JPS62235745A - Automatic change-over device of mask - Google Patents

Abstract

PURPOSE:To prevent any accident such as collision of cassette etc. from occuring eliminating any wasteful operation due to an operational mistake etc. by a method wherein, after checking if a specified slot in a cassette carrier is loaded with a mask cassette or a cover in normal state, the feeding and collecting operations of mask are started. CONSTITUTION:When a feed starting command is inputted in a control box 5, the title device starts operations. A cover senser 32 and a base senser 33 check if a specified slot is loaded with a cover and a base of a mask cassette and in case the slot is not yet loaded with the same by loading mistake etc. of an operator, an error mark is displayed. When it is confirmed that the specified slot is loaded with the mask cassette, the mask is taken out by respective actuators actually to start the mask feeding operation to an exposure device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an automatic mask exchange device for supplying and recovering masks (including reticles) used in a pattern exposure transfer step of a semiconductor photolithography process to an exposure apparatus, and particularly relates to The present invention relates to a cassette carrier for accommodating a plurality of mask cassettes consisting of possible upper lids and lower pans.

[Background of the Invention] A cassette carrier of an automatic mask exchange device can accommodate a plurality of mask cassettes. The mask cassette can be separated into an upper lid and a lower tray. To attach the mask to the exposure apparatus, the mask placed on the lower plate is taken out from the cassette carrier together with the lower plate, and the mask taken out together with the lower plate is transported to the exposure apparatus with the upper cover remaining on the carrier. Here, only the mask is attached to a predetermined position of the exposure apparatus while the lower plate remains outside the exposure apparatus. The lower plate waits until the exposure process for this mask is completed. Therefore, while exposure is being performed, only the upper cover of the mask cassette is accommodated in the mask storage position (slot) of the cassette carrier during exposure use, and the lower plate remains taken out. When the exposure is completed, the automatic mask exchange device takes out the mask from the exposure device and places it on the waiting lower tray. Subsequently, the mask is transported together with the lower tray to the cassette carrier, returned to the original slot, and sealed with the upper lid in the slot.

[Prior art and problems] In the conventional automatic mask exchange device, as soon as the slot number of the mask cassette to be used is designated, the supply operation of taking out the mask from the designated slot of the cassette carrier and sending it to the exposure device is started. Further, as soon as the exposure is completed and the mask is returned to the waiting lower tray, the drive is controlled so that a recovery operation for storing the mask in the designated slot of the original cassette carrier is started. Therefore, if a mask cassette is not loaded in the designated slot, or if the top cover of the mask cassette in use is removed from the mask cassette by mistake, or if another mask cassette is mistakenly placed in the slot position of the mask cassette in use. When the mask is loaded, the mask is supplied and retrieved immediately without detecting and confirming this condition, causing wasteful operations such as taking out the mask from an unloaded slot, and also causing collisions between cassettes and the like during the retrieval operation. There was a situation where the collection was defective due to the lack of a top lid.

[Object of the Invention] The present invention has been made in view of the drawbacks of the prior art described above, and provides for the supply of masks after confirming that the mask cassette or the top cover is properly stored in the designated slot of the cassette carrier. The purpose of this invention is to provide an automatic mask exchange device that eliminates unnecessary operations due to operational errors, etc. by starting the collection operation, and prevents accidents such as cassette collisions, thereby facilitating mask exchange work. .

[Example] FIG. 1 is an external view of an automatic mask changing device according to the present invention. 1 is an exposure device, only a part of which is shown. 2
3 is a mask loader, 3 is an automatic mask exchange device, 4 is a cassette carrier, and 5 is a control box. There are multiple mask cassettes in the cassette carrier 4, for example, one mask cassette.
They are stacked vertically in the 0th stage and stored in each slot (accommodation position). The automatic mask exchange device 3 takes out a designated mask lower plate from the cassette carrier 4 as will be described later, and transfers it to the mask loader 2. The mask loader 2 loads the mask onto a mask stage (not shown) in the exposure apparatus 1.
Transport to. Mask automatic exchange device 3, mask loader 2
, the operations of the exposure apparatus 1 and the like are sequentially controlled by a microcomputer in the control box 5.

The external appearance of the mask cassette is shown in FIG. 2, and the operation of taking it out from the cassette carrier is shown in FIG. mask cassette 6
consists of a separable upper lid 7 and a lower tray 8, a mask is placed on the lower tray 8, and the upper lid 7 seals the mask. FIG. 2 shows a state in which the lower plate 8 is slightly shifted. The mask cassette 6 is loaded into each slot of the cassette carrier in a sealed state (FIG. 3(a)). When taking out the mask from this mask cassette 6, move the upper lid 7 along the arrow A with the hinge part 9 as the center.
Rotate and lift as shown. (Figure 3(b)). Next, the mask removal means of the automatic mask exchange device (not shown)
The lower tray 8 containing the mask is pulled out in the direction of arrow B (FIG. 3(C)).

As shown in FIG. 4, an upper lid sensor 32 and a lower tray sensor 33 for separately detecting the upper lid 7 and lower tray 8 of each mask cassette 6 are arranged in each slot of the cassette carrier 4 (FIG. 1). Sensors 32 , 33 are connected to control box 5 . Upper lid sensor 32 and lower tray sensor 3
3 are reflective photosensors, the configuration of which is shown in FIG. The upper lid sensor 32 (the lower plate sensor 33 is also the same) has a light emitting element 29 and a light receiving element 3 connected to the DC power supply 31.
The light receiving element 30 is connected to an inverter 51 and a transistor 52 via an amplifier 50. When the DC power supply 31 is turned on by a switch means (not shown), the light emitting element 29 emits light, which is reflected by the mask cassette 6, and the reflected light is detected by the light receiving element 30. An electric signal corresponding to the amount of light is amplified by an amplifier 50, and an inverter 51 converts it to °゛H゛.

The "L" level is inverted, turning the transistor 52 on and off. This on/off signal is the control box 5
is man-powered. Based on this detection signal, the control box 5 controls the operation of the automatic mask exchange device as described later.

FIG. 6 is a control circuit diagram for operating the automatic mask exchange device of the present invention. The exposure apparatus 1 includes an actuator 34 for mounting the mask in a predetermined position, and a sensor and switch circuit 35 for detecting the operation of each actuator, etc.
Consisting of Similarly, the automatic mask exchange device 3 includes an actuator 36, a sensor, and a switch circuit 37. A control box 5 for driving and controlling the exposure device 1 and the automatic mask changing device 3 includes a memory 40 that stores various data necessary for driving, and controls operations according to a sequence program created in advance based on the stored data and input data. A microcomputer 3 that performs
9, and is connected to the exposure device 1 via an interface 41.
and an automatic mask exchange device 3. The man-machine interface 42 is the control box 5
An operator or the like inputs drive data from the outside. The control box 5 is further connected to a mask presence/absence detection switch 38 comprising the above-mentioned upper lid sensor 32 and lower tray sensor 33 provided on the cassette carrier of the automatic mask exchange device 3.

The operation of the automatic mask exchange device that is driven and controlled by the control circuit configured as described above will be described. FIG. 7 is a flowchart of the mask supply operation. The operator loads mask cassettes into each of the plurality of slots of the cassette carrier in advance (step 10). By operating the keyboard on the console box (not shown), the operator specifies the slot number in which the mask to be used is loaded (step 11), and issues a supply start command (step 12).
is input into the control box 5 (Fig. 6). This starts the operation of the automatic mask exchange device. Before each actuator actually operates, the upper lid sensor 32 and lower tray sensor 33 detect and confirm whether the upper lid and lower tray of the mask cassette are correctly loaded in the designated slots (step 13). here,
If a mask cassette is not loaded in the specified slot, such as when the slot is not loaded due to an operator's loading error, or when an empty slot is specified due to a keyboard operation error or human data error, an error will be displayed ( In step 14), the operator correctly loads the mask cassette into the designated slot and performs the return process (step 1).
5). At this point, the supply start command is input again (step 1).
2), then the confirmation of the presence or absence of the cassette in the designated slot is repeated again (step 13). When the upper lid sensor and the lower tray sensor detect the upper lid and the lower tray and confirm that the mask cassette is loaded in the designated slot, each actuator performs the mask removal operation and actually supplies the mask to the exposure equipment ( Step 1B) is started.

Next, a flowchart of the mask exchange operation is shown in FIG.

The operator inputs a mask replacement command into the control box (step 17), and as a result, a mask recovery operation (step 18) is first performed. Here, before the actuator is actually driven, it is determined whether or not there is a lower plate of the mask cassette in the return slot for masks to be collected after use in the exposure apparatus (step 19). If there is a lower tray in the specified return slot, the return is in a high performance state and an error is displayed (step 20).The operator must remove the lower tray from the return slot and perform the recovery process (step 21).
) and repeat step 19 again. If the lower plate sensor does not detect a lower plate and it is confirmed that there is no lower plate in the return slot, then the upper cover sensor determines whether there is a top cover in the same return slot (step 22). If there is no top cover in the return slot, such as when the top cover is removed from the slot by mistake while using a mask, an error will be displayed (step 23), and the operator will be required to correctly attach the top cover to the return slot and perform the recovery process (step 23). 24) and repeat step 22 again. When the upper lid sensor detects the upper lid in the return slot and confirms that the upper lid is present, each actuator is driven to return the lower tray and mask to the cassette carrier (step 25), and the lower tray and mask are returned to the cassette carrier in the return slot. Then, the mask is returned and the top cover left in the slot is sealed. This completes the collection operation (step 26). Subsequently, the operation of supplying the mask to the exposure apparatus is performed. This mask supply operation is similar to the above-described operation described with reference to FIG. As described above, before the collection operation, check whether the upper lid is present or the lower tray is not present in the slot, and before the supply operation, check whether the upper lid is present or the lower tray is present, and then perform the respective collection and supply operations. The mask exchange operation ends.

[Effects of the Invention] As explained above, in the automatic mask exchange device according to the present invention, an upper lid sensor and a lower tray sensor are installed in each slot of the cassette carrier to independently detect the upper lid and lower tray of the mask cassette. This is connected to the control circuit for the mask exchange operation to confirm whether there is a top cover or a bottom tray in the specified slot before starting the mask supply operation, and to check whether the top cover in the return slot is present before the mask return operation starts. Yes, we have confirmed that there is no lower plate. Therefore, the operation of removing a cassette from an unloaded slot due to an operator's operation error, loading error, etc. is prevented, and unnecessary operations are avoided. Further, in the event that another mask cassette is mistakenly loaded into the return slot, the retreating operation of the cassette is stopped in advance, so collisions between cassettes are prevented, and the mask replacement work is carried out smoothly. In addition, when the operator loads a mask cassette into the cassette carrier and the upper lid sensor and lower pan sensor confirm that the cassette is loaded, the mask data can be automatically entered into the memory along with the slot number, allowing mask replacement commands to be sent to the console box. The number of input operations required by the operator is reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of an automatic mask exchange device and its peripheral equipment according to the present invention, Fig. 2 is a perspective view of a mask cassette to which the present invention is applied, and Fig. 3 is a mask from the mask cassette of Fig. 2. FIG. 4 is an explanatory diagram of the arrangement of the mask cassette detection means of the present invention, FIG. 5 is a circuit diagram of the mask cassette detection means of the present invention, and FIG. 6 is a control diagram of the device shown in FIG. 1. The block diagram, FIG. 7 is a flow chart of the mask supply operation of the automatic mask exchange device according to the present invention, and FIG. 8 is a flow chart of the mask exchange operation of the automatic mask exchange device according to the present invention. 1: Exposure device 3: Automatic mask exchange device 4: Cassette carrier 5: Control box 6: Mask cassette 7: Upper lid 8: Lower tray 32: Upper lid sensor 33: Lower tray sensor. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito Figure 3

Claims (1)

[Claims] 1. A cassette carrier is provided that accommodates a plurality of mask cassettes each having a separable upper lid and a lower tray, and the upper lid of a designated mask cassette is left in the cassette carrier, and the mask is removed from the cassette carrier from the lower tray. 1. An automatic mask exchange device for removing a mask and transporting the cassette to an exposure apparatus, wherein the cassette carrier is provided with an upper lid detection means and a lower tray detection means for separately detecting an upper lid and a lower tray. 2. The automatic mask exchange apparatus according to claim 1, wherein the upper lid detection means and the lower plate detection means are connected to a control means for sequentially controlling the mask exchange operation. 3. The control means is configured such that the operation of supplying the mask to the exposure apparatus is started only when the upper lid detection means and the lower tray detection means detect that the upper lid and the lower tray are respectively located at designated positions on the cassette carrier. An automatic mask changing device according to claim 2, characterized in that the mask automatic changing device is configured as follows. 4. The mask return operation from the exposure apparatus is started only when the upper lid detection means detects the upper lid at a specified position of the cassette carrier and the lower plate detection means does not detect the lower plate at the specified position. 4. The automatic mask changing device according to claim 3, further comprising the control means. 5. The automatic mask changing device according to any one of claims 1 to 4, wherein the upper lid detection means and the lower plate detection means are reflective photosensors.