JPH10116869A - Wafer inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer inspecting apparatus that makes it unnecessary for the inspector to change the point of view during macro inspection and does not damage the periphery or surface of a wafer. SOLUTION: The wafer inspecting apparatus consists of a wafer holding arm 20 that holds a wafer 1 placed thereon with its surface facing upward; a spinning means that spins the wafer holding arm 20 on a rotation axis provided on the same plane as the wafer 1; and an elevating means that moves up the wafer holding arm 20. The wafer holding arm 20 spins on the rotation axis while going up, and the rotating means is moved up by the elevating means. A converting means for converting the ascent of the rotating means into the rotational motion of the wafer holding arm 20, may be included.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer inspection apparatus for inspecting the front and back surfaces of a semiconductor wafer in a semiconductor device manufacturing process or the like.

[0002]

2. Description of the Related Art A semiconductor wafer having a predetermined pattern formed on its surface is visually inspected by an inspector to inspect the surface of the wafer for color unevenness and adhesion of dust, and to inspect the state of the surface pattern by a microscope. Inspection by micro inspection.

Recently, in order to reduce the defect rate of a wafer, not only the inspection of the front surface of the wafer but also the inspection of the back surface has been regarded as important. For example, Japanese Patent Application Laid-Open No. 6-349908 discloses a wafer inspection apparatus. The described inspection devices and the like are known. This conventional apparatus has a structure including a wafer holding arm that sandwiches a peripheral portion of a wafer, and a swing arm that lifts the wafer and the entire wafer holding arm. A pinch operation of the wafer peripheral edge by the holding arm and a back surface macro inspection are performed.

[0004]

However, in the above prior art, since the back surface macro inspection mechanism has a swinging arm structure that lifts the wafer and the entire wafer holding arm, the wafer position and the front surface macro at the time of the back surface macro inspection. Since the wafer position at the time of inspection differs from the inspector, there is a problem that the inspector must change the viewpoint for each macro inspection.

[0005] Further, since the wafer holding arm sandwiches the peripheral portion of the wafer, there is a defect that the peripheral portion of the wafer and the wafer surface are damaged.

In addition, since the wafer holding arm performs the pinching operation of the peripheral portion of the wafer in an arc locus due to the rotation of the swinging arm, it is necessary to maintain the parallelism between the wafer and the wafer holding arm (swinging arm) when transferring the wafer. Have difficulty. Therefore, there is a problem in that there is a high risk of damaging the wafer by pinching the wafer in a state where the wafer does not enter the groove of the wafer holding arm or slipping the wafer in an attempt to tilt and pinch the wafer. Was.

Further, there is a problem that a complicated mechanism having a plurality of driving sources must be employed in order to realize the above-mentioned conventional technology.

Therefore, the present invention solves such a conventional problem, and it is not necessary for the inspector to change the viewpoint for each macro inspection, and the structure which does not damage the wafer peripheral portion or the wafer surface is provided. An object of the present invention is to provide a simple, low-cost, and space-saving wafer inspection apparatus.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a wafer holding arm for holding a wafer placed with its surface facing upward, and a rotation provided on a plane of the wafer. A rotating means for rotating the wafer holding arm about an axis; and a raising means for raising the wafer holding arm, wherein the wafer holding arm rotates about the rotation axis while being raised. An inspection device is provided.

[0010] The rotation axis given on the plane of the wafer may be the diameter of the wafer or the chord of the wafer.

Further, the rotating means may have a converting means which is raised by the raising means and converts the rising of the rotating means into a rotating motion of the wafer holding arm.

[0012] It is preferable that the rotation axis is disposed substantially at right angles to a line of sight of an inspector at an inspection position toward the wafer holding arm.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to the embodiment.

FIG. 1 is an overall schematic configuration diagram of a wafer inspection apparatus according to an embodiment of the present invention. A wafer carrier 3 accommodating a plurality of semiconductor wafers is mounted on the left side of the base 2 so as to be vertically movable.
And placed on the wafer standby unit 6.
Then, after the state of the surface of the wafer 1 is visually inspected,
An inspector exposes the back surface of the wafer 1 by a wafer back surface inspection mechanism 5 according to the present invention, which will be described later, and a visual inspection of the back surface of the wafer 1 is performed.

The wafer 1 is returned to the wafer standby section 6 again, and the microscope 9 is moved by a moving mechanism (not shown) according to the arrow c.
On the stage 7. Then, the micro inspection of the surface of the wafer 1 is performed by the optical system 8. When the micro inspection is completed, the wafer 1 is returned into the wafer carrier 3 along the arrows c and a. Then, the wafer carrier 3
Moves up and down, the next wafer is taken out, and the same macro inspection and micro inspection are performed.

FIG. 2 is a top view of the backside macro inspection mechanism 5. 3 is a front view of the same, FIG. 4 is a left side view of the same,
FIG. 5 is a right side view of the same. As shown in FIG. 2, the back surface macro inspection mechanism 5 includes a wafer holding arm 2 for holding the wafer 1.
0, and as described later, when the wafer holding arm 20 rises and engages with the wafer 1, the back surface of the wafer 1 is vacuum-sucked by the vacuum suction portion 22 provided on the wafer holding arm 20, The wafer is held by the wafer holding arm 20. In the present embodiment, a vacuum suction unit is provided at three places in a shape surrounding the wafer standby unit 6 at the tip of the wafer holding arm 20, and is illustrated through a flow path (not shown) in the wafer holding arm 20. Not connected to a vacuum pump,
The rear surface of the wafer 1 can be sucked.

The wafer holding arm 20 rotates around the diameter of the wafer 1 indicated by a dashed line A in FIG. Further, the rotation axis may be an axis that is parallel to the diameter of the wafer 1 indicated by a two-dot chain line B in FIG. 2 and slightly deviates from the diameter. This is accomplished by slightly offsetting the axis of rotation from the diameter, as described below.
When the wafer holding arm 20 is raised and further rotated, the rising distance of the wafer holding arm 20 can be shortened, and the center of the wafer 1 is shifted vertically when the back surface of the wafer 1 is exposed to the inspector. Can be reduced, so that the shift of the viewpoint of the inspector is reduced.

FIG. 3 is a front view of the back surface macro inspection mechanism 5. According to FIG. 3, the wafer holding arm 20 is attached to the upper end of the vertically movable unit 26 for vertically moving the wafer holding arm 20, and is coaxial with the wafer holding arm 20 at the upper end of the vertically movable unit 26. Wafer holding arm pulley 24
Is attached. Further, the wafer holding arm pulley 24 is interlocked with a cam pulley 30 attached to the lower end of the vertically movable unit 26 via a timing belt 28.

A drive unit 32 for driving the vertically movable unit 26
Has a driving pulley 44, a driven pulley 46, and a timing belt 38, and the rotational force of the motor 40
0 to the drive pulley 44. Then, the timing belt 38 moves according to the rotation of the driving pulley 44.

In the present embodiment, a timing belt 38 and a rotary motor 40 are used for the drive unit 32. However, as means for linearly moving the vertically movable unit 26,
Feed screw and rotation motor, rack pinion and rotation motor,
A pneumatic cylinder or a linear motor may be used.

FIG. 4 is a left side view of the back surface macro inspection mechanism 5. According to FIG. 4, a linear motion guide 34 is
Is mounted, and the vertically movable unit 26 is connected to the connecting unit 4.
2, it is slidably connected to the straight guide 34. Furthermore, since the connecting portion 42 is fixed to the timing belt 38, the vertically movable portion 26 moves up and down along the linear guide 34 as the timing belt 38 moves.

FIG. 5 is a right side view of the backside macro inspection mechanism 5. According to FIG. 5, the groove cam 36 which the cam follower 52 mounted eccentrically on the cam pulley 30 fits.
Is provided. Up and down movable part 2
6 moves in the vertical direction along the linear guide 34, the cam follower 52 rotates the cam pulley 30 along the groove cam shape of the groove cam 36, and the rotation moves the wafer holding arm pulley 24 via the timing belt 28. Then, the wafer holding arm 20 is rotated.

Next, the basic operation of the backside macro inspection mechanism 5 will be described. In the initial state, as shown in FIG. 5, the wafer suction unit 22 of the wafer holding arm 20 of the back surface macro inspection mechanism 5 is located below the surface of the wafer standby unit 6 on the front surface macro inspection mechanism 4 shown in FIG. So waiting.

The vertically movable unit 2 is driven by the motor 40.
When the wafer 6 rises, the wafer holding arm 20 attached thereto also rises while keeping parallel to the surface of the wafer standby unit 6. Then, as shown in FIG. 6, the wafer 1 is received from the surface of the wafer standby unit 6 during the ascent. Subsequently, the wafer 1 is held by the wafer holding arm 20 by vacuum suction at a predetermined position where the parallelism of the vacuum suction unit 22 of the wafer holding arm 20 is maintained.

As shown in FIG. 7, the wafer holding arm 20
When the vertical moving movable portion 26 continues to move up along the linear motion guide 34, the cam follower 52 moves, that is, the cam pulley 30 starts rotating according to the shape of the groove cam 36. The rotation of the cam pulley 30 causes the wafer holding arm pulley 24 of the wafer holding arm 20 connected via the timing belt 28 to rotate in conjunction therewith, and the wafer holding arm 20 having a rotation axis coaxial with the wafer holding arm pulley 24 rotates together with the wafer 1. I do.

FIG. 7 shows that the cam follower 52 moves along the shape of the groove cam 36 and the cam pulley 30 moves 90 degrees clockwise.
FIG. The rotation of the cam pulley 30 is controlled by a timing belt 28 so that the wafer holding arm pulley 2 is rotated.
4, the wafer 1 held by the wafer holding arm pulley 24 and the wafer holding arm 20 reaches an upright state as shown in FIG. At this time, by setting the rotation axis of the wafer holding arm 20 to be substantially perpendicular to the line of sight of the inspector (not shown) toward the direction of the wafer holding arm (not shown) in front of the microscope 9, the inspector can The back can be seen from the front.

As shown in FIG. 8, when the cam follower 52 moves to the position shown in the figure, the cam pulley 30 rotates 180 degrees. In this state, the wafer 1 is held downward,
The inspector can see the back surface of the wafer 1 from directly above.
In this way, by appropriately setting the position of the cam follower 52, the back surface of the wafer 1 can be rotated at a desired wafer rotation angle.
Can be inspected.

In order to control the rotation angle of the wafer, for example, since the rotation angle of the wafer 1 and the vertical movement position of the vertical movement movable section 26 have a correlation, the vertical movement position of the vertical movement movable section 26 can be controlled. Thus, a desired wafer rotation angle can be obtained. As a method of controlling the vertical movement position, there are an open loop control that outputs a pulse number corresponding to a predetermined vertical movement amount and rotates the pulse motor, and a semi-closed loop by detecting the rotation amount of the DC motor with a potentiometer or a rotary encoder. Or the vertically movable part 2
6, a closed-loop control by detecting the position of the vertically movable unit 26 by a linear encoder or the like attached along the moving direction of the moving unit 6.

After the back side macro inspection is completed, the vertically movable unit 26 starts to descend. With the lowering of the vertically movable unit 26, the cam pulley 30 rotates counterclockwise,
After the state shown in FIG. 6, the vacuum holding of the wafer holding arm 20 is cut off at a predetermined position similar to the above, and the wafer 1 is set in a free state. Further, as shown in FIG. 5, the wafer 1 is transferred onto the wafer standby unit 6 during the descent, and is lowered to the standby position shown in FIG.

As described above, in the back surface macro inspection mechanism 5 of the wafer inspection apparatus according to the present invention, the central axis of the wafer 1 before the wafer 1 shown by the dotted line C in FIG. 5 rotates and the dotted line C 'in FIG. Since the wafer 1 to be rotated rotates and the center axis of the wafer 1 when the back surface is exposed is arranged substantially coaxially,
It contributes to space saving of the whole wafer inspection device.

In the above description, in order to clarify the correlation between the rotation angle of the wafer 1 and the vertical movement position of the vertical movement movable section 26, the vertical movement amount is set larger than the rotation angle of the wafer. However, in practice, in order to avoid raising or lowering the line of sight of the inspector in accordance with the wafer rotation angle, a groove cam shape or a wafer holding arm pulley and a cam pulley that take a large ratio of the rotation angle of the wafer 1 to the vertical movement amount are used. It is desirable to select a diameter ratio. That is, it is preferable that the wafer 1 is not rotated as much as possible while being raised, but is raised to a predetermined position and then quickly rotated.

[0032]

As described above, according to the present invention, it is possible to raise the wafer holding arm, hold and rotate the wafer by a single rotary drive source, and the structure is simple, low cost and space saving. is there.

Further, by setting the rotation axis of the wafer to be the diameter of the wafer and arranging the rotation axis at right angles to the line of sight of the inspector, the inspector can perform the front surface macro inspection and the back surface macro inspection. It is possible to work without moving the focus position and the line of sight in the horizontal and vertical directions. Therefore, it is possible to reduce the eye fatigue of the inspector in the conventional wafer inspection, and to improve the inspection efficiency and the accuracy of the defective product detection.

Further, since the wafer is lifted and held by the wafer holding arm which is kept parallel to the wafer, the wafer holding arm does not cause the wafer to slide against the one-sided contact of the wafer. And can be securely held.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of a wafer inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a top view of the back surface macro inspection mechanism according to the embodiment of the present invention.

FIG. 3 is a front view of the back surface macro inspection mechanism according to the embodiment of the present invention.

FIG. 4 is a left side view of the back surface macro inspection mechanism according to the embodiment of the present invention;

FIG. 5 is a right side view of the back surface macro inspection mechanism according to the embodiment of the present invention.

FIG. 6 is a right side view of the back side macro inspection mechanism showing a state where the wafer holding arm 20 is lifted and the wafer 1 is suction-held.

FIG. 7 is a right side view of the back side macro inspection mechanism showing a state in which the wafer 1 is rotated 90 degrees while being raised, and the back side is exposed to an inspector while the wafer 1 is in an upright state.

FIG. 8 is a right side view of the back side macro inspection mechanism showing a state in which the wafer 1 is further rotated and the back side of the wafer 1 faces upward and is exposed to an inspector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 20 Wafer holding arm 26 Vertically movable part 32 Drive part 36 Groove cam 37 Cam part

Claims (4)

[Claims] 1. A wafer holding arm for holding a wafer, rotating means for rotating the wafer holding arm about a rotation axis provided on a plane of the wafer, and lifting means for lifting the wafer holding arm. A wafer inspection apparatus, wherein the wafer holding arm rotates around the rotation axis while rising. 2. The wafer inspection apparatus according to claim 1, wherein said rotating means rotates said wafer holding arm about a diameter of said wafer as a rotation axis. 3. The wafer according to claim 1, wherein the rotating means is lifted by the lifting means, and has a converting means for converting the rising of the rotating means into a rotating motion of the wafer holding arm. Inspection equipment. 4. The wafer inspection device according to claim 1, wherein the rotation axis is disposed substantially at right angles to a line of sight of an inspector at an inspection position toward the wafer holding arm. apparatus.