JPH10233427A - Cassette inspecting device for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cassette inspecting device for a wafer wherein presence of cassette's deformation and distortion is inspected in a short time. SOLUTION: A device 1 is used for inspecting the deformation of a cassette comprising a slit for housing a wafer. A bottom plate 2, a positioning member 3 which, provided on the bottom plate 2, positions a cassette, a pair of side plates 4a and 4b, and a back plate 5 provided on one side of the side plates 4a and 4b are provided. On the side plates 4a and 4b, the first optical sensor 13, comprising a light-emitting part and photo-detecting part, is provided so as to face each other, while provided at four places: lower part front side, lower part rear side, upper part front side, and upper part rear side of the cassette. At the rear plate 5, the second optical sensor 17 for detecting whether and edge is positioned at front surface or not is provided near, while outside, the edge on both sides on wafer inlet side of the cassette positioned by the positioning member 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer cassette apparatus for inspecting the deformation and distortion of a cassette for aligning and storing wafers.

[0002]

2. Description of the Related Art Along with the development of the semiconductor industry, in a semiconductor device manufacturing factory, automation of transport of a cassette in which wafers are aligned and stored has been advanced. Such automation of the transfer is realized mainly by the transfer performed by a transfer machine such as a robot. By the way, in the transfer method using such a transfer machine such as a robot, when the cassette is deformed or distorted, a transfer trouble may occur. Therefore, in order to prevent trouble, it is necessary to inspect the cassette for deformation or distortion. Conventionally, when inspecting the deformation and distortion of a cassette, a robot-type inspection device that measures these deformation and distortion with high accuracy has been used.

[0003]

However, this robot-type inspection apparatus has a complicated structure and expensive due to high-precision measurement, is difficult to handle, and has many failures. In addition, in the inspection using this, since the inspection (measurement) time takes about 10 minutes for one cassette, the loss of the inspection time increases when a large number of cassettes are used. It is also conceivable to provide a dedicated process in order to eliminate such an inspection time loss. In this case, a TAT (turn-around-timing) is required.
e) causes new inconveniences, such as a decrease in e).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object a simple structure, which is inexpensive and easy to handle. It is an object of the present invention to provide a wafer cassette inspection apparatus which can be performed by the above-mentioned method.

[0005]

According to the wafer cassette inspection apparatus of the present invention, a bottom plate for mounting a cassette, a positioning member provided on the bottom plate for positioning the bottom of the cassette, A pair of side plates disposed on the side surface of the cassette, and a back plate disposed on one side of the pair of side plates and disposed on the wafer entrance side of the cassette. The first optical sensor consisting of the unit and the light receiving unit, the light emitting unit is arranged on one of the side plates so that the light emitting unit and the light receiving unit face each other, and the light receiving unit is arranged on the other, and The first optical sensor, the lower front side of the cassette positioned by the positioning member,
The lower plate, the upper front, and the upper rear are disposed at four positions, respectively, and the back plate is located outside the edges on both sides on the wafer entrance side of the cassette positioned by the positioning member. And near each of said edges,
The second means for solving the above-mentioned problem is provided with a second optical sensor for detecting whether or not the edge is located at the front thereof.

According to this wafer cassette inspection apparatus,
By aligning each of the first optical sensors with the slit position of the cassette in advance, it becomes possible to detect four positions of the front and rear of the cassette and the front and rear of the upper portion,
Further, it is possible to detect the displacement of the edges on both sides of the cassette by the second optical sensor. Therefore, the first optical sensor can determine whether the four slits at the front and rear lower and front and rear of the cassette are respectively located at predetermined positions with respect to the cassette bottom surface, and the second optical sensor can detect both slits at both sides of the cassette. By knowing whether or not there is a displacement of the edge of the cassette, it is possible to know whether or not the cassette is deformed or distorted.

Further, in the wafer cassette inspection apparatus, it is preferable that the first optical sensors be mounted on the side plates in a state where their positions are variable. Even if the height of the slit changes, the position can be detected correspondingly. In the wafer cassette inspection apparatus, it is preferable that a plurality of types of shapes are prepared as positioning members according to the type of the cassette, and one of these is detachably fixed on the bottom plate. By preparing a plurality of positioning members in this way, it is possible to inspect each of a plurality of cassettes having different shapes for the presence or absence of deformation or distortion.

Further, in the wafer cassette inspection apparatus, it is preferable that the second optical sensors be mounted on the back plate in a state where their positions are variable. Therefore, even if the lateral width changes, it is possible to detect the displacement of the edge corresponding to the change. In the wafer cassette inspection apparatus, it is preferable that at least one of the side plates is movably provided on the bottom plate so that the side plates are separated or approached. Even if the type is changed and thus the width is changed, the cassette can be set correspondingly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a wafer cassette inspection apparatus according to the present invention will be described in detail. FIGS. 1, 2 and 3 are views showing an embodiment of the wafer cassette inspection apparatus according to the present invention. FIG. 1 is a plan view of the wafer cassette inspection apparatus.
Is a front view (view from the side opposite to the back plate 5 side in FIG. 1), and FIG. 3 is a side view thereof. In these figures, reference numeral 1 denotes a wafer cassette inspection apparatus, which inspects a wafer cassette having a plurality of slits for aligning and storing wafers for deformation. .

Prior to the description of the wafer cassette inspection apparatus 1, a wafer cassette to be inspected by the inspection apparatus 1 will be described with reference to FIG. In FIG. 4, reference numeral 50 denotes a wafer cassette (hereinafter abbreviated as a cassette). The cassette 50 has a substantially box shape with one opening, and the opening is used as a wafer entrance 51. The left and right side plate portions 5 correspond to the wafer entrance 51.
A large number of slits 53 are formed in each of 2, 2 in the horizontal direction. These slits 53 are slits 5 facing each other at left and right side plate portions 52, 52.
3 and 53, and a pair of slits 53, 5
The wafer W is fixed between the pair of slits 53 by bridging both sides of a single wafer W to 3. Therefore, since a large number of pairs of the slits 53 are formed at equal intervals from the lower side to the upper side of the cassette 50, the cassette 50 can arrange and store the wafers W by the number of pairs of the slits 53. It is. The width of the slit 53 is, of course, formed sufficiently larger than the thickness of the wafer W.

On the wafer inlet 51 side of the cassette 50, a front extension plate 54 is formed to extend outwardly (laterally) continuously to the edges of the left and right side plate portions 52, 52.
Further, on the side of the cassette 50 opposite to the wafer entrance 51,
A pair of rear extension plates 5 extending in the opposite direction to the wafer entrance 51
5, 55 are formed. The front extension plate 54 and the rear extension plate 55 are used for positioning the cassette 50 when the cassette 50 is inspected by the wafer cassette inspection apparatus 1 of the present invention as described later.

The wafer cassette inspection apparatus 1 shown in FIGS. 1, 2 and 3 is for inspecting the presence or absence of deformation of the cassette 50 having such a configuration, and a bottom plate for mounting the cassette 50 thereon. 2 and a cassette 5 provided on the bottom plate 2.
A positioning member 3 for positioning the bottom of the bottom plate 2;
A pair of side plates 4 arranged on the side of the cassette 50 above
a, 4b and a back plate 5 arranged on one side of the pair of side plates 4a, 4b to receive the wafer inlet side of the cassette 50.

The bottom plate 2 is provided with a cassette 5 as shown in FIG.
The rectangular shape is formed sufficiently larger than the bottom surface of 0, and a pair of grooves 6 along the long side direction is formed on one short side of the upper surface. These grooves 6, 6
Functions as a guide groove when the position of one side plate 4a of the pair of side plates is moved as described later.

The positioning member 3 is detachably fixed to the bottom plate 2 by well-known fixing means (not shown) such as a screw, and has an internal shape fitted to the bottom of the cassette 50. That is, the positioning member 3 has an internal shape corresponding to the outer shape of the bottom of the cassette 50, and is located on the back surface of the front extension plate 54 (the rear extension plate 55) of the cassette 50.
(A side surface), an edge positioning portion 8 that contacts the outer edge of the front extension plate 54 outside the front positioning portion 7, and engages with the rear extension plate 55 of the cassette 50. And a lateral positioning portion 10 in the form of a thin plate which is in contact with the side plate portion 52 of the cassette 50 on both sides. A plurality of types of positioning members 3 having different shapes are prepared in advance in accordance with the type of the cassette to be inspected. Therefore, by using the positioning member 3 corresponding to the target cassette for each test, the positioning can be performed not only for a single type of cassette but also for a plurality of types of cassettes.

The side plates 4a and 4b are, as shown in FIG. 2, a fixed plate portion 11a which comes into contact with the upper surface of the bottom plate 2, and a cassette 50.
And a side plate main body 11b which is positioned on the side surface of the base plate. The fixing plate portion 11a is fixed to the bottom plate 2 by screwing the fixing plate portion 11a to the bottom plate 2. The position of one of the side plates 4a and 4b is movable on the bottom plate 2. That is, the screw 12 for fixing the side plate 4a moves in the groove 6 along the groove 6 formed in the bottom plate 2, so that the side plate 4a maintains a state facing the other side plate 4b. In addition, the position can be moved on the bottom plate 2. The position of the other side plate 4 b is fixed to the bottom plate 2 by being screwed to the bottom plate 2.

On these side plates 4a and 4b, first optical sensors 13 are provided at a total of four locations. The first optical sensor 13 includes a light emitting unit 13a formed of a light emitting element and a light receiving unit 13b formed of a light receiving element. These are configured such that, for example, a light-emitting portion 13a is provided on one side plate 4a and a light-receiving portion 13b is provided on the other side plate 4b so as to face each other on a plane parallel to the bottom plate 2. The light emitted from the light emitting unit 13a is received by the light receiving unit 13b, and thereby it is detected whether or not there is an object that blocks light between the light emitting unit 13a and the light receiving unit 13b.

As shown in FIGS. 1, 2 and 3, these first optical sensors 13 are provided at the lower part of the side plate 4a (4b) at the front and the lower part and at the upper part at the front and the upper part at the rear. These are arranged at four places on the side, and are attached in a state of being inserted into vertically long holes 14 formed at the four places on the side plates 4a and 4b as shown in FIG. It was done. That is, the first optical sensor 13
Is a cassette 5 positioned by the positioning member 3
It is arranged so as to be located at four places: a lower part, a rear part and a lower part, a front part, and an upper part, a rear part and an upper part.

Here, two light-emitting portions 13a, 13a and the light-receiving portion 1 which are laterally adjacent to each other on the same side plate 4a (4b).
3b and 13b are integrated by the sensor frame 15 as shown in FIG. The sensor frame 15 has an elongated rectangular plate shape, and has a light emitting unit 13a or a light receiving unit 13b fixed in a pair of holes (not shown) formed at both ends thereof. The sensor frame 15 is screwed and fixed to the outer surface of the side plate 4a (4b) so that the sensor frame 15 can be moved up and down. That is, the side plates 4a and 4b are provided with the long holes 14 through which the light emitting portion 13a or the light receiving portion 13b of the first optical sensor 13 is inserted.
Separately, a long hole 16 for mounting the sensor frame 15 is formed, and the sensor frame 15 is screwed and fixed in this long hole 16 with a screw composed of a bolt and a nut so that the vertical movement can be adjusted. is there.

The back plate 5 is disposed so as to be on the wafer inlet 51 side of the cassette 50 positioned by the positioning member 3 as shown in FIG. It is fixed to the bottom plate 2 while being in contact with the end 8a. At both ends of the back plate 5, second optical sensors 17 are disposed on an extension of the edge positioning portion 8 of the positioning member 3 in a plan view. The second optical sensor 17 disposed on the extension of the edge positioning portion 8 in this manner allows the second optical sensor 17 to be slightly outside the edges on both sides of the cassette 50 positioned by the positioning member 3 on the wafer entrance side. , That is, disposed near each of the edges.

Unlike the first optical sensor 13, the second optical sensor 17 is, for example, an optical fiber type in which a light emitting unit and a light receiving unit are integrated, and emits light from the light emitting unit to the front side thereof. The light receiving section receives the emitted light reflected from an obstacle on the exit side and returns.
Therefore, the second optical sensor 17 determines whether there is an obstacle up to a predetermined distance on the front side (light emission side), that is, the wafer of the cassette 50 It is configured to detect whether or not the side edge on the entrance side is located. The second optical sensor 17 is fixed while being inserted into a horizontally long hole (not shown) formed at each end of the back plate 5. Similarly to the above, it is fixed so that lateral movement can be adjusted in the elongated hole.

Next, a method of inspecting the cassette 50 by the wafer cassette inspecting apparatus 1 having such a configuration will be described. First, prior to the inspection of the cassette 50, the positions of the first optical sensor 13 and the second optical sensor 17 are respectively adjusted using, for example, a normal cassette 50 having no deformation or distortion, and set to a normal position. Here, the normal position means that the optical path connecting the light emitting portion 13a and the light receiving portion 13b is positioned and fixed by the positioning member 3 at each position on the side plate 4a (4b) for the first optical sensor 13. Of the cassette 50 passing through the slit 53 at an appropriate position.

When the inspection is performed with the wafer W stored in the slit 53, a portion corresponding to the difference between the width of the slit 53 and the thickness of the wafer, that is, an opening portion between the upper surface of the wafer and the upper edge of the slit. Is the normal position,
The optical path position of the first optical sensor 13 is set to correspond to this position. Further, as for the second optical sensor 17, the front extension plate 54 on the cassette entrance 51 side of the normal cassette 50 that is positioned and fixed and has no deformation or distortion,
Positions facing slightly outward from each of 54 are regarded as normal positions.

Subsequently, the normal cassette 50 is removed from the wafer cassette inspection apparatus 1, and the cassette 50 to be inspected is set at a proper position determined by the positioning member 3 in the inspection apparatus 1. Here, regarding the positioning by the positioning member 3, the outer ends of the front extension plates 54, 54 of the cassette 50 are brought into contact with the edge positioning portions 8, respectively, and the rear surfaces (rear extension) of the front extension plates 54, 54 are set. Board 55
Side surface) is brought into contact with the front positioning portion 7, and the side plate portion 52 of the cassette 50 is brought into contact with the horizontal positioning portion 10,
Further, this is performed by engaging the rear positioning portion 9 with the rear extension plate 55 of the cassette 50.

The cassette 5 to be inspected in this way is
When 0 is set at a normal position, the cassette 50 is inspected for deformation or distortion according to the inspection flowchart shown in FIG. First, the upper light sensor 13 on the front side (opposite to the back plate 5) of the first light sensor 13 detects whether light from the light emitting portion 13a reaches the light receiving portion 13b (step 1). , ST1), thereby determining whether or not the position of the pair of slits 53 is shifted from the position of the pair of slits 53 in the normal state.
That is, when the light from the light emitting unit 13a does not reach the light receiving unit 13b, the cassette 50 is determined to be deformed, and the cassette inspection determination is rejected as the upper cassette groove NG. Further, the light from the light emitting portion 13a of the optical sensor 13 is received by the light receiving portion 13b.
If it is determined that the position of the front side (the rear side in the case of the cassette 50) in 3 is not shifted, the process proceeds to step 2.

In step 2, the light sensor 13 on the upper rear side (backboard 5 side) of the first light sensor 13 detects whether light from the light emitting portion 13a reaches the light receiving portion 13b. . If it is determined by such detection that there is a position shift on the rear side (the front side in the case of the cassette 50) of the upper slit and the cassette 50 is deformed, as in the case described above, the cassette 50 is also deformed. Upper cassette groove N
As G, the cassette inspection judgment is rejected. On the other hand, when it is determined that the position of the slit 53 is not shifted,
The upper cassette groove is OK, and the process proceeds to step 3.

In step 3, the light sensor 13 on the front side (the side opposite to the back plate 5) in the lower part of the first light sensor 13 determines whether or not the light from the light emitting portion 13a reaches the light receiving portion 13b. It is detected and determined in the same manner as the previous detection. When it is determined that the cassette 50 is deformed, the cassette inspection determination is rejected as the lower cassette groove NG. On the other hand, when it is determined that the position of the slit 53 is not shifted, the process proceeds to step S4.

In step 4, the light sensor 13 on the rear side (back plate 5 side) of the lower part of the first light sensor 13 detects whether the light from the light emitting part 13a reaches the light receiving part 13b. , In the same manner as in the previous detection. When it is determined that the cassette 50 is deformed, the cassette inspection determination is rejected as the lower cassette groove NG.
On the other hand, when it is determined that the position of the slit 53 is not shifted, the lower cassette groove is determined to be OK, and the process proceeds to step S5.

In step 5, one side of the second optical sensor 17, for example, the left optical sensor 17, determines whether the front extension plate 54 of the cassette 50 is positioned on the light emission side of the optical sensor 17. That is, the emitted light from the light emitting unit is reflected by the front extension plate 54 due to the position of the front extension plate 54, and it is detected whether or not this returns and is received by the light receiving unit. Then, the reflected light is received by the light receiving portion, and the front extension plate 5 is received.
If it is detected that the position No. 4 is located, since the front extension plate 54 is located at a position that should not originally exist, the cassette inspection determination is rejected as the cassette inclination NG. If the reflected light is not received by the light receiving unit, and thus it is determined that the front extension plate 54 is at the proper position, the process proceeds to step 6.

In step 6, the other extension of the second optical sensor 17, for example, the right optical sensor 17, puts the front extension plate 54 of the cassette 50 on the light emission side of the optical sensor 17 in the same manner as in step 5. Detect if it is not located.
Then, when the reflected light is received by the light receiving unit and it is detected that the front extension plate 54 is positioned, the cassette inspection determination is rejected as the cassette inclination NG. Further, when the reflected light is not received by the light receiving unit, and therefore, it is determined that the front extension plate 54 is at the normal position, the cassette inclination is OK,
As a result, it is determined that the cassette 50 has no deformation or distortion, and the cassette inspection determination is passed.

That is, according to such an inspection, at the four positions of the cassette 50, that is, up, down, front and rear, the pair of slits 53, 53 on the left and right are at the same height with respect to the bottom surface of the cassette 50. It is confirmed by the first optical sensor 13 that the horizontal is maintained, and further, it is confirmed by the second optical sensor 17 that the cassette 50 is not tilted to the left or right. It is determined that there is no deformation or distortion.

Therefore, the wafer cassette inspection apparatus 1
, The cassette 50 is placed (set) at a regular position determined by the positioning member 3, and the optical sensors 13, 1
By automatically detecting the presence or absence of the positional deviation in each of the cassettes 7, it is possible to easily inspect the cassette 50 for deformation or distortion in a short time (within 3 seconds). Therefore, the inspection can be performed in such a short time,
In addition, since the inspection can be performed even in a state in which the wafer W is stored, the inspection can be performed in the working process without providing a dedicated process for the inspection, thereby improving the TAT.

In the wafer cassette inspection apparatus 1, the first optical sensor 13 is mounted on the side plates 4a and 4b via the sensor frame 15 in a state where its position is variable. Therefore, even if the height of the slit 53 changes, the position can be detected correspondingly. In addition, since a plurality of shapes having different shapes according to the type of the cassette are prepared as the positioning member 3, the positioning member 3 corresponding to the target cassette is selected and used by each inspection, so that a single type is used. Can be positioned for not only the cassettes but also for multiple types of cassettes,
A plurality of cassettes having different shapes can be inspected for deformation or distortion.

Further, since the second optical sensors are attached to the back plate 5 in a state where their positions are variable, even if the type of cassette is changed and the width is changed, the end of the second optical sensor is correspondingly changed. Edge displacement can be detected. Also, one side plate 4a is
4b is movably provided on the bottom plate 2 so as to be separated or approached, so that the cassette can be set correspondingly even if the type of the cassette changes and therefore the width changes.

[0034]

As described above, in the wafer cassette inspection apparatus of the present invention, the first optical sensor and the second optical sensor can be used simply by placing (setting) the cassette at a regular position determined by the positioning member. Since the presence / absence of displacement can be automatically detected by the sensors, it is possible to easily and quickly (within 3 seconds) inspecting the cassette for deformation or distortion. it can.
Therefore, since the inspection can be performed in such a short time and the inspection can be performed even in a state where the wafer is stored, it is necessary to perform the inspection in the working process without providing a dedicated process for the inspection. And thus T
AT can be improved. In addition, since the structure is simpler than that of a conventional robot type inspection apparatus, it is inexpensive and easy to handle, thus contributing to a reduction in the manufacturing cost of the semiconductor device.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of an embodiment of a wafer cassette inspection apparatus according to the present invention.

FIG. 2 is a front view showing a schematic configuration of an embodiment of a wafer cassette inspection apparatus according to the present invention.

FIG. 3 is a side view showing a schematic configuration of a wafer cassette inspection apparatus according to an embodiment of the present invention.

FIG. 4 is a perspective view showing a schematic configuration of a cassette to be inspected by the wafer cassette inspection apparatus shown in FIGS. 1, 2 and 3;

FIG. 5 is an inspection flowchart for explaining a cassette inspection method by the wafer cassette inspection apparatus shown in FIGS. 1, 2 and 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Wafer cassette inspection apparatus 2 Bottom plate 3 Positioning member 4a, 4b Side plate 5 Back plate 13 First optical sensor 17 Second optical sensor 50 Wafer cassette
51 Wafer entrance 53 Slit

Claims (5)

[Claims] 1. An apparatus for inspecting deformation of a cassette having a plurality of slits for aligning and storing wafers, comprising: a bottom plate on which the cassette is mounted; and a bottom plate provided on the bottom plate. A positioning member for positioning the bottom portion; a pair of side plates disposed on the side surface of the cassette on the bottom plate; a back plate disposed on one side of the pair of side plates and disposed on the wafer entrance side of the cassette The side plate has a first light sensor including a light emitting unit and a light receiving unit, and a light emitting unit is provided on one of the side plates so that the light emitting unit and the light receiving unit face each other. , A light receiving unit is provided on the other side, and the first optical sensor is a lower front side of the cassette positioned by the positioning member, a lower rear side,
The cassette is positioned at four positions on an upper front side and an upper rear side, and the back plate is located outside the edges on both sides of the wafer entrance side of the cassette positioned by the positioning member. And a second optical sensor for detecting whether or not the edge is located in front of the wafer cassette inspection device. 2. The wafer cassette inspection apparatus according to claim 1, wherein each of the first optical sensors is attached to a side plate in a state where its position is variable. 3. A positioning member having a plurality of shapes according to the type of a cassette is prepared, and one of the positioning members is detachably fixed on the bottom plate. Item 2. A wafer cassette inspection apparatus according to Item 1. 4. The wafer cassette inspection apparatus according to claim 1, wherein each of the second optical sensors is attached to a back plate such that its position is variable. 5. The wafer cassette inspection apparatus according to claim 1, wherein at least one of the side plates is movably provided on the bottom plate so that the side plates are separated or approached.