to the elevator drive circuit 33, the wafer take-out / accommodation drive circuit 34, and the fixed pin circuit 35. The drive output of the elevator drive circuit 33 is applied to the pulse motor 11, and the drive output of the wafer unloading / accommodating drive circuit 34 is applied to the pulse motor 13.

The addresses and wafer positions stored in the RAM 23 are as shown in Table 1.

[0018]

[Table 1]

The control operation of detecting, taking out and storing the wafer 4 thus constructed will be described with reference to the flow charts shown in FIGS. As shown in FIG. 7, in step S1, the contents stored in the RAM 23 are erased by initialization, and the process proceeds to step S2. In step S2, it is determined whether the start switch a is on or off. If the start switch a is on, the process proceeds to step S3. In step S3, it is determined whether or not the input is the initial input. If the input is the initial input, the process proceeds to step S4, and the initial input process (FIG. 8) is called and the process is executed. If it is determined in step S3 that it is not the initial input, the process proceeds to step S5, it is determined whether the wafer is to be taken out or stored, and if it is stored,
The process moves to step S6, and in the case of taking out, step S9
Move to In step S6, it is determined whether it is automatic or manual. If it is automatic, the process proceeds to step S7 to read the wafer storage location, and if it is manual, the process proceeds to step S8 to read the wafer storage stage number. After being broken
Control goes to step S12.

If it is determined in step S5 that the wafer is to be taken out, the process proceeds to step S9 to determine whether it is automatic or manual. If it is automatic, the process proceeds to step S10 to read the wafer to be taken out. Step S if manual
After shifting to 11 and reading the number of wafers to be taken out, the process proceeds to step S12.

After the moving amount of the elevator 2 is calculated in step S12, the process proceeds to step S13. In step S13, the process of adding the correction amount to the position of the elevator 2 is performed, and then the process proceeds to step S14. In step S14, it is determined whether the wafer is taken out or stored,
If it is stored, the process proceeds to step S15, and if it is taken out, the process proceeds to step S16. In step S15, after the storage process is called and the process (FIG. 9) is performed,
Control goes to step S17. Further, in step S16, a wafer unloading process is called and its process (FIG. 10).
After that, the process proceeds to step S17. Step S
In step 17, it is judged whether or not the wafer to be processed is completed. If there is a wafer to be processed, the process returns to step S3, the above-described steps S3 to S17 are performed again, and the wafer to be processed is When the processing is completed, all processing is completed.

Next, FIG. 8 shows an initial input process. That is, in step S18, the takeout arm 9 is moved to the elevator 2
The origin position of the stage is set, and the process proceeds to step S19. In step S19, the take-out arm 9 is set to the initial setting value of the elevator 2, and the process proceeds to step S20.
In step S20, the fixing pin is lowered, and in step S21
Move to If it is determined to be automatic in step S21, the process proceeds to step S22 to set the wafer loading / unloading, and then the process proceeds to step S23. If it is determined to be manual, step S22 is omitted and the process proceeds to step S23. Transition.

In step S23, the stage of the elevator 2 is driven, and the process proceeds to step S24 to determine the presence / absence of a wafer. That is, if it is determined in step S24 that a wafer is present based on the detection output of the wafer detection device, the process proceeds to step S25, and if no wafer is present, the process proceeds to step S27. After the wafer position is calculated in step S25, step S25 is performed.
Move to 26. In step S26, an address table is created from the wafer number and wafer position, and the process proceeds to step S27. In step S27, it is determined whether or not it is the upper limit, and if it is not the upper limit, step S23 is performed again.
, And if it is the upper limit, step S in FIG.
Returning to step 3, the initial input process is completed.

Next, FIG. 9 shows a process of storing the wafer 4.
In this storage process, the stage of the elevator 2 is driven to the wafer storage position of the storage box 5 in step S30, and the process proceeds to step S31. In step S31, the fixed pin vacuum is turned off and the wafer take-out vacuum is turned on. Next, in step S32, the fixing pin is lowered, and in step S33, the takeout arm 9 is driven to the wafer storage position. Next, in step S34, the vacuum of the take-out arm 9 is released, and the wafer 4 on the take-out arm 9 is stored in the storage position of the storage box 5. Next, in step S35, the stage of the elevator 2 is lowered, and in step S36, the take-out arm 9 is returned to the origin position, the storage process is completed, and the process proceeds to step S17 shown in FIG.

Next, FIG. 10 shows a process for taking out the wafer 4. In this take-out process, the stage of the elevator 2 is driven to the wafer storage position of the storage box 5 in step S37,
Control goes to step S38. In step S38, the take-out arm 9 is driven to the center position of the wafer 4 stored in the storage box 5, and the process proceeds to step S39. Step S
At 39, the vacuum of the take-out arm 9 is turned on,
The wafer 4 to be taken out is adsorbed to the taking-out arm 9.
In step S40, after raising the stage of the elevator 2, the process proceeds to step S41. In step S41, the take-out arm 9 is returned to the origin position of the stage of the elevator 2, and then the process proceeds to step S42, the vacuum for the take-out arm 9 is released, the vacuum of the fixing pin is operated, and the process proceeds to step S43. In step S43, the fixing pin is raised, the process of taking out the wafer 4 is completed, and the process proceeds to step S17 shown in FIG.

In the transfer control program processing as described above, when taking out the designated wafer 4 from the storage box 5,
The detection data obtained by detecting the wafer position state in the storage box 5 by the wafer detection device e is read from the RAM 23, and the CPU 2
The output from 1 is converted into a drive output by the elevator drive circuit 33. As a result, the pulse motor 11 is driven and the ball screw 12 is rotated to raise the elevator 2 to a position where the wafer is taken out.

Regarding the relationship between the wafer 4 in the storage box 5 and the upper surface of the taking-out arm 9, the suction surface of the taking-out arm 9 is located at a position slightly lower than the wafer 4 to be taken out. The take-out arm 9 is formed thinly according to the storage interval of the wafers 4 in the storage box 5, and its moving position is set to the wafer 4
Since it is set within the interval, even if the takeout arm 5 of the storage box 5 is inserted, it does not collide with the wafer 4 to be taken out.

Then, the take-out arm 9 inserts the center of the suction surface to the center of the wafer 4. When the wafer 4 is placed on the suction surface of the take-out arm 99 in this state, the CPU 21
When a vacuum is applied in response to a command from the wafer 4, the wafer 4 is attracted to the attraction surface of the take-out arm 9. At this time,
The hole of the suction surface of the take-out arm 9 is closed by the wafer 4, the pressure of the vacuum hole is lowered, the suction of the wafer 4 is detected by the vacuum detector 31, and the vacuum switch is activated by the detection output to cause the CPU 21 to send the wafer 4 to the wafer 4. Adsorption information is transmitted. Based on this suction information, the CPU 21 outputs a command to move the take-out arm 9, and as a result, a drive output is issued from the wafer take-out / accommodation drive circuit 34 to rotate the pulse motor 13 to move the take-out arm 9 to the B point position. Move to. After the elevator 2 is moved to the position of the reference height, the vacuum for the takeout arm 9 is released. The fixed pin located at the point B rises by vacuum, and the wafer 4 is lifted by the fixed pin and set at the reference position. At this time, the vacuum is acting on the upper surface of the fixed pin, and the wafer 4 is adsorbed.

Further, when the wafer 4 is stored in the designated position of the storage box 5, the fixing pin is lowered from the pick-up arm 9 so that the pick-up arm 9 is vacuumed so that the wafer 4 is sucked. A switch operates and is transmitted to the CPU 21, a control output is obtained from the CPU 21, a drive output is applied from the wafer take-out / accommodation drive circuit 34 to the pulse motor 13, and a wafer in which the take-out arm 9 is accommodated up to a position designated by its rotation. Move at a height that does not collide with 4. That is, the removal arm 9 is moved to a height at which the wafer 4 can be inserted in the middle portion of the pocket of the storage box 5, the wafer 4 is stored at that position, the vacuum is released, and then the above-described removal of the wafer 4 is performed. Similarly, the take-out arm 9 is retracted to return to the original position.

In the embodiment, the reflecting mirror 3 is installed and the light beam Lr is returned to the light emitting element 7 side to be received by the light receiving element 8. However, instead of the reflecting mirror 3, a light receiving element is installed,
The presence or absence of the wafer 4 in the storage box 5 may be detected by directly receiving the light beam Li after passing through the storage box 5.

Further, in the embodiment, the optical detecting device is used as the wafer detecting means, but the wafer can be similarly detected by using a detecting medium other than the light beam as the wafer detecting means.

[0032]

According to the wafer transfer device of the present invention, the wafers stored in the storage box at arbitrary intervals are selectively taken out from an arbitrary position with respect to the storage box, and the wafers are stored in the storage box. In a wafer transfer device for storing the wafer in an arbitrary position with respect to the wafer, the data of the position or the empty position of the wafer stored in the storage box is stored in the first storage unit.
Can be received by the control unit, and automation of controlling the advance / retreat operation of the arm advance / retreat mechanism by the first control unit can be performed based on the information on which position in the storage box the wafer is stored. Becomes When transferring the wafer from the storage box to the arm advancing / retreating mechanism,
After the arm of the arm advancing / retreating mechanism is advanced to below the wafer in the storage box, the arm is raised to securely cover the vacuum hole provided on the mounting surface of the arm by the wafer. Since the second controller receives the pressure change of the vacuum hole via the vacuum detector, it is possible to reliably transfer the wafer to detect the transfer error such as the positional deviation on the mounting surface of the wafer and the inclination. Becomes or,
Since the second controller issues an advancing / retreating command to the arm advancing / retreating mechanism, when the transfer failure of the wafer occurs, the advancing / retreating operation of the arm is prevented in advance, and the wafer is missed from the arm. It is possible to prevent damage due to. Furthermore, since the transfer of the wafer is detected by the lowering of the vacuum hole provided on the mounting surface of the arm, it is assumed that there is an abnormality such as a positional deviation on the front mounting surface of the wafer or an inclination. If this is found, it will be stopped before the start of the forward / backward movement of the arm forward / backward mechanism to prevent accidents such as damage due to wafer drop or collisions due to wafer transfer by the arm forward / backward mechanism when the wafer is misaligned. can do. Further, since the wafer is attracted to the mounting surface of the arm at least while the advancing / retreating mechanism advances / retracts, the wafer is placed on the mounting surface due to vibration or inertia generated along with the movement of the advancing / retreating mechanism. Accurate transfer without causing positional displacement. Further, the insertion portion of the arm into the storage box is inserted between the wafers stored in the storage box, and the suction surface of the arm is located at a position slightly lower than the wafer to be taken out. For any of a plurality of wafers stored at arbitrary intervals in the box, the arms are inserted into the storage box, and then are moved by a slight distance with the movement in the horizontal direction being stopped, so that the storage is performed. Since the wafers are transferred from the box to the arm, the wafers are transferred to the arm above the mounting position of the wafer in the storage box without causing horizontal displacement of the wafer.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a wafer transfer device of the present invention.

FIG. 2 is a perspective view showing a wafer taking-out state in the wafer transfer device shown in FIG.

3 is a perspective view showing a wafer detection device in the wafer transfer device shown in FIG. 1. FIG.

4 is a perspective view showing detection of a wafer by the wafer detection apparatus shown in FIG.

FIG. 5 is a block diagram showing a control system of the wafer transfer device of the present invention.

6 is a block diagram showing a control device in the control system shown in FIG.

FIG. 7 is a flowchart showing a wafer transfer control program.

FIG. 8 is a flowchart showing a wafer transfer control program.

FIG. 9 is a flowchart showing a wafer transfer control program.

FIG. 10 is a flowchart showing a wafer transfer control program.

[Explanation of symbols]

 e Wafer Detecting Device (Wafer Detecting Unit) h Wafer Ejecting / Storing Device 2 Elevator (Elevating Mechanism) 4 Wafer 5 Storage Box 9 Ejecting Arm 13 Pulse Motor (Arm Advance / Retract Mechanism) 14 Pulley (Arm Advance Mechanism) 15 Belt (Arm Advance Mechanism) ) 20 control unit (control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B65H 1/28 321 8712-3F 3/44 344 8712-3F G06M 9/00 Z H01L 21/66 G 7514-4M 21/68 L

Claims (4)

[Claims] 1. An accommodating box for accommodating a plurality of wafers at arbitrary intervals, wafer detection means for detecting the presence / absence of wafers in the accommodating box, and an arm for placing the wafer to be transferred from inside or outside the accommodating box. And an arm advancing / retreating mechanism for advancing / retreating the arm inside / outside the storage box to transfer the wafer between the inside of the storage box and a predetermined position outside the storage box, and the arm advancing / retreating mechanism and the storage box. And an elevating mechanism for changing the relative relative position in the up-down direction to transfer the wafer between the storage box and the arm, and a mounting surface of the arm on which the wafer is mounted. ,
A vacuum hole for adsorbing the wafer, and a vacuum detector for detecting the pressure of the vacuum hole. Based on the detection output of the wafer detecting means, detection data indicating a wafer or an empty position in the storage box. A first storing means for storing and storing the storage means in the storage means, and controlling the elevating mechanism based on the data to elevate the elevating mechanism with respect to the storage box.
And a second controller for receiving the output of the vacuum detector and outputting an advance / retreat command to the arm advance / retreat mechanism. 2. The vacuum detector detects that the pressure of the vacuum hole is lowered by closing the vacuum hole provided on the mounting surface on the arm by the wafer. The wafer transfer device according to claim 1. 3. The wafer transfer apparatus according to claim 1, wherein the suction of the wafer to the arm by the vacuum hole is performed at least while the arm advancing / retreating mechanism advances and retracts. 4. The insertion portion of the arm into the storage box,
2. The wafer transfer according to claim 1, wherein the wafer is housed in the housing box to be thinner than the space between the wafers and the suction surface of the arm can be located at a position slightly lower than the wafer to be taken out. apparatus.