JPH0622258B2 - Wafer surface inspection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer surface inspection apparatus, and more particularly, to a wafer surface that allows a cassette to be exchanged without dropping foreign matter on the wafers stored in the cassette. Regarding inspection equipment.

[Prior Art] As a conventional art of this kind, one wafer is taken out from a cassette accommodating wafers by a handling arm provided in a loader and placed on a positioning stage, where the wafer is aligned with the center of a wafer mounting table. There is known a wafer surface inspection apparatus that positions and inspects a wafer so as to perform the inspection.

Such a wafer surface inspection apparatus is provided with a plurality of cassettes including a cassette on the loader side and a cassette on the unloader side in order to continuously inspect many wafers. They are arranged in a line in the direction.

Of these cassettes, when all the wafers stored in the cassette are inspected and emptied, or when the inspected wafers are full in the dedicated unloader-side cassette for storing the inspected wafers, these cassettes are It will be replaced with a new one.

In the wafer surface inspection apparatus, the generation of foreign matter is disliked as much as possible because of the inspection of the scratches on the wafer and the state of adhesion of foreign matter.

[Problems to be Solved] When a plurality of cassettes are arranged in a line as described above,
There is no choice but to increase the width of the entire device in the arrangement direction. Moreover, when a plurality of cassettes are arranged in a line at right angles to the apparatus, there is a risk that foreign matter may fall onto the wafers stored in the preceding cassettes when replacing the cassettes in the back.

On the other hand, when a plurality of cassettes are arranged in a line on the front surface, it is easy to replace each cassette, but a relatively long linear movement mechanism for moving between the cassettes in a line is required, and foreign matter is easily generated, Moreover, the device is inevitably large in the lateral direction.

The present invention solves the above-mentioned problems of the prior art, and when replacing a cassette, it is possible to replace the cassette without affecting other cassettes, and to provide a compact wafer surface inspection apparatus with less foreign matter. The purpose is to provide.

[Means for Solving the Problems] Means for achieving the above object in the wafer surface inspection apparatus of the present invention is a wafer handling mechanism having an arm for taking out a wafer from a cassette or loading a wafer into the cassette. Two replaceable cassettes, which are placed on both the left and right sides of the wafer handling mechanism, have wafers taken out by the arm or loaded with the wafers, and the wafer handling mechanism from the operation front side of the apparatus to the back side. A surface condition measuring unit which is arranged and receives the wafer to be inspected from the arm, and the wafer which has been inspected is taken out by the arm, and the arm rotates between each cassette and the surface condition measuring unit. Is.

The rotating arm is rotatably supported on a rotating table and is supported by a first arm that rotates and a tip end side of the first arm that is rotatably supported above the rotating shaft. A second arm that is connected to the first arm of the second arm.
A holding portion for sucking and holding a wafer is provided on the side opposite to the side supported by the second arm, and the second arm rotates at a rotation angle twice that of the first arm. The length of the second arm is selected so that the center of the wafer taken out when folded to the first arm side is above the rotation axis of the first arm, and the wafer is rotated in the folded state. When the table is rotated, the rotation arm moves from the position of taking out or loading the wafer to one of the first cassette, the second cassette and the surface state measuring unit to the position of taking out or loading the wafer to the other one. And move.

[Operation] As described above, since the folding rotary arm including the first and second arms is placed on the rotary table and rotates, the wafer is held at the center of the upper side of the rotary shaft of the rotary arm. It is possible to take out or load other stages such as cassettes and surface condition measuring parts simply by rotating in a state, and the stages such as cassettes arranged in the surroundings correspond to the turning radius of the folded arm. Can be placed with minimal space around.

As a result, a very small device can be realized.

Moreover, since the joint arm and the rotary table that rotate at a double angle are used, only a rotating operation is required when taking out or loading the wafer from the cassette or the surface condition measuring unit, and therefore, no foreign matter or dust is generated. Very few.

Furthermore, by arranging the cassettes on the left and right and arranging the wafer surface inspection device side in the center back of these cassettes,
The left and right cassettes can be replaced without interfering with each other.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic plan view of an embodiment of a wafer surface inspection apparatus to which the present invention is applied, FIG. 2 is a schematic vertical sectional view centering on a handling device, and FIG. 3 is a surface condition measuring unit. FIG. 4 is a side view centering on the wafer mounting mechanism of FIG. 4, and FIG. 4 is a plan view of the wafer mounting mechanism for explaining the center positioning mechanism.

In FIG. 1, reference numeral 1 denotes a wafer handling mechanism arranged at a substantially central portion of the apparatus of the wafer surface inspection apparatus 30, which has two rotary arms 8 and 9 for taking out a wafer from a cassette and loading the wafer into the cassette. Have

On the outer periphery of the wafer handling mechanism 1, three cassettes 3, 4 and 5 are replaceably mounted on an apparatus table (not shown), and these are mounted on the wafer surface inspection apparatus 30.
It is located on the front side and both left and right sides.

When viewed from the front side of the apparatus, the surface condition measuring unit 6 is arranged on the back side of the wafer handling mechanism 1,
A plurality of wafers 7 before inspection are stacked and stored in the cassette 3 at predetermined intervals in the vertical direction, and this serves as a cassette on the loader side. Also, cassette 4 and cassette 5
Are initially empty and inspected wafers 7
It is a cassette on the unloader side that stores the. Then, one of these is a cassette that stores the wafer 7 that has passed the inspection result, and the other is a cassette that stores the wafer 7 that has failed the inspection result.

Here, the wafer 7 taken out from the cassette on the loader side by the wafer handling mechanism 1 is inserted into the surface condition measuring unit 6, and the inspected wafer 7 is taken out from the surface condition measuring unit 6 and the wafer is transferred depending on the inspection result. It is loaded into the cassette 4 or 5 which is the unloader cassette designated by the user. When the wafers 7 stored in the unloader cassettes 4 and 5 are full, the cassettes 4 and 5 are
A new empty unloader cassette is installed and removed from the machine table. Similarly, when the cassette 3 on the loader side becomes empty, it is removed and replaced with a cassette containing a wafer 7 to be newly inspected.

Which of the loader cassettes is to be assigned to the unloader cassette, which unloader cassette is acceptable and which unloader cassette is to be rejected can be set in advance on the apparatus side. It is also possible to specify an empty cassette after completing all the inspections in 1. to the unloader side. These are performed by the microprocessor installed in the apparatus and its control program, and the setting is specified by the information input by the operator via the keyboard, for example.

Two rotating arms 8 and 9 of the wafer handling mechanism 1
Is fixed to a rotary shaft 10 arranged concentrically, and the rotary shaft 10 is rotatably fixed to a turntable 11 as shown in FIG. When it rotates, it rotates, and when it rotates, it rotates and rotates.

The rotating shaft 10 includes an outer cylinder shaft 10a arranged outside the lower portion and an inner cylinder shaft 10a arranged inside the outer cylinder shaft 10a.
And a central shaft 10b protruding above it,
The rotating arm 9 is fixed to the upper surface of the outer cylinder shaft 10 a, and this serves as a drive shaft of the rotating arm 9. Also, the outer cylinder shaft 1
The rotating arm 8 is attached to the shaft portion of the center shaft 10b protruding from 0a.
Is fixed, and this serves as the drive shaft of the rotary arm 8. Therefore, these rotating arms 8 and 9 rotate independently.

These rotating arms 8 and 9 are respectively connected to the hinge shaft 2
It is composed of a first arm 2a and a second arm 2b linked by a link c, and the second arm 2b is rotatable on the tip side of the first arm 2a.

A suction chuck hole 2 (see FIG. 1) for sucking and holding a wafer is provided on the tip side of the second arm 2b.
The second arm 2b is shorter than the first arm 2a, and when the second arm 2b is in a folded state as seen by the rotating arm 9, the suction chuck hole 2 is in a state of being adjacent to the rotating shaft 10. Further, as seen from the rotating arm 8 showing the extended state, the suction chuck hole 2 is positioned slightly before the center of the cassette when the rotary arm 8 is extended most.

When the wafer 7 is taken out from the cassette, one arm is changed from the posture shown by the rotary arm 9 to the posture shown by the rotary arm 8, and the wafer 7 is sucked and returned to the state shown by the rotary arm 9 again. As a result, the wafer 7 is taken out from the cassette while rotating. Further, when the wafer 7 is loaded in the cassette, one arm is changed from the posture shown by the rotating arm 9 to the posture shown by the rotating arm 8 in the state where the wafer 7 is sucked, and the suction of the sucked wafer 7 is prevented. The wafer 7 is released and the wafer 7 is left in the cassette, and the state shown in the rotating arm 9 is restored. As a result, the wafer 7 is stored in the cassette while rotating. As shown in FIG. 2, since the second arm 2b is located above the rotary shaft 10, when the wafer 7 is held by suction on the second arm 2b, the wafer 7 is rotated. Above the top of 10.

In order to perform such control, the first arm 2a and the second arm 2b are internally coupled by a pulley and a timing belt, and the rotation angle of the second arm 2b is the first arm 2b.
It is set to be twice the rotation angle θ of a (= 2θ). In this way, the second arm 2b moves forward and backward on a straight line by rotating the second arm 2b interlockingly with the front end of the first arm 2a at a double angle with respect to the first arm 2a. become.

FIG. 2 is an overall view of the wafer handling mechanism 1 including this mechanism. The unloader-side cassette 5 is located on the back side of the drawing, and the unloader-side cassette 4 is located on the right side of the drawing. The cassette 3 is on the front side of the drawing.
The surface condition measuring unit 6 is located in the upper left part of the drawing.

In the wafer handling mechanism 1, the turntable 11 is fixed to the bracket 12a of the vertical movement mechanism 12,
The bracket 12a is coupled to the ball nut portion of the ball screw feeding mechanism 12b and moves up and down to sequentially take out the wafers from the lower wafer 7 among the wafers stored in the cassette. The procedure is reversed when the wafer 7 is stored in the cassette.

In the figure, 12c is a ball screw portion, which is driven by the pulse motor 13.

The turntable 11 has two pulse motors 1 on the lower side.
4 and 15 are mounted, and the pulse motor 14 has the outer cylinder shaft 1
0a is rotationally driven, and the pulse motor 15 rotationally drives the center shaft 10b. Further, in order to double the rotation of the outer cylinder shaft 10a and the center shaft 10b and transmit it to the second arm 2b side, pulleys 17 and 18 are fixedly mounted on these rotation shafts. A pulley for rotating the second arm by the timing belts 17a and 18a that are rotated and hung on the pulleys 17 and 18 (the pulley on the rotating arm 8 side is shown as a pulley 19. The pulley on the rotating arm 9 side is not shown).
The hinge shaft 2c is rotated via the, and thus the second arm 2b is rotated.

Here, the positioning of the rotary arms 8 and 9 with respect to the cassettes 3, 4, 5 or the surface state measuring unit 6 is performed by rotating the turntable 11 by a pulse motor (not shown).

By the way, the center of the rotary table 28 of the wafer mounting mechanism 26 in the surface state measuring unit 6 shown in FIG.
(See the drawing) and the center when the wafer 7 of each cassette 3, 4, 5 is set is shown by + sign in FIG. 1, but the center position shown by these + is equal to the center of the rotary shaft 10. At a distance, the rotating arms 8 and 9 are positioned on the same outer circumference for scanning (or positioning).

The wafer mounting mechanism 26 of the surface condition measuring unit 6 has a third
As shown in the figure, it is mounted on the linear reciprocating mechanism,
It moves from the position shown in FIG. 1 to the surface inspection position at the back (the position shown in FIG. 3).

The wafer mounting mechanism 26 shown in FIG. 1 is fixed on the X-direction moving mechanism 20 via a supporting base 21, and the supporting base 21 is a ball screw mechanism arranged inside the X table 22. It is connected to the ball nut portion 23.
The screw 24 is driven by the stepping motor 25 to linearly move the support base 21 in the X direction, and move the wafer mounting mechanism 26 from the loader / unloader side (left end in the drawing) to the inspection position (position shown in the drawing). At the inspection position, an optical observation system (not shown) arranged on the upper side of the wafer mounting mechanism 26 rotates the wafer 7 adsorbed on the rotary table 28 to spirally scan the surface of the wafer 7 for surface inspection. Be seen.

FIG. 4 illustrates a center positioning mechanism of the wafer mounting mechanism 26. Reference numeral 28 denotes its rotary table, and a ring-shaped plate 29 (hereinafter referred to as a ring plate 29) around the rotary table 28. Is provided,
The ring plate 29 has seven rotating arms 31, 31 ...
(1.4 degrees), and is fitted and fixed to the cylindrical support body 30 arranged in the central portion. The rotary table 28
Are arranged so that they can rotate through the space inside the cylindrical support 30.

Each rotating arm 31 rotates in association with the center of the rotary table 28, and the distance between the shaft 31b, which is the center of rotation of each rotating arm 31, and the contact surface of the roller 31a is equal. As a result, the roller 31a of each rotating arm 31
Operate similarly to the iris diaphragm.

Here, the center of the circle of each rotating arm 31 arranged in a circle and the center of the rotary table 28 coincide with each other.

As shown in FIG. 3, the ring plate 29 is located outside and on the lower side of the rotary table 28, and is provided on the tip end side of the rotating arm 31 so as to stand upright.
Of the wafer is placed at a position retracted with respect to the rotary table 28 to a position where the wafer 7 placed on the rotary table 28 comes into contact with the periphery thereof.

A large number of holes are provided on the surface of the turntable 28, and the wafer 7 is adsorbed and held through the holes.

If the central positioning mechanism is integrally provided with the rotary table inside the surface condition measuring unit 6 as in this embodiment, the central positioning device is not required outside, and therefore, only the wafer handling mechanism is arranged at the center. This has the advantage that a smaller layout can be achieved.

As described above, in the embodiment, three cassettes are provided on the front side and the left side and the right side. However, the number of the cassettes may be two on the left side and the right side. The pass / fail wafers can be managed at the position stored in the cassette.
Also, only the rejected items may be returned to the original state.

The rotating arm of the wafer handling mechanism shown in the embodiment is
This is an example, and the present invention is not necessarily limited to such a configuration, and various types of rotary arms can be applied.

[Effects of the Invention] As can be understood from the above description, in the present invention, since the folding and rotating arm including the first and second arms is placed on the rotating table and rotates, the center of the wafer is rotated. It is possible to support the removal or loading of other stages such as cassettes and surface condition measuring units by simply holding the unit above the rotation axis of the rotating arm and rotating in this state. Can be arranged with a minimum space around it, corresponding to the turning radius of the folded arm.

As a result, a very small device can be realized.

Moreover, since the articulated arm that rotates at a double angle is used, only the rotating operation is required when the wafer is taken out from the cassette or the surface state measuring unit, so that an apparatus in which the generation of foreign matter and dust is extremely small can be realized.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an embodiment of a wafer surface inspection apparatus to which the present invention is applied, FIG. 2 is a schematic vertical sectional view centering on a handling device, and FIG. 3 is a wafer of a surface condition measuring unit. FIG. 4 is a side view centering on the mounting mechanism, and FIG. 4 is a plan view of the wafer mounting mechanism for explaining the center positioning mechanism. 1 ... Wafer handling mechanism, 2 ... suction chuck hole, 2a ... first arm, 2b ... second arm, 2c ... hinge shaft, 2d ... wafer stopper, 3, 4, 5 ... cassette,
6 ... Surface condition measuring unit, 7 ... Wafer, 8, 9 ... Rotating arm, 26 ... Wafer mounting mechanism, 28 ... Rotating table, 30 ... Wafer surface inspection device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-228640 (JP, A) JP-A-58-216835 (JP, A) JP-A-60-45023 (JP, A) Actual development Sho-61- 191886 (JP, U) Actual development Sho 62-44439 (JP, U) European patent application publication 219826 (EP, A2)

Claims (2)

[Claims] 1. A wafer handling mechanism, which is provided on the operation front side of the apparatus and has a rotating arm for taking out a wafer from a cassette or loading a wafer into the cassette; and a left and right side of the handling mechanism as seen from the operation front side. A replaceable first cassette, which is arranged on either side of the operation front side and from which a wafer is taken out by the rotating arm, and arranged on either of the left and right sides or the remaining side of the operation front side. And a replaceable second cassette on which wafers are loaded by the rotating arm, and a wafer to be inspected from the rotating arm, which is arranged behind the wafer handling mechanism with the wafer handling mechanism interposed therebetween. And a surface condition measuring unit for taking out the wafer that has been received and inspected by the rotating arm. The tip side of the moving arm is moved back and forth with respect to the first cassette to take out the wafer to be inspected from the first cassette, and the turning arm is turned to load the taken-out wafer into the surface state measuring unit. Then, the tip side is moved back and forth with respect to the surface state measuring section, the wafer for which the inspection is completed is taken out from the surface state measuring section, and the rotating arm is rotated to move the tip side forward and backward. The rotating arm comprises a first arm which is rotatably supported by a rotary table and is rotatable, and a tip end side of the first arm which is closer to the rotary shaft than the rotary shaft. A second arm rotatably supported on the upper side,
A holding portion for adsorbing and holding the wafer is provided on the side opposite to the side of the first arm supported by the first arm, and the second arm rotates at a rotation angle twice that of the first arm. , The length of the second arm is selected such that the center of the wafer taken out when the second arm is folded to the side of the first arm is above the rotation axis of the first arm. When the rotary table is rotated in the folded state, the rotating arm causes the wafer to be taken out of or loaded into the one of the first cassette, the second cassette and the surface state measuring unit. A wafer surface inspecting apparatus, wherein the wafer surface inspecting apparatus moves the wafer from one of the positions to the other of the positions for picking up or loading the wafer. 2. A replaceable third cassette, on which a wafer is loaded by the rotating arm, is arranged on the remaining side of either of the left and right sides or the operation front side, and the surface state measuring section comprises: The wafer handling mechanism has a center positioning mechanism for positioning the center of the wafer to be inspected at the center of the inspection position, and the wafer handling mechanism moves the tip end side of the rotating arm forward and backward with respect to the first cassette to perform the inspection. The wafer is taken out from the first cassette, the rotating arm is rotated to load the taken-out wafer into the surface condition measuring unit, and the tip side is moved back and forth with respect to the surface condition measuring unit to perform the inspection. The completed wafer is taken out from the surface condition measuring unit, and the rotating arm is rotated to move the tip end side forward and backward to load the wafer into either the second cassette or the third cassette. Wafer surface inspection device of the range first claim of claims, wherein.