JPH0964154A - Substrate detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sharply reduce substrate detection time by detecting the presence of the substrate in a substrate cassette without interruption of a movement of the substrate cassette. SOLUTION: A substrate detector is constructed such that it detects the position at which a substrate is accomodated in a substrate cassette 1 where the substrates are accomodated, laminated at a predetermined distance. The detector includes a substrate detection sensor 8 for detecting the presence of the substrate 5 in the substrate cassette 1, a plate 6 having a slit 7 of the saw pitch as those of substrate accommodation positions in the substrate cassette 1, a position detection sensor 9 for detecting the slit 7 in the plate 6, and a cassette base 2 for simultaneously relatively moving the substrate cassette 1 and the plate 6 in the direction of substrate lamination of the substrate cassette 1 with respect to the substrate detection sensor 8 and the position detection sensor 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate detecting device for detecting the presence / absence of a substrate at each substrate accommodation position in a substrate cassette used in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, as a substrate detecting device for detecting the presence or absence of a substrate arbitrarily placed in a substrate cassette, a pulse motor moves the substrate cassette and an optical sensor detects the presence or absence of the substrate at each position. It is known to do so.

FIG. 6 shows a conventional substrate detecting device. In FIG. 6, reference numeral 11 denotes a substrate cassette, which is installed on the cassette table 12. The cassette table 12 is moved by rotating the ball screw 14 with the pulse motor 13. A plurality of substrates 15 are accommodated in the substrate cassette 11 in a stacked state with a space therebetween. 16 is a substrate detection sensor,
An optical sensor is used to detect the presence or absence of the substrate at the position of the optical sensor 16.

The operation of the above substrate detecting apparatus will be described. First, the pulse number corresponding to the movement amount of the cassette base 12 is given to the pulse motor 13, the ball screw 14 is rotated by the pulse motor 13, the substrate cassette 11 is moved, and the position where the first substrate 15 of the substrate cassette 11 is inserted. Is positioned at the detection position of the substrate detection sensor 16, and the presence or absence of the first substrate 15 is detected by the substrate detection sensor 16 and stored therein. Next, the position where the second substrate 15 is inserted is moved to the detection position of the substrate detection sensor 16,
The presence or absence of is detected by the substrate detection sensor 16 and stored. By repeating this, the position where the substrate 15 is accommodated in the substrate cassette 11 can be detected. In this example, substrate detection in one substrate cassette 11 is completed in about 50 seconds.

[0005]

However, since the substrate cassette 11 is positioned by the number of pulses given to the pulse motor 13 in the above-mentioned conventional configuration, the pulse motor 13 is given a number of pulses determined from the substrate accommodation position interval or the like. It is necessary to set the amount of movement of the substrate cassette 11 by using the cassette cassette 12, and it is necessary to repeatedly move and stop the cassette table 12 each time the substrate housing position in the substrate cassette 11 is moved to the detection position of the substrate detection sensor 16. There is a problem that it takes a long time to detect the substrate due to the acceleration and deceleration of the movement of the table 12 and the time during which the table is stopped.

In view of the above problems of the prior art, the present invention provides a substrate detection device capable of detecting the presence or absence of a substrate in a substrate cassette without stopping the movement of the substrate cassette and greatly shortening the substrate detection time. It is an object.

[0007]

A substrate detecting device of the present invention is a substrate detecting device for detecting a position where a substrate is accommodated in a substrate cassette in which substrates are accommodated in a stacked state at a predetermined interval. A substrate detection sensor for detecting the presence or absence of a substrate in the substrate cassette, a plate having slits or holes with the same pitch as the substrate accommodation position of the substrate cassette, a position detection sensor for detecting the slits or holes of the plate, and a substrate cassette It is characterized by comprising a substrate detecting sensor and a moving means for moving the plate relative to the position detecting sensor in the substrate stacking direction of the substrate cassette.

[0008]

According to the above configuration of the present invention, during the movement of the substrate cassette, the position detection sensor can detect whether or not the substrate accommodation position of the substrate cassette corresponds to the detection position of the substrate detection sensor. While moving the substrate cassette,
The presence / absence of the first substrate is detected by the substrate detection sensor at the first position detection timing of the position detection sensor, and the presence / absence of the second substrate is detected by the substrate detection sensor at the next position detection timing. The substrate detection can be performed without stopping the movement of the substrate cassette by repeating the same for the subsequent substrates, and the substrate detection time can be greatly reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the substrate detecting apparatus of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 is a substrate cassette, which is installed on a cassette table 2. The cassette base 2 is moved by rotating the ball screw 4 with the pulse motor 3. A plurality of substrates 5 are accommodated in the substrate cassette 1 in a stacked state with a space therebetween.

A plate 6 is provided with slits 7 at the same pitch as the pitch of the housing positions of the substrates 5 in the substrate cassette 1, and is fixed to the cassette base 2. Reference numeral 8 denotes a substrate detection sensor including an optical sensor, which detects the presence or absence of the substrate 5 at the detection position of the substrate detection sensor 8. 9
Is a position detection sensor that detects the slit 7 of the plate 6.

The operation of the substrate detecting device constructed as described above will be described below with reference to FIGS. First, in FIG. 1, the position detection sensor 9 does not detect the slit 7 of the plate 6. From this state, the pulse motor 3 rotates the ball screw 4 and the cassette base 2 moves downward. When the cassette table 2 moves downward and the accommodation position of the first substrate 5 in the substrate cassette 1 reaches the detection position of the substrate detection sensor 8, the state shown in FIG. 2 is obtained. In FIG. 2, since the position detection sensor 9 detects the first slit 7 of the plate 6 and the substrate detection sensor 8 also detects the presence of the substrate, it can be detected that the substrate is in the first accommodation position. .

Since this detection continues for a certain length of time with the detection of the slit 7 of the position detection sensor 9, it is sufficient for the substrate detection sensor 8 to detect the presence of the substrate even for a moment during this period. It is possible even in the moved state.

The cassette table 2 is further moved downward from the state of FIG. 2, and the accommodation position of the second substrate 5 in the substrate cassette 1 is at the detection position of the substrate detection sensor 8 in FIG.
It is a state of. In FIG. 3, the position detection sensor 9 detects the second slit 7 of the plate 6, and the substrate detection sensor 8
Since it also detects the presence of the substrate, it is possible to detect that the substrate 5 is in the second accommodation position as in the case of the first substrate 5. The third sheet can be detected in the same manner as the first and second sheets.

After the cassette table 2 is moved downward from the state of FIG. 3 and the third sheet is searched, the substrate cassette 1
In the state of FIG. 4, the accommodation position of the fourth substrate 5 in FIG. 4 has reached the detection position of the substrate detection sensor 8. In FIG.
Since the position detection sensor 9 detects the fourth slit 7 of the plate 6 and the substrate detection sensor 8 detects the absence of the substrate, it can be detected that the substrate 5 is not placed at the fourth position.

In this manner, the information of the presence / absence of the substrate 5 is taken in, and the cassette table 2 is moved to the position where the detection of all substrate accommodation positions in the substrate cassette 1 is completed in the state of FIG. is there. The position of the substrate 5 in the substrate cassette 1 can be known from the information acquired up to this state. In this example, the information that the first, second, third, fifth, eighth, and tenth substrates 5 are contained in the substrate cassette 1 containing ten substrates 5 is fetched. Can be done, and all substrate detection is completed in about 8 seconds.

Although the motor for moving the cassette base 2 is a pulse motor in the above embodiment, it may be a servo motor. Moreover, although the plate 6 having the slit 7 formed therein is used, a hole may be formed instead of the slit 7.

In the above embodiment, the substrate detection sensor 8 and the position detection sensor 9 are fixed and the substrate cassette 1 and the plate 6 are moved by the motor. However, the substrate cassette 1 and the plate 6 are fixed and the substrate detection sensor is fixed. 8 and position detection sensor 9
The same effect can be obtained by moving both at the same time.

[0019]

According to the substrate detecting apparatus of the present invention, as is clear from the above description, the substrate detection position in the substrate cassette is detected by the position detection sensor during the movement of the substrate cassette. It is possible to detect whether or not it is compatible, and by detecting the presence or absence of the board by the board detection sensor at the position detection timing by this position detection sensor,
The substrate can be detected without stopping the relative movement of the substrate cassette, and the substrate detection time can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an embodiment of a substrate detection device of the present invention.

FIG. 2 is a front view of the first operating state of the embodiment.

FIG. 3 is a front view of the second operating state of the embodiment.

FIG. 4 is a front view of the third operation state of the embodiment.

FIG. 5 is a front view of the fourth operating state of the embodiment.

FIG. 6 is a front view showing a schematic configuration of a conventional substrate detection device.

[Explanation of symbols]

 1 substrate cassette 2 cassette stand (moving means) 5 substrate 6 plate 7 slit 8 substrate detection sensor 9 position detection sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Izushi Matsuda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A substrate detection device for detecting a position where a substrate is accommodated in a substrate cassette, wherein the substrate is accommodated in a stacked state at predetermined intervals, and a substrate for detecting the presence or absence of the substrate in the substrate cassette. A detection sensor, a plate having slits or holes with the same pitch as the substrate accommodation position of the substrate cassette, a position detection sensor that detects the slits or holes of the plate, and a substrate cassette and a plate for the substrate detection sensor and the position detection sensor. A substrate detecting apparatus comprising: a moving unit that relatively moves the substrate cassette in a substrate stacking direction.