JPH0475063A - Aligner - Google Patents

Abstract

PURPOSE:To minimize the sticking of dust on a reticle in the exposure device by providing a means for pre-alignment and a means which takes a reticle out of a reticle cassette and carried it into a reticle stage after the pre- alignment. CONSTITUTION:Reticle conveyance in a wafer stepper is carried out by reticle cassettes 2 and the reticle 1 is taken out of the reticle cassette 2 only on the reticle stage 3 or right before or nearby the reticle stage 3. Further, processes a read of the number of the reticle in the wafer stepper and the pre-alignment are performed from outside the reticle cassette 2 while the reticle 1 is put in the reticle cassette 2. Consequently, the reticle 1 is stored in the reticle cassette 2 on the nearly whole reticle conveyance path, so the sticking of dust on the reticle 1 in the exposure device is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure apparatus, for example, an exposure apparatus equipped with a reticle transport system that can minimize the adhesion of dust to a reticle inside a wafer stepper apparatus. [Prior Art] Conventionally, for example, in a reticle transport system in a wafer stepper, a reticle is first taken out from a reticle cassette inside a reticle stocker, and then the reticle number displayed on the reticle is read out or the reticle is pre-aligned. After this, the reticle was moved onto the reticle stage by a carry-in hunt.

[Problems to be Solved by the Invention] Therefore, in the conventional sea urchin chipper, there is a considerable possibility that dust or dirt may adhere to the reticle while the reticle is taken out from the reticle cassette and moved onto the reticle stage.

SUMMARY OF THE INVENTION In view of the problems in the conventional example described above, it is an object of the present invention to provide an exposure apparatus that can minimize the adhesion of dust to a reticle inside the exposure apparatus.

[Means and Effects for Solving the Problem] In order to achieve the above object, the exposure apparatus according to the present invention transports the reticle together with the reticle cassette within the exposure apparatus, for example, a wafer stepper, and transports the reticle from the reticle cassette. It is characterized in that the reticle is taken out at a position on the reticle stage or immediately before or in the vicinity of the reticle stage.

Further, processing such as reticle number reading and pre-alignment inside the sea urchin chipper is performed from outside the reticle cassette while the reticle is held in the reticle cassette.

With the above configuration, the reticle is housed in the reticle cassette in most of the reticle transport path, so that dust adhesion to the reticle can be minimized.

[Example code] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a perspective view showing a reticle conveyance system of a sea urchin chipper which is an exposure apparatus according to an embodiment of the present invention. In the figure, 1 is a reticle, and 2 is a reticle cassette that stores the reticle 1. The reticle cassette 2 is made of a transparent material so that the reticle number and pre-alignment mark on the reticle 1 stored therein can be observed from the outside.

3 is a reticle stage for holding the reticle 1 in the wafer stepper, 4 is a reticle hand for pulling out the reticle 1 from the reticle cassette 2 and moving it to the reticle stage 3, and 5 is a reticle for opening the reticle cassette 2. It is a hand that opens and closes the cassette folding. Further, 6 is a reticle cassette hand movable in the XYZθ directions that pulls out the reticle cassette 2 from the reticle cassette stocker 8, moves it to below the microscope objective lens 7, and positions the reticle cassette 2 with respect to the reticle stage 3; A microscope objective lens 8 is used to observe the reticle number and pre-alignment mark on the reticle 1, and a reticle cassette stocker 8 is capable of storing a plurality of reticle cassettes 2.

FIG. 2 is a block diagram showing the configuration around the reticle transport system of the wafer stepper of this embodiment.

In the figure, 11 is a CPU (central processing unit) that controls the entire wafer stepper, and 12 is a memory that stores programs for operating the wafer stepper. Further, 13 is an operation panel interface for human outputting data to the operation panel; 14 is a reticle cassette hand interface that issues a drive command to the pulse motor driver 20 to move the reticle cassette hunt 6 in the XYZθ directions;
Reference numeral 15 denotes a reticle cassette door opening/closing hunt interface which issues a drive command to the pulse motor driver 21 to open and close the reticle cassette folding.

16 is a reticle hand interface that issues a drive command to the pulse motor driver 22 to move the reticle hand 4 in the XZ directions, and 17 is the pulse motor driver 2 to move the reticle stage 3 in the XYθ directions.
This is a reticle stage interface that issues drive commands to 3. Reference numeral 18 denotes an image processing device that inputs an image observed by the objective lens of the microscope 9 through a CCD camera 30 or 31, and performs various recognition and position measurements from the input image.

Further, 20 to 23 are drivers for each pulse motor PM, and 26 is an operation panel for giving various operation instructions to the operator or the sea urchin chipper of this embodiment.

In the wafer stepper as described above, the operator first issues a setting instruction for a specific reticle from the operation panel 26. In response, the CPU 11 issues a command to the reticle cassette hand interface 14 to move the reticle cassette hand 6 to the position of the reticle cassette stocker 8 where the reticle is stored. Then, move the reticle cassette hand 6 to the designated reticle 1.
Move the reticle cassette 2 in two directions until it reaches the height of the reticle cassette 2 containing it. After this, move this reticle cassette 2 to arrow A.
Pull it out like this.

Next, the reticle cassette 2 that has been pulled out is moved in the direction of arrow B to below the microscope objective lens 7. A microscope objective lens 7 is attached to a microscope 9 in a predetermined positional relationship with the reticle stage 3. The microscope objective lens 7 projects an image of the reticle number and pre-alignment mark (not shown) attached to the reticle 1 onto the imaging surface of the CCD camera 30.31. CCD camera 30
．． This image input through 31 is manually input to the image processing device 18.

In this position, the CPU II first commands the reticle cassette hunt interface 14 so that the pre-alignment marks on the reticle 1 are below the microscope objective 7.

That is, after first moving the reticle cassette 2 to below the microscope objective lens 7, the CPU II moves the image processing device 1
8, a command to measure the position of the image and pre-alignment marks from the two CCD cameras 30131 is issued. In response to this command, the image processing device 18 executes position measurement of the pre-alignment mark and outputs the position measurement result. If the position measurement result is greater than or equal to the allowable tolerance amount with respect to the target position, a correction drive command in the XYθ directions is issued to the reticle cassette hand interface 14. The above process is repeated until the position of the reticle 1 within the reticle cassette 2 is within the allowable tolerance.

After this, the CPU II issues a command to the reticle cassette hand interface 14 so that the reticle number on the reticle 1 is placed below the microscope objective lens 7. In response to this command, the reticle cassette hand 6 is driven, and the reticle number on the reticle 1 is positioned below the microscope objective lens 7.

After this movement, the CPU II issues a command to the image processing device 18 to manually image the reticle number from the CCD camera 30, 31 and to recognize the reticle number. The image processing device 18 recognizes and outputs the reticle number in response to this command. If this recognized reticle number does not match the reticle number instructed by the operator,
At the same time as the operation is interrupted, a warning is generated to the operator.

If the reticle number matches the reticle number instructed by the operator, the CPU 11 calculates various parameters necessary for performing exposure using this reticle 1. Next, a command is issued to the reticle cassette hand interface 14 to move the reticle 1 to a predetermined position necessary to carry the reticle 1 to the reticle stage 3. In response to this movement command, the reticle cassette hand 6 moves to a predetermined position necessary to carry the reticle 1 into the reticle stage 3.

After the reticle cassette hand 6 moves, the CPU 11 issues a command to the reticle cassette door opening/closing hand interface 15 to open the door on the left side of the reticle cassette 2.

In response to this command, the reticle cassette folding/closing hand operates to open the door on the left side of the reticle cassette 2.

After this operation is completed, the CPU II issues a command to the reticle hunt interface 16 to carry the reticle 1 in the reticle cassette 2 onto the reticle stage 3. In response to this command, the reticle hand interface 16 issues a drive command to the pulse motor driver 22.

In response to this drive command, the pulse motor of the reticle hunt 4 operates, and the reticle hunt 4 inserts its tip into the inside of the reticle cassette 2. After this, the reticle hand 4 rises slightly. As a result, the reticle 1 is lifted up and then returned to the reticle stage 3 side as shown by arrow C and lowered. In this way, the reticle 1 inside the reticle cassette 2 is carried into the reticle stage 3.

In the manner described above, the reticle 1 is held inside the reticle cassette 2 until just before it is transferred to the reticle stage 3. Therefore, it is possible to minimize the adhesion of dust inside the device.

[Other Embodiments] The reticle cassette 2 shown in FIG. 1 may be of a vertically separated type. In this case, it is sufficient to separate only the lower cover of the reticle cassette 2 immediately before the reticle stage 3 and carry the reticle 1 together with the upper cover of the reticle cassette 2 onto the reticle stage. This has the advantage of preventing dust from falling from above while the reticle 1 is being moved from the position immediately before the reticle stage 3 onto the reticle stage 3.

[Effects of the Invention] As described above, according to the present invention, processes such as reticle number reading and pre-alignment can be performed while the reticle is held in the reticle cassette, and the reticle can be moved together with the reticle cassette on the reticle stage or Since the reticle is moved to a position immediately before or near the reticle stage, it is possible to minimize the adhesion of dust to the reticle inside the exposure apparatus.

This is due to the increasing demand for miniaturization in recent years.
This greatly reduces the need for each exposure device to have a large, expensive dust inspection device that is required to detect dust (about 0.4 μm), and contributes to the miniaturization and cost reduction of exposure devices. It has a big effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a reticle transport system of a wafer stepper according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration around the reticle transport system of the wafer stepper of the above embodiment. 1. Reticle cassette, 2. Reticle cassette, 3. Reticle stage, 4. Reticle hunt, 5. Reticle cassette door opening/closing hand, 6. Reticle cassette hand, 7. Microscope objective lens, 8. Reticle cassette stocker, 9. Microscope, 11. :CPU. 12: Memory, 13-17: Interface of each unit, 18: Image processing device, 20-23: Pulse motor driver, 26: Operation panel.

Claims (3)

[Claims] (1) A means for transporting the reticle while it is held in the reticle cassette or while it is covered by the upper cover of the reticle cassette to a position directly in front of or near the reticle stage, and pre-alignment of the reticle inside the reticle cassette from the outside. An exposure apparatus comprising: means for detecting marks and performing pre-alignment; and means for taking out a reticle from the reticle cassette and carrying it into a reticle stage after performing the pre-alignment. (2) A means for carrying the reticle onto the reticle stage while holding the reticle in the reticle cassette or covering the reticle with the upper cover of the reticle cassette, and detecting the pre-alignment mark of the reticle inside the reticle cassette from the outside. An exposure apparatus comprising: means for performing pre-alignment; and means for taking out a reticle from the reticle cassette and placing it on a reticle stage after performing the pre-alignment. (3) The reticle cassette further comprises means for reading a reticle number of an internal reticle from outside the reticle cassette, and automatically confirming the reticle number and/or setting various parameters determined by the reticle number. 2. The exposure apparatus according to 2.