JP2002252267A - Wafer conveyance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer conveyance device which can position a wafer accurately and test it without using an aligner. SOLUTION: In the wafer conveyance device in which a wafer is taken out of a wafer cassette for storing many wafers and is conveyed to a predetermined mounting position, a sensor for detecting the wafer position is arranged in at least either one of the wafer cassette and the mounting position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing and inspection apparatus and the like relating to semiconductor manufacturing, wherein wafers are taken out one by one from a wafer accommodating section for accommodating a large number of wafers in a cassette. The present invention relates to a wafer transfer device that is precisely positioned and arranged at a predetermined mounting position in order to perform the above operation.

As an example, there is a wafer inspection apparatus for inspecting a wafer for a defect or an attached foreign substance. In this case, a predetermined mounting position corresponds to an inspection stage for inspecting the wafer.

[0003] Further, other processes correspond to processes such as a resist process and an exposure process. In this case, a transfer apparatus for a wafer to be processed in these processes.

[0004]

2. Description of the Related Art Generally, wafers are stored in a cassette capable of storing a plurality of wafers as shown in FIG. The cassette has a structure having an entrance which can be taken out in a predetermined direction (in the direction of the right opening in the case of the cassette 5 in FIG. 5) in a substantially horizontal plane.

Due to this structure, the movement is restricted in the direction perpendicular to the predetermined one direction, but each wafer is freely movable in the predetermined one direction of the cassette. In the above-mentioned predetermined direction, the storage position in the cassette tends to vary.

Although a wafer is basically disliked by the generation of foreign substances, it is handled with care for vibrations and shocks. However, it is not completely fixed, so that variations due to vibration during transfer and inclination during installation are completely eliminated. Is difficult to prevent.

However, positioning of a wafer in a semiconductor manufacturing process is extremely important.

For example, in a wafer surface inspection apparatus, a wafer mounted on a stage rotates at a high speed during an inspection process. Therefore, if the mounting position is misaligned, not only the inspection accuracy is reduced, but also the wafer is damaged. And so on.

In the case of a mechanism for holding a wafer by holding means such as a holder for holding the wafer, if the position of the wafer is misaligned, an uneven force is applied to the wafer by the holding means and the wafer may be damaged. There is.

For these reasons, it is necessary to precisely position the wafer on the stage.

As a means for increasing the positioning accuracy by adjusting the center position of the wafer to a predetermined position, an apparatus called an aligner has been generally used.

During the process of moving the wafer from the wafer storage unit to a predetermined mounting position, the wafer is placed on this aligner and the center position of the wafer is adjusted to a predetermined position, thereby being affected by variations in the storage unit. This makes it possible to always place a wafer at a predetermined mounting position without any problem.

The wafer transfer process will be specifically described using a wafer inspection apparatus as an example.

As shown in FIG. 6, a conventional wafer inspection apparatus includes a wafer storage section for storing a large number of wafers 2 in a cassette 5 and a wafer storage section for loading the wafers 2 one by one. An inspection stage unit 3 for inspection and a transfer device 6 for transferring each wafer 2 between the wafer storage unit and the inspection stage unit 3 were provided. Then, an aligner 7 is provided between the wafer storage unit and the inspection stage unit 3 in order to correct the position of the wafer accurately.

The wafer 2 housed in the cassette 5 is taken out of the cassette 5 and, while being transported to the inspection stage 3, the wafer 2 is placed on the aligner 7 and aligned at the aligner 7 so that the wafer 2 is positioned at a predetermined position. And the wafer 2 is placed at an accurate position on the inspection stage unit 3 by the arm of the transfer device 6.

The aligner 7 repositions the wafer 2 at a predetermined position in two-axis coordinates and angles in a horizontal plane. The aligned wafer 2 is always positioned at a predetermined position on the inspection stage 3. Strictly positioned.

[0017]

The use of the aligner 7 has the following disadvantages.

(A) Since it is necessary to apply the wafer to the aligner 7 for each wafer, the inspection time (especially, the transport time) becomes longer (at least 10 seconds per wafer), and it is difficult to improve the inspection efficiency. .

(B) A space for arranging the aligner 7 is required, and the apparatus becomes large.

(C) Since the aligner 7 is an expensive device, the manufacturing cost of the entire device increases.

An object of the present invention is to provide a wafer transfer device capable of accurately positioning and inspecting a wafer without using an aligner.

[0022]

Means for solving the problems are exemplified in claims 1 to 9 of the present invention.

The following is another example of the solution of the present invention.

(1) A wafer transfer device for transferring each wafer from a wafer storage unit for storing a large number of wafers in a cassette to an inspection stage unit for mounting the wafers one by one and inspecting the wafers. , Wherein a sensor for detecting a position of a wafer is provided in at least one of the wafer storage section and the inspection stage section.

(2) In a wafer transfer apparatus for transferring wafers from a wafer storage unit for storing a large number of wafers in a cassette to an inspection stage for inspecting wafers by placing the wafers one by one, A wafer transfer device, wherein a sensor for detecting a position of a wafer is provided in a passage area of the wafer between a wafer storage unit and an inspection stage unit.

(3) The wafer transfer apparatus as described above, wherein the sensor is a light transmission type optical sensor.

(4) The wafer transfer apparatus as described above, wherein the sensor is a light reflection type optical sensor.

(5) The wafer transfer apparatus as described above, wherein the sensor is a light-blocking optical sensor.

(6) At least two sensors are provided on the inspection stage unit, and one sensor is provided on an approach axis intersecting the rotation axis of the wafer. The wafer transfer device as described above, wherein one sensor is provided in a direction at an angle of 90 degrees with respect to.

(7) A sensor is provided near the wafer entrance of the wafer storage section to detect the position of the wafer when the wafer is slightly removed from the cassette or when the removal is completed. The above-described wafer transfer device characterized by the above-mentioned.

(8) The above-described wafer transfer device in which the sensor detects the position of the edge portion of the wafer.

(9) One wafer in the wafer inspection device
The above-described wafer transfer device in which an inspection stage unit that inspects wafers by mounting them one by one is set as a mounting position.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sensor capable of detecting a wafer is provided at a transfer position when a wafer transfer apparatus transfers a wafer between a wafer storage section and an inspection stage section, and an aligner is used by using a detection signal of the sensor. Made unnecessary.

The movement of the wafer from the wafer storage unit (especially the cassette) to the inspection stage unit is performed by a cassette, a transfer unit, an aligner (alignment operation), a transfer unit, and an inspection stage unit in a conventional general transfer. However, according to the present invention, the position correction (alignment operation) by the aligner becomes unnecessary. As a result, the transfer of the wafer
The cassette → transfer device → inspection stage section became possible.

A preferred wafer inspection apparatus according to the present invention comprises:
This is a wafer inspection apparatus that can detect the presence of a defect or foreign matter on the wafer surface.

In the patterned wafer,
A wafer inspection apparatus that can detect a defect in a pattern by learning a non-defective image and comparing the pattern with each observation image may be used.

It is preferable that the sensor for detecting the position of the wafer is particularly capable of accurately detecting the peripheral portion of the wafer.
In particular, by utilizing the reflection of the edge part corresponding to the side surface of the disk-shaped wafer, it is possible to detect the position with higher accuracy.

The sensor for detecting the position of the wafer is preferably a transmission type, reflection type or light shielding type optical sensor.

The transfer device and its arm are controlled based on the detection signal from the optical sensor, and the arm accurately determines the wafer mounting position.

In one embodiment of the present invention, when a wafer is transported to a position at the time of the initial inspection, the position where the wafer is displaced in the cassette is reflected as a positional deviation even after the transport, and the difference from the optical sensor. , The shift state of the wafer position is determined, and the mounting position of the wafer is corrected and moved according to the determination.

There are various ways of correcting the wafer, but it is preferable to stop the correction movement by detecting that the wafer is at the correct position by an optical sensor.

In particular, if a sensor is arranged on the stage and the correct position when the wafer is placed on the stage can be detected, even if an abnormality occurs in the previous transfer process, the wafer can be placed on the stage. The mounting position can be accurately determined without being affected by abnormalities.

By devising the number and position of the optical sensors, more accurate wafer positioning can be performed in accordance with the direction and speed of wafer movement.

Further, by using a plurality of sensors, it is possible to use it as an auxiliary sensor for detecting an orifice notch.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wafer transfer apparatus according to the present invention stores a large number of wafers in a cassette, which is used in a wafer inspection apparatus for inspecting defects on a wafer on which a pattern has not been formed and foreign substances attached thereto. It is optimally used as a device for transferring wafers from the wafer storage section to an inspection stage section for placing wafers one by one and inspecting the wafers. In addition, in addition to the above, transfer in a wafer inspection device for inspecting a defect of a circuit pattern (micro-order fine pattern) of a chip formed on a wafer of silicon or the like, or a device used in a process such as a resist process or an exposure process. It may be used as a device.

The wafer inspection apparatus provided with the wafer transfer device according to the present invention comprises: a wafer storage unit for storing a large number of wafers in a cassette at predetermined intervals; a movement in the XZ direction; A rotating inspection stage,
An observation unit (consisting of an observation optical system, a CCD sensor, etc.) for observing the wafer for inspection at the inspection stage unit, a wafer transfer unit for transferring wafers one by one between the wafer storage unit and the inspection stage unit, and an arithmetic unit Processing unit, control unit, display unit (monitor), input unit (keyboard, operation stick,
Mouse or the like).

In a wafer inspection apparatus, a light beam such as a laser beam is made incident on the surface of a wafer placed on an inspection stage, the reflected light is observed by an observation unit, and processed by an arithmetic processing unit to process the light on the wafer surface. Detect defects, foreign matter, etc.
The result is displayed on a display unit (monitor).

Embodiment 1 of FIG . 1 In FIG. 1, a sensor 1 is disposed at the back of the inspection stage 3 (near the outer peripheral portion of the wafer 2) in the direction of the approach path of the wafer 2 intersecting with the rotation axis of the wafer 2. I have.

The sensor 1 can be of a light transmission type, a light reflection type, a light blocking type, or other detection method. However, the sensor 1 should be arranged so that the reflected light at the wafer edge is incident only when the wafer is at a predetermined position. Thus, the predetermined position of the wafer can be detected.

The cassette 5 is arranged in a storage section (not shown), in which a large number of wafers 2 are stored at predetermined intervals in a vertically overlapping manner as shown in FIG. Have been.

The inspection stage section 3 is to place the wafers 2 one by one horizontally and inspect each wafer 2.

The wafer transfer device 6 mainly uses an arm, and the wafer storage unit (cassette 5) and the inspection stage unit 3
Each wafer 2 is transferred without passing through an aligner between the two, and each wafer 2 is delivered to each of a wafer storage unit (cassette 5) and an inspection stage unit 3 at a predetermined position.

Embodiment of FIG . 2 In FIG . 2 , two sensors 1 are provided on the inspection stage section 3. That is, one sensor 1 is connected to the wafer 2
Is disposed near the periphery of the wafer at the back of the inspection stage unit 3 in the direction of the approach path of the wafer 2 that intersects the rotation axis of
The other sensor 1 has a direction of 9
It is located near the wafer periphery in the direction perpendicular to 0 degrees.

A large number of wafers 2 are stored at predetermined intervals in a cassette 5 arranged in a storage section (not shown) so as to overlap in the vertical direction (see FIG. 5).

The inspection stage section 3 is to place the wafers 2 one by one and inspect each wafer 2.

The wafer transfer device 6 mainly uses an arm, and the wafer storage unit (cassette 5) and the inspection stage unit 3
Each wafer 2 is transferred between the wafer storage unit (cassette 5) and the inspection stage unit 3 at a predetermined position.
Is to be delivered.

FIG . 3 shows an embodiment in which two optical sensors 1 and 4 are connected to a cassette 5.
And the inspection stage unit 3 side. The two sensors 1, 4 are preferably of another type. A large number of wafers 2 are accommodated in the cassette 5 at predetermined intervals as shown in FIG.

One sensor 1 is arranged at the back of the inspection stage 3 (in the vicinity of the periphery of the wafer 2) in the direction of the approach path of the wafer 2 intersecting with the rotation axis of the wafer 2. Another one of the sensors 4 is located outside (e.g., 5 m) near the outlet of the cassette 5 in the direction of the exit path of the wafer 2.
In particular, after the wafer 2 has been completely removed from the cassette 5, it is arranged to detect a state where the wafer 2 has moved a minute predetermined distance.

The wafer accommodating section accommodates and accommodates a large number of wafers 2 in a cassette 5 in a vertically overlapping manner at predetermined intervals as shown in FIG.

Also in the embodiment shown in FIG. 3, the wafer transfer device 6 transfers each wafer 2 between the wafer storage section (cassette 5) and the inspection stage section 3 mainly using an arm.
Each wafer 2 is transferred to each of the wafer storage unit (cassette 5) and the inspection stage unit 3 at a predetermined position.

Preferred Examples of Sensors Preferred sensors 1 and 4 used in the above three embodiments will be described.

It is preferable that the sensor 1 provided on the inspection stage section 3 is arranged near the peripheral portion of the wafer 2 when the wafer 2 is placed at an accurate position. In addition, it is desirable to use two sensors 1 so as to correspond to the orifice notch formed on the wafer (that is, to detect a notch formed on a part of the periphery of the wafer).

In this case, as shown in FIG. 7, the two sensors (indicated by black circles) are arranged with an interval wider than the width of the orifice notch (the straight outer peripheral portion in the figure), thereby The position of the wafer can be reliably detected without being affected by the position of the notch. In the state on the left (a), two sensors are located on the circular outer periphery of the wafer, in the state on the right (b), one sensor is located on the circular outer periphery of the wafer, and the other is located on the linear outer periphery of the wafer. It is located outside.

When a light-shielding type sensor 1 (not limited to the present invention) is used, the wafer 2 is moved coarsely (for example, in units of 1 mm) in the direction in which the wafer 2 enters, and the wafer 2 is moved to a desired set position. When the wafer 2 has passed through, the wafer 2 is densely (eg, in units of 0.1 mm) in a direction opposite to the approach direction.
It is best to move the wafer slowly so that the wafer is moved coarser and faster in one direction and densely and slowly in the other direction, and ultimately precisely positioned.

FIG. 4 shows an example of an operation procedure when such a light shielding type sensor 1 is installed in the wafer inspection apparatus of FIG.

First, the operation of the wafer inspection apparatus is started. The arm of the transfer device 6 moves to the position of the cassette 5, sucks the wafer 2, and moves directly to the predetermined position of the inspection stage 3. If there is no output from the sensor 1, it continues to move in the + direction, and if there is an output from the sensor 1,
Immediately moves in the opposite-direction. Thereafter, if there is an output from the sensor 1, the movement in one direction is continued as it is. (At this time, the moving speed is reduced and the moving is performed slowly.) When the output of the sensor is detected again, the movement of the wafer by the arm is immediately stopped, and the wafer 2 is placed on the inspection stage unit 3. Thereafter, the wafer 2 is measured (inspected), and when the measurement is completed, the arm of the transfer device 6 sucks the wafer 2,
The wafer 2 is moved from the mounting stage 3 to a predetermined position of the cassette 5 and stored in the cassette 5.

As for the sensor 4 on the cassette 5 side, it is preferable to move the arm of the transfer device 6 as follows. That is, when pulling out the wafer 2 from the cassette 5, first, a predetermined distance immediately before the entire wafer comes out of the cassette is quickly pulled out, and thereafter, the wafer 2 is slowly drawn out with the moving speed reduced. Then, when the sensor 4 detects a predetermined end of the wafer, it sends a detection signal from the actual position of the wafer to a control unit (not shown) based on the state of the arm at that detection position, and stops the actual stop. The control unit (not shown) for the transport device 6 stores the position. This enables the transfer device 6 to place the wafer 2 at an accurate position on the inspection stage unit 3.

Using the light reflection type sensor 1,
By making it possible to detect that the peripheral portion of the wafer 2 has reached an accurate position, more precise positioning of the wafer 2 can be performed smoothly.

When the wafer 2 conveyed from the cassette 5 in the wafer accommodating section is close to the desired set position of the stage section 3 by the arm of the transfer device 6, the wafer 2 is densely moved in the approach direction as described above. Move slowly. Wafer 2
When the sensor 1 outputs a signal indicating that the peripheral portion of the wafer 2 is at the predetermined position during the movement of the wafer 1, the transfer device 6 is controlled so that the wafer 2 stops at that position.
The wafer 2 can be precisely positioned on the stage 3.

[0070]

According to the present invention, the wafer can be accurately placed on the inspection stage without using an aligner when transferring the wafer.

As a result, the following effects can be obtained.

(A) Inspection of a wafer can be realized in a shorter time.

(B) Since no aligner is required, the size of the inspection apparatus can be reduced.

(C) Since the aligner is an expensive device, the cost of the entire device can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a wafer detection device according to one embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a wafer detection device according to another embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a wafer detection device according to still another embodiment of the present invention.

FIG. 4 shows an example of an operation procedure of the wafer inspection apparatus of FIG.

FIG. 5 shows a relationship between a conventional cassette and a wafer.

FIG. 6 is a conceptual diagram showing a conventional wafer detection device.

FIG. 7A shows an example of a positional relationship between two sensors and a wafer. (B) shows another example.

[Explanation of symbols]

 1, 4 sensor 2 wafer 3 inspection stage section 5 cassette 6 transfer device 7 aligner

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/66 H01L 21/66 Z F term (Reference) 2G051 AA51 AB01 AB02 CA03 CA04 DA03 4M106 AA01 DG21 DJ40 5F031 CA02 FA01 FA11 GA36 GA43 JA05 JA06 JA17 JA22 JA23 JA25 JA34 JA35 JA36 KA13 KA14 MA27 MA33

Claims (9)

[Claims] In a wafer transfer apparatus for taking out a wafer from a wafer storage section storing a large number of wafers and transferring the wafer to a predetermined mounting position, a sensor for detecting the position of the wafer is provided with a sensor for detecting the position of the wafer storage section and the mounting position. A wafer transfer device provided at least on one side. 2. In a wafer transfer apparatus for taking out a wafer from a wafer storage section for storing a large number of wafers and transferring the wafer to a predetermined mounting position, a sensor for detecting the position of the wafer is provided between the wafer storage section and the mounting position. A wafer transfer device provided above the wafer passing range. 3. The wafer transfer apparatus according to claim 1, wherein the sensor is a light transmission type optical sensor. 4. The wafer transfer apparatus according to claim 1, wherein the sensor is a light reflection type optical sensor. 5. The wafer transfer device according to claim 1, wherein the sensor is an optical sensor of a light blocking type. 6. At least two sensors are provided at the mounting position, and one sensor is provided on an approach axis that intersects the rotation axis of the wafer, and one sensor is provided on the approach axis and the rotation axis. The wafer transfer device according to any one of claims 1 to 5, wherein one sensor is provided in a direction at an angle of 90 degrees. 7. A sensor is provided in the vicinity of the wafer entrance of the wafer storage unit, and detects a position of the wafer when the wafer is slightly removed from the state stored in the cassette or when the removal is completed. Claim 1
6. The wafer transfer device according to any one of 5. 8. The wafer transfer device according to claim 1, wherein the sensor detects a position of an edge portion of the wafer. 9. The apparatus according to claim 1, wherein the mounting position is an inspection stage for mounting the wafers one by one in a wafer inspection apparatus and inspecting the wafers. Wafer transfer device.