JP2537310B2 - Wafer detector - 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 detecting device used for detecting a wafer in a wafer storage box or the like.

[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 wafers to be inspected are stored, and the wafers are taken out one by one from the lower stage by a belt. In such an apparatus, since the wafers are sequentially taken out, it is impossible to selectively take out any wafer from the storage box. For example, once the measured wafer is returned to the storage box, it is difficult to re-measure the wafer because it is not possible to selectively take out an arbitrary wafer from the storage box unless the wafer is at the bottom end. I was doing.

[0003]

By the way, when measuring a wafer stored in such a storage box, an arbitrary wafer in the storage box is selectively taken out or the measured wafer is stored in the storage box. As a prerequisite for the automation of, the automation of detection of the presence / absence of wafers in the storage box is indispensable, and higher accuracy is required.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wafer detection apparatus which detects a wafer in a storage box in a non-contact manner and realizes high accuracy of the detection.

[0005]

That is, the wafer detecting apparatus of the present invention is, as illustrated in FIG. 1 to FIG.
A storage box that is opened to transmit light in the front-rear direction and that can store a plurality of wafers at a constant interval, and an arm that moves in and out of the storage box are provided, and by this arm, the wafer is taken out of the storage box or Wafer taking-out / storing means for storing, light beam irradiation means for irradiating the wafer arbitrarily stored in the storage box with a light beam from the front side of the storage box, and irradiation by the light beam irradiation means. Received the light beam on the back side of the storage box,
A reflecting mirror that reflects the reflected light beam from the back side to the front side of the storage box; and a light receiving unit that receives the reflected light beam that has passed through the storage box and generates a detection signal indicating the presence or absence of the wafer. At least one of the light receiving means and the light beam irradiating means and the storage box is moved according to the taking out or storing of the wafer by the wafer taking out / storing means. Elevating means for changing the position and sequentially irradiating the wafer in the storage box with the light beam.

[0006]

According to such a structure, the storage for storing the wafer is performed.
The storage box is open to allow light to pass through in the front-rear direction and at regular intervals.
Multiple wafers can be stored in this storage box.
Wafers can be taken out or stored in the wafer take-out / storage means.
Therefore, it is done. This wafer unloading / storing means is a storage box
It is equipped with an arm that moves in and out of the
Wafers are removed from the storage box by moving forward or backward, or the storage box
The wafer can be stored in the wafer. Then, the light beam is irradiated to the wafer in the storage box by the light beam irradiation means, the light beam passing through the storage box of the rear side of the storage box
The reflected light beam received by the reflector and obtained from this reflector is
Light is received by the light receiving means through the storage box . When the light receiving means receives the reflected light beam representing the presence or absence of the wafer in the storage box, the light receiving means obtains a detection signal indicating the presence or absence of the wafer. Then, the relative positions of the light receiving means and the light beam irradiating means and the storage box are changed by the elevating means, and the light beam is sequentially applied to the wafers in the storage box, so that the light receiving means is changed in accordance with the change in the position. A detection signal indicating the presence or absence of a wafer is obtained, and the wafer can be detected with high accuracy.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the wafer detecting apparatus of the present invention. An elevator 2 is attached to the apparatus body 1 as an elevating means, and a storage box 5 in which a wafer 4 to be detected is stored is installed on the upper surface of the apparatus body 1. The storage box 5 is
A plurality of groove portions for holding the wafer 4 at regular intervals are formed on the inner wall portions on both sides thereof, which are opened in the front-rear direction. 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 light beam L to the storage box 5 side through the half mirror 6, and the storage box 5 is also installed. A reflecting mirror 3 is installed as a means for receiving the light beam L that has passed through, and a light receiving element 8 is installed as a light receiving means for receiving the light beam L as a reflected light beam obtained from this reflecting mirror 3. That is, as shown in FIG. 2, the elevator 2 sets the light emitting element 7 and the light receiving element 8 in the vertical direction (Y: up and -Y: dow).
n), the light emitting element 7 and the light receiving element 8 are transferred.
And a storage box 5 relative to each other so that the light beam L can be sequentially applied to the wafers 4 in the storage box 5 to form a position changing means.

According to such a structure, the light beam L emitted from the light emitting element 7 passes through the half mirror 6, and the light beam L reflected by the reflecting mirror 3 passes through the original optical axis to pass through the half mirror. It returns to 6 and is incident on the light receiving element 8. Therefore, when the elevator 2 is scanned from the bottom to the top with respect to the apparatus main body 1, as shown in FIG. 1, when the wafer 4 is not present, the light beam L passes through a portion where the wafer 4 is absent and is reflected by the reflecting mirror 3. Then, the light beam L that has entered the light receiving element 8 and is reflected by hitting the wafer 4 is reflected upward through the half mirror 6 as shown in FIG. The intensity of the beam L changes, and the light beam L representing the presence or absence of the wafer 4 is received by the light receiving element 8, and a slight current change is obtained as a detection signal of the wafer 4.

Next, FIG. 3 shows an embodiment of a wafer detecting / removing / accommodating device in which a wafer extracting / accommodating device is arranged in parallel with the wafer detecting device shown in FIG. 1, and the wafer detecting device e shown in FIG. The same reference numerals are given to the same portions as. That is, the elevator 2 provided with the light emitting element 7, the light receiving element 8 and the half mirror 6 is attached to the ball screw 12 driven by the pulse motor 11 and is slidably supported by the two guide shafts 16. .

The wafer unloading / housing device h is a wafer transfer means for taking out the wafer 4 from the housing box 5 or housing the wafer 4 in the housing box 5, and also serves as an elevator 2 as a vertical position changing means. . The wafer unloading / accommodating device h is provided with a unloading arm 9 having a flat plate-shaped wafer placing portion for inserting the wafer 4 into the accommodation box 5 and taking out 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
It is a means for moving the take-out arm 9 toward the storage box 5 in the front-rear direction and in the X direction in the figure by rotation, and receives the rotational force applied from the pulse motor 13 via the belt 15 and rotates.

A vacuum hole is provided on the wafer 4 mounting portion of the take-out arm 9, that is, on the suction surface of the wafer 3, so that a vacuum for sucking the wafer 4 acts on the wafer 4.

According to this structure, after the presence / absence of the wafer is detected, as shown in FIG. 4, the take-out arm 9 taken out by driving the belt 15 by the pulse motor 13 is moved forward and taken out. Insert on the bottom side of 4. The pulse motor 13 is stopped, and then the elevator 2 is slightly raised, and then the vacuum is operated to adsorb the wafer 4 to the wafer mounting surface of the takeout arm 9. When the pulse motor 13 is reversed in this state, the take-out arm 9 moves backward together with the belt 15 and the wafer 4 is taken out from the storage box 5 by the take-out arm 9.

Next, FIG. 5 shows the wafer detection / detection shown in FIG.
The system configuration of the take-out / storing device is shown. 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. It is determined.

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 13 and the elevator drive device i of the wafer unloading / housing device h are subjected to positioning control based on information from the unloading control device means c or the housing control device d, and the wafer 4 is taken out from the housing 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.

Next, FIG. 6 shows a control system of the wafer detection / unloading / storing device. That is, a control unit 20 including a one-board microcomputer is installed in the wafer detection / removal / accommodation device, and the wafer 4 is installed in the control unit 20.
CPU2 which executes the detection / removal / storage control program
1. An input port 24 is installed together with a ROM 22 as a storage means for storing a detection / removal / storage 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. Input port 24
A detection signal from the wafer detection device e, the vacuum detector 31, and the limit detector 32 is added to. CP
The control output obtained from U21 is the elevator drive circuit 3
3, wafer unloading / storing drive circuit 34 and fixed pin circuit 3
Added to 5. The drive output of the elevator drive circuit 33 is the pulse motor 11, the wafer unloading / storing drive circuit 34.
Is output 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 in the above-mentioned structure 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, if it is stored, the process proceeds to step S6, and if it is taken out, step S6 is performed.
Move to 9. In step S6, it is determined whether 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 number of wafer storage stages and then 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,
Move to 21. If it is determined to be automatic in step S21, the process proceeds to step S22 to set the wafer loading / unloading, and then proceeds to step S23. If it is determined to be manual, step S22 is omitted and step S23 is performed.
Move to

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 such a program process, when taking out the designated wafer 4 from the storage box 5, the storage box 5
The detection data obtained by detecting the wafer position state in the inside by the wafer detection device e is read from the RAM 23, and the output from the CPU 21 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 can be 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 of,
Even if the wafer 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. In this state, the wafer 4 is placed on the suction surface of the take-out arm 99, and when a vacuum is applied by a command from the CPU 21, the wafer 4 is sucked on the suction 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, and the CPU 21 The suction information of the wafer 4 is transmitted to. 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 reference height position, 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. The 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 the take-out arm 9 moves the take-out arm 9 to the designated position by its rotation. Wafer 4 inside
Move at a height that does not collide with. That is, the take-out 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, and the wafer 4 is stored at that position.
After releasing the vacuum, the take-out arm 9 is retracted and returned to the original position as in the case of taking out the wafer 4 described above.

In the embodiment, the reflecting mirror 3 is installed and the light beam L 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. Thus, the presence or absence of the wafer 4 in the storage box 5 may be detected by directly receiving the light beam L after passing through the storage box 5.

[0031]

As described above, according to the present invention, the storage box is irradiated with the light beam, the light beam transmitted through the storage box is reflected by the reflecting mirror, and the reflected light beam is converted into the light beam.
Since the side that emits light receives light,
A storage box that can be simplified and facilitated
The position and presence of wafers in the wafer can be detected with high precision in a non-contact manner, and when wafers are transferred, that is, when an arbitrary wafer is taken out of the storage box or stored at an arbitrary position in the storage box. It is possible to contribute to higher efficiency and automation of wafer transfer.

[Brief description of drawings]

FIG. 1 is an embodiment of a wafer detection device of the present invention.

FIG. 2 is a perspective view showing detection of a wafer by the wafer detection apparatus shown in FIG.

3 is a perspective view showing a wafer detecting / accommodating / removing device which is an embodiment of the wafer detecting device shown in FIG. 1. FIG.

FIG. 4 is a view showing a wafer taking-out state by the wafer detecting / accommodating / taking-out device shown in FIG. 3;

5 is a block diagram showing a control system of the wafer detection / storage / unloading device shown in FIG.

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

FIG. 7 is a flowchart showing a control program of the wafer detection / storage / unloading device.

FIG. 8 is a flowchart showing a control program of the wafer detection / storage / unloading device.

FIG. 9 is a flowchart showing a control program of the wafer detection / storage / unloading device.

FIG. 10 is a flowchart showing a control program of the wafer detection / storage / unloading device.

[Explanation of symbols]

e Wafer detection device 2 Elevator (elevating means) 3 Reflector 4 Wafer 5 Storage box 7 Light emitting element (light beam irradiating means) 8 Light receiving element (light receiving means) 9 Extracting arm

Claims (1)

(57) [Claims] 1. A storage box which is opened so that light can be transmitted in the front-rear direction and which can store a plurality of wafers at regular intervals, and an arm which moves in and out of the storage box. Wafer unloading / accommodating means for unloading or accommodating the wafer; light beam irradiating means for irradiating the wafer arbitrarily accommodated in the accommodating box with a light beam from the front side of the accommodating box; A reflecting mirror that receives the light beam emitted by the irradiation means on the back side of the storage box and reflects the reflected light beam from the back side to the front side of the storage box; and the reflected light that has passed through the storage box. light receiving means for generating a detection signal indicative of the presence or absence of the wafer by receiving the beam, depending on the extraction or storage of the wafer by the wafer unloading-storing means, said receiving means and By moving at least one of the climate beam irradiation means and said receiving box, to change their relative positions, to the light beam allows sequentially irradiating the wafer in said storage box A wafer detection device comprising: a lifting unit.