JPH1148057A - Detecting device board thin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately discriminate whether a slot is charged with a board or not by respectively forming a light projector and a light receiver of an light sensor with a light path obliquely crossing a surface of the board which is normally charged, at symmetrical positrons in relation surface of the board so as to detect the arrangement of the board. SOLUTION: In the case where boards 1 are charged in a fifth slot and a sixth slot at a different stage from each other, each output signal S1 and S2 of light sensors 4, 5 to each slot 3 are different from each other in the fifth slot and the sixth slot. A comparing and discriminating circuit 14 discriminates whether a difference between the signal S1, S2 exists within a set value of a tolerance setting circuit 15 or not in the fifth slot and the sixth slot. In the case where the difference between the signal S1, S2 exceeds the tolerance set value, inappropriate charge of the board 1 is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a substrate loaded state in each slot of a cassette loaded with a thin substrate (hereinafter, referred to as a substrate) such as a semiconductor wafer, a liquid crystal glass substrate, a compact disk, a laser disk, and the like. The present invention relates to an improvement in a substrate detection device.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing process or a liquid crystal manufacturing process, a substrate is transported between various processing apparatuses.
A plurality of substrates are loaded into a cassette as shown in FIG. 11 and transported. In the drawing, a plurality of substrates 1 are horizontally loaded in slots 2 having a predetermined pitch in a cassette 2. In various types of processing apparatuses, one substrate 1 is loaded from the cassette 2.
After being taken out one by one and transported to the substrate processing chamber to perform necessary processing, the substrate 1 is loaded into the cassette 2 and transported to the next processing device. In this manner, the work of taking out the substrate 1 from the cassette 2 or loading the same into the cassette 2 is not performed manually, but is performed by an automatic transfer device. Therefore, the presence or absence of the substrate 1 in each slot 3 of the cassette 2 is determined. It is necessary to confirm that the prior art uses FIG.
Has been proposed.

FIG. 12 is a block diagram showing a conventional substrate detecting apparatus. In the figure, reference numeral 1 denotes a substrate, and 2 denotes a cassette for loading these substrates 1 at a predetermined pitch. Slots 3 for inserting substrates at a predetermined pitch are formed on the left and right inner side surfaces of the cassette 2 vertically. Have been. Reference numeral 4 denotes a non-contact type substrate detection sensor (hereinafter, referred to as an optical sensor) including a set of a light projector 4a and a light receiver 4b provided on the left and right sides of the cassette 2. Reference numeral 6 schematically shows the optical path of the optical sensor 4. Reference numeral 8 denotes a cassette mounting table on which the cassette 2 is mounted, 9 denotes an elevating shaft, 10 denotes a cassette mounting table raising / lowering driving means for raising and lowering the cassette mounting table 8, and 11 denotes a cassette position signal corresponding to the amount of movement of the cassette mounting table 8 from a reference position. This is a cassette position detection circuit that outputs S3. Reference numeral 12 denotes an optical sensor control circuit that outputs an output signal S1 while the optical path 6 of the optical sensor 4 is blocked by the substrate 1 while the cassette mounting table 8 is being moved up and down. Reference numeral 18 denotes a determination circuit which receives the output signal S1 and the cassette position signal S3 as inputs, and determines that the substrate 1 is present when the output signal S1 is ON for each slot 3. Reference numeral 16 denotes a storage circuit for storing data of these determinations. Reference numeral 17 reads data of the presence / absence of the board 1 in each slot 3 stored in the storage circuit 16 and, for the slots 3 determined to have the board 1, This is an automatic transfer device that takes out the substrate 1 from the cassette 2 and performs necessary processing, and then loads the substrate 1 into the cassette 2.

In FIG. 12, for example, the substrate 1 is moved from the lowermost first slot to the uppermost seventh slot of the cassette 2.
Is properly loaded. In this case, when the cassette mounting table 8 is detected by the optical sensor 4 in order from the substrate 1 loaded in the first slot while the cassette mounting table 8 is lowered from the uppermost position by the cassette mounting table raising / lowering driving means 10, the cassette 2 is lowered. Therefore, while the optical path 6 of the optical sensor 4 is blocked by the substrate 1, the optical sensor control circuit 12 outputs the signal S1. Further, the cassette position detection circuit 11 outputs a cassette position signal S3 according to the amount of movement of the cassette mounting table 8 from the reference position. Judgment circuit 18
Receives the output signal S1 and the cassette position signal S3. FIG. 13 shows the output signal S of the optical sensor for each slot 3 when the substrate 1 is loaded as shown in FIG.
FIG. The determination circuit 18 outputs the output signal S1 of the optical sensor 4 to all the slots 3 as shown in FIG.
Is ON, it is determined that the substrate 1 is loaded in all the slots 3. FIG. 14 is a diagram showing data at this time when the determination circuit 18 determines the presence or absence of the board 1 for each slot 3, and indicates H when the board 1 is present,
When there is no, it is shown as L.

In FIG. 12, the determination data of the presence or absence of the substrate 1 shown in FIG. 14 is stored in the storage circuit 16, and the automatic transfer device 17 transmits the determination data of the presence or absence of the substrate 1 in each slot 3 stored in the storage circuit 16. The substrate 1 is taken out of the cassette 2 for the slot 3 that is read out and determined to have the substrate 1, and after the necessary processing is performed, the substrate 1 is loaded into the cassette 2.

In FIG. 12, for example, when the substrate 1 is appropriately loaded in the cassette 2 and the optical sensor 4 is provided so that the optical path 6 of the optical sensor 4 is completely parallel to the surface of the substrate 1, Since the optical path 6 is blocked only by the thickness of 1, the ON time width of the output signal S1 becomes extremely narrow.
There are cases where the determination circuit 18 erroneously determines that there is no substrate 1. Therefore, in order to improve the detection accuracy of the optical sensor 4,
The optical sensor 4 is provided at a slight angle such that the optical path 6 does not cross the two or more substrates 1, and the substrate 1 with respect to the optical sensor 4 is provided.
Is increased to increase the ON time width of the output signal S1.

[0012]

For example, as shown in FIG. 15, a foreign substance 19 enters the third slot and the substrate 1 tilts, or the substrate 1 is loaded into the sixth slot and the seventh slot stepwise, and There is a case where the inclination of 1 is close to the inclination of the optical path 6. FIG. 16 is a diagram showing the output signal S1 of the optical sensor for each slot 3 at this time. As shown in the figure, ON of the output signal S1 in the third slot
The time width is slightly narrowed, and the ON time width of the output signal S1 in the sixth and seventh slots is extremely narrow. In these cases, the determination circuit 18 may erroneously determine that the substrate 1 is not present. Further, as shown in FIG. 17, when the foreign matter 19 enters under the cassette 2 and the inclination of all the substrates 1 becomes close to the inclination of the optical path 6, the determination circuit 18 erroneously determines that all the substrates 1 are absent. There is a defect.

[0014]

SUMMARY OF THE INVENTION The present invention is an apparatus for accurately detecting a loaded state of a substrate in a cassette for loading a plurality of substrates, wherein an optical sensor comprising a light emitter and a light receiver is provided. An optical path is formed obliquely to the surface when properly loaded in the cassette, and two sets are provided at symmetrical positions with respect to the substrate surface so that the cassette and the optical sensor are positioned relative to the substrate loading direction. From a relative position signal corresponding to the amount of movement from the reference position when moved and a signal output while the optical path is interrupted by the substrate during the relative movement period between the cassette and the two sets of optical sensors, This is a board detection device that compares signals corresponding to two sets of optical sensors in each slot, determines at the same time whether a board is present and whether the loaded state is appropriate, and stores the determination data.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing embodiments thereof. FIG. 1 is a block diagram showing a substrate detecting apparatus according to the present invention. In the figure,
1 is a substrate and 2 is a cassette for loading these substrates 1 at a predetermined pitch. Slots 3 for inserting substrates at a predetermined pitch are formed on the left and right inner side surfaces of the cassette 2 vertically. 4 and 5 are light projectors 4a and 5a which form an optical path oblique to the surface of the substrate 1 at the time of normal loading and are provided at symmetrical positions with respect to the substrate surface.
And an optical sensor including the light receivers 4b and 5b. Reference numerals 6 and 7 schematically show the optical paths of the optical sensors 4 and 5, respectively. Reference numeral 8 denotes a cassette mounting table on which the cassette 2 is mounted, 9 denotes an elevating shaft, 10 denotes a cassette mounting table raising / lowering driving means for raising and lowering the cassette mounting table 8, and 11 denotes a cassette position signal corresponding to the amount of movement of the cassette mounting table 8 from a reference position. This is a cassette position detection circuit that outputs S3. Reference numeral 12 denotes an optical sensor control circuit that outputs a signal S1 while the optical path 6 of the optical sensor 4 is blocked by the substrate 1 while the cassette mounting table 8 is moving up and down. 1 is an optical sensor control circuit that outputs a signal S2 while the optical path 7 of the optical sensor 5 is interrupted. 1
4 receives the output signals S1 and S2 of the optical sensors 4 and 5 and the cassette position signal S3, compares the output signals S1 and S2 corresponding to each slot 3, and determines whether or not the substrate 1 is present. This is a comparison determination circuit that determines whether the state is appropriate. 1
Reference numeral 5 denotes a margin setting circuit for providing a margin to the judgment data of the comparison judgment circuit 14. Reference numeral 16 denotes a storage circuit that stores the determination data of the comparison determination circuit 14. Reference numeral 17 is outside the scope of the present invention, but reads the determination data stored in the storage circuit 16 and the substrate 1 is properly loaded. This is an automatic transfer device that takes out the substrate 1 from the cassette 2 for the slot 3 determined to be and performs necessary processing to load the substrate 1 into the cassette 2.

The tolerance setting circuit 15 converts the substrate 1 into the cassette 2
The output signals S1 and S1 are used to exclude from the abnormality detection when the substrate 1 is tilted to such an extent that there is no trouble in taking it out of the substrate 1.
This is to provide a certain margin in advance by experiment on the difference between the ON time width and the ON time width.

In FIG. 1, for example, it is assumed that the substrate 1 is properly loaded from the lowermost first slot to the uppermost seventh slot of the cassette 2. In this case, the cassette mounting table 8 is moved from the uppermost position to the cassette mounting table raising / lowering driving means 1.
When the optical sensors 4 and 5 sequentially detect the substrate 1 loaded in the first slot while descending by 0, the optical path 6 of the optical sensor 4 is blocked by the substrate 1 as the cassette 2 descends. The optical sensor control circuit 12 outputs a signal S1, and the optical sensor control circuit 13 outputs a signal S2 while the optical path 7 of the optical sensor 5 is blocked by the substrate 1. The cassette position detection circuit 11 outputs a cassette position signal S3 according to the amount of movement of the cassette mounting table 8 from the reference position. Comparison judgment circuit 1
Reference numeral 4 inputs the output signals S1 and S2 and the cassette position signal S3. FIG. 2 is a diagram showing output signals S1 and S2 for each slot 3 when the substrate 1 is loaded as shown in FIG. 1, and FIG. 2A shows the output signal S1 and FIG. Indicates the output signal S2. When the substrate 1 is loaded horizontally in all the slots 3,
2 (A), the optical receivers 4b and 5b form optical paths 6 and 7 oblique to the surface of the substrate 1 and are provided at symmetric positions with respect to the substrate surface. ), (B)
As shown in the figure, the output signals S1 and S2 completely match. As a result, when the signals S1 and S2 are compared, the difference is within the setting range of the tolerance setting circuit 15, and the comparison determination circuit 14 determines that all the substrates 1 loaded in the cassette 2
Is determined to be properly loaded. FIG. 3 is a diagram showing data at this time when the comparison / determination circuit 14 determines whether or not the board 1 is properly loaded in each slot 3. And L when not properly loaded.

In FIG. 1, the judgment data shown in FIG. 3 is stored in the storage circuit 16, and the automatic transporting device 17 reads the judgment data stored in the storage circuit 16 and reads out the slot in which the substrate 1 is properly loaded. With respect to 3, the substrate 1 is taken out of the cassette 2, and after necessary processing is performed, the substrate 1 is loaded into the cassette 2.

Next, detection of the substrate 1 when the substrate 1 is not properly loaded in the cassette 2 will be described. FIG.
FIG. 4 is a diagram showing a state of detection of the substrate 1 when the substrate 1 is loaded in the slot 3 of the cassette 2 at a different upper and lower step. FIG. 5 is a diagram showing output signals S1 and S2 of the optical sensors 4 and 5 for each slot 3 when the substrate 1 is loaded as shown in FIG. 4, and FIG.
FIG. 4B shows an output signal S2 of the optical sensor 5. FIG. As shown in FIG. 4, when the substrate 1 is loaded stepwise in the fifth slot and the sixth slot, FIG.
As shown in (A) and (B), the fifth slot and the sixth slot
The output signals S1 and S2 do not match in the slot. The comparison determination circuit 14 determines whether the difference between the signals S1 and S2 is within the set value of the tolerance setting circuit 15 in the fifth slot and the sixth slot. Is determined not to be properly loaded. FIG. 6 shows that the comparison judgment circuit 14 at this time
FIG. 6 is a diagram showing data for determining whether or not the substrate 1 is properly loaded, wherein H is shown when the substrate 1 is properly loaded, and L when it is not properly loaded.

Further, as shown in FIG. 15, the foreign matter 19 enters the slot 3 and the substrate 1 tilts. As shown in FIG. 17, the foreign matter 19 enters under the cassette 2 and all the substrates 1 tilt. In the case where the difference between the output signals S1 and S2 corresponding to the two sets of optical sensors 4 and 5 exceeds the set value of the tolerance setting circuit 15, the comparison determination circuit 14
Is determined not to be properly loaded.

The light projectors 4a and 5a and the light receivers 4b and 5b of the optical sensors 4 and 5 are provided so as to form optical paths 6 and 7 oblique to the surface of the substrate 1 at the time of normal loading. However, examples of the arrangement of the optical sensors 4 and 5 are shown in FIGS. 7A to 10, (A) is a plan view, and (B) is a front view. In any of these examples, the light projectors 4a, 5a and the light receivers 4b, 5b are provided at positions where the respective optical paths 6, 7 are oblique to the surface of the substrate 1.

It is to be noted that the optical paths 6 and 7 of the optical sensors 4 and 5 cross the two or more slots 3 respectively.
When 5 is provided, a plurality of substrates 1 are detected in an overlapping manner, and the arrangement of the substrates 1 cannot be accurately determined. Therefore, it is necessary to determine the inclination of the optical sensors 4 and 5 so that the optical paths 6 and 7 cross only one slot 3.

In the above embodiment, when detecting the substrates 1 in order, the cassette 2 is moved up and down. Instead, the cassette 2 is fixed and the optical sensors 4 and 5 are moved up and down. Alternatively, both the cassette 2 and the optical sensors 4 and 5 may be moved up and down.

[0040]

As described above, in the substrate detecting apparatus according to the present invention, the light emitter and the light receiver of the optical sensor are formed so as to form an optical path oblique to the surface of the substrate when it is properly loaded, and to be provided on the surface of the substrate. By arranging the two sets at symmetrical positions and detecting the arrangement of the substrates, even if the substrates are loaded into slots in the cassette at different heights or if the substrates are inclined due to foreign substances entering the slots, the substrates are loaded by mistake. It is possible to simultaneously and accurately determine whether a slot is loaded with a substrate and whether the loaded state is within an allowable range without determining that the slot is not loaded, thereby improving the productivity of the substrate. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a block diagram of a substrate detection device of the present invention.

FIG. 2 is a diagram showing an output signal of an optical sensor for each slot when a substrate is properly loaded in all slots of the cassette of the present invention.

FIG. 3 is a diagram showing determination data of a comparison determination circuit when substrates are properly loaded in all slots of the cassette of the present invention.

FIG. 4 is a view showing a state of detection of a substrate when a substrate is loaded in a slot of a cassette of the present invention in which the upper and lower steps are different.

FIG. 5 is a diagram showing output signals of an optical sensor with respect to each slot when a substrate is loaded in slots at different heights of the cassette according to the present invention.

FIG. 6 is a diagram illustrating determination data of a comparison determination circuit when a substrate is loaded in a slot of a cassette of the present invention in which the upper and lower steps are different.

FIG. 7 is a diagram showing an example of the arrangement of the optical sensor of the present invention.

FIG. 8 is a diagram showing another example of the arrangement of the optical sensor of the present invention.

FIG. 9 is a diagram showing still another example of the arrangement of the optical sensor of the present invention.

FIG. 10 is a diagram showing still another example of the arrangement of the optical sensor of the present invention.

FIG. 11 is a diagram showing a general cassette loaded with a plurality of substrates.

FIG. 12 is a block diagram showing a conventional substrate detection apparatus.

FIG. 13 is a diagram showing output signals of an optical sensor for each slot when a substrate is properly loaded in all slots of a conventional cassette.

FIG. 14 is a diagram showing determination data of a determination circuit when substrates are properly loaded in all slots of a conventional cassette.

FIG. 15 is a diagram showing a state of detection of a substrate when a substrate is not properly loaded in a slot of a conventional cassette.

FIG. 16 is a diagram showing output signals of an optical sensor for each slot when a substrate is not properly loaded in a slot of a conventional cassette.

FIG. 17 is a view showing a state of detection of a substrate when a foreign substance enters under a conventional cassette.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Cassette 3 Slot 4, 5 Non-contact type substrate detection sensor (optical sensor) 4a, 5a Projector 4b, 5b Receiver 6, 7, Optical path 8 Cassette mounting table 9 Elevating axis 10 Cassette mounting table elevating drive means 11 Cassette position detection Circuits 12, 13 Optical sensor control circuit 14 Comparison / determination circuit 15 Tolerance setting circuit 16 Storage circuit S1, S2 Output signal of optical sensor S3 Cassette position signal

Claims (1)

[Claims] 1. An apparatus for detecting an array of thin substrates in a cassette having slots formed on an inner surface thereof for loading a plurality of thin substrates at a predetermined pitch, comprising: A light emitter and a light receiver that form an optical path oblique to the surface of the substrate, and output a detection signal while light incident on the light receiver is blocked, and at a position symmetric with respect to the substrate surface. (B) relative movement means for relatively moving the cassette and the two sets of detection sensors in the substrate loading direction, and (c) the relative movement means. A relative position detection circuit for outputting a relative position signal corresponding to the amount of movement from the reference position, and (d) inputting the output signal of the detection sensor and the relative position signal to correspond to each slot of the cassette. The two sets of detection sensors A comparison determination circuit that compares the output signals of the above to determine the presence or absence of a board and the suitability of the loaded state;
And (e) a storage circuit for storing the output of the determination circuit as data for each slot.