JPH0817901A - Semiconductor wafer storage apparatus and its imperfect accommodation detection method - Google Patents

Abstract

PURPOSE:To detect erroneous insertion of a wafer and prevent a scratch on a wafer, when a wafer is placed in a carrier or taken out from the carrier, or the set position of a wafer is changed when handling. CONSTITUTION:When a wafer is placed in a carrier or taken out from the carrier when handling, the carrier is set on a carrier cassette 5 equipped with a light emitting part 50 and a photo detection sensor 60. The light emitting part 50 and the photo detection sensor 60 are arranged in the part (a protruding part 21 between carrier trenches) which a wafer essentially does not intersect. When a wafer 32 intersects the part, an alarm sound is generated, and a scratch on the wafer 32 is prevented. Handling is not disturbed and abnormality can be detected in an early stage, by arranging the light emitting part 50 and the photo detection sensor 60 on the diagonal line of the front surface of the carrier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer storage device and a semiconductor wafer defective storage detection method, and more particularly to an apparatus for detecting the defective storage state of a semiconductor wafer and its detection method.

[0002]

2. Description of the Related Art FIG. 5 is a top view of a storage box called a carrier, which is a conventional semiconductor wafer storage device, viewed from above. In FIG. 6, in order to accommodate a large number of semiconductor wafers arranged in parallel in this carrier 2, a groove 20 for accommodating the peripheral edge portion (end portion) of each wafer is provided with a first side 3 and a first side 3 facing this side. 2 and the side 9 of the wafer, and in some cases, it is also formed on the lower peripheral edge of each wafer. Wafer 1
The convex portion 2 is provided between the groove 20 between 0 and the adjacent wafer 13.
1 is formed, and the width of the convex portion 21 is determined so that handling of storing and taking out is not difficult.
The groove width and the groove depth of the groove 20 have a certain dimensional margin from the thickness and diameter of the wafer to be housed.

The carrier 2 is mounted in a cassette (not shown). Such a carrier 2 has been used conventionally and is indispensable during each manufacturing process of semiconductor wafers. Here, the wafers 10 and 13 are in a normally stored state, and the wafer 12 is in an erroneously stored state because one of the wafers 12 is in the adjacent groove 20.

On the other hand, the tilted state of a semiconductor wafer that has been erroneously stored is detected using a two-position sensor.
According to Japanese Patent Laid-Open No. 300525/1993, a structure in which a carrier accommodating a semiconductor wafer is moved up and down is measured, and the inclination of the wafer is obtained by calculation and calculation.

Referring to FIG. 7 showing this apparatus, a wafer position detecting mechanism is provided between the wafers 91 in the traveling path of the arm 93, and this mechanism uses an optical sensor, and an accommodated carrier 92 is interposed. On the other hand, for example, on the side of the arm 93, two systems of light emitting units 94a and 94b having a light emitting element are disposed, and two systems of light receiving units 95a and 95b having a pair of light receiving elements are provided via a carrier 92. It is provided on the fixed portion 98b on the opposite side.

[0006]

When semiconductor wafers are successively stored in the conventional carrier 2 shown in FIG. 6 by handling means or the like, the semiconductor wafers are stored in the grooves 20 at the correct facing positions like the wafer 12 shown in FIG. However, one of them may enter the groove next to the other, resulting in an inclined state.

This is an accident caused by the fact that the width of the groove 20 is narrow but the distance between the grooves facing each other is large. This is likely to occur when the semiconductor wafer is stored by visual inspection, but may also occur with mechanical handling means.

In FIG. 6, the wafer 12 tilted to the right is shown, and of course, the wafer 12 may tilt to the left, but in either case, the wafer 12 comes into contact with the adjacent wafer 1 or 13, and this contact causes the wafer 12 to tilt. Not only is the semiconductor layer, etc., already formed on the edges of the main surface of the wafer destroyed, but when scraps are generated due to scratches, these scraps adhere to the main surface of other wafers, significantly reducing the defect rate. Cause

Further, in the technique of the above publication, the semiconductor wafer is handled in a horizontal position, and it is not possible to let a part of the storing process fall naturally, and dust is likely to adhere to the main surface. There is a drawback that reliability is reduced. In addition, this configuration is not a configuration for preventing the tilt storage, but is for measuring the inclination of the wafer once stored, and the configuration is also extremely complicated. Further, since the two systems of sensors have light rays that are parallel to the storage / removal direction of the semiconductor wafer, the storage / removal method becomes complicated. Furthermore, since each semiconductor wafer is detected while moving up and down, further determination time is required.

In order to solve the above-mentioned problems of the prior art, the present invention has the following problems. (A) To prevent the tilted storage of the semiconductor device. (B) Of the main surface of the semiconductor wafer, the peripheral surface should not be destroyed. (C) Prevent the generation of scraps due to scratches and the like. (D) To improve the manufacturing yield of semiconductor wafers. (E) To enable detection with a relatively simple structure and quickly. (F) The handling operator should also be notified of defective storage. (G) To be able to detect tilted storage of many semiconductor wafers at the same time. (H) Do not reduce workability and increase the number of manufacturing processes. (I) It can also be used as a batch type turning machine. (J) The semiconductor wafer should be handled in the vertical position, not in the horizontal position. (K) Even semiconductor wafers with a large diameter should not be stored in an inclined manner.

[0011]

The first structure of the present invention is as follows.
In a storage device for a semiconductor wafer, wherein a groove into which an end portion of a semiconductor wafer is inserted has a plurality of protrusions arranged with a protrusion having a predetermined width, and in the semiconductor wafer storage device, one of the protrusions is opposed to the other protrusion. A light emitting means for emitting a predetermined light beam and a light receiving means for detecting the light beam from the light emitting means are provided along a plane toward the detecting means, and a detecting means for outputting the light beam detected by the light receiving means as a predetermined electric signal is provided. It is characterized by having.

According to another structure of the present invention, when a semiconductor wafer is stored in a carrier, the semiconductor wafer defect storage detection is performed by detecting the positional deviation of the wafer depending on whether or not the light beam projected by the wafer is blocked. In the method, the light beam is emitted in an oblique direction that forms a predetermined angle with the housing direction of the wafer.

[0013]

1 is a top view showing a semiconductor wafer defect storage detecting means of a semiconductor wafer storage device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along the light emitting part-light receiving sensor of FIG. It is the sectional view which it tried.

In FIGS. 1 and 2, in this embodiment, a carrier 2 for accommodating a large number of semiconductor wafers, a carrier cassette 5 in which the carrier 2 is set, and a protrusion 21 between the grooves 20 are provided substantially in the center. Light emitting parts 50, 51, 52,
Light receiving sensors 60, 61, 62 facing the light emitting units 50, 51, 52 respectively are provided.

The light emitting section 50 and the like are provided with a light emitting body such as a light emitting diode or a laser beam, and a lens system for optically converging and projecting the light beam from the light emitting body, and the carrier cassette 5 Is provided at one end of each of the projections 2 and is a light ray 40 emitted obliquely upward from below.
A large number are arranged corresponding to each one. This light emitting unit 50
Rays 40, 41, etc. from the like pass through an opening 48 formed in the carrier 2. Light-transmissive glass, resin, or the like may be fitted into the opening 48. here,
The opening 48 is not necessary as long as the carrier 2 can transmit light rays.

The light rays 40 and the like traveling obliquely upward go out from the inside of the carrier 2 and enter the light receiving sensor 60 and the like provided at the other end of the carrier cassette 5. Here, it is preferable that about half of the length of the light ray 40 is located outside the line of the opening 2 ′ of the carrier 2, and at least a part of the light ray 40 needs to be outside the opening 2 ′. There is. With this configuration, the tilted storage can be detected before the semiconductor wafer 35 has completely entered the carrier 2.

The light beam 40 is preferably an oblique light beam at a predetermined angle with respect to the storage / removal direction of the wafer 35. In FIG. 2, the light beam 40 is 45 ° with respect to the vertical storage / removal direction. It is shown as a front-back diagonal direction,
This is the most preferred embodiment. This light ray 40 is a light ray which is along the plane substantially parallel to the plane formed by the main surface of the wafer 35 properly inserted into the carrier 2 and which is oblique.

This structure is also because one side needs to be opened in order to secure the handling workability especially in the vertical state of the wafer. That is, by providing the light emitting unit 50 and the light receiving sensor 60 on the diagonal line of the side surface of the carrier 2, there is no hindrance to the handling at the time of storing and taking out, and early detection is possible. The positions of the light emitting unit 50 and the light receiving sensor 60 can be interchanged with each other.
It is more preferable that the light emitting portion is located below since it is not affected by illumination.

The light beam 40 in FIG. 2 is most preferably present on a plane obtained by connecting the substantially central positions of the convex portions 21 facing each other in FIG. 1, and it is preferable that there is no deviation from the central position. .

The light emitting portion 50 and the light receiving sensor 60 require input / output wiring, but this wiring may use the air space between the carrier 2 and the cassette 5, and is not shown here. The output wiring processing circuit will be described later. Carrier 2,
The cassette 5 is preferably made of a resin having a low electrical insulation property in order to prevent the formation elements in the wafer 35 from being destroyed by static electricity.

The carrier 2 has a semi-circular convex portion 21 on the lower side along the direct line of the semiconductor wafer 35. However, the carrier 2 may have a rectangular shape instead of such a semi-circular shape, and a groove is formed on the bottom. Although not necessary, it is indispensable to provide the groove 20 and the convex portion 21 at positions facing each other as seen from the upper surface as shown in FIG. The rays 40, 41, etc. are not interrupted if the semiconductor wafer is stored in the normal position, and are not blocked even if the semiconductor wafer is actually stored in the normal position.

In the work of storing the semiconductor wafer in the carrier 2, the light rays from the light emitting parts 50, 51, 52, etc.
It is incident on the corresponding light receiving sensor 60, 61, 62, etc., and if any one of the light receiving sensors is not incident, means for directly issuing an alarm sound is provided. As the light receiving sensor, a light sensing element such as a CCD element is used. Instead of an alarm sound, an alarm lamp may be turned on or blinked, or these lamps and an alarm sound may be used together.

Now, the semiconductor wafer 35 sucked or fitted by the handling 49 should be carefully checked from above the carrier 2.
It is moved downward so as to enter a predetermined pair of grooves 20. At this time, the first wafer 30 and the second wafer 31 are
It has already been stored normally without touching the light rays 40, 41 and the like.

Next, when the third wafer 32 is moved closer to the inside of the carrier 2 from the upper side to the lower side, the third wafer 32 is obtained.
Since one of the grooves 20 is inclined so as to enter the groove 20 next to the regular position, the light beam 42 is interrupted immediately before being housed in the carrier 2 and the light receiving sensor 62
Then, the light beam 42 does not reach, an alarm sound is immediately emitted, the downward movement of the wafer 32 is stopped, and the inclination of the wafer 32 can be corrected until the alarm sound disappears. Therefore, it is possible to prevent the tilt storage.

Although one of the third wafers 32 is accommodated in the groove on the right side, conversely, the third wafer 32 is accommodated in one groove of the second wafer 31 already accommodated. There is a case where there is such an inclination, but in such a case, the same operation is performed.

FIG. 3 is a block diagram showing a circuit for processing a signal obtained by the light receiving sensor of the first embodiment. In FIG. 3, light emitting units 70 and 7 common to FIGS.
The light rays emitted from No. 1 reach the light receiving sensors 72 and 73, respectively, and the signal level here reaches the required level by the amplifier 7
4, 75 are amplified respectively, and the outputs are respectively logic levels [1],

It is converted to [0] by the converters 76 and 77, the output is input to the OR gate 78, and the output is processed by the output processing unit 79 according to the purpose.

One of the processing outputs here is connected to an alarm means 80 which emits an alarm sound, and is connected to a light emitting means 81 composed of a visually illuminating or blinking light emitting body, or input to a computer or industrial industry. It is connected to an output terminal 82 used as a stop signal or the like of the handling means of the robot. For each of the above-mentioned means 80, 81, 82, one means is selected or two or more means are selected as required. In the configuration of FIG. 3, only the two series from the light receiving unit to the converter have been described, but in reality, a necessary number is prepared according to the number of wafers to be stored.

In the above structure, the light receiving sensors 72, 73
Without at least one of the incident light, the converter 76,
It is output to 77 as a level of "1" or "0",
When at least one of the OR gates 78 is in the state of “no incident light”, this state is detected and sent to the output processing unit 79. As described above, the tilted storage of the semiconductor wafer can be prevented in advance.

In addition to the block diagram of FIG. 3, the following modes can be adopted. That is, the amplifiers 74 and 75, the converters 76 and 77
The input part of the amplifier may be scanned by the control circuit so as to be shared, and input to one amplifier in a time division manner. In this case, it is necessary to prepare a register for temporarily storing at the input portion of the OR gate 78, which is advantageous in simplifying the circuit when there are many wafers.

In addition to the block diagram of FIG. 3, the following modes can also be adopted. That is, a structure including a light emitting unit, a light receiving sensor, an amplifier, a light emitting body, or a warning sound body is provided on each carrier between semiconductor wafers. This configuration is a very simple circuit,
Moreover, there is an advantage that the position of the blocked light ray can be recognized immediately (in the case of the light emitter).

FIG. 4 is a perspective view partially showing a semiconductor wafer storage device according to a second embodiment of the present invention. In FIG. 4, this embodiment is almost the same as FIG. 1 and FIG. 2 showing the first embodiment except that a light receiving sensor is not used. Therefore, common parts are indicated by common reference numerals. , The description is omitted.

In this embodiment, the light receiving sensors 60 and 6 shown in FIG.
1, 62, etc. are not provided, and the light-receiving surfaces 60, 61, 62, etc. on which the emitted light rays strike are used, or the light-receiving part 64 including these light-receiving surfaces is provided with an adhesive seal having aluminum powder adhered to the surface. Therefore, it is preferable to improve the visibility. Each light ray 40 from the light emitting parts 50, 51, 52,
41, 42, etc. are radiated from the lower front to the upper rear (common to FIG. 2), and the direct system of each ray is preferably 3 mm to 6 mm or more, but the width of the convex portion 21 is particularly preferable in order to improve visibility. It is preferable to extend to. Moreover, each light ray is limited to a visible light ray.

The perspective view of FIG. 4 is a view actually seen from the position of the operator's eyes. This operator is about to grasp the exclusive grip 65 sandwiching the third wafer 32 with the right hand 55 and to insert it into the groove 20 in the carrier 2 along the insertion direction 64 indicated by the arrow. Light rays 42 and 43 are emitted on both main surfaces of the third semiconductor wafer 32, respectively.

As shown in the figure, when the third semiconductor wafer 32 is tilted to be accommodated out of a predetermined position, the light beam 42 is received in a long elliptical shape on one main surface of the third semiconductor wafer. As the surface 62 'is formed, the light receiving surface 62 does not illuminate. Since this can be visually recognized by the operator immediately, it is possible to correct the inclination of the third wafer 32, return it to the position of normal insertion, and store it in the predetermined groove 20.

At this time, if the third semiconductor wafer 32 is tilted too much and tilted in the opposite direction, the light ray 43 is blocked and the light-receiving surface 63 is no longer illuminated, and the operator immediately makes an overcorrection. Since it can be visually recognized, the insertion can be advanced while returning to the proper position.

In this embodiment, since it is not necessary to use the light receiving means or the circuit for electrically converting, for example, the detecting means as shown in FIG. 3, the structure is extremely simple, and the erroneous insertion preventing means can be provided at a low cost. There is.

In the above embodiments, the case where the semiconductor wafers are sequentially stored one by one has been described. However, even when the semiconductor wafers are stored two by one by the handling means, the same effect can be obtained with the above configuration.

Next, a case of so-called batch processing in which a large number of semiconductor wafers stored in a carrier cassette are transferred to another carrier cassette at one time will be described.

Next, as a third embodiment of the present invention, an example of a batch type sorting machine will be described with reference to FIG. In FIG. 4, this second embodiment can be used not only alone but also widely for replacement of wet processing devices and boards for diffusion processing. In the case where the wafer 1 is already stored in the carrier 2 and is to be transferred to the carrier 2, the upright machine 100 is turned upside down, but since the chuck portion 8 is provided, the wafer 1 does not drop. First, the upright machine 100 upside down
Is set on the carrier 2 (setting means is not shown).

In this state, first, positional deviations of a large number of wafers are detected by using the light receiving section 7 and the light receiving sensor 6 as in the first embodiment. If there is already a displacement,
Then, the setting machine is returned to the original position to correct this positional deviation and set again on the carrier 2 of the carrier cassette 5. When there is no displacement, the chuck part 8 is released and a large number of semiconductor wafers 1 are dropped into the carrier 2 at once. The displacement of the wafer 1 after being dropped is also checked.
This completes the transfer.

As described above, in the batch type turnover machine, when the wafers are turned from carrier to carrier, the parallel state of the wafers at the time of turnover is confirmed, and if there is a wafer extending over the adjacent groove, it is detected. it can.

In both the first and second embodiments, not only ultraviolet rays and visible light rays but also laser rays can be used as the light emitter and the light sensor. Further, in the third embodiment, not only the alarm but also the feedback mechanism of the control system can be input.

[0043]

As described above, according to the present invention, since at least the light emitting portion is provided so that the tilted storage of the semiconductor wafer can be detected in advance, the above problems are solved and the semiconductor wafer is tilted and stored. This prevents the occurrence of scratches on the wafer and other effects.

[Brief description of drawings]

FIG. 1 is a top view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along a ray plane of FIG.

FIG. 3 is a block diagram showing a detection device used in the first embodiment.

FIG. 4 is a perspective view showing a second embodiment of the present invention.

FIG. 5 is a side view showing a third embodiment of the present invention.

FIG. 6 is a top view showing a conventional carrier.

FIG. 7 is a perspective view showing a conventional tilt storage detection device.

[Explanation of symbols]

2, 92 carrier 2'carrier storage port 3 first side 5 carrier cassette 9 second side 10 to 13, 30 to 32, 35, 91 semiconductor wafer 20 groove 21 convex portion 40 to 42 light beam 48 opening portion 49 handling 50, 51, 52, 70, 71 Light emitting part 60, 61, 62, 72, 73 Light receiving sensor 74, 75 Amplifier 76, 77 Converter 78 OR gate 79 Output processing part 80 Warning means 81 Light emitting means 82 Output terminal 93 Arm 95a , 95b Light receiving part 98a Fixed part 100 Rebuilding machine

Claims (7)

[Claims] 1. A groove into which an end portion of a semiconductor wafer is inserted,
In a storage device for semiconductor wafers provided with a large number of carriers arranged with convex portions having a predetermined width, a predetermined light ray is emitted along a plane from one of the convex portions to the other convex portion facing the convex portion. 2. A semiconductor wafer storage device, comprising: a light emitting means for detecting a light beam from the light emitting means; and a light receiving means for detecting a light beam from the light emitting means, and a detecting means for outputting the light beam detected by the light receiving means as a predetermined electric signal. 2. The semiconductor wafer storage device according to claim 1, wherein the detecting means is provided with means for emitting an alarm sound or an alarm light. 3. The semiconductor wafer storage device according to claim 1, wherein the light beam from the light emitting means is an oblique light beam forming a predetermined angle with respect to the insertion direction of the wafer. 4. The semiconductor wafer storage device according to claim 1, wherein a part of the light beam reaching the light receiving means from the light emitting means is arranged so as to exist outside the storage opening of the carrier. 5. A groove into which an end portion of a semiconductor wafer is inserted,
In a storage device for a semiconductor wafer provided with a plurality of carriers arranged with a convex portion having a predetermined width, the visible light along a plane extending from one of the convex portions to the other convex portion opposed to the convex portion at a predetermined angle. A semiconductor wafer storage device, characterized in that it is provided with a light emitting means for radiating the semiconductor wafer. 6. When a semiconductor wafer is housed in a carrier, whether or not the wafer blocks a projected light beam,
In this semiconductor wafer defect storage detection method for detecting a wafer misalignment, the semiconductor wafer defect storage detection method is characterized in that the light beam is emitted in an oblique direction forming a predetermined angle with the wafer storage direction. 7. The method for detecting defective storage of a semiconductor wafer according to claim 6, wherein the oblique light rays are used when a large number of semiconductor wafers in the first carrier are transferred to the second carrier at a time.