JPH11204623A - Substrate detection device - Google Patents

Abstract

(57) [Summary] To provide a substrate detecting apparatus which has a simple structure and can be easily adjusted, and can accurately detect a substrate such as a wafer. A substrate 5 received on a substrate transport plate 16 is provided.
The capacitance sensor 32 is provided so as to face the substrate, and the capacitance sensor detects the amount of change in capacitance to detect the presence or absence of a substrate on the substrate transport plate.

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 provided in a substrate transfer machine for transferring a substrate to be processed such as a wafer in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art A substrate to be processed is transferred inside a semiconductor manufacturing apparatus by a substrate transfer machine. In the substrate transfer machine, a plurality of substrate transfer plates are provided so that a plurality of substrates to be transferred can be transferred at a time, and each substrate transfer plate is provided for detecting the presence or absence of the substrate to be processed on the substrate transfer plate. On the other hand, a substrate detection device is provided.

First, referring to FIG. 3, an outline of a semiconductor manufacturing apparatus including a wafer transfer machine will be described.

[0004] A reaction furnace 2 is provided at an upper rear position in the housing 1, and a reaction tube 3 is provided inside the reaction furnace 2. A boat elevator 4 is provided below the reaction furnace 2, and a boat 6 loaded with a wafer 5 as a substrate to be processed can be loaded and unloaded into the reaction tube 3 by the boat elevator 4.

A wafer cassette transfer section (not shown) is provided at a front portion of the housing 1, and a cassette transfer device 7 is provided behind the wafer cassette transfer portion. Is provided with a buffer cassette shelf 8 and a cassette shelf 9 in two stages from the top. A first air clean unit 10 is provided between the reaction furnace 2 and the buffer cassette shelf 8, and a second air clean unit 11 is provided below the first air clean unit 10. A wafer transfer device 12 is provided between the cassette shelf 9 and the boat elevator 4.

The wafer 5 is transported between the semiconductor manufacturing apparatus and the outside while being loaded in the wafer cassette 13. The wafer cassette 13 is relayed by the wafer cassette transfer section (not shown), and the buffer cassette shelf 8 and the cassette shelf 9 are
Is stored in. The wafer transfer machine 12 transfers the wafers 5 between the wafer cassette 13 stored in the cassette shelf 9 and the boat 6 in a lowered state.
The boat elevator 4 connects the boat 6 to the reaction tube 3.
When the film formation on the wafer 5 is completed, the boat 6 is pulled out from the reaction tube 3.

The wafer 5 after processing is transferred from the outside of the semiconductor manufacturing apparatus to the boat 6 by reversing the procedure of transferring the wafer 5 from the outside of the semiconductor manufacturing apparatus to the wafer cassette 13 on the cassette shelf 9. Further, the wafer cassette 13 is carried out of the semiconductor manufacturing apparatus.

Next, referring to FIGS. 3 to 6, a description will be given of the wafer transfer machine 12 provided with a conventional substrate detecting device.

The wafer transfer unit 12 has a vertically movable and rotatable advance / retreat mechanism 14, and a chucking head 15 is provided on the advance / retreat mechanism 14 so as to be able to advance and retract in the horizontal direction. At the front of the chucking head 15, a wafer transfer plate 16 is mounted vertically (five steps in the figure) in the vertical direction.

The wafer transfer plate 16 has a rectangular shape with a concave end, and a concave portion 17 into which the wafer 5 is fitted is formed on the upper surface of the wafer transfer plate 16.

At the front of the chucking head 15, a support arm 18 is provided so as to project in parallel with the longitudinal direction of the wafer transfer plate 16. At the tip of the support arm 18, a sensor holder 19 which is bent in a tangential direction of the wafer 5 mounted thereon is fixed. The sensor holder 19 has a rod-shaped light emitting sensor 20 and a light receiving sensor 2.
A pair of wafer detection sensors, a transmission type fiber sensor in FIG.
The required pairs (five pairs in the figure) are provided in parallel up and down with. The light emitting sensor 20 and the light receiving sensor 21 are arranged in such a manner that the lower sensor pair is shifted in parallel in the horizontal direction with respect to the upper sensor pair in order to avoid mutual interference. A light emitter 22 is provided at the tip of each of the light emitting sensors 20, and a light receiver 23 is provided at the tip of each of the light receiving sensors 21. Each pair of the light emitter 22 and the light receiver The optical axes 24 of each of the 23 coincide.

The axes of the light projecting sensor 20 and the light receiving sensor 21 point to the center of the wafer 5 received on the wafer transfer plate 16, and the tip is separated from the side edge of the wafer transfer plate 16. Further, the optical axis 24 is located inside the outline of the wafer 5 received on the wafer transfer plate 16.

When five wafer transfer plates 16 are provided, as shown in FIG.
The light emitting sensor 20a for detection is the uppermost sensor holder 1
9, a light receiving sensor 21a for detecting the uppermost wafer 5 and a light emitting sensor 20b for detecting the second wafer 5 from the top,
The light receiving sensor 21b for detecting the wafer 5 in the second stage from the top and the light receiving sensor 21b in the third stage from the top
The light projecting sensor 20c for detecting the wafer 5 in the third stage, the light receiving sensor 21c for detecting the wafer 5 in the third stage from the top, and the wafer 5 The light emitting sensor 20d for detection, the light receiving sensor 21d for detecting the wafer 5 at the fourth stage from the top, and the light emitting sensor 20e for detecting the wafer 5 at the lowest stage are provided on the wafer holder 19 at the fifth stage from the top. , Lowermost wafer holder 1
9 is a light receiving sensor 2 for detecting the lowermost wafer 5.
1e are provided.

Hereinafter, a description will be given of a transfer operation of the wafer 5, for example, a case where the wafer 5 is extracted from the wafer cassette 13 in which the wafer 5 is loaded in multiple stages in a horizontal posture.

The wafer transfer machine 12 is opposed to the wafer cassette 13, the chucking head 15 is advanced, the wafer transfer plate 16 is loaded into the wafer cassette 13, and the wafer 5 is transferred to the wafer cassette 13. It is received on the recess 17 of the plate 16. The detection of the wafer 5 is performed in a state where the wafer 5 is received on the wafer transfer plate 16.

The presence or absence of the wafer 5 on the wafer transfer plate 16 is determined by whether or not the detection light emitted from the light projector 22 is blocked by the wafer 5. That is, if the detection light is not detected by the light receiver 23, the presence of the wafer 5 is determined, and if the detection light is detected by the light receiver 23, the absence of the wafer 5 is determined.

[0017]

In the above-described conventional substrate detecting device, the light emitting sensor 20 and the light receiving sensor 21 are used.
And the optical axis 2 of the light projector 22 and the light receiver 23
4 need to be matched, so that the light emitting sensor 20,
It is difficult to adjust the position of the light receiving sensor 21 and the like, and it takes a long time to adjust.

In order to avoid mutual interference, the light emitting sensor 20 and the light receiving sensor 21 need to be arranged so that the lower sensor pair is shifted in parallel with the upper sensor pair in the horizontal direction. is there. Accordingly, the structure of the sensor holder 19 becomes complicated and the shape thereof becomes large, so that the sensor holder 19 may interfere with the wafer cassette 13.

Further, one stage of the wafer transport plate 1
6, a pair of the light emitting sensor 20 and the light receiving sensor 21 are required above and below, and depending on the shape of the top plate 25 of the wafer cassette 13, the detection light from the uppermost projector 22 is not There is a possibility that the wafer 5 may not be detected due to being blocked by the plate 25.

Further, in order to solve the above-mentioned problem, one reflection type sensor is provided for one wafer transfer plate 16 immediately below the wafer 5 received on the wafer transfer plate 16. Sometimes. The reflection-type sensor has the light-emitting device 22 and the light-receiving device 23 provided inside a single sensor. If the detection light from the light-emitting device 22 is detected by the light-receiving device 23, the detection light is transmitted to the wafer. It is determined that there is a wafer assuming that the light is reflected on the light receiving device 5 and the light is incident on the light receiving device 23.

However, in such a case, even if the wafer 5 is received on the wafer transfer plate 16,
Depending on the surface condition of the wafer 5, there is a problem that the detection light does not enter the light receiver 23, and there is a possibility that the determination of the absence of the wafer may be erroneously made.

The present invention has been made in view of the above circumstances, and provides a substrate detecting apparatus which has a simple structure, is easily adjusted, and can accurately detect a substrate such as a wafer.

[0023]

SUMMARY OF THE INVENTION The present invention relates to a substrate detecting apparatus provided with a capacitance type sensor facing a substrate received on a substrate carrying plate, wherein the capacitance type sensor has a capacitance type. The presence / absence of a substrate on the substrate transport plate is detected by detecting the amount of change.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Note that the same components as those in the related art are denoted by the same reference numerals and description thereof is omitted.

On one width end surface of the base end of the plurality of wafer transfer plates 16, sensor holders 31 are horizontally protruded so as to be perpendicular to the longitudinal direction of each wafer transfer plate 16.

Each of the sensor holders 31 has a capacitance type sensor 32 detachably held therebetween, and the capacitance type sensor 32 is parallel to the longitudinal direction of the wafer transfer plate 16. The tip end of the capacitance type sensor 32 is located immediately below the wafer 5 received on the wafer transfer plate 16, and the required length of the tip end overlaps with the wafer 5. . The thickness of the capacitance type sensor 32 is about 1 mm, and the main part is made of a material free from metal contamination, for example, alumina, and has heat resistance. The capacitance type sensor 32 is charged to a positive or negative charge by a power supply (not shown).

When five wafer transfer plates 16 are provided, as shown in FIG. 2, the sensor holder 31 has a capacitive sensor 32a for detecting the uppermost wafer 5 in order from the top, as shown in FIG. A capacitive sensor 32b for detecting the second-stage wafer 5, a capacitive sensor 32c for detecting the third-stage wafer 5 from the top, and a capacitive sensor for detecting the fourth-stage wafer 5 from the top 32d, and a capacitive sensor 32e for detecting the lowermost wafer 5 are provided.

The operation of the capacitance type sensor 32 will be described below.

The presence or absence of the wafer 5 on the wafer transfer plate 16 is determined by the capacitance type sensors 32a, 32
b, 32c, 32d, and 32e are determined by detecting the amount of change in the capacitance. That is, when the capacitance detected by the capacitance type sensor 32 exceeds a predetermined value,
It is determined that there is a wafer, and the capacitance type sensor 3
When the capacitance detected by No. 2 becomes equal to or less than a predetermined value,
A determination is made that there is no wafer.

The value of the change in capacitance corresponding to the presence or absence of a wafer is determined by comparing the tip of the capacitance type sensor 32 with the wafer 5.
Mainly determined by the polymerization length. Therefore, the value of the change in the capacitance is not greatly affected by the posture of the capacitance type sensor 32 itself, and the change in the capacitance due to the variation in the alignment is caused by the presence or absence of the wafer. Since the change is sufficiently small as compared with the change caused by the above, the positioning of the tip of the capacitance type sensor 32 is easier than the adjustment of the optical axis alignment in the optical type sensor.

In the above embodiment, the capacitance type sensor 32 is fixed to the wafer transfer plate 16 via the sensor holder 31. It may be directly embedded in the wafer transfer plate 16.

[0032]

As described above, according to the present invention, since light is not used as a detection medium, there is no need to form a pair of sensors. Since there is no board, the top plate of the board cassette does not hinder the board detection. The positioning of the sensor may be performed with respect to the substrate to be detected. Further, since the change in capacitance is detected, the positioning may be rougher than that of the optical sensor, and the positioning operation is extremely simple. Furthermore, since the sensors can be provided within the range of the thickness of the substrate transport plate and there is no need to arrange them vertically and horizontally, various excellent effects such as a great saving of installation space can be achieved. Demonstrate.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is an explanatory view schematically showing a semiconductor manufacturing apparatus.

FIG. 4 is a plan view showing a conventional example.

FIG. 5 is a view taken in the direction of arrows BB in FIG. 4;

6 is a view taken in the direction of the arrows CC in FIG. 4;

[Explanation of symbols]

 12 Wafer transfer machine 16 Wafer transfer plate 31 Sensor holder 32 Capacitance sensor

Claims (1)

[Claims] 1. A substrate detecting apparatus, wherein a capacitance type sensor is provided so as to face a substrate received on a substrate transport plate.