JPH0547905A - Detection equipment of substrate in substrate accommodating vessel - Google Patents

Abstract

PURPOSE:To detect whether substrate exist in a substrate accommodating vessel, by quickly handling the case even when a vessel with different substrate accommodation pitch is set. CONSTITUTION:An optical sensor elevating mechanism 25 continuously moves an optical sensor for detecting a substrate, along a substrate accommodating vessel. A pitch member 30 moves together with the optical sensor elevating mechanism 25, and a timing detection sensor 32 detects slits 31 of the pitch member 30 and intermittently outputs a timing signal. The slits 31 are arranged at a pitch shown by the greatest common measure of trench pitches of substrate accommodating vessels having different kinds of specifications. A CPU counts the timing signal while referring trench pitch information of the substrate accommodating vessel set by a pitch information setting apparatus. When the counted value coincides with a value corresponding to the trench pitch information, the CPU takes in the output from the optical sensor, and detects whether substrates exist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate storage container in which substrates such as semiconductor wafers are stored in multiple stages, for example, a cassette for storing wafers in a semiconductor manufacturing process, a heat treatment boat for carrying the wafers into a heat treatment furnace, and the like. The present invention relates to an apparatus for detecting a substrate stored in each stage of a container when the substrate is taken out of the container or stored in the container.

[0002]

2. Description of the Related Art Conventionally, there are the following types of substrate detecting devices of this type. For example, a cassette containing a substrate is intermittently moved up and down at the same pitch as the substrate storage groove in the cassette, and the presence or absence of the substrate in each groove in the cassette is detected by an optical sensor fixedly installed at a predetermined position. There are various types of substrate detection devices.

According to this apparatus, when the cassette is moved up and down, the cassette vibrates, so that the dust adhering to the inside of the cassette is detached and adheres to the substrate, or the inner wall of the substrate storage groove and the substrate end portion. However, there is an inconvenience that they are rubbed against each other to generate dust.

In order to eliminate such inconvenience, the cassette is fixedly installed, and the optical sensor for detecting the substrate is intermittently fed up and down along the cassette, so that the presence or absence of the substrate in the cassette can be maintained without moving the cassette. An apparatus for detecting is also proposed and implemented.

[0005]

However, in any of the above-mentioned substrate detecting devices, it is necessary to intermittently feed the cassette or the optical sensor with high precision in accordance with the groove pitch of the cassette. Therefore, a pulse motor or the like is used. It is necessary to provide a highly accurate intermittent feeding mechanism, and as a result, the structure of the device becomes complicated.

Further, since the substrate is detected while the cassette or the optical sensor is intermittently fed, it takes a considerable time to detect the presence or absence of the substrate in all the grooves in the cassette.
As a result, there is an inconvenience that the time required to take out and store the substrate from the cassette becomes long.

In order to solve the above problems, the present applicant has previously proposed the following substrate detection device in a cassette (Japanese Patent Application No. 2-100167). This device is a substrate detection device in a cassette that detects the presence or absence of a substrate in each groove of the cassette by moving an optical sensor up and down along a fixedly installed cassette. And an optical sensor elevating mechanism for integrally elevating and lowering an optical sensor including a light emitting element and a light receiving element, a pitch member having a plurality of detection target portions formed at a pitch corresponding to a substrate storage groove of a cassette, and timing detection Sensors, and these are moved relative to each other in association with the movement of the optical sensor elevating mechanism to generate timing signal generating means for providing a substrate detection timing by the optical sensor, and an address area corresponding to a substrate storing groove in the cassette. Storage means for storing information on the presence / absence of a substrate in each storage groove, and a substrate detection timing signal from the timing signal generating means. The write address is set in the storage means by counting, the detection signal from the optical sensor for detecting the substrate is taken in when the substrate detection timing signal is given, and the presence / absence information of the substrate obtained from the detection signal is set. And a memory control means for writing in the designated address area.

According to this apparatus, the optical sensor for detecting the substrate is continuously moved along the fixedly installed cassette, and the pitch member and the timing detection sensor are relatively moved in association with the movement of the optical sensor. By doing so, it is detected whether or not the substrate is stored in each groove in the cassette, and the information is stored in the storage means in association with the groove of the cassette. The structure of the device can be simplified because there is no need to intermittently feed. Further, since the optical sensor is continuously fed to detect the presence / absence of the substrate in the cassette, the presence / absence of the substrate in the cassette can be detected in a short time.

However, it has been found that the above-mentioned device (hereinafter referred to as the proposed device) proposed by the applicant of the present invention has some points to be further improved. That is, the groove pitch of the cassette set in this type of device is not the same for cassettes of various specifications. For example, when the size of the substrate changes, the groove pitch of the cassette also changes accordingly. Is. Therefore, according to the above proposed device,
When cassettes having different groove pitches are set, the pitch member must be replaced accordingly, which is troublesome.

The present invention has been made in view of the above circumstances, and it is possible to quickly and relatively easily obtain information about the presence / absence of a substrate in each groove in a substrate storage container. An object of the present invention is to provide a substrate detection device that can quickly cope with the case where containers with different substrate storage pitches are set.

[0011]

The present invention has the following constitution in order to achieve such an object. That is, the present invention is a substrate detection device in a substrate storage container for detecting the presence or absence of a substrate in each groove of the container by moving an optical sensor up and down along a fixedly installed substrate storage container, An optical sensor elevating mechanism for integrally elevating and lowering an optical sensor composed of a light projecting element and a light receiving element, which are opposed to each other with the substrate storage container sandwiched therebetween, and represented by the greatest common divisor of the groove pitch of the substrate storage container of various specifications. It is composed of a pitch member having a plurality of detected portions formed at a pitch and a timing detection sensor, and these are moved relative to each other in association with the movement of the optical sensor elevating mechanism, so that a timing signal is output from the timing detection sensor. Timing signal generating means for generating, pitch information setting means for setting information on the groove pitch of the substrate storage container to be the substrate detection target, and the timing signal The timing signal given from the generating means is counted, and when the count value becomes a value according to the groove pitch information set by the pitch information setting means, the output from the optical sensor of the optical sensor lifting mechanism is set. And a detection timing control means for taking in and detecting the presence or absence of the substrate.

[0012]

The operation of the present invention is as follows. The optical sensor elevating mechanism continuously and integrally moves the light projecting element and the light receiving element for detecting the substrate along the fixed substrate storage container. At this time, in conjunction with the movement of the optical sensor lifting mechanism,
By the relative movement of the pitch member of the timing signal generating means and the timing detection sensor, the timing detection sensor intermittently outputs the timing signal according to the arrangement pitch of the detected portions of the pitch member. Since the detected parts are formed at the pitch represented by the greatest common divisor of the groove pitch of the substrate storage containers of various specifications, one or more is set every time the optical sensor advances one groove pitch in the substrate storage container. A plurality of timing signals are output. Therefore, the detection timing control means refers to the groove pitch information of the substrate storage container set by the pitch information setting means, the count value of the timing signal given from the timing signal generating means, the value according to the groove pitch When, ie, when the optical sensor for detecting the substrate comes to a position facing the groove in the substrate container, the output from the optical sensor is taken in and the presence or absence of the substrate is detected.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. Before explaining the detailed configuration of this device, FIG.
An example of a semiconductor manufacturing apparatus in which the present apparatus is used will be briefly described with reference to FIG. The apparatus shown in FIG. 4 is an apparatus for coating a substrate such as a semiconductor wafer with a photoresist or the like and heat-treating it, and roughly divides the substrate W from the cassette C or carries the substrate W into the cassette C. It comprises a substrate loading / unloading unit 1 for carrying out the process, and a process unit 2 for performing a required process on the substrate W taken out from the cassette C.

As shown in the plan views of FIGS. 4 and 5,
A plurality of cassettes C for accommodating the substrates W in multiple stages are installed on the cassette installation table 3 of the substrate loading / unloading unit 1. Inside the cassette installation table 3, the substrate detection apparatus according to the present embodiment. Is provided. Board loading
The carry-out unit 1 is provided with a substrate take-out mechanism 4 that horizontally moves along the cassette installation table 3.

The substrate pick-up mechanism 4 has a substrate suction arm 5 that can be moved up and down and moved back and forth (up and down in FIG. 5). By this substrate suction arm 5, the substrate W stored in the groove in each cassette C can be taken out. Alternatively, the processed substrate W is stored in the cassette C.

The substrate take-out mechanism 4 supports a substrate W taken out by the substrate suction arm 5 and is vertically movable.
Book support pins 6 _{1 to} 6 ₃ and the support pins 6 _{1 to} 6
Positioning plates 7 ₁ and 7 ₂ for centering the substrate W supported by the substrate ₃ are provided. Alignment plate 7
A plurality of protrusions 8 arranged so as to have substantially the same curvature as the outer diameter of the substrate W are provided on the ₁ and 7 _2.
1, by 7 ₂ is horizontally reciprocated, the projection 8 is in contact and away from the periphery of the substrate W, thereby performing the center alignment of the substrate W.

By the substrate take-out mechanism 4, the cassette C
The substrate W taken out from the substrate and aligned with the substrate W is moved to the substrate delivery position (P in FIG. 4) by the substrate take-out mechanism 4.
After being transferred to the position), the substrate is transferred to the substrate transfer mechanism 9 provided in the process unit 2.

The substrate transfer mechanism 9 transfers the substrate W while the substrate W is placed on the U-shaped substrate support arm 10, and the spinner portions 11 ₁ and 11 provided in the process unit 2 are provided.
₂ and the substrate W is sequentially set in the heat treatment parts 12 _{1 to} 12 ₃ . The substrate W processed by the process unit 2 is
At the substrate transfer position P, the substrate is transferred from the substrate transfer mechanism 9 to the substrate removal mechanism 4 and then returned to the cassette C by the substrate removal mechanism 4.

An example of the substrate detection device provided in the above semiconductor manufacturing apparatus will be described with reference to FIGS. 1 to 3. 1 is a partially cutaway front view of the substrate detection device, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view taken along the line BB of FIG.

Each of the cassettes C placed on the cassette setting table 3 is provided with a bracket 21 having a U-shape that can be raised and lowered, and a substrate W stored in the cassette C is attached to the tip of the bracket 21. An optical sensor 24 including a light projecting element 22 and a light receiving element 23 for detecting is attached. The light projecting element 22 and the light receiving element 23 are attached at an angle (for example, 2 to 3 degrees) whose optical axes are slightly inclined with respect to the horizontal direction, so that the light emitted from the light projecting element 22 is applied to the substrate W. Even if the thickness is not reduced to less than or equal to, the light-shielding / light-transmitting state can be obtained depending on the presence or absence of the substrate W.

As shown in FIG. 2, an optical sensor integrally attached to a bracket 21 is provided below the cassette installation table 3.
There is an optical sensor lifting mechanism 25 for lifting 24. The optical sensor elevating mechanism 25 includes a rodless cylinder 26 and a guide rod 27, which are vertically supported side by side on a support plate 20, and a movable member 28 slidably fitted into these is installed on the cassette mounting table 3.
It is configured to be connected to the bracket 21 via a vertical member 29 penetrating the. When air (not shown) in the rodless cylinder 26 is moved up and down by supplying air from the upper and lower ends of the rodless cylinder 26, the movable member 28 is moved up and down accordingly, and the optical sensor attached to the bracket 21 is moved. 24 moves up and down along the cassette C.
The optical sensor elevating mechanism 25 is not limited to the rodless cylinder 26 as described above, but can be configured by an ordinary air cylinder, a screw feeding mechanism using a motor, or the like.

A comb-shaped pitch member 30 is vertically connected to the movable member 28. The pitch member 30 is provided with slits 31 as detected parts at a pitch represented by the greatest common divisor of the groove pitches of the cassettes C having various specifications. For example, when the cassette C having groove pitches of 1/8 inch, 3/16 inch, and 1/4 inch is used, the slit 31 of the pitch member 30 is formed with 1/16 inch. A timing detection sensor 32 such as a photo interrupter is attached to the support plate 20 in order to detect each slit 31 of the pitch member 30 described above. The pitch member 30 and the timing detection sensor 32 described above correspond to the timing signal generating means in the present invention.

FIG. 6 is a block diagram showing the outline of the configuration of the control system of the above-mentioned substrate detection apparatus. Substrate detection optical sensor 24, timing detection sensor 32, optical sensor lifting mechanism
25 and the pitch information setting device 40 are connected to the CPU 34 via the input / output interface 33. The pitch information setting device 40 provides information on the groove pitch of the cassette C that is the substrate detection target (in the above example, the set cassette C is 1
/ 8 inch, 3/16 inch, or 1/4 inch). Although the configuration of the pitch information setting device 40 is not particularly limited, for example, an operator operates the key switch to set the pitch information, or a bar code representing the pitch information is attached to the cassette C, and this bar code is displayed. The pitch information may be set by reading with a bar code reader. Further, in the semiconductor manufacturing apparatus as described with reference to FIG. 4, since it is usual to input and set the information designating the type of the substrate to the substrate transfer control system, such substrate information is used for the groove pitch of the cassette C. It may be used as information.

The CPU 34 also includes a pitch information setting device 40.
A table memory 41 that correlates the pitch information of the cassette C set in step 1 and the count information of how many timing signals are input from the timing detection sensor 32 for one groove pitch of the cassette C is connected. .. In particular,
In the case of the pitch member 30 in which the slits 31 are formed at a pitch of 1/16 inch as in the above example, as shown in FIG. 7, the count information is "1/8 inch" for the cassette C pitch information "1/8 inch". 2 ”, the count information is“ 3 ”with respect to the pitch information“ 3/16 inch ”, and the count information is“ 4 ”with respect to the pitch information“ 1/4 inch ”. The pitch information setting device 40 and the table memory 41
Corresponds to the pitch information setting means in the present invention.

As will be described later, the CPU 34 refers to the contents of the table memory 41 while referring to the timing detection sensor 32.
The timing signal from the optical sensor 24 is counted to obtain the timing of taking in the detection signal of the optical sensor 24, the presence or absence of the substrate is detected based on the detection signal, and the information on the presence or absence of the substrate is written in the memory 35. The CPU 34 corresponds to the detection timing control means in the present invention.

The operation of the apparatus of this embodiment will be described below with reference to the flow chart shown in FIG. Step S1:
Prior to the detection of the substrate in the cassette C, the CPU 34 sets the count values N _T and N _A of the internal counters 34a and 34b to the initial value "0", respectively. Here, the internal counter 34a is a counter for counting the timing signal from the timing detection sensor 32, and the internal counter 34b is a counter for detecting the groove position of the cassette C.

Step S2: The pitch information set by the pitch information setting device 40 is fetched and the corresponding count information is read from the table memory 41.

Step S3: A command for raising the optical sensor 24 is issued to the optical sensor elevating mechanism 25. Here, the initial position of the optical sensor 24 is set to the lower end of the cassette C. Optical sensor 24
Is issued, the rodless cylinder 26 of the optical sensor elevating mechanism 25 is driven, the bracket 21 to which the optical sensor 24 is attached is continuously driven from the lower end to the upper end of the cassette C, and The pitch member 30 moves up accordingly.

Step S4: The CPU 34 monitors whether or not the timing detection sensor 32 is in the translucent state, that is, whether or not the slit 31 of the pitch member 30 is detected, after issuing the command to raise the optical sensor 24.

Steps S5 and S6: When the slit 31 is detected, the count value N _T (initial value "0" at the time of starting) is set to "1".
Is added, and it is determined whether the count value N _T matches the count information read in step S2. If they do not match, the process returns to step S4 to detect the next slit 31, and if they match, the process proceeds to next step S7. For example,
If the set pitch information is 3/16 inch, the count information corresponding to this is "3", so when the count value N _T becomes "3", the process proceeds to step S7. As is apparent from the above description, the fact that the count value N _T matches the count information means that the optical sensor 24 is at the position corresponding to the groove of the cassette C.

Step S7: In this step, the count value N _T is cleared and "1" is added to the count value N _A (initial value "0" at the time of starting), and the memory 35 for writing the presence / absence information of the substrate is written. Specify address A. The address A _i specified when N _A = i corresponds to the i-th substrate storage groove from the bottom of the cassette C.

Steps S8, S9: Next, the detection signal from the optical sensor 24 is fetched, and the detection signal of the optical sensor 24 is stored in the address A ₁ area of the memory 35 corresponding to the present count value N _A (= 1). Write the obtained information with and without the substrate.
Here, "1" is written when the substrate is present, and "0" is written when the substrate is not present.

Step S10: Next, it is judged whether or not the count value N _A is a numerical value N ₀ determined according to the number of stages of the cassette C. If the count value N _A is N ₀ , it means that the presence / absence of the substrate has been confirmed for all the grooves in the cassette C, and the process is terminated. Count value N _A
Is not N ₀ , the process proceeds to step S11.

Step S11: Here, it is confirmed whether or not the slit 31 detected in step S4 has passed. That is, if the timing detection sensor 32 is in the light-shielded state, it means that the slit 31 detected in step S4 has passed, so the process returns to step S4 to monitor whether or not the next slit 31 is detected. , And similar processing is repeated.

As described above, the information regarding the presence / absence of the substrate is written in the predetermined address area of the memory 35 for all the grooves in the cassette C.

In the semiconductor manufacturing apparatus shown in FIG. 4, while the substrate W is being taken out from a certain cassette C, the other substrate C is subjected to the above-described substrate detection processing, so that the inside of each cassette C is removed. Information about whether or not the board is present is collected in advance. Then, when the substrate in the next cassette C is to be taken out by the substrate take-out mechanism 4, the information regarding the presence or absence of the substrate in the cassette C stored in the memory 35 is read out in order, and the groove in the cassette C in which the substrate W is inserted is read. After that, the substrate suction arm 5 is continuously moved up and down to the position of the groove, and the substrate W is taken out.

As described above, if the optical sensor 24 is continuously moved up and down in advance to collect the presence / absence information of the substrate of the cassette C, and the substrate suction arm 5 is driven based on the collected information, The time required for taking out the substrate is shortened as compared with the conventional method of taking out the substrate after confirming the presence or absence of the substrate for each groove in the cassette C while intermittently feeding the sensor. The processing speed can be improved.

The present invention can be modified as follows. (1) In the embodiments, the apparatus for coating the photoresist on the substrate W has been described as an example, but the present invention can be applied to other semiconductor manufacturing apparatuses. Further, the substrate is not limited to the semiconductor wafer, and can be used for detecting various substrates accommodated in the cassette such as a substrate for a liquid crystal display.

(2) The substrate storage container according to the present invention is not limited to the cassette described in the embodiment, but includes a heat treatment boat for storing semiconductor substrates in a heat treatment furnace.

(3) In the embodiment, the pitch member 30 is moved as the optical sensor 24 moves up and down, and the slit 31 of the pitch member 30 is detected by the timing detection sensor 32 fixedly installed. It may be fixedly installed and the timing detection sensor 32 may be moved.

(4) Further, the timing signal generating means in the present invention is not limited to the pitch member 30 in which the slit 31 is formed as in the embodiment, and for example, a protrusion corresponding to the groove of the cassette C is used as the pitch member. The protrusion may be formed and detected by a proximity switch or the like.

(5) Further, when the cassette C is transferred to another device, the information regarding the presence or absence of the substrate written in the memory 35 of the embodiment device is transferred to the next device as the cassette C is transferred. It may be transmitted and used.

[0043]

As is apparent from the above description, according to the present invention, the optical sensor for detecting a substrate is continuously moved along the fixedly installed substrate storage container, and the movement of the optical sensor is prevented. In conjunction with each other, the pitch member and the timing detection sensor are moved relative to each other, and the detected portion formed on the pitch member is formed at the pitch represented by the greatest common divisor of the groove pitch of the substrate storage containers of various specifications, The count value of the timing signal obtained by detecting the detected member,
When the value corresponding to the preset pitch information is reached, the output of the optical sensor is taken in to detect the presence or absence of the substrate, so when the substrate storage container with a different groove pitch is set, the pitch information It is possible to improve the processing efficiency of the device without the trouble of replacing the pitch member as in the conventional device.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a substrate detection device in a substrate storage container according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along the line BB of FIG.

FIG. 4 is an external perspective view showing an example of a semiconductor manufacturing apparatus using the apparatus of the embodiment.

5 is a plan view of a substrate loading / unloading unit of the apparatus shown in FIG.

FIG. 6 is a block diagram showing a schematic configuration of a control system of the embodiment apparatus.

FIG. 7 is a schematic diagram showing the contents of a table memory.

FIG. 8 is an operation flowchart of the apparatus according to the embodiment.

[Explanation of symbols]

 C ... Cassette W ... Substrate 22 ... Light emitting element 23 ... Light receiving element 24 ... Optical sensor 25 ... Optical sensor elevating mechanism 30 ... Pitch member 32 ... Timing detection sensor 34 ... CPU 35 ... Memory 40 ... Pitch information setting device 41 ... Table memory

Claims (1)

[Claims] 1. A substrate detection device in a substrate storage container for detecting the presence or absence of a substrate in each groove of the container by moving an optical sensor up and down along a substrate storage container fixedly installed. An optical sensor elevating mechanism that integrally raises and lowers an optical sensor consisting of a light-emitting element and a light-receiving element that are arranged opposite to each other with the substrate storage container sandwiched between them, and the pitch expressed by the greatest common divisor of the groove pitch of the substrate storage containers of various specifications. And a timing detection sensor having a plurality of detection target portions formed by the above, and these are moved relative to each other in conjunction with the movement of the optical sensor elevating mechanism, thereby issuing a timing signal from the timing detection sensor. Timing signal generating means, pitch information setting means for setting information on the groove pitch of the substrate storage container to be the substrate detection target, and the timing signal generating means The timing signal given from the step is counted, and when the count value becomes a value according to the groove pitch information set by the pitch information setting means, the output from the optical sensor of the optical sensor elevating mechanism is taken in. And a detection timing control means for detecting the presence or absence of the substrate, and a substrate detection device in the substrate storage container.