JP4538883B2 - Flat substrate observation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar substrate observation apparatus that conveys a planar substrate such as a silicon wafer or a glass substrate and observes the planar substrate.
[0002]
[Prior art]
In a semiconductor manufacturing process, a circuit formed on a silicon wafer is appropriately inspected. For example, after a circuit pattern is formed on a silicon wafer and the back surface of the wafer is ground, the quality of the circuit pattern may be evaluated by performing an appearance inspection of the silicon wafer using a microscope apparatus or the like. In such a microscope apparatus, a microscope observation stage for observing the wafer under a microscope and a macro observation stage for visual inspection are provided. A wafer transfer device provided in a microscope apparatus is used for transferring the wafer onto these observation stages.
[0003]
The wafer transfer device is equipped with a suction hand that sucks the wafer using vacuum, and the back of the wafer stored horizontally in the wafer cassette is sucked with the suction hand to bring the wafer into a horizontal state before the observation stage. Transport. Each observation stage is also provided with a suction device using vacuum. When the wafer is transferred from the suction hand to the observation stage, the wafer W is observed on the observation stage 100 (for macro observation) as shown in FIG. Then, the suction hand 101 is gradually lowered as shown in FIG. If the wafer W comes close to the observation stage 100, the vacuum suction of the suction hand 101 is released, and the suction hand 101 is lowered as shown in FIG. 11C, so that the wafer W is sucked to the suction device of the observation stage 100. And mounted on the observation stage 100.
[0004]
Conversely, when the wafer W is transferred from the observation stage 100 to the suction hand 101, the suction hand 101 is raised from below the wafer W held on the observation stage 100, and the suction hand 101 approaches the back surface of the wafer W. Then, the suction by the suction device of the observation stage 100 is canceled, the suction hand 101 is raised, and the wafer W is sucked and held by the suction hand 101.
[0005]
[Problems to be solved by the invention]
By the way, the thickness of the wafer W after the back surface grinding is as thin as about 0.2 to 0.3 (mm), and sometimes it is ground to about 0.1 (mm). As described above, since the wafer W is very thin, the wafer W may be bent and damaged by its own weight when the wafer W is transported while being held horizontally by the suction hand 101. The wafer diameter tends to increase year by year, and when it becomes close to 300 mm as in recent years, breakage due to bending tends to occur. In particular, when the wafer is transferred between the suction hand 101 and the observation stage 100, there is a problem that the wafer W is easily damaged by a shock at the time of transfer.
[0006]
In addition, a protective film for protecting the circuit pattern is formed on the wafer surface, and “warping” caused by the protective film and the above-described back surface grinding occurs in the wafer W, and the vacuum in the suction hand 101 and the observation stage 100 is generated. At the time of adsorption, an adsorption holding error is likely to occur, resulting in wafer breakage.
[0007]
An object of the present invention is to provide a substrate hand capable of preventing wafer breakage during wafer transfer, a transfer apparatus, an inspection apparatus including them, and a flat substrate storage apparatus used in the inspection apparatus or the like. is there.
[0008]
Planar substrate observation apparatus according to a first aspect of the present invention, with the substrate surface of the flat base plate is extended in a vertical direction, and the planar substrate and the grip portion, which is gripped by the gripping portion for gripping the upper portion of the planar substrate and a conveying section for conveying while maintaining a state of extending in the vertical direction, the planar substrate conveyed to the first position by the transport unit, in a state of being extended in the vertical direction by the gripper An illuminating unit that illuminates so as to be visually observable while gripping, and the rotating shaft in the vertical direction while gripping the planar substrate at the first predetermined position while extending in the vertical direction by the gripping unit. And a rotating part that rotates around.

[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an embodiment of an inspection apparatus according to the present invention, and is a perspective view showing a schematic configuration of a microscope inspection apparatus 1 used for observing a silicon wafer or the like on which a semiconductor chip is formed. A plurality of inspection wafers W are stored in the wafer cassette 2, and each wafer W is stored vertically such that the substrate surface extends in the vertical plane. The microscope inspection apparatus 1 includes a microscope 3 for observing the appearance of the wafer W, 3a is an objective lens, and 3b is an eyepiece. The objective lens 3a is provided so that the optical axis J is horizontal.
[0011]
The microscope inspection apparatus 1 is provided with operation switches (not shown) for inspection by an inspection operator, and the operation robot is operated to operate the transport robot 4 provided in the microscope inspection apparatus 1. The operation switches described above are provided with a microscope observation operation switch, a macro observation operation switch, a wafer take-out operation switch, a manual operation switch, and the like, which will be described later. When the operator operates the microscope observation operation switch, the transfer robot 4 takes out one of the wafers W stored in the wafer cassette 2 by using the hand 5 attached to the tip of the arm 4a, and takes out the wafer W from the microscope 3. The objective lens 3a is disposed at a predetermined position on the optical axis J.
[0012]
At this time, if the arm 4a of the transfer robot 4 is driven to the position indicated by the two-dot chain line P1, the arm 4a is finely driven by manual operation to move the wafer W in the optical axis J direction (Z direction) as shown in FIG. ) And the X and Y directions perpendicular to the optical axis J, and the wafer W is positioned. In the microscopic observation, a specific portion in the chip formed on the wafer W is observed, and the quality is determined from the color and the pattern shape.
[0013]
When positioning the wafer W, an observation image observed by the eyepiece 3b is rotated using an image rotator (a prism is used) provided in the microscope 3, and the optical axis J of the wafer W is rotated. Manually perform the rotation correction. When performing macro observation of the wafer W, when a macro observation operation switch (not shown) is operated, the transfer robot 4 drives the arm 4a to a position indicated by a two-dot chain line P2. In the macro observation, the surface of the transferred wafer W is obliquely irradiated with uniform parallel light emitted from the macro illumination 6, and the scattered light from the wafer W is observed to evaluate the state of the protective film on the wafer W. .
[0014]
At this time, the arm 4a is driven by manual operation, and the wafer W held by the hand 5 is observed by rotating in the R1 direction or tilting in the R2 direction. When gripping the wafer W with the hand 5, the wafer W stored in the wafer cassette 2 is pushed upward by the assist device 7, and the wafer W is protruded above the wafer cassette 2.
[0015]
2A and 2B are diagrams showing the hand 5 in detail, where FIG. 2A is a view of the wafer W as viewed from the front, FIG. 2B is a view taken along the arrow B in FIG. It is a figure which shows 5a. The hand 5 is provided with a pair of fingers 5a for gripping the wafer W, and the pair of fingers 5a are positioned at a solid line position as shown in FIG. 2B by an actuator (not shown) provided on the finger drive unit 5b. Is driven horizontally between the two-dot chain line position. As the actuator for driving the finger 5a, an air cylinder, an actuator using a motor and a feed screw, or the like is used.
[0016]
The hand 5 is attached to a rotating part 4b provided at the tip of the arm 4a, and the rotating part 4b can be rotated in the R1 direction with respect to the arm 4a by an actuator (not shown). Furthermore, the hand 5 fixed to the rotating part 4b can be driven in the R2 direction integrally with the rotating part 4b by an actuator (not shown) provided at a connecting part between the arm 4a and the rotating part 4b. FIG. 2 (c) shows one of the fingers 5a, as viewed from the side of the wafer W held by the fingers 5a. A groove 5d is formed in the edge portion of the U-shaped cutout 5c formed in the finger 5a, and the curvature of the arc portion of the cutout 5c is substantially equal to the curvature of the edge of the wafer W. When the pair of fingers 5a are closed as shown in FIG. 2B, the wafer W is held in the grooves 5d of the fingers 5a.
[0017]
When the wafer W stored in the wafer cassette 2 of FIG. 1 is held and taken out by the hand 5, the assist device 7 pushes the wafer W out of the wafer cassette 2 as described above, and the edge of the pushed wafer W. The part is gripped with the fingers 5a. FIG. 3A is a perspective view showing the assist device 7. The assist device 7 is provided with an assist plate 7a for pushing up the wafer W, and the assist plate 7a is vertically driven by a vertical drive unit 7b. The vertical drive unit 7b is horizontally driven by a horizontal drive unit 7c. Driven. The upper end surface of the assist plate 7a has an arc shape (having a curvature substantially equal to the curvature of the edge of the wafer W). As shown in the cross-sectional view of FIG. 7d is formed. When the wafer W is pushed upward, the lower end surface of the wafer W vertically stored in the wafer cassette 2 is in a state of being inserted into the groove 7d.
[0018]
4 and 5 are views showing a procedure for taking out the wafer W stored in the wafer cassette 2 by using the hand 5, and FIGS. 4A to 4C and FIG. The extraction operation is performed in the order of (c). First, when a wafer removal operation switch (not shown) is operated, the hand 5 is moved directly above the wafer W1 to be inspected. Thereafter, the finger 5a is opened, and the horizontal driving device 7d is driven rightward in the figure to move the assist plate 7a provided on the vertical driving unit 7b to a position directly below the wafer W1 (FIG. 4A). Next, as shown in FIG. 4B, the vertical plate 7b drives the assist plate 7a upward to push up the wafer W1 and insert the wafer W1 between the open fingers 5a.
[0019]
When the wafer W1 is inserted between the pair of fingers 5a, the fingers 5a are closed and the wafer W1 is held as shown in FIG. Next, as shown in FIG. 5A, the arm 4a is driven upward to completely take out the wafer W1 held by the hand 5 from the wafer cassette 2. Thereafter, when the macro observation or microscope observation operation switch is operated, the wafer W1 is transferred to a predetermined observation position as described above. At this time, the position of the assist plate 7a may be kept at the upper end position as shown in FIG. 5A, or may be lowered to the lower end position (see FIG. 4A). A transfer method from the wafer cassette 2 to the observation position will be described later. When the observation of the wafer W1 is completed and the operation switch for returning the wafer W1 to the wafer cassette 2 is operated, the wafer W1 held by the hand 5 reaches the predetermined position (position shown in FIG. 5A) of the wafer cassette 2. The hand 5 is lowered.
[0020]
If a part of the wafer W1 is stored in the wafer cassette 2 and the wafer W1 is placed on the groove 7d (see FIG. 3) of the assist plate 7a, the assist plate 7a is lowered after opening the finger 5a. The wafer W1 is completely stored in the wafer cassette 2. Thereafter, the hand 5 is moved directly above the adjacent wafer W2, and the horizontal driving device 7c is driven to move the assist plate 7a to just below the wafer W2. The wafer W2 is taken out, transferred, and observed in the same manner. .
[0021]
Next, a conveying method will be described. 6 and 7 are diagrams for explaining the conveying method, FIG. 6 is a side view of the inspection apparatus, and FIG. 7 is a plan view. As indicated by a two-dot chain line in FIG. 6, when the wafer W is gripped by the hand 5 and taken out from the wafer cassette 2 vertically, the arm 4a is rotated about the rotation axis J2 of the transfer robot 4 by the angle θ1. The wafer W is transferred to the macro observation position P2 (FIG. 7). When the wafer cassette 2 is mounted in a state where the surface of the wafer W is deviated from the transfer direction, the rotation center J2 of the transfer robot 4 and the center of the wafer W are rotated before the entire arm 4a is rotated with respect to the rotation axis J2. The rotating portion 4b provided at the tip of the arm 4a is rotated so that the straight line J3 connecting O (see FIG. 2) and the substrate surface are orthogonal to each other. That is, the wafer W is transferred so that the center O draws an arc centered on the rotation center J2, and the substrate surface of the wafer W extends in the tangential direction of the arc (moving direction of the wafer W) during the transfer. Retained.
[0022]
If the arm 4a is moved to the macro observation position P2, the rotation unit 4b (see FIG. 6) is driven so that the reflected light L from the surface of the wafer W is incident on the observer's eye point, thereby moving the wafer W to the angle θ2. Just rotate. When the macro observation is completed, the wafer W is rotated by an angle (−θ2) so that the straight line J3 and the substrate surface of the wafer W are orthogonal to each other, and the arm 4a is further rotated by the angle θ3 and moved to the microscope observation position P1. . In the case shown in FIG. 7, the arm 4a is further driven to finely drive the wafer W rightward in the drawing to position it at a predetermined position. FIG. 6 shows a state in which the wafer W is positioned on the optical axis J of the objective lens 3a. At this time, if the substrate surface of the wafer W is inclined with respect to the optical axis J, the arm 4a The rotation unit 4b is rotated and manually corrected so that the substrate surface is orthogonal to the optical axis J. When the microscope observation is completed, the wafer 4 is stored in a predetermined position of the wafer cassette 2 after the arm 4a is rotated by an angle (−θ1−θ3).
[0023]
In the above-described embodiment, the wafer W is observed in the order of the macro observation and the microscope observation. However, the observation may be performed in the reverse order, or only one of the observations may be performed. .
[0024]
FIG. 8 is a view showing a modification of the hand 5, (a) is a view of the hand 5 as seen from the front of the wafer, and (b) is a sectional view taken along the line DD of (a). A pair of fingers 5f provided on the hand 5 opens and closes in the horizontal direction in the figure. When the fingers 5f are closed, the arc portion 5g of the finger 5f contacts the substrate end surface of the wafer W so that the substrate end surface is sandwiched between them. The wafer W is gripped. As shown in FIG. 8B, the arc portion 5g has a V-groove shape, and the wafer W is gripped so that the end portion of the arc W is inserted into the V-groove.
[0025]
The closed position of the finger 5f is set so that an excessive force is not applied to the wafer W when the wafer W is gripped. For example, the gap may be set so that a slight gap is formed between the wafer end surface and the V-groove, and the wafer W may be held so as not to fall at a portion below the wafer center O of the finger 5f.
[0026]
9 and 10 are views showing the operation of taking out and holding the wafer W from the wafer cassette 2 using the hand 5 shown in FIG. 8, and FIGS. 9A to 9C and FIG. The operation is performed in the order of (b). First, as shown in FIG. 9A, if the hand 5a is lowered directly above the wafer W with the fingers 5f open, the assist plate 7a is moved upward as shown in FIG. 9B. The wafer W in the wafer cassette 2 is pushed up. FIG. 9C is a diagram showing a state where the assist plate 7 a has moved to the upper end position. The wafer W is pushed up to a position where the substrate center O is above the upper end of the wafer cassette 2. Next, as shown in FIG. 10A, after the fingers 5f are closed and the wafer W is gripped, the hand 5 is moved vertically upward to take out the wafer W from the wafer cassette 2, and the assist plate 7a is moved downward.
[0027]
When the wafer W is in the wafer cassette 2 as shown in FIGS. 9A and 9B, the left and right ends of the wafer W are inserted into the grooves 2a formed on the inner surface of the wafer cassette 2. In addition, the wafer W is maintained in a vertical state. However, as shown in FIG. 9C, when the wafer W is pushed up by the assist plate 7a and a part of the wafer W is pushed out from the wafer cassette 2, the left and right ends of the wafer W may be detached from the groove 2a. There is. Therefore, in the present embodiment, the end portion of the assist plate 7a is formed in an arc shape matching the shape of the wafer W, the V groove 7g is formed on the end surface, and the wafer W is inserted into the V groove 7g. I made it. Therefore, even in the state as shown in FIG. 9C, the wafer W can be held vertically by the assist plate 7a.
[0028]
The above-described embodiment has the following advantages.
(1) As shown in FIG. 2, the wafer 5 is held between the front and back surfaces by fingers 5a provided on the hand 5, or the wafer end surface is held between fingers 5f as shown in FIG. Even when there is a warp or the like in W, the wafer W can be reliably held.
(2) During a series of operations (transfer, observation) from taking out the wafer W from the wafer cassette 2 and storing it again, the wafer W is always held vertically, so that it does not bend due to its own weight. W damage can be prevented. Further, since the substrate surface of the wafer W is moved so as to be kept parallel to the moving direction at the time of transfer, damage due to deformation of the wafer W due to air resistance can be prevented. Further, by transferring the wafer W in this way, the transfer speed can be increased as compared with the conventional case, and the efficiency of the inspection process can be improved.
(3) Since the macro observation and the microscope observation are performed while the wafer W is held on the hand 5, it is not necessary to transfer the wafer W between the hand 5 and the observation stage as in the prior art, so the number of times of transfer is increased. It is possible to reduce the troubles at the time of delivery (adsorption holding error, breakage of wafer W due to delivery mistake, etc.).
(4) When the wafer W is transferred between the wafer cassette 2 and the hand 5 in a vertical state, a part of the wafer W is pushed out above the wafer cassette 2 by the assist plate 7a. It is possible to reliably hold the wafer W and store the wafer W in the wafer cassette 2 after observation.
[0029]
In the present embodiment, the “vertical” state of the wafer W is not strictly vertical, but is “substantially vertical” to the extent that the problem caused by the wafer W being a planar substrate being bent by its own weight can be avoided. It means that if there is anything. Similarly, “parallel” may be “substantially parallel” to the extent that the problem due to air resistance during movement of the wafer W can be avoided.
[0030]
In the above-described embodiment, the apparatus for observing the silicon wafer W with a microscope has been described as an example. However, the present invention can also be applied to a transfer apparatus and a substrate hand used in other apparatuses. In addition to the silicon wafer, the object includes a glass substrate of a liquid crystal panel and the like, which is effective for holding and transporting a thin substrate regardless of the shape (circular or rectangular) of the substrate.
[0031]
In the correspondence between the embodiment described above and the elements of the claims, the wafer W is a flat substrate, the hand 5 is a substrate hand and a holding means, the robot 4 is a transfer means, and the hand 5 and the transfer robot 4 are transferred. The objective lens 3a constitutes an objective optical system, the wafer cassette 2 constitutes a substrate cassette, the assist plate 7a constitutes a push-up jig, the vertical drive portion 7b constitutes a drive device, and the horizontal drive portion 7d constitutes a positioning device.
[0032]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the edge of the flat substrate is gripped so as to be sandwiched from both the front and back surfaces, even if the flat substrate is warped, it can be reliably held by the substrate hand.
According to the second to fourth aspects of the present invention, since the flat substrate is always held vertically, the flat substrate is not bent by its own weight, and the substrate surface of the flat substrate is parallel to the moving direction during conveyance. Therefore, the damage caused by the deformation of the planar substrate due to the air resistance can be prevented.
In particular, in the invention of claim 4, since the optical axis of the objective optical system is horizontal and the plane substrate vertically held by the holding means is observed with a microscope, the number of times of transfer of the plane substrate can be reduced, and the transfer is performed. It is possible to reduce a substrate holding error or a flat substrate breakage due to a delivery mistake.
According to the fifth aspect of the present invention, since the flat substrate stored in the substrate cassette in the vertical state can be protruded above the substrate cassette by the lifting jig, when the flat substrate is taken out from the substrate cassette by the substrate hand or the like. Can be taken out smoothly.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an inspection apparatus according to the present invention, and is a perspective view showing a schematic configuration of a microscope inspection apparatus.
FIGS. 2A and 2B are diagrams showing the details of the hand 5, in which FIG. 2A is a view of the wafer W as viewed from the front, FIG. 2B is a view taken along the arrow B in FIG. It is a figure which shows the finger 5a.
FIGS. 3A and 3B are diagrams showing the assist device 7, in which FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional view of a tip portion of the assist plate 7a.
FIG. 4 is a diagram illustrating an operation of taking out a wafer from the wafer cassette 2, and the operations are performed in the order of (a) to (c).
FIG. 5 is a diagram showing a wafer take-out operation following FIG. 4, and the operations are performed in the order of (a) to (c).
FIG. 6 is a side view of the apparatus, illustrating a conveying method.
FIG. 7 is a diagram for explaining a conveying method, and a plan view of the apparatus.
8A and 8B are diagrams showing a modification of the hand 5, wherein FIG. 8A is a diagram viewed from the front of the wafer W, and FIG. 8B is a cross-sectional view taken along DD in FIG.
9 is a diagram for explaining an operation when a wafer W is taken out from the wafer cassette 2 using the hand 5 of FIG. 8, and the operation is performed in the order of (a) to (c).
10 is a diagram showing an operation following FIG. 9, and the operations are performed in the order of (a) and (b). FIG.
FIG. 11 is a diagram for explaining a wafer transfer operation in a conventional apparatus, in which operations are performed in the order of (a) to (c).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Microscope inspection apparatus 2 Wafer cassette 3 Microscope 3a Objective lens 3b Eyepiece 4 Transfer robot 5 Hand 5a, 5f Finger 7 Assist apparatus 7a Assist plate 7b Vertical drive part 7c Horizontal drive part W, W1, W2 Wafer

Claims (5)

With the substrate surface of the flat board is vertically extending and gripping portion for gripping the upper portion of the planar substrate,
Said planar substrate which is gripped by the gripping portion, a conveying portion for conveying while maintaining a state of extending in the vertical direction,
An illumination unit that illuminates the flat substrate conveyed to the first predetermined position by the conveyance unit so as to be visually observable while holding the planar substrate in a state extending in the vertical direction by the holding unit ;
A rotating unit that rotates around the rotation axis in the vertical direction while holding the planar substrate in the first predetermined position in a state of being extended in the vertical direction by the holding unit ; Planar substrate observation device. The planar substrate observation apparatus according to claim 1, wherein the planar substrate is substantially circular, and a portion of the gripper that grips the planar substrate has a curvature that is substantially equal to the curvature of the circle .   The microscope further comprises a microscope for observing the planar substrate gripped in a vertical state by the gripper at a second predetermined position where the optical axis of the objective optical system is horizontal and can be transported by the transporter. The flat substrate observation apparatus according to claim 1 or 2. Planar substrate observation apparatus according to claim 3, wherein the benzalkonium that Yusuke further observation image rotation unit for rotating the observed image observed by the microscope. The transport unit can transport the planar substrate along an arc including the first predetermined position and the second predetermined position;
The planar substrate observation apparatus according to claim 3, wherein the gripping unit grips the planar substrate such that a substrate surface of the planar substrate extends in a tangential direction of the arc.

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