JP3331361B2 - Inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for irradiating a surface of a test object with a laser beam and detecting an abnormality on the surface of the test object by reflected light thereof, and more particularly, to a flaw on a surface such as a wafer. The present invention relates to an inspection apparatus suitable for inspecting dust and dirt.

[0002]

2. Description of the Related Art A surface inspection apparatus for irradiating a laser beam onto a surface of a test object such as a wafer and detecting reflected light to inspect the surface of the wafer for scratches, dust and the like is well known.

[0003] For example, Japanese Utility Model Laid-Open No. 60-41045 and Japanese Patent Publication No. 6-20922 disclose a transfer device used for a surface inspection device.

As shown schematically in FIG. 8, these transfer devices sequentially take out wafers from a cassette 3 on a supply side on which a large number of wafers are placed by a conveyor 5 and a chuck section 6.
The wafer is fixed and transported to the measuring section, the surface is inspected while rotating and horizontally moving the wafer at the measuring section, and the wafer after the inspection is sequentially transported to the cassette 3 'on the storage side using the conveyor 5'. It is configured to be stored.

As described above, the conventional inspection apparatus requires the first cassette 3 on the supply side and the second cassette 3 'on the storage side, and wafers are usually exchanged between the two. Was.

[0006]

However, in an inspection apparatus in which an inspected test object is transferred to another cassette as in a conventional inspection apparatus, two cassettes 3 and 3 'are used.
Two elevators 4 and 4 'are indispensable in order to move up and down separately. Similarly, two transporting means 5 and 5 'such as a conveyor for loading and unloading the test object from the cassette are required. Therefore, the whole device is inevitably large and
It becomes heavy.

In view of the above problems of the prior art, an object of the present invention is to provide an inspection apparatus which can be reduced in size and weight as a whole, can greatly reduce the manufacturing cost, and is easy to handle. I have.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided an inspection apparatus for irradiating a laser beam onto the surface of a test object and detecting an abnormality on the surface of the test object by reflected light thereof, wherein a plurality of test objects are stored. A cassette for carrying out each test object from the cassette sequentially, and a transfer arm for storing the test object which has been inspected in the original place of the cassette, and a transfer arm from the cassette by the transfer arm. A holding unit for receiving and temporarily holding the test object, and receiving the test object held by the holding unit and conveying the test object to the abnormality detecting unit, and after the detection is completed, transferring the test object to the transfer unit. And a chuck unit for delivering the arm to the arm.

[0009]

The operation of the test object (3) stored in the cassette (111)
0) is carried out by the transfer arm (110) and the holding unit (11)
6) and temporarily hold it. Then, the test object (30) is transferred from the holding section (116) to the chuck section (112).
Hand over. Next, the chuck part (112) is moved, the test object (30) is transported to the abnormality detection part (10), and the abnormality of the surface of the test object is inspected according to a predetermined procedure. On this occasion,
The next test object (30) is held in the empty holding section (116) by the same means, and the holding section (116) is moved to the standby position. After the inspection, the chuck unit (112) is withdrawn from the abnormality detecting unit (10), and the chuck unit (112) is removed.
The test object (30) is transferred to the transfer arm (110). Then, the test object (30) that has been inspected by the transfer arm (110) is stored in the original location of the cassette (111). Further, the test object (30) is transferred from the held holding unit (116) to the chuck unit (112), and the next cycle is started. Repeat the above cycle,
A plurality of test objects (30) are inspected.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a main part of an inspection apparatus according to the present invention. The inspection device includes a casing, a control unit,
Although a display and the like are also provided, these components can be configured in the same manner as a conventional inspection apparatus, and are not shown in the figure for easy viewing.

The main part of the inspection apparatus is comprised of a detecting unit 10 and a transporting unit 20.

[0013] As shown in FIG.
1 and a photomultiplier 12. Light source 11
Irradiates the surface of the wafer 30 with a laser beam, and receives the scattered and reflected light generated by the surface abnormality by the photomultiplier 12, extracts the scattered light as an electric signal, performs predetermined data processing, and scratches, dust, and the like on the wafer surface. The presence or absence of dirt and the like and the position of the defect are detected. Detector 1
0 can be configured similarly to the detection unit (measurement unit) of the conventional inspection apparatus.

The transfer section 20 includes one transfer arm 11
0, 1 cassette 111, 1 chuck 112,
And one receiving tray 116.

FIG. 3 shows the transfer arm 110 and the tray 116 directly below the transfer arm 110.

The transfer arm 110 unloads the wafer 30 to be inspected from the cassette 111 and
6 and the operation of receiving the inspected wafer 30 from the chuck unit 112 and storing it in the original location of the cassette 111.

The transfer arm 110 has a C-shaped grip 110a at the tip. The grip portion 110a is thin and has a thickness of, for example, about 2 mm. A vacuum hole 110b for adsorbing a wafer is provided near the base of the grip portion 110a. The vacuum hole 110b is
It is connected to a vacuum device via a piping system.

The transfer arm 110 can move only in the X-axis direction in FIG. 1 (see arrow a), but does not move in the Y and Z directions. A drive mechanism (not shown) of the transfer arm 110 can be configured by a moving mechanism using a screw shaft, for example.

The receiving tray 116 is an L-shaped flat plate as a whole, and a stepped receiving portion 116a for mounting a wafer is formed inside the L-shaped plate. The reason why the tray 116 is L-shaped is that the transfer arm 1 is used when transferring the wafer.
This is to avoid interference with the number 10. That is, as shown in FIG. 5, when the tray 116 is lifted while the transfer arm 110 is on the center axis of the tray 116, the two can smoothly transfer the wafer without interference.

The tray 116 is configured to be movable up and down, that is, in the Z-axis direction (see arrow b in FIG. 1). As the moving mechanism (not shown), for example, a cam / cam follower type moving mechanism using an elliptical cam or a moving mechanism using a screw shaft can be adopted.

FIG. 4 shows the cassette 111 and the cassette n.
The transfer arm 110 in a state where the wafer 30 placed on the top is accessed is shown.

The cassette 111 is also called a carrier or a transport case. N partitions 109 are provided on both sides of the cassette 111 so as to accommodate the wafers 30 one by one. The wafers can be stored one by one between the partitions 109 on both sides.

The cassette 111 is set on an elevator 114 as shown in FIG. Elevator 114
Can be moved up and down, that is, in the Z direction by a step motor 115 via a moving mechanism using a screw rod 108 (see arrow c).

The chuck unit 112 performs an operation of receiving the wafer 30 placed on the tray 116 and moving to the detection unit 10. Therefore, it can be moved in the Y direction by a driving mechanism using the screw rod 118 (see the arrow d in FIG. 1).

The chuck 113 has a disk-shaped support plate 112b as shown in FIG. 1, and a vacuum hole 112a is provided in the center of the plate. Support plate 1
The outer diameter of 12b is equal to the gripper 110a of the transfer arm 110.
Is set slightly smaller than the inner diameter. Therefore, the two can be adjacent to each other at a small distance, and can relatively move up and down depending on the positional relationship (see FIG. 7). The vacuum hole 112a is connected to a vacuum device via a piping system. The wafer is attracted to the support plate 112b by the vacuum action, thereby preventing the wafer from being displaced or dropped during transport and detection.

The chuck section 112 has a motor 117, and can rotate the support plate 112b at a predetermined speed (see arrow e). Further, the support plate 112b or the entire chuck portion 112 is configured to be finely movable in the Z direction (see arrow f). This moving mechanism (not shown) can also be constituted by, for example, a guide mechanism using a screw shaft or a cam mechanism having an elliptical cam.

Next, an example of the operation of this embodiment will be described with reference to FIGS.

[Step 1] A cassette on which N wafers to be inspected are placed is set in the elevator 114 of the inspection apparatus, and a start button (not shown) provided in the control unit is pressed.

[Step 2] The pulse motor 115 of the elevator 114 is operated, and the cassette 11 is moved until the first stage of the cassette 111 is almost at the same height as the transfer arm 110.
1 moves upward.

Next, the transfer arm 110 is
It moves in the direction of 1 and moves directly below the first-stage wafer 30. Then, the elevator 114 moves slightly downward. The vacuum device is operated, and the wafer 30 is attracted to the grip 110a. Thereafter, the transfer arm 110 on which the wafer 30 is placed moves in the direction of the tray 116.

[Step 3] The wafer 30 is placed in the tray 11
6 (see FIG. 5A), the tray 116
Moves upward (arrow b1), and at the same time, suction by vacuum is released (see FIG. 5B). Then, the wafer 30 is transferred from the transfer arm 110 to the tray 116. Receiving tray 116 which received wafer 30,
It moves further upward and moves to a position higher than the transfer arm 110 (see FIG. 5C).

[Step 4] Receiving pan 116 for wafer 3
When 0 is received, the chuck unit 112 moves to the lower part of the tray 116 (arrow d1 in FIG. 6). Chuck unit 11
When 2 reaches directly below the tray 116, the tray 116 moves downward (arrow b2). Then, the vacuum device operates, and the wafer 30 is attracted to the chuck portion 112. Thus, the wafer 30 is transferred from the tray 116 to the chuck 112.

At the same time as the movement of the chuck portion 112, the elevator 114 moves upward by one stage. Then, the transfer arm 110 moves to the second-stage partition of the cassette 111, and grips the second-stage wafer.

[Step 5] The chuck unit 112 that has received the wafer moves the wafer to the detection unit 10.
At the same time, the transfer arm 110 moves to transfer the second-stage wafer in the direction of the empty tray 116. When the second-stage wafer held by the transfer arm 110 reaches just above the tray 116, the tray 116 moves upward, and the second-stage wafer is moved from the arm 110 to the tray 116.
Passed to. The tray 116 moves further upward and waits at a position higher than the transfer arm 110.

[Step 6] The detecting section 10 starts a detecting operation. At that time, the chuck portion 112 reciprocates in the Y direction while being rotated by the motor 115.

[Step 7] When the detection operation is completed, the chuck portion 112 moves in the Y direction (arrow d1), and reaches the position of the transfer arm 110 stopped immediately below the tray 116. When the chuck portion 112 reaches the transfer position shown in FIG. 7B (that is, the position where the support portion 112b and the grip portion 110a are adjacent to each other), the vacuum operation of the chuck portion is released, and at the same time, the vacuum of the transfer arm is released. In operation, the wafer 30 is transferred from the chuck portion 112 to the transfer arm 110. Then, the chuck portion 112
Moves a little downward (arrow f1). At the same time,
The elevator 114 moves downward, and the position of the first stage of the cassette 111 is almost at the height of the transfer arm 110.

Thereafter, the transfer arm 110 moves in the X-axis direction, and the inspected wafer is inserted into the first stage of the cassette 111. At this time, the vacuum effect of the transfer arm 110 is released, the elevator 114 moves slightly upward, and the wafer is placed on the first-stage partition 109. In this way, the inspected wafer is returned to the original position of the cassette. Then, the holding unit 11 that has been waiting
The wafer is transferred from 6 to the chuck unit 112, and the next cycle is started.

The above operation is repeated for N wafers.

A series of operations after the switch is turned on are automatically performed in accordance with a control signal sent from the control unit.
The above operation is an example, and the order and timing of the operation can be changed.

[0040]

According to the inspection apparatus of the present invention, only one elevator for moving the cassette up and down and one transfer arm are sufficient, so that the inspection apparatus can be downsized as a whole and the manufacturing cost can be greatly reduced. It is.

The present invention is not limited to the above embodiment. For example, the receiving portion 116a of the tray may have a polygonal line shape instead of an arc shape. At this time, the grip portion 110a of the transfer arm is also formed in a polygonal line shape. Other members can be modified without departing from the spirit of the present invention. Further, the inspection apparatus of the present invention can be used for inspection of not only semiconductor wafers but also magnetic disks and optical disks.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a main part of an inspection device of the present invention.

FIG. 2 is a schematic diagram showing an inspection unit of the inspection device.

FIG. 3 is a perspective view showing a transfer arm and a tray of the inspection device.

FIG. 4 is a perspective view showing a cassette of the inspection device.

FIG. 5 is an explanatory diagram showing the operation of the inspection device.

FIG. 6 is an explanatory diagram showing the operation of the inspection device.

FIG. 7 is an explanatory diagram showing the operation of the inspection device.

FIG. 8 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Detecting part 20 Conveying part 30 Wafer 109 Partition 110 Conveying arm 110a Gripping part 110b Vacuum hole 111 Cassette 112 Chuck part 112a Vacuum hole 112b Support plate 115 Motor 116 Receiving tray 116a Receiving part 117 Motor 118 Screw axis

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 21/89 H01L 21/68

Claims (1)

(57) [Claims] 1. An inspection apparatus for irradiating a laser beam onto a surface of a test object and detecting an abnormality on the surface of the test object by reflected light thereof, comprising: a cassette for accommodating a plurality of test objects; A transport arm for sequentially transporting the objects from the cassette, and storing the inspected specimen in the original place of the cassette; and receiving the specimen transported from the cassette by the transport arm, temporarily A holding unit that holds the test object, a chuck unit that receives the test object held by the holding unit, conveys the test object to the abnormality detection unit, and transfers the test object to the transfer arm after detection is completed; An inspection apparatus comprising: