JP2001148409A - Wafer transfer apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer transfer apparatus which can take out a wafer from a carrier 13 and transfer the wafer to the stage of a treatment apparatus smoothly, even if there are variations in the positions of slot grooves among the resin-molded carriers 13. SOLUTION: When a wafer 14 is taken out from a carrier 13, the relative distance between the surface of a conveyance arm 1 and the surface of the wafer 14 is obtained, the conveyance arm 1 is inserted into the carrier 13, so as to face the rear surface of the wafer 14 with a gap therebetween, and the wafer 14 is put on the conveyance arm 1 and taken out from the carrier 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer apparatus for extracting a plurality of wafers one by one from a carrier for vertically arranging a plurality of wafers and transferring the same to a stage of a processing apparatus.

[0002]

2. Description of the Related Art Usually, in a wafer processing step in a semiconductor device manufacturing process, a wafer is transferred between processing apparatuses by:
It has been performed with a carrier capable of storing a plurality of wafers.
This carrier has an opening through which a wafer is taken in and out in one direction, and a plurality of slot grooves for guiding and storing the wafer are formed on both side walls of the opening.

A wafer transfer device has been used to take out wafers one by one from a carrier accommodating a plurality of the wafers and transfer them to a stage of a processing apparatus. This wafer transfer device has an elevator mechanism that can move a carrier and move up and down, and a transfer arm that transfers a wafer.

In order to transfer a wafer to a stage of a processing apparatus, first, a transfer arm is inserted between two upper and lower wafers stored in a carrier mounted on an elevator mechanism. The carrier is lowered by the elevator mechanism, the upper wafer is transferred to the transfer arm, the transfer arm is pulled out of the carrier, the transfer arm on which the wafer is mounted is moved, and the wafer is transferred to the stage of the processing apparatus. Was transferred.

This wafer transfer apparatus teaches in advance the operation of the transfer arm and the operation of the vertical movement of the elevator mechanism using a dummy wafer or the like, and transfers the transfer arm as taught.
The wafer transfer is performed by operating the system and the elevator mechanism.

[0006]

However, since the carrier is molded in a resin mold, the carrier has variations in dimensions. For this reason, if the carrier is different, there is a problem that the transfer arm comes into contact with the stored wafer or hits the wafer, thereby damaging the wafer to be taken out and making it impossible to deliver the wafer smoothly.

Further, when the carrier is changed, it is only necessary to teach again, but there is a problem that much time is wasted on this teaching.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wafer transfer apparatus capable of smoothly transferring a wafer even when the carrier changes.

[0009]

SUMMARY OF THE INVENTION The present invention is characterized in that a carrier is provided from a carrier which is mounted on an elevator which can move up and down and which has a plurality of slot grooves formed therein for accommodating a plurality of wafers vertically. A height of a surface of the wafer to be transferred in the carrier from a reference surface in a wafer transfer device for transferring the wafer to a stage of a processing device by extracting one wafer by a system And a fork surface detection sensor for detecting the height of the surface of the transfer arm from the reference surface. The height of the surface of the wafer to be transferred is A
When the height of the surface of the transfer arm is B and the predetermined distance between the surface of the transfer arm and the surface of the wafer to be transferred is C, ABC is defined as A calculation unit for calculating,
It is preferable that a control unit be provided for moving the elevator up and down by the distance calculated by the arithmetic unit and extracting the wafer to be transferred by the transfer arm. Further, it is preferable that a storage unit is provided for storing height data of the slot groove from the top to the bottom corresponding to the unique number of the carrier from the reference surface.

On the other hand, it is desirable that the wafer surface detection sensor includes a light emitting unit for projecting laser light and a light receiving unit for receiving laser light from the light emitting unit. Further, it is desirable that the fork surface detection sensor is a laser interferometer. Further, it is desirable that the stage rises when the wafer is transferred to the stage.

[0011]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a structure for explaining a wafer transfer device according to an embodiment of the present invention.
As shown in FIG. 1, the wafer transfer apparatus includes an elevator mechanism 1 capable of vertically moving a carrier 13 for accommodating a plurality of wafers 14 in slot grooves 13a on both sides thereof on a mounting surface 12.
1 and the wafer 1 in the carrier 13 by extending the transport arm 1
4, the transport arm 1 is contracted, the wafer 14 is pulled out from the carrier 13, and the wafer 14 is moved in the direction of the arrow.
The transfer arm on which the wafer 14 is placed is extended, and the wafer 14 is moved to the stage 7.
And an arm expansion / contraction mechanism 2 to be transferred to the vehicle.

A wafer surface detecting sensor comprising a light projecting section 3 for projecting laser light into the carrier 13 and a light receiving section 4 for receiving laser light leaking out of the carrier 13;
Fork-shaped transport area in front of stage 7 of die 15
An arm surface detection sensor 5 for detecting the height of the surface of the arm 1 is provided.

The light projecting portion 3 of the wafer surface detecting sensor projects a laser beam having a spot diameter substantially equal to the thickness of the wafer 14, and there is no wafer 14 to be taken out and the carrier 13
In this space, the laser beam passes through the carrier 13 and enters the light receiving unit 4 to generate a maximum current. When the carrier 13 is raised by the elevator mechanism 11 and the laser beam starts to hit the wafer 14 to be taken out, the current of the light receiving section 4 decreases as the light-shielded portion of the laser beam increases. start. When the laser beam is completely shielded from light by the wafer 14, the current of the light receiving section 4 becomes zero. When the current value of the light receiving unit 4 is zero, the distance from the reference surface 15b to the wafer 14 to be taken out is defined as A.

On the other hand, it is desirable that the arm surface detecting sensor 5 is a laser interferometer. And an elevator mechanism 1
The loader reference surface 15a having the same height as the reference surface 15b near 1
Is irradiated with laser light to the reflecting mirror 6a placed at the position, and the height of the loader reference surface 15a is measured. Next, the transport arm 1 is positioned as indicated by a two-dot chain line, and the reflecting mirror 6a of the transport arm 1 is positioned.
Is irradiated with laser light to determine the distance of the transport arm 1. Then, the transport arm 1 is determined based on the height of the loader reference surface 15a.
Is subtracted, the height of the transport arm 1 can be determined. The height of the transport arm at this time is defined as B.

FIG. 2 is a sectional view for explaining the operation of the wafer transfer device of FIG. Next, the operation of the wafer transfer device will be described with reference to FIGS. First, the carrier 13 conveyed from the upstream process is moved to the elevator 11
On the mounting surface 12. At this time, the elevator mechanism 11 has the mounting surface 12 at the lower position. Next, the carrier 13 starts to be lifted by the elevator mechanism 11.

A laser beam is emitted from the light projecting section 3 as the carrier rises, passes through the space of the carrier 13, and enters the light receiving section 4. When the laser beam further rises, the laser beam starts to hit the wafer 14 and the light-shielded portion increases, and the current of the light receiving section 4 decreases. Then, the current of the light receiving unit 4 is sent to the signal conversion unit 8 and is converted into a digital signal. When the laser beam spot is completely blocked by the end face of the wafer 14,
The signal converter 8 outputs a pulse signal defining zero current to the arithmetic unit 9
Send to At the same time, a stop signal is sent to the control mechanism 10 via the arithmetic section 9 to the control section 10 to send the stop signal to the control section 10.
Is maintained as it is.

The distance A between the reference surface 15b of the fixed base near the elevator mechanism 11 and the surface of the wafer 14 to be taken out.
Are read by a resolver or a magnescale incorporated in the elevator mechanism 11 and stored in the arithmetic unit 9 via the control unit 10.

On the other hand, the transport arm at the position indicated by the two-dot chain line
As described above, the height of the transport arm 1 is measured by the arm surface detection sensor 5 and the signal thereof is transmitted to the signal converter 8.
Is sent to the arithmetic unit 9 via the CPU and stored.

Next, as shown in FIG. 2, the distance between the transfer arm 1 and the loader reference surface 15a (or the reference surface 15b) is subtracted from the distance between the reference surface 15b and the wafer 14 to be taken out. The arithmetic unit 9 calculates a distance value obtained by subtracting a constant value C including the clearance between the upper surface of the transfer arm 1 and the rear surface of the wafer, the thickness of the wafer, and the warpage of the wafer 14. The distance signal obtained by the arithmetic unit 9 is sent to the control unit 10, and the control unit 10 sends a signal of the number of pulses corresponding to the distance value to the pulse motor of the elevator mechanism 11.

As a result, the elevator mechanism 11 moves up or down and stops at a predetermined position. On the other hand,
The system 1 moves before the carrier 13. Then, the transport arm 1 is extended by the arm extending / contracting mechanism 2 and inserted into the carrier 13, and the transport arm 1 is located between the wafers 14 located above and below. In this state, as shown in FIG. 2, the transfer arm 1 is located below the upper wafer 14 by a distance C. The carrier 1 is moved by the elevator mechanism 11.
3 is lowered by a predetermined distance (a distance at which the wafer 14 floats from the side wall of the slot groove and comes into contact with the transfer arm 1), and the wafer 14 floating from the slot groove 13a is transferred to the transfer arm 1. This lowering amount is hereinafter referred to as D.

Next, the transport arm 1 is pulled out of the carrier 13 by the arm expansion and contraction mechanism 2, and the arm expansion and contraction mechanism 2 moves sideways and stops in front of the loader 15. Next, the transfer arm 1 on which the wafer 14 is placed is extended by the arm expansion / contraction mechanism 2, and the wafer 14 is positioned on the stage 7. And
The two blocks constituting the stage 7 are lifted to lift the wafer 14 from the transfer arm 1 and transfer the wafer 14 from the transfer arm to the block. Then, the transfer arm 1 retreats and stops at the original position (the position indicated by the two-dot chain line). On the other hand, the carrier 13 is raised by the height D by the elevator mechanism 11 and returns to the original height. Then, the wafer 14 descends while being placed on the block.

Here, the transfer arm 1 may be lowered to transfer the wafer 14 to the stage 7.
It is more desirable to raise. The reason is that the transfer arm, which is a loader on the processing apparatus side, can easily transfer the wafer, and the arm expansion / contraction mechanism 2 does not need to have a mechanism for moving up and down. The mechanism is simple, which is advantageous from the viewpoint of maintaining accuracy.

As described above, when the wafer 14 is transferred to the stage 7 of the loader 15 and then processed by the processing apparatus, and the processed wafer 14 is stored in the carrier 13 again, First, the transport arm 1 at the original position is extended, and the wafer 14 pushed up by the block of the stage 7 is moved.
The transport arm 1 is inserted under the box. Next, the block of the stage 7 is lowered, and the wafer 14 is transferred to the transfer arm 1.

Then, the transport arm 1 is pulled in, and the
The transfer arm 1 is positioned in front of the carrier 13 by moving the telescopic mechanism 2. Next, the transport arm 1 is extended, and the wafer 14 is inserted between the empty slot grooves 13a of the carrier 13. Next, the carrier 13 moves up by the distance D to transfer the wafer 14 to the slot 13a, and the transfer arm 1 retreats and exits from the carrier 13.

To transfer the next wafer 14 to the loader 15, the above-described operation may be repeated. That is, the carrier 13 is raised by the elevator mechanism 11, the height of the wafer 14 to be taken out of the carrier 13 is set by the laser beam received by the light receiving section 4, and A is obtained. A certain C is subtracted from A, and the transfer arm 1
To take out the next wafer 14 carrier 13.

FIG. 3 is a view showing a carrier for explaining a wafer transfer device according to another embodiment of the present invention. Since the carrier for accommodating the wafer is a resin molded product, the position of the slot groove 13a varies. Therefore, in this wafer transfer device, the ID number is carved for each carrier 13, the heights of the pitches h 1, h 2,... Hn of the slot grooves 13 of each carrier 13 are measured in advance, and the measured values and That is, the data is stored in the additional memory unit of the control unit 10 in FIG. 1 in association with the ID number.

The operation of taking out the wafer 14 in this wafer transfer device is performed by the slot groove 1 on the top of the carrier 13.
When the wafer 14a is taken out, the height of the wafer 14 is measured by the wafer surface detection sensor of FIG. 1, and the height of the transfer arm 1 is measured by the arm surface detection sensor 5 of FIG. Then, as described above, the carrier 13 is raised by the elevator mechanism 11 by the distance ABC, and the uppermost wafer 14 is taken out of the carrier 13 by the transfer arm 1.

When the second wafer from the top is taken out, the I memory stored in the additional memory unit of the control unit 10 is used.
H1 corresponding to the D number is read from the control unit 10 to h1.
A signal having the number of pulses corresponding to 1 is sent to the pulse motor, the carrier 13 is raised by the elevator mechanism 11, the transfer arm 1 is inserted into the carrier 13, and the wafer 14 is removed from the carrier 13 as described above. Take out. When the third wafer is to be taken out, h3 is similarly read from the memory and the carrier 13 is raised by the elevator mechanism 11 to take out the wafer.

When the processed wafer is stored in the uppermost slot groove 13a, it is lowered by D from the height when the transfer arm 1 is inserted into the carrier 13.
The carrier arm 1 on which the processed wafer 14 is placed is inserted into the carrier 13 so that the wafer 14
In the slot grooves 13a on both sides, and only D
3 and lower the processed wafer 14 into the slot groove 13a.
Transfer to

Therefore, when the processed wafer 14 is stored in the uppermost slot groove 13a and the wafer in which the second slot groove is stored is taken out, as described above,
Since the carrier 13 has been raised, the transport arm 1 is inserted into the carrier 13 by raising it by h1 including the rise, and the wafer 14 is taken out. Thus, the wafers 14 can be sequentially taken out.

[0032]

As described above, according to the present invention, when a wafer is taken out from a carrier, the relative distance between the surface of the transfer arm and the surface of the wafer to be taken out is determined, and a gap is provided from the back surface of the wafer to be taken out. Since the arm is inserted into the carrier and the wafer is transferred and taken out of the carrier, the wafer can be transferred very smoothly even if the slot position of the carrier varies, so that there is no damage to the wafer. There is.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration for explaining a wafer transfer device according to an embodiment of the present invention.

FIG. 2 is a sectional view for explaining the operation of the wafer transfer device of FIG.

FIG. 3 is a diagram showing a carrier for explaining a wafer transfer device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveying arm 2 Arm expansion / contraction mechanism 3 Light emitting part 4 Light receiving part 5 Arm surface detection sensor 6 Reflecting mirror 7 Stage 8 Signal converter 9 Operation part 10 Control part 11 Elevator mechanism 12 Mounting Surface 13 Carrier 14 Wafer

Claims (6)

[Claims] 1. A transfer arm pulls out one wafer from a carrier which is placed on a vertically movable elevator and has a plurality of slot grooves for vertically arranging and storing a plurality of wafers. A wafer transfer device for transferring the wafer to a stage of a processing apparatus, a wafer surface detection sensor for detecting a height of a surface of the wafer to be transferred in the carrier from a reference surface; A fork surface detection sensor for detecting a height of the surface of the transfer arm from the reference surface. 2. The height of the surface of the wafer to be transferred is A, the height of the surface of the transfer arm is B, and the height of the transfer arm and the wafer to be transferred are Assuming that a predetermined distance from the surface is C, an arithmetic unit for calculating ABC is used, and the elevator is moved up and down by the distance calculated by the arithmetic unit to move the wafer to be transferred to the surface. 2. The wafer transfer device according to claim 1, further comprising a control unit that pulls out by a transfer arm. 3. A storage unit for storing height data of the slot groove from the top surface to the bottom surface of the carrier corresponding to a unique number of the carrier. The wafer transfer device according to claim 1 or 2. 4. The wafer surface detecting sensor according to claim 1, further comprising: a light emitting unit for projecting laser light, and a light receiving unit for receiving laser light from the light emitting unit. Item 2
Alternatively, the wafer transfer device according to claim 3. 5. The wafer transfer apparatus according to claim 1, wherein said fork surface detection sensor is a laser interferometer. 6. The stage according to claim 1, wherein said stage rises when said wafer is transferred to said stage. Wafer transfer equipment.